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relap5/mod3 code manual volume ii: user`s guide and

1. 2 37 2 3 3 THomolesous headieueye o eee usa ei NM SASS SS p ede Dee 2 30 2 3 4 Homologous torque curve 5 5 nce rete a 2 40 2 3 5 Schematic of Mx ICONS s esee red dvi S m aaa dob i as 2 44 2 3 6 Jet pump MO GSS Si Oi sooo ease cg U SA GG uu us 2 46 2 3 7 Schematie of SEPT circos dali iia adas 2 50 2 3 8 Physical picture of a separator ii 2 51 2 3 9 Separator volume fraction of water fluxed out the water outlet 2 52 2 3 10 Separator volume fraction of steam fluxed out the steam outlet 2 52 2 3 11 Schematic of a cylindrical accumulator eene 2 57 2 3 12 Schematic of a spherical accumulator 2 58 2 3 13 Schematic of an accumulator showing standpipe surgeline inlet 2 59 2 3 14 Possible accumulator COn SUS indi 2 60 3 1 1 MES PA a US ease 3 2 6 0 1 Input data for a power type general table and raph 6 2 8 3 1 Exar ple orqajor edits ee tier es 8 6 8 3 2 Example of additional output for pumps turbines and accumulators 8 13 8 3 3 Example of reflood major edit 5 ette tet ertet eei 8 19 8 3 4 Example of cladding oxidation and rupture major edit 8 20 8 3 5 Example of radiation major edit A A 8 21 8 3 6 Example of minor edit aiii iii ias 8 22 8 3 7 Example of printout before the diagnosti
2. 3 4 1omod euueb 00 0000000 0 09 000 0 30000000 9 SOS 000 99S 0 3000000 I 3p bez 0c oes 0 4000000 T 3p bae 0c 3p xeu 0 3p uru oz 956 ZT 6v6 cl 956 01 Sr6 ZT Sv6 cl 956 01 gu bx Soya 00 400000 0 v89 v 0 9S66E 0 OZET O 6SScv 0 v8cvv O 81 9v 0 L606v 0 Sv09S 0 veLEL O vvc88 0 S0L68 0 S8TT6 0 919516 0 0LST6 0 LTL06 0 S8068 0 VLOL8 0 69 98 0 62688 0 2EL8 0 FPTOA ZOT TT OT HL66S7 9 saqem Zemod UOTSSTI S Seu 85 0 8 000090 SL 0 8 0000S0 v6 0 8 0000v0 86 0 8 0000 0 EL DES 0000Z0 08 0 8 000010 gu bx joua OU OA G0 H00000 T 000010 S Toadpua Apqaua 90 4vLISC Z 00000Z 90 H6P88C C O0006T E 90 HLTTOE Z O0008T 90 HE0LTE Z 0000LI E 90 d3v89 Z 00009L 90 HLTZ9IE Z 0000SI E 90 HSETOD Z 0000vI E 90 H9 69b Z 0000 1 E 90 H6699S 2 0000cI 90 H 0Z85 Z 00001I E 90 H7668S 2 000001 90 H0TE65 Z 000060 90 49c 6S8 2 000080 90 HTET6S Z 000040 90 H7T6E8S 2 000090 90 H6bL85 Z 000080 90 H8S98S 2 O00070 90 HL798S 2 O000E0 90 4LZ2985 Z 000020 90 H 985 Z2 000010 edid s paewpe ed eansseaud ou ToA x uoux I wu qs s 1omod OT H1DLO9D 9 s338m Te301 000000 1 109 000000 1 TOS 34173 dtzq adequnu driL 5 Tn3sseoons pareada pa2dus
3. indicates OR and the bar indicates the complement The expression is derived by combining with OR operations terms from each line having a true value in the output column Each term consists of the combining of each input variable with AND operations using the direct variable if the value is true and the complement if the value is false Table 4 1 2 shows that two of the combinations are impossible This is because if P is true P must also be true that is if the pressure is gt 12 bar it is also gt 11 bar Because of the relationship between P and P o N a I o N o N e a P 4 1 4 Using the Boolean identities from Table 4 1 3 the logical expression can be reduced to NUREG CR 5535 V2 4 4 RELAP5 MOD3 2 V V P V P P 0P V OP V P 4 1 5 Table 4 1 2 Truth table examples Output Input Vo Vi P Py Num 0 0 0 0 0 0 0 0 1 1 impossible 0 1 0 2 1 0 1 1 3 0 1 0 0 4 1 1 0 1 5 impossible 1 1 0 6 1 1 1 1 7 Table 4 1 3 Boolean algebra identities AGA A A A A A 0 0 A 0 A A A 0 AGA 1 AOL ZA A 1 1 A B B A A B B A AG B C AGB AG O AGO B C A B 6 AG O a denotes AND denotes OR bar above quantity denotes complement The following trip input implements the logic Trips 601 through 603 implement the rightmost expression in Equation 4 1 5 Trip 603
4. fluid velocity are similar to pump The second problem is identical to the first except that shaft and generator acting as a motor components are used 100 new transnt 102 british british 104 none 201 1 0 1 0 6 0 010 15001 1 20 1000 202 40 0 1 0 6 0 200 15001 1 20 1000 301 p 1010000 302 p 1040000 303 p 1060000 304 p 1070000 305 p 1100000 306 p 1150000 307 p 1180000 308 p 2010000 309 velfj 1010000 310 velfj 1070000 311 velfj 1180000 312 velfj 2010000 313 velfj 2020000 314 pmpvel 002 315 pmphead 002 316 pmptrq 002 35 p 3010000 352 p 3040000 353 p 3060000 354 p 3070000 NUREG CR 5535 V2 4 16 RELAP5 MOD3 2 Table 4 2 1 Input data for a sample problem to test pump generator and shaft Continued 355 p 3110000 356 p 3150000 357 p 3180000 358 p 4010000 359 velfj 3010000 360 velfj 3070000 361 velfj 3180000 362 velfj 4010000 363 velfj 4020000 364 pmpvel 004 365 pmphead 004 366 pmptrq 004 501 time 2 q null 0 20 2 1 10000 loop pipe 10001 19 10101 0 0376 19 10201 0 0376 6 0 01 7 0 0376 18 10301 2 0 19 10601 0 0 4 90 0 9 0 0 14 90 0 19 10801 0 0 19 11001 0 19 11101 0 6 100 7 0 18 11201 3 2244 780 540 0 0 0 0 19 11301 0 0 0 18 20000 loop pump 20101 0 0468 0 0 16600000 20108 1010000 0376 00 0 20109 1000000 0376 00 0 20200 3 2264 78 540 0 0 20201 0000 202020000 20301 10 2 1 1 501 1 20302 3560 0 0 66573 180 0 192 0 34 8
5. Consequently low interfacial heat transfer regimes such as the vertical stratification flow regime may give heat transfer coefficients that are too low for stable calculations as evidenced by oscillatory behavior When this occurs the vertical stratification model should be turned off on a volume basis The highest probability for this occurrence is under very low flow conditions A second problem may occur when noncondensables first appear in a system volume At times again depending on the convection of noncondensable into the volume the noncondensable iteration may fail or water property errors occur at the minimum time step This problem can usually be overcome by reducing the size of the minimum time step If this procedure fails the convection rate or the concentration of the noncondensable convection must be changed This may be accomplished by modifying the boundary conditions or by renodalizing the problem areas with acceptable thermodynamic conditions Last the output from the code may contain discontinuities as noncondensables appear or disappear The variables that will have these discontinuities are the partial pressure of steam phasic temperatures saturation temperature vapor specific internal energy and noncondensable quality The partial pressure of steam 16 set to the system pressure if noncondensables are not present to 1 0 Pa if the volume state is pure noncondensable or to the calculated value otherwise When a pure non
6. Techniques from Boolean algebra can assist in formulating the logical trip statements Consider a motor operated valve that operates such that if the valve stem is stationary it remains stationary until a specified pressure exceeds 12 bar or drops below 8 bar The valve starts opening when the pressure exceeds 12 bar and continues opening until the pressure drops below 11 bar The valve starts closing when the pressure drops below 8 bar and continues closing until the pressure exceeds 9 bar The motor valve requires two trips one to be true when the valve should be opening the other to be true when the valve should be closing The following procedure is used to derive the open trip logic A Boolean variable has one of two possible values false 0 or true 1 Define as Boolean variables Vo which is to be true when the valve should be opening V as the current value of the valve motion P true when the pressure is gt 11 bar and P gt true when the pressure is gt 12 bar Table 4 1 2 is a truth table that has been constructed by listing all possible combinations of the three input variables V P5 and Pj and the desired output Vo The number in the rightmost column is the number resulting from assuming the input values form a binary number this is done to ensure that all combinations are listed From the truth table the following expression can be written V V 8P 6P V P 6 P V P P 4 1 3 where indicates AND
7. coc 20S 005 coc 20S 005 cos 20S ZOS Gm OTSE 1090 9L60 PELE ELLE 7660 6190 L SL86 T ETSL 0 L98c LZ 106 vs T6L eS VOL 005 8 605 8 cos 8 ZOS 8 c0sS 8 Tog 8 gOS 8 ZOS 8 ZOS 8 c0sS 8 00 400000 0 00 H00000 0 00 400000 0 00 400000 0 00 400000 0 00 400000 0 00 H00000 0 00 400000 0 00 400000 0 00 H00000 0 00 400000 0 00 400000 0 00 H00000 0 00 400000 0 ZOS 8T zZ0S gog 8T gOS TOS 81 20S 005 81005 70S BT 20S 605 81 605 005 8r 20S TOS 8605 cos 81 20S8 Zog LT ZOS 91 005 T 20S 91 c0S ET ZOS 91 c0S I c0S 91 c0S T 20S 91 c0S ET ZOS 91 c0S I c0S 91 c0S ET QS SI c0S e LE 20S vT ZOS OT ZOS 60005 c0 20S s znaez du q qurod useu oznos 3ae u 3ur jo ung 00 400000 0 00 H00000 0 00 H00000 0 06S 00 300000 0 6908S 00 400000 0 06999 00 H00000 0 60679 00 400000 0 6092S 00 400000 0 TOT6D 00 H00000 0 OLLED 00 400000 0 CEVIE 00 H00000 0 56850 00 H00000 0 8ESET 00 400000 0 8LvzT 00 H00000 0 98STT S O s O s OTTO TFT O s OT OFT OFT OFM OT OT OO LT ZOS LT ZOS ET TOS LT ZOS LT ZOS LT ZOS LT ZOS LT ZOS 91 c0S vT ZOS OD 00 0 00 30000 00 0 00430000 00 0 00 40000 L8 0 90 4L850 00 0 00 30000 98 0 90 HL7S0 00 0 00 40000 98 0 90 HLTSO
8. v8 voL 90 H98ZL9 ET LOL 90 HP6EL6 D ST9 98 90 HL9OZL Z 8 LEST dppusp 00 H00000 0 00 H00000 0 00 400000 0 00 H00000 0 00 H00000 0 00 400000 0 00 H00000 0 00 H00000 0 00 300000 0 00 H00000 0 00 H00000 0 00 400000 0 00 H00000 0 00 H00000 0 00 400000 0 00 400000 0 20 382c 8 00 400000 0 0 SNvPcEt68 00 400000 0 20 3S10S6 00 400000 0 20 3c9v66 00 400000 0 0 3610 6 00 400000 0 20 398 8L 00 400000 0 20 3S 692 G 00 400000 0 vev cc BES OT 966 61 71081 ZTE BT 666 71 000 ST SEES A 07L9 8 TP 96 08 v26 cl 9vI 80 9vI 00 H00000 0 00 H00000 0 S89L8 0 0000 T 6vL88 0 0000 T 650060 0000 T 8vTT6 0 0000 T 065066 0 0000 T 0L086 0 ZO HOLLTO L CLlLC O v0 3S8L9v L 6 666 0 v0 301880 9 amp S666 0 vO 18LST8 b 19666 0 vO 4LOLL8 L666 0 v0 3 8LL9 C 6666 0 S0 S3cV8SC L 7S066 0 0 SETE9T 6 FUSSTI 0 00430000070 00 400000 0 0000 T 90 H900LS 90 4 818b 90 4 8T8b 90 HEL86 90 HE L86 90 50566 SOTHPZECE V 90 3v08927 90 H7089C 90 Hp00S 90 H700SE 90 H6ZOSS 90 H6ZOSS SO 06LSL Z 90 806 95 Z 0 ASSOE8 g 0 ASSOE8 SC 0 ASSOE8 16 O ASSOE8 SC 0 ASSOE8 SC 0 ASSOE8 S 0 ASSOE8 SC 0 ASSOE8 SC 0 ASSOE8 Z 0 ASSOE8 lt 0 ASSOE8 SC 0 ASSOE8 TS 0 ASSOE8 SC 00 H00000 0 00 400000 0 0000410900
9. 00 0 00 40000 98 0 90 4T8b0 00 0 00 30000 98 0 90 HZ9D0 00 0 00 40000 580 90430870 00 0 00 0000 S8 0 90 H7L9S 00 0 00 30000 v8 0 90 H07SL 00 0 00 40000 8 0 90 4p8Sp 00 0 00430000 L 0 90 3ELZ76 00 0 00 80000 VL O 90 HSEES 00 0 00 40000 SL 0 90 HZT66 0 0 0 0 0 0 Y 0 0 y 0 0 v 0 0 Y 0 0 v 0 0 v 0 0 Y 0 0 cv 0 0 vs 0 0 S G 0 0 vos 0 0 v G SO IPLOT I 00 400000 0 00 400000 0 GO H8E99T S 00 400000 0 SO HL98BEZ Z 00 400000 0 SO W L6ZLZ Z 00 400000 0 SO Wp68L2 Z 00 400000 0 GO HLETIS C 00 400000 0 SO H08v9T Z 00 400000 0 GO HEEPTO S 00 400000 0 GO HSPZES T 00 400000 0 LLv8S 00 400000 0 8 81T 00 400000 0 Sv ISI 00 400000 0 OLEDT 90005 L0 20S 80 20S 80 20S 80 20S 80 20S LO 20S LO 20S POZOS 06 10S 0U 138 OTSE 00 H00000 0 00 H00000 0 1c90 00 400000 0 9L60 00 400000 0 5511 00 H00000 0 ELTT 00 300000 0 v660 00 400000 0 190 00 H00000 0 L SL86 00 400000 0 C ETSL 00 H00000 0 0 L982 00 H00000 0 LZ T06 00 400000 0 vs T6L 00 H00000 0 cS VOL S6 L6 86 66 66 66 66 86 v6 vL oes 000 0 022 6 CST gos 09v 96Yv 81 c0S TS8 96P EBT 20S 6cE LOD 8T 20S 7298 LOD EBT ZOS 69v 86v 8T 20S S91 66v 81 20S 00 00S 81 c0S 1T6 00S EBT ZOS TT9 TOS EBT ZOS EEL TOS EBT 20S SLET TOS
10. 667 SSO0 660 GO H86ESL 6 96 867 L66 867 S0 3928vL 6 676 867 6 6 867 GO HOSTIL 6 016 86v v68 86v SO S OFL 6 v06 86v 0L8 86v S0 3268TvL 6 v06 86v cL8 86v GO H8E97L 6 S06 860 L98 867 64 0 en en 3n due3 3es dus23 90 38S168 989 119 ZO TOT T 09s potiad 091 eura oes 08000 Z ndo 038 1 WU 90 3v8S168 t 7 S9 119 SU 303 99S 0 3Sv9S70 L 3p quzo pe42 su 99S 0 3000000 I 3P 3SeI L0 0zZ LT v6 290 LZ 299 0 4000000 T 99S 0 4000000 T uezbozda srs Teuy querTooo IQ SSOT 102089Y ccSE T 00 H00000 0 89 DSL FE T T 00 300000 0 6v IvVL 66vL8 0 00 300000 0 TZ SZL TI819 0 00 4300000 0 Lb OTL Z6L 0 00 H00000 0 EL ORL OT8SZ O 00 H00000 0 CT LOL 98s u gu bx gu bx ptnbt Tea uoaoq oua x1iUu oua c8L cLE 0000 T 0000 T EEL COP 829S8 0 9TE9S 0 T66 26v 18669 0 vv009 0 OIE 6Yv 7098S 0 0898S 0 VOL E67 OLELS O TPVLS IO 81 v6v T9SSS 0 9TLSS O 0L v6ov 6vtt S 0 Z89EG 0 tt G6Yv 8Lv0S 0 060S 0 099 967 Lc9t v 0 SS6tv 0 T86 867 TTSEZ O 9029c 0 cLV 00S 6c911 0 9SLIT O F8S 00S LLTOI O S6201 0 V69 00S ZO H06SLZL 8 ZO0 H09bT8 8 vTL 00S cC0 36S0IvV 8 ZO HATSE8D 8 LIL 00S 2ZO0 3IvV8TE 8 CO HOEOED S LvY9 00S8 20 38L281 6 Z0 4L0 8Z 6 vcS 00S S6L0T1 0 ST601 0 GLE JQS 90871 0 90601 0 S 00S 16661 0 TESE TO 8696 009 Z960T 0 TEOTEO 8v 00S vosct o LL9ZT O O Jdu a obptoA bproA bx 0 H61L8L l 10119 sseu bx 800S T 90 31vVISL L SZeTTOP S33 M
11. EST ZOS OT8 TOS 05 059 OS 05 059 05 0S 0S OS 09 000001 0 000000 0 000000 0 000000 0 00000Z 000000 0 00006 000000 0 00008 6 000000 0 00004 000000 0 00009 000000 0 0000S SE 000000 0 00007 000000 0 0000 000000 0 00008 000000 0 00001 000000 0 00000 000000 0 000060 gr eT T8 eT 8 eT S8 81 98 eT 98 8T S8 81 S8 eT 08 8T vs 05 ZOS 0S cos 0S coc 05 ZOS 09 cos 0S ZOS 05 cos 0S coc 0S ZOS 09 010 0 600 0 800 0 L00 0 900 0 00 0 v00 0 00 0 200 0 100 0 euti av yta 4391 346 7 2397 TOO 00Z 020 0 Figure 8 3 1 Example of major edit Continued 8 10 NUREG CR 5535 V2 RELAP5 MOD3 2 ezo I 8T Z0S 8T Z0S 8T Z0S gT gOS 81 c0G 81 c0S 81 20S 81 c0G 81 c0S 81 0S T6v8 c GT CUS 81 0S 81 c0S 8T Z0S 8T Z0S 8T Z0S 8T Z0S 81 c0G 81 c0S 81 c0S L9100 c 000001 0 OOOL8E 0 9L8L9 0 00 4000000 0 0 4000000 S 00000 2 L99661 0 066SL 6 000001 0 00000 T LO ADT9OC8ED 90 ZL80FI I 2581 LT 208 LT ZOS 81606 81 20S 81 0S 81 c0S 8T Z0S 8T Z0S 8T Z0S 8T Z0S T30ue s3s quez3suoo queijsuoo ber AeTep 11emod
12. User experience shows that temperature oscillations may develop in Volume V2 It may be necessary to increase the length of Volume V2 to remove the oscillations In general a user loss coefficient will be needed at Junction J3 This coefficient should be determined to obtain the proper pressure drop A tee can also be modeled using the branch component as illustrated in Figure 2 2 2 This approach has the advantage that fewer volumes are used Disadvantages are that the calculated result may be altered depending on whether Junction J gt is connected to Volume V or V and that the flow division has less resolution at the tee in the presence of sharp density gradients In cases where the Volumes V and V3 are nearly parallel the model illustrated in Figure 2 2 2 may be a more accurate representation of the physical process such as for a wye 2 13 NUREG CR 5535 V2 RELAP5 MOD3 2 Va x J J Vi V z V3 Figure 2 2 1 A 90 degree tee model using a crossflow junction V3 J Vi V5 Jy Branch Figure 2 2 2 Tee model using a branch component 2 2 3 2 Branch The branch model approximates the flow process that occurs at merging or dividing flows such as at wyes and plenums This model does not include momentum transfer caused by mixing and thus is not suited for high velocity merging flows A special component the JETMIXER is provided for modeling the
13. V and MIN V Vo Only MAX and MIN may have multiple arguments 4 2 1 10 Delay DELAY The delay component is defined by Y SVi t ta 4 2 10 where ta is the delay time A user input h determines the number of time function pairs in the table used to store past values of Vi The maximum number of time function pairs is h 2 The delay table time increment is t h The delayed function is obtained by linear interpolation using the stored past history As time is advanced new time values are added to the table Once the table is filled new values replace values that are older than the delay time 4 7 NUREG CR 5535 V2 RELAP5 MOD3 2 4 2 1 11 Unit Trip TRIPUNIT Y SUG tr 4 2 11 4 2 1 12 Trip Delay TRIPDLAY Y ST 4 2 12 In the two definitions above t is a trip number and if negative indicates that the complement of the trip is to be used and U is 0 0 or 1 0 depending on trip t or its complement if t is negative being false or true T is 1 0 if the trip is false and the time the trip was last set true if the trip is true The trip delay result is S if the trip is false and can be values between 0 and St t is time if the trip is true The trip delay can be limited to values between 0 and St instead of S and St by use of the optional minimum value for the component 4 2 1 13 Integration INTEGRAL SV s Y s V dt orY s 4 2 13 i 0 1 1 S 4 2 1 1
14. c 6v8 c 6c6 c 996 c 8L6 c 9L6 c 996 c 119 sseuw 23sb1T PTDTOA 00 400000 0 TZ90T 9L60T 55117 ELTII 56601 1901 L SL86 Z ETSL 0 L98Z LZ 106 FS T6L cSG VOL ZV IL9 L9 vv9 89 SE9 II 9 vE 129 V0 G6G 9 909 08 PEs saqen dur 3u 30o3 6 856 gu bx Joya 6L 0F8 SG 0v8 Vl Ov8 v9 6 8 20668 9 8 8 95 LE8 S8 G 8 c8 c 8 28 0 8 L9 0 8 26068 6b 0 8 6b 0 8 000020 000010 OU TOA ou TOA 000010 S 00000Z 00006 00008 0000 00009 00009 00005 0000 00008 00001 00000 000060 000080 0000L0 000090 00008S0 0000v0 0000 0 000020 000010 OU TOA 000010 S Ou OA 00000Z 00006 00008 0000 00009 0000S 00005 0000 00008 00001 00000 000060 000080 0000L0 Figure 8 3 1 Example of major edit Continued NUREG CR 5535 V2 8 7 RELAP5 MOD3 2 oo Oo Si Q QOO Qo O S O0 O0 O0 Qo oou Te3oq pexouo OQ oO Q O O0 O Q O O lt O Q QO Oo c O oco o N oOo ooo OOo 00 oo 0 O O O O 00 0 gt 9 00 0 QUO Q Q oO OO O S Q QO O QOO BTS 67 67 i 67 67 61 Aga Aq 3su nn nH Hn 0 3su 3s 3su 3su 3s 3su 3S4 3s 3su qsy 31700 seq 1602 sape COCO COO OOOO OC YC Qy Ey O 5 C h Dt o 00U000000000000o0o0o0omn Nno ou MOTJ 0000000 0000000 0000000 0000000 0000000 000000
15. entering N as 3 through 6 specifies a crossflow connection to a volume Average volume velocities are computed along each coordinate direction that is active The x coordinate is assumed active and a warning message is issued during input processing if no junctions attach to normal faces A y or z coordinate is active only if a junction attaches to one of the associated faces The average volume velocity for each coordinate direction involves only junction velocities at the NUREG CR 5535 V2 2 4 RELAP5 MOD3 2 Face 2 ar Face 4 de Volume coordinate direction lt L Face 5 _ gt A x P Z 4 y Face 6 L lt Face 3 Face 1 Figure 2 1 2 Volume schematic showing face numbers faces associated with that coordinate direction Thus a crossflow entering a y face does not contribute to the computation of the volume velocity in the x direction But that crossflow does contribute to the average velocity in the y direction Users of previous versions of RELAPS will note that the crossflow discussed above is different from older versions The crossflow capability has been improved but unfortunately the differing meanings for the term crossflow may lead to misunderstanding The previous use of crossflow implied the following Flow entered a face orthogonal to the normal flow crossflows never contributed to any average volume velocity a limited form of the momentum equation was used and face numbers 3
16. table can have an associated trip number If the trip number is not entered or zero time is the search argument If the trip number is nonzero the search argument is 1 0 if the trip is false If the trip is true the search argument is time minus the time at which the trip last turned true These tables can be used to describe reactivity changes from rod motion Control variables can be defined to represent power control systems or to implement alternate feedback models However reactor kinetics advancement precedes control system evaluation thus feedback from control variables is delayed one time step The separable option uses two tables one defining reactivity as a function of volume density and the other defining reactivity as a function of volumetric average fuel temperatures The tables allow nonlinear feedback owing to moderator density and fuel temperature changes A constant temperature coefficient allows for linear moderator temperature feedback and an additional linear fuel temperature feedback is provided The separable option is so named because of the assumption that each feedback mechanism is independent and the total reactivity is the sum of the individual effects The separable option does not directly allow boron feedback but boron effects can be modeled through the control system Data for the separable option can be obtained from reactor operating data reactor physics calculations or a combination of the two The require
17. the installation script is supplied with the transmittal on the CRAY X MP UNICOS DECstation 5000 ULTRIX DEC Alpha Workstation OSF 1 IBM Workstation 6000 UNIX SUN Workstation UNIX and HP Workstation UNIX The code has been installed although the installation script is not supplied with the transmittal on the CDC Cyber NOS VE IBM 3090 MVS and IBM PC DOS The code should be able to be installed on all 64 bit machines integer and floating point and any 32 bit machine that provides for 64 bit floating point The RELAPS MOD3 code manual consists of seven separate volumes The modeling theory and associated numerical schemes are described in Volume I to acquaint the user with the modeling base and thus aid in effective use of the code Volume II contains more detailed instructions for code application and specific instructions for input data preparation Both Volumes I and II are expanded and revised versions of the RELAPS MOD2 code manual and Volumes I and III of the SCDAP RELAP5 MOD2 code manual Volume III provides the results of developmental assessment cases run with RELAP5 MOD3 to demonstrate and verify the models used in the code The assessment matrix contains phenomenological problems separate effects tests and integral systems tests a V H Ransom et al RELAP5 MOD2 Code Manual Volumes I and II NUREG CR 4312 EGG 2396 August and December 1985 revised April 1987 b C M Allison and E C Johnso
18. the new time of switching to true is placed in TIMEOF The TIMEOF quantities are used to effect delays in general tables time dependent volumes time dependent junctions and pump speed tables and can be referenced in the control system Two card formats are available for entering trip data All trips for a problem must use the same format At restart the same format must be used for trip modifications unless all trips are deleted Card 400 and desired trips are reentered The default format uses Cards 401 through 599 for variable trips and Cards 601 through 799 for logical trips The trip number is the same as the card number Up to 199 variable trips and up to 199 logical trips can be defined An alternate format is selected by entering Card 20600000 Trip data are entered on Cards 206TTTTO where TTTT is the trip number Trip numbers 1 through 1000 are variable trips and trip numbers 1001 through 2000 are logical trips The alternate format allows 1000 trips each for variable and logical trips As trips are input the default initial value is false Optionally the TIMEOF quantity may be entered If 1 0 is entered the trip is false if O or a positive number is entered the trip is true and the entered quantity is the time the trip turned true This quantity must be less than or equal to the time of restart For a new problem 0 0 must be entered Several options are available on restart If no trip data are entered trips are defined at rest
19. zero no bits set attempts to advance both the hydrodynamic and heat conduction advancements at the requested time step However the hydrodynamic time step will be reduced if necessary such that the Courant limit is satisfied If out of range thermodynamic property conditions are encountered the hydrodynamic advancement will be retried with reduced time steps The problem will be terminated if the time step must be reduced beyond the minimum time step Each time step reduction halves the previously attempted time step At the beginning of an advancement for a requested time step a step counter is set to one Whenever a reduction occurs the step counter is doubled When a successful advancement occurs the step counter is reduced by one When the step counter is decremented to 0 the problem has been advanced over one requested time step Doubling of the time step is allowed only when the step counter is even and the step counter is halved when the time step is doubled With no bits set the time step is doubled whenever possible At the completion of advancements over a requested time step the next requested advancement is obtained and may be different from the previous requested time step 1f data from the next time step control card are used If necessary the new requested time step is reduced by halving until the new actual time step is lt 1 5 times the last successful time step Setting bit one entering 1 3 5 7 9 11 13 15 17 19 21 23
20. 00956 St6 vc 026 c 6 8 cc 966 T Tce GT JOC OT 976 TT T6v6 G SLEPE 08TT Z EL8 I 0S69 T DEES T 0 0 0 0 1e102 31p3 de13xa9 sonpaz S s w AITA 00 300000 0 v9ST 9 80LE 9 808v 9 ects 9 57505 9 St2c 9 0818 G covv v T869 T 06809 0 68 9v 0 LLclv O ct 6t 0 9LLE O CEECEE O SLOLE O 8L 9 0 06856 0 vosse o vS88v 0 gu oes bx buruserj TT 004000000 gu bx uodoq oua 004000000 00 400000 0 00 H00000 0 00 400000 0 00 400000 0 00 H00000 0 00 400000 0 00 400000 0 00 H00000 0 00 400000 0 00 400000 0 00 H00000 0 00 400000 0 00 400000 0 0 0 T2707 w A TTOA 00 400000 0 01905 IFE VS 220 09 9IS LL 6Lv 86 9 9 69 76 cL GOS 99 080 BET L T80 L 808 1 0100 908 0 EES 96 9 069 L 905 8t9 G 8cc G gu oes bx ueb aiodeA 150695 0 gu bx xTu oua VL ELE PL CPE 26 EGE TO v9 80 8L 99 POE SESLET 88 ELD v6 LT9 L9 TEL 8v 9vL 9v 8SL vI I9L LS T9 A3TtTenb sonpoz 0 0 0 9 0 0 3766 I 303 arpe ATPTOA 00 H00000 0 00 400000 0 00 400000 0 00 300000 0 004000000 0043000000 00 H00000 0 00 400000 0 00 400000 0 00 H00000 0 00 400000 0 00 400000 0 00 H00000 0 00 300000 0 00434000000 00 H00000 0 00 300000 0 00 400000 0 00 H00000 0 00 300000 0 00440000070 saqen dur qau deA 15069 0 gu bx Soya 05511 9Lv T SEGI ST9 T ELLE FC8 l L OZ 9
21. 1 Input Initial Values Input initial values are required in order to begin a new problem regardless of whether a steady state or a transient run is specified These initial values are supplied by the user through input for each component Heat structures are an exception and can be initialized either by input or by steady state initialization using the heat structure boundary conditions at time zero The hydrodynamic volume components have seven options for specifying the volume initial conditions see Section 2 3 1 for more detail Four options are provided for pure steam water systems and the remaining three options allow noncondensables Boron concentration can be specified with all seven options by adding 10 to the control word Word W1 I Regardless of what option is used the initialization computes initial values for all primary and secondary dependent variables The primary variables are pressure void fraction two phasic energies noncondensable quality and boron concentration Secondary variables are quality density temperature and so on The most common specification will be an equilibrium condition for the steam water system The options 1 3 control word W1 I on Card CCC0200 in Appendix A are equilibrium specifications using temperature and quality pressure and quality and pressure and temperature The first two conditions are valid combinations for single at the saturation point or two phase conditions The third combinati
22. 16 00S I0 0 81 20G 91 20S8 Z1 ZOS S0 20S T6 TOS T9 TOS ZTO 0 81 Z0S 91 ZOS ZT 70S G0 Z0S 6 TOS PL TOS TTO 0 81 Z0S Figure 8 3 1 Example of major edit Continued NUREG CR 5535 V2 8 11 RELAP5 MOD3 2 ratio of the cumulative mass error to the total mass at the start of the transient M RATN is the ratio of the cumulative mass error to the current total mass The output lists the ratio with the largest denominator thus the smaller of the two ratios TIME is the simulated time for the entire problem up to the time of the major edits 8 3 2 2 Trip Information At major edits each defined trip number and the current TIMEOF quantity are printed The TIMEOF quantity is 1 0 when the trip is false and when gt 0 indicates that the trip is true and is the time the trip last switched to true Figure 8 3 1 includes an example of a trip edit 8 3 2 3 Reactor Kinetics Information At major edits the total reactor power labeled TOTAL POWER fission power labeled FISSION POWER decay power labeled GAMMA POWER reactivity labeled REACTIVITY and reciprocal period labeled REC PERIOD are printed Either the total power fission power or decay power can be specified as the time varying part of the heat source in heat structures Figure 8 3 1 illustrates a reactor kinetics edit however it is not intended to be physically realistic 8 3 2 4 Hydrodynamic Volume Information First Section Systems are labe
23. 16150E 03 no 31 007 1 01248E 04 6 15719E 03 no 31 008 1 05442E 04 6 15135E 03 no Figure 8 3 4 Example of cladding oxidation and rupture major edit NUREG CR 5535 V2 8 20 RELAP5 MOD3 2 Radiation set 1 last time when radiation calculation became active was 0 25000 last time when radiation calculation became inactive was 0 00000E 00 Num str no side radiation radiation heat flux energy watt m2 watt 1 2111 1 right 8159 0 1507 2 1 2222 1 right 8534 2 2627 5 1 2333 1 right 7788 8 1918 4 1 2444 1 right 6320 7 1264 9 k 2555 1 right 677 39 31 282 1 2666 1 left 34278 7349 6 The sum of the radiation energy 0 28 Figure 8 3 5 Example of radiation major edit that activates this output is the variable HELP Normally HELP 0 and no diagnostic printout occurs The various ways that this diagnostic edit can occur will be presented along with the value of the variable HELP Some examples of the type of printout that occurs in the diagnostic edit will also be presented One way a diagnostic edit occurs is when it is forced out for more than one time step This can be done by inputting Words 4 and 5 on Card 105 which sets HELP 3 which will force out the hydrodynamic diagnostic edit This in turn will set IWRITE 1 in the heat transfer subroutines forcing out the heat transfer diagnostic edit The diagnostic edit will continue to appear for successive time steps until the count number reaches W5 Then the calculat
24. 2 4 See Volume I of this manual for the equations and variables used The equilibrium quality used in option 4 is the static quality since in equilibrium and is given by M M My where M M My The capability for initializing and performing transients with pure noncondensables has been implemented Input Options 4 and 6 have provisions for initializing a system volume to a pure noncondensable state This is accomplished in Option 4 by using the equilibrium quality variable as a flag By setting this quantity to 0 logic specifies an ideal gas equation of state The variable is reset to 1 0 for transient calculations To use Option 6 for initializing a pure noncondensable both void fraction and NUREG CR 5535 V2 2 20 RELAP5 MOD3 2 noncondensable quality must be set to 1 0 and the vapor energy must be set to a value that gives the desired gas temperature The code will not allow a noncondensable to exist as just liquid water and no steam The code will add a little bit of steam keeps steam quality X M M Mp gt 1078 Thus we recommend that users input some steam when noncondensables and liquid water are present At the present time a value of 4 for the control word in the volume initial condition card is recommended Only a saturated noncondensable state 100 humidity is obtained by this option Improvement of input conveniences for initial noncondensable states is under consideration Users have reported some success wit
25. 25 27 29 or 31 includes the features described for entering zero and in addition uses the halving and doubling procedures to maintain an estimate of hydrodynamic truncation error within program defined limits The estimate is based on the mass error computed by comparing densities derived from the mass conservation equations and the equations of state If an acceptable error is not reached and the next reduction would lead to a time step below the minimum time step the advancement is accepted The first 100 such occurrences are noted in the output If the second bit is set entering 2 3 6 7 10 11 14 15 18 19 22 23 26 27 30 or 31 the heat structure time step will be the same as the hydrodynamic time step The time step control for the hydrodynamics is determined by the status of the first bit as described above and both the heat conduction and hydrodynamic advancements are repeated when a time step reduction occurs If the third bit is set entering 4 5 6 7 12 13 14 15 20 21 22 23 28 29 30 or 31 the heat conduction transfer and the hydrodynamics are advanced implicitly When the third bit is set indicating implicit coupling of heat conduction transfer the second bit indicating that the two advancements use the same time step must also be set Input checking does not now enforce this but a future code change will include this checking If the third bit is not set the heat conduction transfer and hydrodynamic ad
26. 3 15 Or 2 3 Los TE EDI for gt S 2 3 16 Or R Or where is the pump rotational velocity Wp is the rated pump rotational velocity and Ion Ipo Ipi Iho 1 3 and S are input data A pump stop card containing limits on problem time forward pump angular velocity and reverse angular velocity may optionally be entered The pump angular velocity is set to zero and remains zero for the remainder of the problem if any of the limits are exceeded Selected tests can effectively be disabled by entering a very large number for the limits If the problem time limit 0 then the problem time test is ignored A time dependent pump velocity table and an associated trip number may be entered If the table is entered and the trip number is zero the pump angular velocity is always determined from this table If the trip number is nonzero the table is used only when the trip is true The default search variable for the time dependent pump velocity table is time but time advanced quantities may be specified as the search variable When time is the search variable by default the search argument is time minus the time of the trip When a time advanced variable is specified as the search variable even if it is time the search argument is just the specified variable The use of the pump velocity implies a pump motor to drive the pump at the specified velocity The following is a possible example of the use of a time advanced
27. 3 8 Physical picture of a separator fraction fluxed out the outlet water or steam and the x axis shows the volume fraction water or steam in the separator volume 2 3 11 1 Input Requirements The input for a SEPARATR component is the same as that for a BRANCH component with the following modifications 1 for a BRANCH component the junctions connected to the branch can be input with the branch or separator components For a SEPARATR the three Junctions representing the vapor outlet liquid fall back and separator inlet must be input with the SEPARATR component i e NJ 3 the three junction card sequences must be numbered as follows Cards CCC1101 and CCC1201 represent the vapor outlet junction Cards CCC2101 and CCC2201 represent the liquid fall back junction and Cards CCC3101 and CCC3201 represent the separator inlet junction the FROM connection for the vapor outlet junctions must refer to the outlet of the separator CCC010000 The FROM connection for the liquid return junction must refer 2 51 NUREG CR 5535 V2 RELAP5 MOD3 2 Out water outlet A 1 0 Af 0 0 In separator VUNDER volume 0 0 1 0 Of Figure 2 3 9 Separator volume fraction of water fluxed out the water outlet Out steam outlet 1 0 Og 0 0 In sa VOVER volume 0 0 1 0 Oe Figure 2 3 10 Separator volume fraction of steam fluxed out the steam outlet to the inlet of the separator CCC000000 The inlet junct
28. 4 0 Cards ccc0101 word 5 3 euam ccc0109 gt word 0 gt word 5 90 word 5 90 gt word 6 gt 0 gt word6 lt 0 word 5 90 gt word 6 lt 0 Y Figure 2 3 14 Possible accumulator configurations NUREG CR 5535 V2 2 60 RELAP5 MOD3 2 3 HEAT STRUCTURES Heat structures represent the selected solid portions of the thermal hydrodynamic system Being solid there is no flow but the total system response depends on heat transferred between the structures and the fluid and the temperature distributions in the structures are often important requirements of the simulation System components simulated by heat structures include fuel rods pipe walls core barrels pressure vessels and heat exchanger tubing In simulations that do not involve core damage heat structures can represent fuel pins control rods and other structural components In core damage simulations the SCDAP RELAPS code should be used Temperatures and heat transfer rates are computed from the one dimensional form of the transient heat conduction equation A heat structure is identified by a number CCCGONN The subfield CCC is the heat structure number and is analogous to the hydrodynamic component number Since heat structures are usually closely associated with a hydrodynamic component it is suggested that the hydrodynamic component number and the CCC portion of the attached heat structures be the same number Since different heat stru
29. 818S c 8982 t 7611 8291 9 vOvE8 0 vsscv O vv8sc 0 vvocc o 808cc 0 66900 0 66666 0 TLIEZ O OvIvVC O Tv0Ec O 0L6Ssc 0 018Sc 0 61SSc 0 6v9Sc 0 vOZLZ 0 199c 0 8c9Sc 0 SELI O 68666 4 00616 0 FSZIC O c6S0 0 I816c 0 659Z 0 08LTZ 0 LZ9ZT 0 66550 2005696 0 T8LTZ 0 00 H00000 0 S s u 000010 319 20 36E829 0 361v61 t 20 31v086 c 20 36SLLL C 20 398E LS C 20 38 08 C ZO HEDEDZ Z ZO HZ9OLT Z 20 3v8vCl C 20 316 80 c Z0 38v2vO c 20 3IECOO0 cC c0 30 ES96 CO ALLZE6 20 319806 20 38 88 Z0 391798 0 399Sv8 20 36v9c8 20 3 9808 20 39928L ZO H6TLSL TOST EZEL 20 38LEZL ZO H9 E90L 20 365889 20 389 L9 20 3018 9 20 306L19 20 36669GS ZO HETOES 0 39vL16 6 0 381986 8 0 WHLLVLT 8 0 JCCIES 8 0 398 82 6 0 3c1890 T ZO APTIT T 20 38G8v2 T 0 3ITIOS 6 0 3L8vGTI 00 400000 0 000002 sTenb 20 3856808 S 20 380S S G c0 3LC9L2 G 20 36 E86 v 20 388899 T 20 38L0vE Yv Z20 499600 b 20 388989 c0 3L9SEZ7 20 3v858S9 cC 20 30L818 T 0 S3LILEG6 8 0 38S01I G E0 H49 EZZ9 V O H68EEE y 0 3cE8S0 Y 0 391208 0 d98S9G E 0 SE9ETE 0 38L9cT O AZEETO SC E0 HTPEOL Z E0 H4ETT8BD Z 0 3169Sc c 0 3IcvVEO c 0 361608 1 0 3L08LS T 0 3E08 T 0 3 EGGCT I v0 3 6S1 6 v0 30 6506 9 v0O 3L6TI V Yv VO A8ETZ6 E v0O 3
30. Code Manual Volume 3 Development Assessment Problems EGG TFM 7952 December 1987 pp 14 17 2 2 2 Ibid pp 61 63 2 2 3 K E Carlson Improvements to the RELAPS5 MOD3 Noncondensable Model EGG EAST 8879 January 1990 2 2 4 W H Grush Pygmalion INEL software 1994 2 2 5 G B Wallis One Dimensional Two Phase Flow New York McGraw Hill 1969 pp 336 341 2 2 6 S G Bankoff R R Tankin M C Yuen and C L Hsieh Countercurrent Flow of Air Water and Steam Water Through a Horizontal Perforated Plate International Journal of Heat and Mass Transfer 24 1981 pp 1381 1385 2 2 T C L Tien K S Chuent and C P Lin Flooding in Two Phase Countercurrent Flow EPRI NP 984 February 1979 2 3 Hydrodynamic Components The basic two fluid model is applied uniformly to all volumes and junctions Thus the programming design of the hydrodynamic calculation is primarily organized on volumes and junctions Components are organized collections of volumes and junctions and to a lesser extent the program is organized on components Components are designed for either input convenience or to specify additional specialized processing A pipe component is an example of a component designed for input convenience since by taking advantage of typical features of a pipe several volumes and junctions can be described with little more data than for one volume Pump and valve components are examples of components requiring addition
31. Edits Major edits are an editing of most of the key quantities being advanced in time The amount of output depends on the input deck and output options chosen by the code user Output includes a time step summary trip information reactor kinetics information one to four sections of hydrodynamic volume information hydrodynamic volume time step control information one or two sections of hydrodynamic junction information metal water reaction information heat structure heat transfer information heat structure temperatures reflood information reflood surface temperatures cladding rupture information surface radiation information control variable information and generator information Major edits are quite lengthy and care should be used in selecting print frequencies Some sections of major edits can be bypassed through input data on time step control cards An example of a major edit is shown in Figure 8 3 1 Each section of information is discussed below in the order that each appears in a major edit In particular what the abbreviated labels stand for as well as how they relate to variables used in Volume 1 of this manual are indicated 8 3 2 1 Time Step Summary s shown in Figure 8 3 1 the first section of a major edit prints the problem time and statistics concerning time step control ATTEMPTED ADV is the total number of successful and repeated advancements REPEATED ADV is the number of advancements that were not accepted and wer
32. N ratio head ratio is the increase in dynamic pressure for the suction discharge path divided by the loss of dynamic pressure for the drive discharge path P tpv pst f P 2pv pgH N os 2 3 18 P ipv peH P ipv peH 2 D 2 Dis Figure 2 3 6 shows an expanded view of the normal operating region first quadrant with several curves representing different flow resistances This figure can be used as a guide for modeling different jet pump geometries Each curve shows the M N performance generated with base case loss coefficients plus a single additional loss coefficient K 0 2 added to either the drive suction or discharge junction This figure gives an indication of the quantitative change in performance caused by the respective drive suction or discharge losses Using this figure one can with a few preliminary runs design a code model 2 45 NUREG CR 5535 V2 RELAP5 MOD3 2 for a specific jet pump if the performance data are available If no specific performance data are available we recommend that standard handbook losses be applied 1 00 D PUE Base case Additional drive loss K 0 2 02751 eem Additional discharge loss K 0 2 i Additional suction loss K 0 2 o 0 50 Z 0 25 0 0 25 0 50 1 0 1 2 3 4 M ratio Figure 2 3 6 Jet pump model design 2 3 9 4 Output There is no special output printed for the JETMIXER component We recommend
33. P t is the heat generated in Watts Within the program this factor is divided by the integral of the space dependent distribution to allow for the arbitrary scaling of that function After this scaling the internal source is in the required units of Watts m The other two factors provide for the direct heating of the fluid in the hydrodynamic volumes attached to the surfaces Heat equal to the factor times the power value is added to the internal energy of the fluid in the hydrodynamic volume If P t is the power in Watts and Pr is the factor then Pr P t is the heat added to the fluid The total direct heating added to a volume is the sum of the direct heating from all structures connected to the volume Zeros are entered where no heat source or hydrodynamic volumes exist In a reactor problem if a power value represents the total reactor power generated and if this power is totally accounted for in the RELAPS model then the sum of these three factors over all the heat structures representing that power value should equal one The summing to one is not required and no checks are performed by the code In many instances the power will not only be applied to the heat structures representing the fuel but also to the heat structures representing such items as the downcomer and pressure vessel walls 3 4 Heat Structure Changes at Restart At restart heat structures may be added deleted or replaced Since heat structure input data are organize
34. Reverse Q N HAR HVD e D 9 0 HVR 10 8 ES Mi A o 0 R 0 y Ce HAR Denotes head H d Uem e J HVN 0 Denotes division by e a or a2 A v or v2 V X vfa or 0 5 0 5 av 0 2n HVR N lt Denotes quadrant N D T R C t q gt gt gt p 0521 Figure 2 3 3 Homologous head curve parameters The question can best be answered by the following statements First the best approach is to use the rated conditions corresponding to the pump used to generate the data Second the rated condition can be changed if the specific head and capacity are kept the same as for the pump used to generate the data Similarity is assured since the modeled pump will have the same specific speed The rated conditions by definition locate the region of pump operation on the homologous performance curve at the design point or point of maximum efficiency The rated conditions can then be safely adjusted in this way They can also be adjusted using the impeller diameter as an additional parameter while still maintaining the rated specific speed head and capacity constant However this type of scaling implies a change in pump geometry and the extrapolation depends more heavily on the validity of the pump similarity relationships 2 39 NUREG CR 5535 V2 RELAP5 MOD3 2 10 2 2 e Normal Q N BAN Bla or B v 2x BVN BAN se 05 o BAD ez Dissipation Q N BAD
35. Standard for Decay Heat Power in Light Water Reactors ANSI ANS 5 1 1979 5 2 Reactivity Feedback Options Five reactivity feedback options are provided One assumes separability of feedback effects the others use three or four dimensional table lookup and linear interpolation The defining equations are given in Volume 1 of this manual Note that the sign of the feedback terms is positive Negative quantities must be entered where negative feedback is desired All options include an input reactivity r a bias reactivity rg and sums over scram curves and control variables The quantity r is an input quantity and is the reactivity corresponding to the assumed steady state reactor power at time equal to zero This quantity must be 0 A nonzero quantity indicates that a neutron source is present For most applications r 0 is acceptable The bias reactivity rg is calculated during input processing such that r 0 ry The purpose of the bias reactivity is to ensure that the initial reactivity is still equal to the input reactivity after including the feedback effects Without this quantity the user would have to manually adjust a scram curve or control variable to obtain the input value of initial reactivity or have a step input of reactivity as the transient starts The bias reactivity rp is printed out during input processing The scram curves are obtained from general tables defining reactivity as a function of time Each
36. combinations of these to be written at each advancement Care should be used since considerable output can be generated Major edits forced by the program testing option or the last major edit of the problem terminated by approach to the job CPU limit may not coincide with the requested time step When this occurs a warning message is printed that states that not all quantities are advanced to the same time points 8 3 NUREG CR 5535 V2 RELAP5 MOD3 2 8 3 Printed Output A program version identification is printed at the beginning of printed output and the first page following the list of input data 8 3 1 Input Editing Printed output for a problem begins with a listing of the input each line of input is preceded by a sequence number The sequence number is not the same as the card number Notification messages are listed when data card replacement or deletion occurs Punctuation errors such as an alphabetic character in numeric fields multiple signs periods etc are noted by an error message and a caret is printed under the card image indicating the column position of the error Input processing consists of three phases The first phase simply reads and stores all the input data for a problem such that the data can later be retrieved by card number Error checking is limited to punctuation checking and erroneous data flagged during this phase nearly always causes additional diagnostics in later phases The second phase does t
37. component are given in Section A7 7 of the input requirements in 2 57 NUREG CR 5535 V2 RELAP5 MOD3 2 Steam and nitrogen Liquid water Lrk lt ATK Standpipe 31 surgeline Figure 2 3 12 Schematic of a spherical accumulator Appendix A of this volume The ECCMIX component calculations are evoked only if there is subcooled ECC injection and if there is any steam to be condensed in that component Otherwise the ECCMIX component is treated as an ordinary BRANCH component 2 3 16 References 2 3 1 E Buckingham Model Experiments and the Forms of Empirical Equations Transactions of the ASME 37 1915 p 263 2 3 2 Aerojet Nuclear Company RELAP4 MODS A Computer Program for Transient Thermal Hydraulic Analysis of Nuclear Reactors and Related Systems User s Manual Volume 1 RELAP4 MODS Description ANCR NUREG 1335 September 1976 NUREG CR 5535 V2 2 58 RELAP5 MOD3 2 Standpipe surgeline inlet Standpipe Surgeline Injection point Figure 2 3 13 Schematic of an accumulator showing standpipe surgeline inlet 2 59 NUREG CR 5535 V2 RELAP5 MOD3 2 Cards ccc0101 Cards ccc0101 ccc0109 ccc0109 word 5 90 word 5 90 word 6 gt 0 word 6 lt 0 word 5 90 gt word 6 lt 0 Cards ccc2200 word 4 gt 0 Card ccc2200 word 4 gt 0 Cards eso TOT Cards ccc2200 ccc0109 word
38. condition At present this capability is specialized to the LWR core reflood process but the plan is to generalize this model to higher pressure situations so that it can be used to track a quench front anywhere in the system The point reactor kinetics model is advanced in a serial and implicit manner after the heat conduction transfer and hydrodynamic advancements but before the control system advancement The kinetics model consists of a system of ordinary differential equations integrated using a modified Runge Kutta technique The integration time step is regulated by a truncation error control and may be less than the hydrodynamic time step however the thermal and fluid boundary conditions are held fixed over each hydrodynamic time interval The reactivity feedback effects of fuel temperature moderator temperature moderator density and boron concentration in the moderator are evaluated using averages over the hydrodynamic control volumes and associated heat structures that represent the core The averages are weighted averages established a priori such that they represent the effect on total core power Certain nonlinear or multidimensional effects caused by spatial variations of the feedback parameters cannot be accounted for with such a model Thus the user must judge whether or not the model is a reasonable approximation of the physical situation being modeled The control system model provides a way for simulating any lumped process su
39. development of the models and code revisions that constitute RELAP5 has spanned approximately 17 years from the early stages of RELAP5 numerical scheme development to the present RELAPS represents the aggregate accumulation of experience in modeling core behavior during accidents two phase flow process and LWR systems The code development has benefitted from extensive application and comparison to experimental data in the LOFT PBF Semiscale ACRR NRU and other experimental programs xiii NUREG CR 5535 V2 RELAP5 MOD3 2 As noted earlier several new models improvements to existing models and user conveniences have been added to RELAPS MOD3 The new models include The Bankoff counter current flow limiting correlation that can be activated by the user at each Junction in the system model The ECCMIX component for modeling of the mixing of subcooled emergency core cooling system ECCS liquid and the resulting interfacial condensation A zirconium water reaction model to model the exothermic energy production on the surface of zirconium cladding material at high temperature A surface to surface radiation heat transfer model with multiple radiation enclosures defined through user input A level tracking model A thermal stratification model Improvements to existing models include New correlations for interfacial friction for all types of geometry in the bubbly slug flow regime in vertical flow passages Use
40. diameters He suggests c of the form c c tanh cg D5 NUREG CR 5535 V2 2 22 RELAP5 MOD3 2 where D is a Bond number defined differently from Equation 2 2 6 as 1 D D g p j p9 o 22 7 The values of m c and cg Tien found for four different conditions are provided in Table 2 2 1 With regard to guidelines for plant specific geometry 1 e tie plates support plates etc flooding data obtained in measurements from the plant geometry should be used to generate an appropriate CCFL model that can be input with CCFL junction data cards Table 2 2 1 Values of m 07 and cg for Tien s CCFL correlation form Tests m C7 Cg Nozzle air supply with tapered inlet 0 8 2 1 0 9 Nozzle air supply with sharp edge inlet 0 8 2 1 0 8 Indirect air supply with tapered inlet and sharp 0 65 1 79 0 9 edge output Indirect air supply with sharp edge inlet and 0 65 1 79 0 8 tapered output Wallis 22 5 Bankoff 2 2 6 and Tien 27 discuss the effects of viscosity surface tension and subcooling on the correlations At the present time these effects have not been directly incorporated into the form of the CCFL correlation used in RELAPS We anticipate that these particularly the subcooling effects will be addressed in future modifications to the code 2 2 8 Level Tracking Model The volume control flag 1 in tlpvbfe is used to activate the level tracking model as described in Volume I If the volume contr
41. down pump tests The scaled pump test data can be for the same physical pump operated at reduced speed or for a pump scaled in size such that similarity is preserved For the case of a pump scaled in size it is necessary to maintain the similarity in specific head capacity speed and torque parameters Note that the diameter was dropped in the development of the homologous performance model since a fixed configuration was considered Consideration of the diameter change must be implicitly included in the selection of rated parameters to properly account for changes in geometric scale The homologous parameters including the impeller diameter are given in Equations 2 3 9 2 3 10 and 2 3 12 When a change in scale is considered an additional degree of freedom is possible since only two parameters the rated specific head and capacity must be held constant The specific speed is also held fixed whenever both specific head and capacity are kept fixed There are many combinations of N and D for which this is possible The usual situation encountered in applications work is that homologous data exist for a similar pump and the question arises Can we use these data to simulate our pump by adjusting the rated NUREG CR 5535 V2 2 38 RELAP5 MOD3 2 Normal Q N HAN HV 5 h a 2 or h v2 Dissipation Q N HAD Jt HVD HAD 1 5 Td Turbine Q N HAT HVT N 0 0 Ne e gt 0 HAN 00
42. flow a hysteresis effect will be observed Also in the strictest sense this type of valve is not a check valve since the model allows reverse flow 2 3 10 1 2 Flow Controlled Check Valve Section 3 in Volume 1 shows the model of a check valve in the strictest sense in that flow is allowed only in the positive or forward direction and the model is again designed to perform as an on off switch If the valve is closed it will remain closed until the static pressure differential becomes positive at which time the valve is instantaneously and fully opened and the switch is on Once the valve is opened it will remain open until flow is negative or reversed regardless of the pressure differential Hence with respect to pressure differential a hysteresis effect may be observed With respect to flow it defines a negligible hysteresis effect since flow is zero when the valve opens and closes if flow becomes infinitesimally negative However since valve actuation lags one time step behind the pressure and flow calculation a significant flow reversal may be calculated before the valve model completes a closed condition 2 3 10 1 3 Dynamic Pressure Controlled Check Valve Section 3 in Volume 1 shows the model of a dynamic pressure actuated valve also designed to perform as an on off switch If the valve is closed there is no flow through the valve hence the valve must be opened by static pressure differential For this condition the valve is opened
43. flow limitation CCFL model discussed in detail in Section 3 of Volume I is controlled by the junction control flag The CCFL flag f can be used with a single junction pipe annulus branch valve pump and multiple junction It cannot be used with a time dependent junction separator jet mixer ECC mixer turbine or accumulator Setting f 1 will activate the CCFL model if all other conditions are met and setting f 0 will not activate the model The other conditions are as follows 1 the orientation of both the connecting volumes cannot be horizontal i e the elevation angle must be greater than or equal to 15 degrees 2 both gas and liquid phases must be present 3 countercurrent flow must exist with liquid flowing down and gas flowing up 2 21 NUREG CR 5535 V2 RELAP5 MOD3 2 As with the choking model we recommend that if a junction is designated CCFL f 1 then an adjacent junction should not be designated CCFL f 0 It is anticipated that this flag will find use in activating the CCFL model in such internal structures as the upper core tie plate downcomer annulus steam generator tube support plates and entrance to the tube sheet in the steam generator inlet plenum Junction data cards can be used to input four quantities junction hydraulic diameter correlation form gas intercept and slope For these CCFL junction data cards all four quantities must be entered must have five quantities for pipe and multiple
44. for solid cylinders or spheres where the inner surface area is zero one surface area can be inferred from the other and the mesh point spacing information Nevertheless both surface areas must be entered and an input error will exist if the surfaces are not consistent Consistency is defined to be such that the difference between the calculated left and right factors or the input left or right factors must be 10 times the sum of the calculated left and right factors or the input left and right factors This requirement is easily met with the second option of entering a geometry dependent factor since the factor is the same for the left and right boundary 3 3 Heat Structure Sources Volumetric heat sources for heat structures consist of the product of a scaling factor a space dependent function and a time function The space dependent distribution has been discussed The time function may be total reactor power fission power or fission product decay power from the reactor kinetics calculation a control variable or may be obtained from a table of power versus time Input data provide for three factors The first factor is applied to the power to indicate the internal heat source generated in the structure This means that in steady state heat equal to the factor times the power value would be generated in the heat structure and transferred out through its left and right surfaces If P t is the power in Watts and Pf is the factor then Pf
45. friction an initializing calculation the presence or absence of two tables and two trips are involved Additional capability is provided if the pump is associated with a shaft component An optional card in the pump component input data specifies whether the pump is associated with a shaft The remainder of this section defines pump capability when not associated with a shaft In Section 4 2 3 the available shaft component capabilities are described and user suggestions are given Pump frictional torque T is modeled as a cubic function of the pump rotational velocity and is given by R R 2 Tr 4 Vero Teri Tia Uus o 2 3 14 R where is the pump rotational velocity Op is the rated pump rotational velocity and tgo 154 Tfyo and tg3 are input data The pump friction torque is negative if Q Op gt 0 and it is positive if 0 0 lt 0 The pump model has special capabilities to accommodate experimental systems For example the LOFT system primary pumps use a motor generator flywheel fluid coupling and an active control system in order to better represent full size PWR pumps Allowing a variable pump inertia provides a simple model of the LOFT pump rotational behavior To facilitate LOFT usage pump input provides for constant inertia or optionally allows input of variable inertia data The variable pump inertia I is given by 2 41 NUREG CR 5535 V2 RELAP5 MOD3 2 ee for 9 S 2
46. function of the independent variable by a table search and linear interpolation scheme There is a separate set of curves for head and torque and each set is composed of eight curves Not all the regimes need be described by the input but a problem is terminated if an empty table is referenced Both head and torque data must be entered for the regimes that are described with input The homologous curves for pump head and torque are for single phase operation These same tables are used by the two phase pump model but additional data must be input to model two phase degradation effects Pump head data are always used in the momentum equations Torque data may or may not be used in computing pump rotational velocity depending on the pump motor model selected and if it is energized or not However both head and torque are used to determine pump energy dissipation and consistent data must therefore be entered The pump homologous data should be checked by computing pump efficiency from the homologous data No such checking is currently included in RELAPS nor is the operating efficiency edited on major edits The sign conventions for various pump quantities are as follows a pump operating in the normal pump regime has a positive angular velocity the volumetric flow is positive if it is in the same direction as the volume coordinate direction the head is positive if it accelerates the flow in the volume coordinate direction and the torque is that e
47. if it appears in the defining equation the new and old values are off by a time step That is V uses V and V uses V For good results the user should try to define a control variable before using it This is not always possible as shown in the second example in Section 4 2 2 Except for a CONSTANT component each control component may optionally specify a minimum a maximum or both After the component is evaluated by its defining equation the value is limited by the minimum and maximum values if they are specified The control system input provides for an initial value and a flag to indicate that the initial value is to be computed during the initialization phase of input processing The initialization of all other systems such as trips hydrodynamics heat structures and reactor kinetics precedes that for control systems If one of those systems needs an initial value of a control system variable the input value is used Thus the control variable value used in servo valve initialization initialization of time dependent volumes and junctions if control variables are specified as search arguments initialization of heat structures when a control variable is specified as a heat source and computation of bias reactivity when control variables contribute to reactivity use input values However the input edit and first major edit after introduction of a control variable show the value after initialization Except for the SHAFT c
48. induction pump are the negative slope of the torque with respect to velocity near the synchronous velocity and the fact that the torque is zero at the synchronous velocity In steady state the velocity is slightly less than the synchronous speed such that a positive torque balances the negative torque imposed by the pump Pump transients such as pump startups from rest to operating speeds can be modeled A simple ac or dc motor could also be modeled by a table that would have only positive torque values and negative slope The motor torque table is not searched when the pump trip is true since the motor torque is always zero when the pump is tripped The motor torque is labeled by MTR TORQUE in the pump output in major edits 4 13 NUREG CR 5535 V2 RELAP5 MOD3 2 If a motor torque table is not entered a pump motor is implied When the pump trip is true the torque from the implied pump motor is zero If the trip is not entered or is false a motor torque is assumed that is equal to the sum of frictional and hydrodynamic torques resulting in no change to the rotational velocity over the time step In this mode the field labeled MTR TORQUE has the same magnitude as the pump torque but has opposite sign The implied pump motor is normally used in cases where the pump is initially operating at normal velocity and if tripped is never restarted Note that with the implied motor if the pump trip is set true pump tripped the pump is free to change
49. is the number to be used on Card 103 to identify the desired restart record The record number is simply a count of the number of restart records written with the restart record at time equal zero having record number zero Quantities written in the restart plot records by default are noted in the input data description User specified input can add additional quantities to the restart plot records PLOT and STRIP are output type runs PLOT generates plots from data stored on the restart plot file The PLOT capability is not now operational but is still documented The PLOT capability may be dropped from the code since NPA 1 and XMGR5 1 2 an INEL extension of XMGR allow very general and high quality plots of RELAPS results and associated information STRIP writes selected information from a restart plot file onto a new file The new file consists of records containing time and the user selected variables in the order selected by the user Data to be plotted or stripped are limited to that written in the plot records on the restart plot file 8 1 1 References 8 1 1 D M Snider K L Wagner W H Grush and K R Jones Nuclear Plant Analyzer Volumes 1 4 NUREG CR 6291 INEL 94 0123 December 1994 8 1 2 K R Jones XMGR5 Extensions Draft INEL document 1995 8 1 3 P J Turner ACE gr User s Manual SDS3 91 3 1991 1993 Beaverton OR 8 2 Time Step Control Input data for time step control consist of one or more cards co
50. listed below followed by a brief review of the evaluation procedure Familiarity with the control system numerical techniques documented in Section 6 of Volume I is recommended In the definitions that follow Y is the control variable defined by the i th control component Aj R and S are real constants input the by user I is an integer constant input by the user V is a quantity advanced in time by RELAPS and can include Y t is time and s is the Laplace transform variable Superscripts involving the index n denote time levels Some components include a definition in Laplace transform notation The name in parentheses is the name used in the input data to select the type of component 4 2 1 1 Constant CONSTANT Y S 4 2 1 4 2 1 2 Addition Subtraction SUM Y S Ag A V A9V5 4 2 2 4 2 1 3 Multiplication MULT Y S V V 4 2 3 4 2 1 4 Division DIV NUREG CR 5535 V2 4 6 RELAP5 MOD3 2 Y S V or S V N 4 2 4 4 2 1 5 Integer Exponentiation POWERI Y SVil 4 2 5 4 2 1 6 Real Exponentiation POWERR Y sVjh 4 2 6 4 2 1 7 Variable Exponentiation POWERX Y SV 4 2 7 4 2 1 8 Table Lookup Function FUNCTION Y S F V 4 2 8 where F is a function defined by table lookup and linear interpolation 4 2 1 9 Standard Functions STDFNCTN Y S F V Vo V3 4 2 9 where F can be IV jl exp V In V sin V 1 cos V p tan V tan V4 V4 7 MAX V
51. mode use time as the independent variable In this mode the use of the trip time is identical to that described for time dependent general tables But the time dependent volumes junctions and pump velocity tables also permit any time advanced quantity to be specified as the independent variable If a trip is specified and is false the table is interpolated with 1 0 x 107 as the search argument If no trip is specified or the trip is true the specified time advanced quantity is the search argument A typical use of tables using a quantity other than time as the independent variable is the modeling of a high or low pressure reactor safety injection system Rather than model the valve pump and motor for the system a time dependent junction is used to approximate the injection system The pressure at the injection point is specified as the independent variable and flow rate is the dependent variable The table would define zero flow for the first zero pressure value then appropriate flow rates for the second zero pressure and following pressure values The last pressure value would be the cutoff pressure of the pump and have a corresponding zero flow In normal reactor operation the trip would be false and the table interpolation would return zero flow When the safety system 16 actuated flow may still be zero if the reactor pressure exceeds the cutoff pressure As the reactor pressure drops flow would start and the table could indicate increa
52. nine junctions is due to a card numbering constraint Junctions from other components such as single junction pump other branch or even time dependent junction components may be connected to the branch component The results are identical whether junctions are attached to the branch volume as part of the branch component or are in other components Use of junctions connected to the branch but defined in other components is required in the case of pump and valve components and may also be used to attach more than the maximum of nine junctions that can be described in the branch component input 2 3 8 Pump The pump component model can be separated into models for hydrodynamics pump fluid interaction and pump driving torque The pump component input provides information for the hydrodynamic and pump fluid interaction models and may optionally include input for an electric motor to drive the pump A pump may also be connected to a shaft that is a specialized component within the control system A shaft component is used when the pump is driven by a turbine or by an electric motor with a control system to regulate speed 2 3 8 1 Pump Model Description The hydrodynamic model of a pump component consists of one volume and two associated junctions The coordinate directions of the junctions are aligned with the coordinate direction of the volume One junction is connected to the inlet and is called the suction junction the other junction is connecte
53. nodalization for hydrodynamics the following general rules should be followed 1 The length of volumes should be such that all have similar material Courant limits i e flow length divided by velocity about the same Expected velocities during the transient must be considered The volumes should have L D gt 1 except for special cases such as the bottom of a pressurizer where a smaller L D is desired to sharpen the emptying characteristic The total system cannot exceed the computer resources RELAPS dynamically allocates memory based on the requirements of each problem and most models require memory based on factors such as the number of volumes junctions number of heat structures and the number of meshes and the number and length of various user input tables The number of hydrodynamic volumes is a reasonable measure of problem size and typical LWR systems with over 600 volumes have been run on workstations with 32 Mbytes of memory The memory should be sufficiently large to avoid paging during transient advancement If possible a nodalization sensitivity study should be made in order to estimate the uncertainty owing to nodalization Volume V provides guidance and examples of appropriate nodalizations for reactor systems Avoid nodalizations where a sharp density gradient coincides with a junction a liquid interface for example at steady state or during most of the transient This type of situation can result in time step r
54. of Junction based interphase drag An improved model for vapor pullthrough and liquid entrainment in horizontal pipes to obtain correct computation of the fluid state convected through the break A new critical heat flux correlation for rod bundles based on tabular data An improved horizontal stratification inception criterion for predicting the flow regime transition between horizontally stratified and dispersed flow A modified reflood heat transfer model Improved vertical stratification inception logic to avoid excessive activation of the water packing model An improved boron transport model A mechanistic separator dryer model An improved crossflow model An improved form loss model NUREG CR 5535 V2 xiv RELAP5 MOD3 2 The addition of a simple plastic strain model with clad burst criterion to the fuel mechanical model The addition of a radiation heat transfer term to the gap conductance model Modifications to the noncondensable gas model to eliminate erratic code behavior and failure Improvements to the downcomer penetration ECCS bypass and upper plenum deentrainment capabilities Additional user conveniences include Code speedup through vectorization for the CRAY X MP computer Computer portability through the conversion of the FORTRAN coding to adhere to the FORTRAN 77 standard Code execution and validation on a variety of systems The code should be easily installed i e
55. of a cylindrical accumulator for a decrease in elevation from the standpipe surgeline inlet to the injection point and it is negative for an increase in elevation from the standpipe surgeline inlet to the injection point 2 3 14 Annulus The annulus component is identical to a pipe component Section 2 3 6 except the annulus component must be vertical and the annular mist flow regime is different If the user specifies this component all the liquid is in the film and none is in the drops when the flow regime is annular mist The annulus component should be used to model a vertical annular region i e reactor vessel downcomer or annular downcomer region in a U tube steam generator 2 3 15 ECC Mixer An ECC mixing component is a specialized branch that requires three junctions with a certain numbering order The physical extent of the ECCMIX is a length of the cold leg pipe centered around the position of the ECC injection location The length of this segment should be about three times the inside diameter of the cold leg pipe Junction No 1 is the ECC connection junction No 2 is the cold leg cross section through which flow enters this component in normal reactor operation and junction No 3 is the one that leads to the reactor vessel The geometrical description of the ECCMIX component is very similar to that of the JETMIXER component except for the specification of an angle for the ECC pipe connection The modeling details of the ECCMIX
56. physical area AX amp 19 the upstream volume length The smooth area option is intended to be used for smoothly varying geometries The length 0 5 Ax would be the actual length of the upstream volume Ax to the throat Aj Since the smooth area change option is not recommended this formula has had little assessment If the user selects the crossflow option for the junction and if the K volume is a crossflow volume the code uses Ak Al dA _ 2 2 3 dx t crossflow 0 5D The length 0 5Dx is the radius of the volume if the default is used and it is one half the length in the cross direction if the optional input is used There has been little assessment of this formula Sometimes it is observed that the choking junction oscillates in time between the inlet and outlet junctions of a control volume This may induce flow oscillations and should be avoided The situation most often occurs in modeling a break nozzle The choking plane is normally located in the neighborhood of the throat The break can be adequately modeled by putting the break junction at the throat and including only the upstream portion of the nozzle If the entire nozzle is modeled the choked flow option should be applied only to the junction at the throat NUREG CR 5535 V2 2 12 RELAP5 MOD3 2 The internal choking option must be removed when supersonic flows are anticipated or when its application causes unphysical flow oscillations Typical cases are propag
57. processing feature that finds all loops or closed systems which are defined by the input and checks for elevation closure around each loop The error criterion is 104 m If closure is not obtained the fail flag is set and no transient or steady state calculations will be made The elevation checker will print out that elevation closure does not occur at a particular junction that formed a closed loop during input processing The junction at which closure of the loop occurs is somewhat arbitrary and depends on the input order of the components 2 7 NUREG CR 5535 V2 RELAP5 MOD3 2 The elevation checking with crossflows differs from earlier versions of RELAPS The elevation checking starts from the center of a volume with the initial volume and its elevation obtained from input data or defaulted Using to and from junction information and elevation change information from the connected volumes the elevation to the common face of the volumes is computed then the elevation of the center of the connected volume is computed This computing of the elevations by tracking the junctions continues until all junctions have been used Whenever a volume is reentered the newly obtained elevation is compared to the previously computed elevation and an error occurs if they do not match With the previous crossflow model the elevation from the center to a face was zero for a crossflow connection This meant that the same elevation would be obtained regardless of
58. quite large compared to the other a modified Bernoulli equation can be used in which the overall loss factor defined by Equation 2 2 4 can be replaced by K 1 In other words the user input loss factor is computed by substituting K 1 for K in Equation 2 2 4 All of the development herein assumes that known pressure drop flow relations exist for the single phase case and that compressibility effects are small If such is not the case then the effective loss factor values must be determined experimentally by running the code for a series of cases Some experimentation NUREG CR 5535 V2 2 18 RELAP5 MOD3 2 may be required since the actual momentum flux calculation is complicated by several factors and may differ slightly from the simple Bernoulli form Another problem relative to a minor leak path can occur when an incorrect flow rate through an orifice for a given AP and loss coefficient K is calculated As noted previously this problem can be avoided if the user inputs reasonable values for the flow area and the loss coefficient K rather than allowing the flow area to default and using a very large K 2 2 4 Reflood Model The reflood model is designed so that it can be activated at low pressure less than 1 2 x 10 Pa with nearly empty conditions average void fraction in connected stack of hydraulic volumes gt 0 9 or dryout beginning average void fraction gt 0 1 or by user command through a trip The model considers a heat
59. run if necessary by trip control or exceeding the end time of the last time step control card Note that combinations of the effects of setting of the individual bits are achieved by setting bits in combination For example entering three setting bits two and one results in the combined effects described above for bits two and one Older versions of RELAPS would convert 2 to 3 to maintain compatibility this is no longer done Entering zero is not recommended except for special program testing situations If bit one is set but not set for 2 and 3 care must be taken in selection of the requested time step Individually the hydrodynamic and heat conduction advancements are stable the hydrodynamic time step is controlled to ensure stability the heat conduction solution with constant thermal properties is stable for all time steps and the change of thermal properties with temperature has not been a problem The serial coupling of the hydrodynamic volumes and heat structures through heat structure boundary conditions can be unstable and excessive truncation error with large time steps can occur This has been observed in test problems Entering three usually eliminates the problem and nearly all assessment of the code has been done using option three Using option seven which includes the implicit coupling of heat conduction and hydrodynamics should lead to an improved advancement Users are encouraged to use option seven but with the caution that
60. spTouAay ZO HLSZ Z dno x Tu Aa3tTenb c0 39v C 20 39L2 c 20 3081I c ZO HLS0 Z ZO H46T6 T 20 STGL TI c0 3L9v T 20 3000 I 0 ULL9 9 0 UvIt 9 0 HvVE L G 0 d06S S 0 8 8S S e0 H9LL S 0 0 T2709 A3doad eonpea 6 90vv 9 8L8 L TOL8 f 1098 v S8v8 8 vLc8 0 0S8L E GEEL L 6 699 60605 T 86LT L 6ST TZ ERPE 70601 e COLE v TTOT Le 628 EL BEY 88 0857 Z0 8LZ ccL 6 zu oes bx xnij sseu TZ SLP S s u punos 8tc 8 8tv Iv VSS OP T88 6 8t6 8 889 L LG9 GE 80 c GLE OE 8c8 9c TOP IZ CGC 9 GETAT Tse 9c 0 0 0 0 0 0 3766 Te3oa 11p3 00 300000 0 90 HL8087 L 90 HES7E8 S 90 HS6678 L LO 4S0672 T L0 3888vL C LO HOTT89 6 80 HST8PEE 80 HCETZE E L0 388S01 6 90 8 S 6F 9 90 HSLL96 C 90 488080 C 90 HE9ETL 90 366918 90 3c0cv8 90 3SvLVO C 90 H78778 90 HETTCS 90 HT8 785 90 H66007 X u s33e 2934 3UT den 8L8 0 S s u 3odeA T 9A SET EE LOE LC 660 9c TES PE 60906 voz oz SET LE 866 T 9900 6 v999 c 69 T Z T8LL T 8685 TI 9vS5b T sseu onp z ZT H00000 T 80 HE60LZ T 8048pPI8 9 T 80 3H8F8S8 1 8048SvPI9Tl Z 80 H0byS9 Z 80 368920 F 80 4570690 6 60 31 891 Z 604392818 L04306068 L0489 906 LO 390 92 LO H6Z690 L04888801 LO EZSTED L043S9868 LO HO09FSI Z LO H00S8L LO H0 80L LO H6L90L X u s33en 914 UT bt 99562 S s u prnbr T9A
61. specifies the open trip in a motor valve The trip logic is written as follows 501 P 1010000 GT NULLO 110 5 N PD 502 P 1010000 GT NULLO 120 45 N P2 601 603 AND 502 N FIRST TERM OF EQ 4 5 NUREG CR 5535 V2 RELAP5 MOD3 2 602 603 AND 501 N SECOND TERM OF EQ 603 601 OR 602 N OPEN TRIP The close trip logic can be written similarly 4 2 Control Components The control system provides the capability to evaluate simultaneous algebraic and ordinary differential equations The capability is primarily intended to simulate control systems typically used in hydrodynamic systems but it can also model other phenomena described by algebraic and ordinary differential equations Another use is to define auxiliary output quantities such as differential pressures so they can be printed in major and minor edits and be plotted 4 2 1 Basic Control Components The control system capability consists of several types of control components each type of component defining a control variable as a specific function of time advanced quantities The time advanced quantities include hydrodynamic volume junction pump valve heat structure reactor kinetics and trip quantities and the control variables themselves including the control variable being defined Permitting control variables to be input to control components allows complex expressions to be developed from components that perform simple basic operations The basic control components are
62. structure First the surface indicator is printed for both sides SIDE printed as either LEFT or RIGHT Next the volume number for the hydrodynamic volume connected on each side is printed BDRY VOL NUMBER 0 000000 is printed if no volume is present Then the surface temperature is printed for both sides SURFACE TEMP After this is the heat transfer NUREG CR 5535 V2 8 16 RELAP5 MOD3 2 rate out of the structure for both sides HEAT TRF CONVECTION This is followed by two fluxes for both sides the heat flux and the critical heat flux HEAT FLUX CONVECTION and CRITICAL HEAT FLUX After these the critical heat flux multiplier the mode of heat transfer and the heat transfer coefficient are printed for both sides CHF MUL HT MODE and HEAT TRF COEF CONV The multiplier is the coefficient multiplied times the critical heat flux found in the CHF table to obtain the final value printed here Section 3 2 describes the meaning of the modes Finally three quantities are printed for the individual heat structure These are the heat generated within the structure INT HEAT SOURCE the net heat transfer rate out of the structure i e convection plus radiation minus generation CONV RAD SOURCE and the volume average temperature for the structure VOL AVE TEMP Figure 8 3 1 shows an example of this section of the major edit Following this section the sum of the sources is given 8 3 2 12 Heat Structure Temperature This section of
63. system through a normal junction and the inflow velocity is determined from the momentum equation solution For this type of boundary some caution is required since the energy boundary condition is in terms of the thermal energy rather than total energy Thus as the velocity increases the total energy inflow increases owing to the increase in kinetic energy This effect can be minimized for simulation of a reservoir by making the cross sectional area of the time dependent volume very large compared to the inlet junction area This policy should be followed for outflow boundaries as well or else flow reversals may occur A second way of specifying a flow boundary is using the time dependent junction in addition to a time dependent volume This type of boundary condition is analogous to a positive displacement pump where the inflow rate is independent of the system pressure In this case the cross sectional area of the time dependent volume is not used because the velocity is fixed and the time dependent volume is only used to specify the properties of the inflow Thus the total energy of the inflow is specified When only time dependent junctions are used as boundary conditions the system pressure entirely depends on the system mass and in the case of all liquid systems a very stiff system results An additional fact that should be considered when using a time dependent junction as a boundary is that pump work is required for system inflow if the
64. the abrupt area model the junction area upon which the velocities are based is the minimum area of the two connecting volumes NUREG CR 5535 V2 2 10 RELAP5 MOD3 2 In addition to the computed form loss from the abrupt area change model users have the option of input form loss factors to achieve the desired pressure drop See Section 2 2 3 3 for discussion for modeling of minor flow paths The pressure drop calculated by using form losses is a function of junction velocity 2 2 2 Choked Flow The choked flow option is specified in the junction flags on the junction geometry card In general the choked flow model should be used at all exit junctions of a system We recommend that the choked flow model be usually used at the choke plane and that the user not model anything past this plane Therefore just use a time dependent volume downstream of the choke plane Internal choking is allowed but may not be desirable under certain conditions Some applications of RELAPS require that volumes downstream of the choke plane be modeled with non time dependent volumes For this case the user should monitor the mass error in the downstream volumes to ensure that the total mass error is not governed by these volumes If the mass error in these volumes is large the user should consider adjusting the size of the volumes The current recommendation regarding the choking model is based on circumventing problems that have been observed when specifying t
65. the other coordinates Figure 3 1 1 illustrates placement of mesh points at which temperatures are computed The mesh point spacing is taken in the positive direction from left to right A composition is a material with associated thermal conductivity and volumetric heat capacity Mesh points must be placed such that they lie on the two external boundaries and at any interface between different compositions Additional mesh points may be placed at desired intervals between the interfaces or boundaries There is no requirement for equal mesh intervals between interfaces and compositions may vary at any mesh point The heat structure input processing provides a convenient means to enter the mesh point spacing and composition placement Each composition is assigned a three digit nonzero number these numbers need not be consecutive For each composition specified corresponding thermal property data must be entered to define the thermal conductivity and volumetric heat capacity as functions of temperature The temperature dependence can be described by tabular data or by a set of functions Defining thermal 3 1 NUREG CR 5535 V2 RELAP5 MOD3 2 Composite boundaries Left boundary V Right boundary 0 0 e 9 0 000090 e e Figure 3 1 1 Mesh point layout property data for compositions not specified in any heat structure is not considered an error but does waste storage space Typical thermal property data for carbon
66. the time step size This can be mitigated if the turbine volumes are used with an exaggerated length This will not affect any steady state results but it will give slightly inaccurate storage terms during a transient The transient storage terms are small so this should not be a problem 2 3 13 Accumulator An accumulator is a lumped parameter component modeled by two methods First the component is considered to be an accumulator as long as some of the initial liquid remains in the component In this state the accumulator is modeled using the special formulations discussed in Volume I of this manual However second when the accumulator empties of liquid the code automatically converts the component to an equivalent single volume with a single outlet junction and continues calculations using the normal solution algorithms In performing this conversion the accumulator wall heat transfer model is retained but the volume flow area A hydraulic diameter Dy and elevation change Az are reset to A VAxqy Ax 2 3 25 Az Azrk Az 2 3 27 respectively In these equations subscript TK is for the tank and subscript L is for the surgeline standpipe In addition the accumulator mass transfer model converts to the normal mass transfer model scheme In setting up an accumulator component the user must remember that at the input processing level the code assumes that the accumulator is initially off that is flow through the accumulato
67. this failure case HELP 1 that are an aid in tracing the code failure Just preceding the diagnostic edit information concerning the reason why the code failed is printed out This information begins with eight asterisks An example of this printout for the case of a thermodynamic property failure at the minimum time step is shown in the middle of Figure 8 3 7 Following this the old time STATE diagnostic printout is forced out The other message often printed out for this case HELP 1 can usually be buried somewhere within the diagnostic edit For the example of a thermodynamic property error information from the STATEP subroutine concerning the faulty volume is printed out see middle of Figure 8 3 8 The information is the label THERMODYNAMIC PROPERTY FAILURE the volume number VOLNO pressure P vapor specific energy UG liquid specific energy 8 21 NUREG CR 5535 V2 RELAP5 MOD3 2 vITZ T 96bzZ T ELSO T 61699 0 21085 0 6LLOV O 98 SE 0 06080 L9 T vOZE E voov L TOD TT 9LES T O08LSS 0 0S91 0 20 30261 8 Z0 HNvZLVO 8 20 390S828 9 ZO H9TZ6 9 20 369L99 8 0 392 0Tv 6 20 396c82 9 ETEL BESET 68601 0 LVLOTL O 9clvl 0 OcLII O ZO HE606T L 20 36v 00 S c0 3cv99v Z 0 316SLV L OvvSIl 0 8 S8c 0 89 6v 0 98008 0 SLOC I 901L I BOSTI O 20056596 0 T8LTZ 0 00 400000 0 S s w 000010 CTA 6960 162 8926 1606 OESE 8015 608 TO8L
68. to continue a problem after a normal termination If the problem terminated because it approached the CPU time limit the problem can be restarted with no changes to information obtained from the restart file If the problem stopped because the advancement time reached the time end on the last time step card new time cards must be entered If the problem was terminated by a trip the trip causing the termination must be redefined to allow the problem to continue Thus the code must provide for some input changes for even a basic restart capability The ability to modify the simulated system at restart is a desirable feature The primary need for this feature is to provide for a transition from a steady state condition to a transient condition In many cases simple trips can activate valves that initiate the transient Where trips are not suitable the capability to redefine the problem at restart can save effort in manually transcribing quantities from the output of one simulation to the input of another One example of a problem change between steady state and transient is 8 27 NUREG CR 5535 V2 RELAP5 MOD3 2 the use of a liquid filled time dependent volume in place of the vapor region of a pressurizer during steady state The time dependent volume provides the pressurizer pressure and supplies or absorbs water from the primary system as needed The time dependent volume is replaced by the vapor volumes at initiation of the transient This techniq
69. to reflect the current state of simulation knowledge 1 2 Areas of Application RELAPS is a generic transient analysis code for thermal hydraulic systems using a fluid that may be a mixture of steam water noncondensables and a nonvolatile solute The fluid and energy flow paths are approximated by one dimensional stream tube and conduction models The code contains system component models applicable to LWRs In particular a point neutronics model pumps turbines generator valves separator and controls are included The code also contains a jet pump component The LWR applications for which the code is intended include accidents initiated from small break loss of coolant accidents operational transients such as anticipated transients without SCRAM loss of feed loss of offsite power and loss of flow transients The reactor coolant system RCS behavior can be simulated up to and slightly beyond the point of fuel damage 1 3 Modeling Philosophy RELAPS is designed for use in analyzing system component interactions it does not offer detailed simulations of fluid flow within components As such it contains limited ability to model multidimensional effects either for fluid flow heat transfer or reactor kinetics Exceptions are the modeling of cross flow effects in a pressurized water reactor PWR core and the reflood modeling that uses a two dimensional conduction solution in the vicinity of a quench front To further enhance the over
70. used when the trip is false The dependent variable of the table is rotational velocity The search variable may be time or any other variable allowed in minor edits including control variables This allows a model for pump velocity to be computed by the control system A motor is implied by the table since a torque is needed to match the friction and hydrodynamic torque and to accelerate the pump velocity from the previous time step value The torque from this implied motor is labeled by MTR TORQUE in the pump output of major edits When the pump speed table is not being used or is not entered the pump rotational velocity equation 1s used I P 7a Ty 4 2 27 where I is the moment of inertia of the pump is the rotational velocity Tm is the pump motor torque and t is the sum of the frictional and hydrodynamic torques An operational pump trip may be specified If not specified trip number is zero or if specified and false electric power is supplied to the pump motor If the trip is true the pump breaker has tripped This is the origin of the name trips for the Boolean logic in RELAPA and the name has been continued in RELAPS No electric power is supplied to a tripped pump and thus the motor torque t is Zero A pump motor is directly specified when a table of pump motor torque versus rotational velocity is entered An induction motor can be modeled by entering a function similar to that shown in Volume I The key features of an
71. which specific capacity head and torque are all constant Thus at any state it is possible within the limitations of similarity theory to predict the performance for other combinations of speed head and flow that have the same homologous state It is also possible to scale pump performance with reasonable accuracy to account for changes in physical pump size through the diameter D by keeping the homologous parameters fixed Pump performance data are usually displayed by plotting head and torque as functions of speed and volumetric flow Figure 2 3 1 is a four quadrant pump curve for the Semiscale MODI pump and has speed and flow as independent variables with lines of constant head Figure 2 3 2 is a comparable four quadrant plot of the Semiscale MODI pump torque data All possible operating states of the pump are represented on such plots These data for a particular pump can be approximately collapsed into a single curve by nondimensionalizing specific head and capacity parameters for corresponding homologous operating points using the design point values for head capacity and speed All points on Figure 2 3 1 having the same specific capacity are straight lines passing through the origin lines of constant Q N The impeller diameter is omitted from the homologous parameters since it is constant for a particular pump The design operating point is indicated by the cross The line of constant Q N passing through the design point and its refl
72. will also come out the junction And for the separator steam outlet notice that if the water level rises above the outlet baffle on the right that water will also come out the junction Thus the critical values of VUNDER and VOVER are given by the following formulas Ar A VUNDER and VOVER 2 2 3 19 A A where Ag the area open to the water At the total area Agi the area open to the steam 2 49 NUREG CR 5535 V2 RELAP5 MOD3 2 Bypass Plenum plenum Vapor outlet Bypass K A A A A AAA Separator Separator inlet Liquid fall back Downcomer Figure 2 3 7 Schematic of separator When the water level drops below the baffle on the left the volume fraction of steam that is fluxed through the water outlet Junction is a linear function of the water level height A similar relationship is used for the steam outlet when the water level rises above the baffle on the right These linear relationships are such that if the separator is empty of water then pure steam comes out the liquid outlet and conversely if the separator is full of water then pure water comes out the steam outlet The behavior of the separator can now be characterized by Figure 2 3 9 and Figure 2 3 10 where the y axis shows the volume NUREG CR 5535 V2 2 50 RELAP5 MOD3 2 Separator Steam Water O O O o O O O O O O O Q o O O O O O O we o 9 Figure 2
73. with the previous section on reflood information this section is not printed until the reflood model is turned on and then it continues to be printed out An example of this section is also shown in 8 17 NUREG CR 5535 V2 RELAP5 MOD3 2 Figure 8 3 3 The temperatures are printed from left to right beginning with the first heat structure In this example of 20 heat structures 59 axial mesh point surface temperatures are printed 8 3 2 14 Cladding Oxidation and Rupture Information If the user has activated the metal water reaction model by using a 1CCCG003 card the cladding inside and outside oxide penetration depth is printed prior to the heat structure output Figure 8 3 4 gives an example where there are two stacks of eight heat structures The second stack 31 at elevation 5 shows some inside cladding oxidation This is because this elevation has ruptured as can be seen in the next section in Figure 8 3 4 The pressure shown 1s the pressure inside the gap 8 3 2 15 Surface Radiation Model Output Figure 8 3 5 shows an example of output from the radiation model This radiation enclosure of six heat structures was tripped on at 0 25 s and was never tripped off The heat flux is out of five structures and into number six In the energy exchange calculation 0 28 W is unaccounted for 8 3 2 16 Control Variable Information This section of output is not optional and always appears in a major edit when control systems are present Figure 8 3
74. 0 Horizontal stratification effects are not modeled in the TURBINE component Thus the horizontal stratification flag must be turned off v 0 If several TURBINE components are in series the choking flag should be left on c 0 for the first component but turned off for the other components c 1 The area changes along the turbine axis are gradual so the smooth junction option should be used at both the inlet and outlet junctions No special modeling has been included for slip effects nor are there any data that could be used as a guide Thus the inlet and outlet junctions must be input as homogeneous junctions h 2 If a steam extraction bleed junction is present it must be a crossflow junction s 1 2 or 3 The standard wall friction calculation is based upon the wetted perimeter Because of all the internal blading surfaces the wall friction based upon the volume geometry will not give a meaningful calculation The turbine volume must be input using the zero wall friction option For some off design cases choking can take place at the nozzle and stator throats in a turbine The junction velocities must represent the maximum nozzle velocities if the critical flow model is to be used Hence the junction areas used in the TURBINE component should represent the average nozzle throat or minimum area for the stage group if proper critical flow modeling is desired Several of the input parameters needed may not always be easily o
75. 0 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 0000000 866 4 uot jounl N o 000U0D00000000000ooooo 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 qeozyy S O O 0 O O O 0 00 o o 000U 00000000000oouoooo E0 H4ZSGL9I6 0 3 09S v 0 3 E09S v 0 3LEO9S y 0 3L 09S v 0 3 09S v 0 3LEO9S y 0 3 09S v 0 3 E09S v 0 3 LE09S v 0 H 809S F 0 3LE09S v 0 3LE09S v 0 3 09S v 0 3 E 09S v 0 3LE09S v 0 3LEO9S y 0 3 09S v 0 3LE09S v 0 3LEO9S y zu ese unf o 000UPO0000000000000o0o00o0oso MOTJ ssew oo OO O 0 0 0 Q O QOO O O O OC O OQ oO CCC 0v 6L6 6 66v 6 v90 6 618 8 9 t LE c08 v T9S TE 890 6Z S969 8 DECESE 6908 9 S891 9 6 19 G 0966 y 26605 506 Then 0 89 T 065580 Das Bx O O O 00000000000000xo amp 6V 64 vI8 9c vLE SC 699 EZE 6vGS Ic 608 8 BLE TG OLE E 0916 zZ c8vE cC 068 9199 SLTS GLEE SEST SIS 8 0 IvVES 0 6L 6 0 8EZZT O S s u l9A C deA Q QO O O Q QO OS O oO oO Q OQ O O o o OQ o 096792 veov Ssc v6t vc 09v tc CUS CS 88S 072 9c1 81 IS vVI 8rS6 6 l6es c v99c c 6TL6 T OSL
76. 0 CNTRLVAR 2 The second example is to solve 2 1 10 0 t AnX A X A XX A x B xdt c 4 2 19 0 Assignment of control variables Y are made to derivative integral and product terms as listed below In addition each line shows equivalent expressions derived from algebraic manipulation and definition of an integral NUREG CR 5535 V2 4 10 RELAP5 MOD3 2 4 2 20 1 Y ed x CHA AY Aga CES 4 2 21 t t sane ia E ras 4 2 22 0 0 t t y gu frar B vs 4 2 23 0 0 t t Y fra z F P 4 2 24 0 0 The control components are defined by the rightmost expression Thus the third order nonlinear equation is defined by a multiplication an addition subtraction and three integration components Note that the above expressions cannot be rearranged so that all control variables are defined on the left before being used as operands on the right The above order is recommended for the current numerical scheme Assuming zero as the initial value for all the quantities no initialization and that the integral should be limited between zero and one no reason except to demonstrate the input input cards in the alternate format would be the following 20500010 XD1 X MULT 1 0 0 0 0 20500011 CNTRLVAR 3 CNTRLVAR 4 20500020 XD2 SUM 1 0 A 0 0 0 20500021 C CA CNTRLVAR 3 A j9 CNTRLVAR I 20500022 Ag CNTRLVAR 4 B CNTRLVAR 5 20500030 XD1 INTEGRAL 1 0 0 0 0 20500031 CNTRLVAR 2 20500040 X INTEGRAL 1 0 0 0 0 205
77. 00000 0 80 4SLTIZ 9 00 400000 0 80 3LS E99 L 00 400000 0 L0 N0v967 cC 600 6c 0 c8 0 vSIvVcC O 2 0 31c881 c LLTSE O ZO 4ELT8SD UY I9ITvL O 20 3816 E2 8 zz TZ 0c 61 000010400 000002900 000061900 000081900 hen a failure occurs it w d lagnostic e Figure 8 3 8 Example of printout buried in the d NUREG CR 5535 V2 8 25 RELAP5 MOD3 2 flecht seaset separate effects reflood calculation test 31504 100 strip fmtout 103 0 1001 httemp 6100407 1020 tempg 006040000 1030 voidg 006040000 1040 quale 006040000 1041 gammaw 006040000 1042 vapgen 006040000 1043 velg 006040000 1044 velf 006040000 1050 floreg 006040000 1060 htrnr 006040101 1061 hthtc 006040101 1062 htmode 006100401 end Figure 8 4 1 Strip input file For convenience to the user a check plot option is provided that will produce plots of input data such as for time dependent volumes and junctions general tables plot comparison data tables valve area and flow coefficients etc This option can be used by the input of the check plot general plot request cards The plots are constructed upon completion of the third phase of input data processing so that all information processed by the code will be included Once the option is activated it will remain in effect for all subsequent restarts and plot only jobs including restarts with renodalization until cancelled by the user with appropriate input
78. 000000 0 aubra v 9L 0 90 309899 G 6v It L9 Vvv9 Lv8e TOS 0000L0 33901 L00 0 0 00 0 00 00000 0 00 00000 0 00 300000 0 8T Z0S 000000 0 aubra v SL 0 90 48790L S 9962 89 Gt9 958 T0S 000090 33901 900 0 0 000 00 00000 0 00 H00000 O 00 H00000 0 8lI Z0S 000000 0 34161 v VL 0 90 HTTOSS S 616 TELES LS8 10S 0000S0 33901 S00 0 0 00 0 00 H00000 O0 00 00000 0 00 00000 0 8T Z0S 000000 0 aubra v ZL O 90 37919 G ELIZ ve EES S8 10S 0000F0 33901 v00 0 0 00 0 00 00000 0 00 00000 0 00 00000 0 8T Z0S 000000 0 JUSTA v IL 0 90 HZ9E0Z S LETS vO S6S 6v8 108 0000 0 3301 00 0 0 000 00 00000 0 00 H00000 O 00 H00000 0 8T Z0S 000000 0 aubra v L 0 90 HSLL90 S ELEC 9 909 08 TOS 0000Z0 33901 200 0 0 00 0 00 00000 0 00 00000 0 00 00000 0 8T Z0S 000000 0 JUSTA v cZL 0 90 3889cL LZOL 08 vt8 S 10S 0000TO0 33901 100 0 zu 13en zu 13eM 332m G0 epou nu xnij a3eeu uorqo Auoo uor3ao Auoo duea iequnu 34 AHO eorarao xnlg a3eeu 313 389y eoegans TOA A1pq apts 0U 1IS oes 000001 0 9Ur3 L dlLl O WH lO WLS LVHH LE sez3ax 441 eseo seq wetTqord edid 9 piempa we1bo1g srs euy JUBTOOD JO SSOT 107089Y ZRZHT E SAVIHA 00 3000 0 v0 408S b 0 4TZS 9 05560 9T 98 0 v89 v 0 000000 p 00 H000 O v0 349 Z 8 ZO H4G6S L 0296 vv009 0 98566 0 00006T 00 3000 0 rv0 3t6t v 20 3698 L 889v 08989 0 OZETE O 00008T 00 3000 0 F70 3968 9 ZO HT8
79. 000020900 904309678 0 46650 8 Z 90 4096765 e0 4660 8 Z 000010900 SO 06LSL Z 00 300000 0 GO HO06LSL 2 00 800000 0 000010800 sdd OA d A OUTOA soetqzedorzd 2 04 SunTon Ayaut3 300 04 0 otysoubetq aeas ou ADOTA ST T6S 28 019 29 99 CB EZE 28 628 89 TT6 68 166 T E Lot 6 v801 v 80II O LOTT LSO0T L LOOT Le 196 89156 LT GEB 85 ZEL ZE 969 vS 69G 87 70S 138 U93431TJ4A O OU JI187I89Y ST TSS ST T6S 28 019 28 019 29 99 29 99 c8 6cL c8 6cL c8 6c8 c8 6c8 89 TT6 89 TT6 68 T66 68 T66 T ELOT T ELOT 6 v801 6 v801 P 8011 P 8011 O LOTT O LOTT LS0T E LSOT L LOOT L LOOT 6196 LE TIG 89 TE6 89 TE6 LI SE8 LT SE8 8S CEL 8S CEL TE 969 ZE 969 vG 69G vG 69G 8v 20S 87 0S 998 00 4000000 0 m in mon o l l 600 800 L00 900 S00 v00 00 c00 T00 9UT3 IW 9 dhnOJIl xxxn xx deqs eur4 unururu YITM 10119 60020 orueu poUJX9UIlL xxxxxxxx XO XO XO XO tO tO XO XO tO XO XO tO XO XO tO tO O tO tO to hen a failure occurs it W d iagnostic e Figure 8 3 7 Example of printout before the d 8 24 NUREG CR 5535 V2 RELAP5 MOD3 2 89 2 G 98 0Lv SL89 v SI 89rv 8TTZ 1 T9 591 LTZ8 ZI RIT GLIP E 09 990 LS8V TO ELY LSS 0T v8 Orv 68 L86 8L 099 90 37v888v 98 EL9 90 H0997S TE S89 90 48TT09 LL 69 904 3816S89
80. 000070 66101 00 400000 0 ET 20S 89 SE9 00 400000 0 6S76 00 400000 0 T Z0S Latte 9 00 400000 0 19008 00 H00000 0 I c0S ve TZ9 00430000070 S bTTL 00 400000 0 ET 70S v0 S6S 00 400000 0 LEEZY 00 400000 0 II c0S 9 909 00 400000 0 0 916GS 00 H00000 0 S0 c0S 08 v 8 0043000000 v ZTZL a 338A 3364 2U 13 M duea3 a21nos a291nos AUOD T OO SAB TOA peI4Auoo 389Y UT 313 3e9u LO 0Z LT v6 28d 0 0 0 00 3000 0 00 H000 O 00 43000 0 0 0 0 00 3000 0 200 3000 0 00 43000 0 0 0 0 00 3000 0 00 43000 0 00 3000 0 0 0 0 004 3000 0 00 H000 O 00 3000 0 0 0 0 00 3000 0 00 H000 O 00 43000 0 0 0 0 00 4000 0 00 443000 0 00 000 0 0 0 0 004 3000 0 00 3000 0 00 43000 0 0 0 0 00 3000 0 00 H000 O 200 43000 0 0 0 0 00 4000 0 00 000 0 00 000 0 0 0 0 004 3000 0 00 H000 O 00 43000 0 0 0 0 004 3000 0 00 H000 O 200 43000 0 0 0 0 00 4000 0 00 443000 0 00 000 0 0 0 0 004 3000 0 00 4000 0 00 3000 0 0 0 0 00 3000 0 00 H000 O 00 000 0 0 0 0 00 4000 0 00 443000 0 00 000 0 0 0 0 004 3000 0 00 43000 0 00 3000 0 0 0 0 00 3000 0 00 H000 O 00 43000 0 0 0 0 00 4000 0 00 4000 0 00 000 0 0 0 0 00 3000 0 00 4000 0 00 3000 0 0 0 0 004 3000 0 00 3000 0 00 43000 0 T 303 3108 4SPT 73506 sap ou Cbuzog 3 42034 aun y 0 000 00 00000 0 200 4300000 0 00 H00000 0 8l Z0S 000000 0 3461 v 9L 0 90 HLS906S S 869 SV ERS 628 10S8 000080 33901 800 0 0 00 0 00 300000 0 00 4300000 0 00 H00000 0 8T Z0S
81. 000090900 000050900 000070900 0000 0900 000020900 000010900 000010800 4 1103 MA soonst 0 0 eubrs ow jop aTenb uozoq eienb uqop sienb I dteu Opet 3unoou 0 d98v L06 T1 32 Z0 dI9I89SS 9 setqzedorzd eanqxtw sunToA Ku ura 3noqurad orqsoubetg eqjeqs TESESESETESTESETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETETE 00 400000 0 0652 T s9 EvT LL89 0 25656 8 vEE9 L 6 8 S cc98 6 T0 H99 S06 6 Jn 90 HIZ99Z F TO HSGE6SD E 00 400000 0 00 400000 0 00 400000 0 00 400000 0 00 400000 0 00 400000 0 00 400000 0 00 400000 0 0000 T 0000 T 87666 0 87666 0 L0666 0 L0666 0 0L866 0 0L866 0 BPTOA 0 s62vt9v 6 JPTOA S0tdvcO6v G S0t dvcO6v G SO HpOZTE L SO HHEOZTE L SO uZZ PTE 8 SO 0ZVIEC 8 S0438S86S88 8 GO H876S8 8 bn 90 HSTLS9 Z 90 HSTLS9 Z 90 H78E09 C 90 3c8 09 2 90 HL8TZ9 Z 90 HL8TZ9 Z 90 HST6Z9 Z 90 3S816c9 c SO H06LSL Z SO H06LSL Z SO OIF6F 8 GO H7ZOP6D 8 90 I90IF I 90 H090Tb T 90 4T0LZ8 T 90 36 L28 T1 00 3000000 0 eTe 90 36820SS T d 0000T09 ou 10119 peu 7160 Aaaedoad eseud prinbIT xxxxxxxx 00 300000 0 S0 39 661 00 H00000 0 L0 3 809T 00 400000 0 LO 3TE 6EL 00 H00000 0 LO dA9DDOD E nb OA INTTEJ aaedoad OTURU PQUIDUL xxxx xx xx 00 400000 0 90 ATPEPL 6 00 4
82. 00041 CNTRLVAR 3 20500050 INT OF X INTEGRAL 1 0 0 0 03 0 0 1 0 20500051 CNTRLVAR 4 4 11 NUREG CR 5535 V2 RELAP5 MOD3 2 4 2 3 Shaft Control Component The shaft component is a specialized control component that computationally couples motor turbine pump and generator components analogously to a shaft mechanically coupling these devices The primary purpose for the shaft component is to couple multiple turbine hydrodynamic components to represent a multi stage turbine with steam extraction and liquid drain lines and to allow the turbines to drive a pump or generator Computations associated with the shaft are advanced in time in the same manner as other control components The shaft component evaluates the rotational velocity equation as Pla br zs f fios 4 2 25 where I is the moment of inertial from component i t is torque from component i f is friction from component i and T is an optional torque from a control component The summations are over the pump generator motor or turbine components that might be connected to the shaft and the shaft itself The rotational velocity is considered positive when rotating in the normal operating direction A torque is positive when it would accelerate the shaft in the positive direction In their normal operating modes motors and turbines would generate positive torque and pumps and generators would have negative torque Each component contains its own model data and storage for
83. 1 001 inside 0 00000E 00 21 001 outside 3 85866E 09 21 002 inside 0 00000E 00 21 002 outside 3 65601E 08 21 003 inside 0 00000E 00 21 003 outside 1 52705E 07 21 004 inside 0 00000E 00 21 004 outside 3 07263E 07 21 005 inside 0 00000E 00 21 005 outside 3 36703E 07 21 006 inside 0 00000E 00 21 006 outside 2 10397E 07 21 007 inside 0 00000E 00 21 007 outside 7 34253E 08 21 008 inside 0 00000E 00 21 008 outside 1 35699E 08 31 001 inside 0 00000E 00 31 001 outside 4 44638E 09 31 002 inside 0 00000E 00 31 002 outside 5 52415E 08 31 003 inside 0 00000E 00 31 003 outside 2 15746E 07 31 004 inside 0 00000E 00 31 004 outside 3 91791E 07 31 005 inside 1 83263E 07 31 005 outside 2 52239E 07 31 006 inside 0 00000E 00 31 006 outside 2 89031E 07 31 007 inside 0 00000E 00 31 007 outside 9 74868E 08 31 008 inside 0 00000E 00 31 008 outside 1 49986E 08 Total hydrogen generated 3 82445E 04 kg Str no gas gap clad radius ruptured pressure m m pa 21 001 07668E 04 6 15165E 03 no 1 25221E 07 21 002 04248E 04 6 15778E 03 no 21 003 02303E 04 6 16311E 03 no 21 004 01429E 04 6 16637E 03 no 21 005 01504E 04 6 16685E 03 no 21 006 02673E 04 6 16458E 03 no 21 007 05300E 04 6 16027E 03 no 21 008 09669E 04 6 15496E 03 no 31 001 04044E 04 6 14859E 03 no 4 13800E 06 31 002 00966E 04 6 15537E 03 no 31 003 9 81420E 05 6 16033E 03 no 31 004 9 61598E 05 6 16288E 03 no 31 005 7 39275E 04 6 80334E 03 yes 31 006 9 92277E 05 6
84. 1 shows examples of such printout which begins with the label CONTROL VARIABLE EDIT Four items are printed for each variable with two sets of information printed per line The four items are the control variable number NNN the alphanumeric name of the control variable the control component type and the value of the control variable at the end of the last advancement 8 3 2 17 Generator Information This section of output is not optional and always appears when a generator control component is present As discussed in Volume 1 the generator component is an optional feature of the shaft component As a result the first column under the GENERATOR label in the major edit is the control variable number NNN of the corresponding shaft component To the right of this under normal operating conditions is the torque exerted by the generator TORQUE Under normal conditions the torque will be negative since it is required to turn the generator The next quantity printed under normal conditions is the power applied by the generator INPUT POWER Again under normal conditions the power will be negative 8 3 3 Minor Edits Minor edits are condensed edits of user specified quantities The frequency of minor edits is user specified and may be different from the major edit frequency Figure 8 3 6 shows one page of minor edits The selected quantities are held until 50 time values are stored The minor edit information is then printed 50 time value
85. 3 data For actinide data the factor is the ratio of 2380 atoms consumed per 235U atoms fissioned but additional conservative factors can be applied Fission product and actinide data can also be entered by the user Earlier versions of the code did not include the G factor which is part of the 1979 standard This factor can now be optionally included and should be for long term transients The built in data for delayed neutrons fission products and actinides are recommended and are listed in the reactor kinetic input edit when used Use of the fission power plus fission product decay power is recommended as is actinide decay power if an appreciable amount of 238U is present The new standard is recommended because it is an approved standard and the variance between 1979 data and experimental data is much less than for the 1973 data The three isotope option is recommended unless the power fractions for each isotope are not available The reactor kinetics output lists total reactor power fission power decay power reactivity and reciprocal period Either the total power fission power or decay power can be specified as the time varying part of the heat source in heat structures 5 1 NUREG CR 5535 V2 RELAP5 MOD3 2 5 1 1 References 5 1 1 American Nuclear Society Proposed Standard ANS 5 1 Decay Energy Release Rates Following Shutdown of Uranium Fueled Thermal Reactors October 1971 revised October 1973 5 1 2 American National
86. 3738 LICA HOPVN 000 T 209 000 1 20S Des Tpe 001 303 Ape 3768 90T 21303 Ape 3TP9 70 Ape Tpe 60T 303 Ape oes 000001 0 Sout yj Se14Xeo YIM aseo sseq wetTqord edrd s piempa 7474T GdqVTIWH Figure 8 3 1 Example of major edit 8 6 NUREG CR 5535 V2 RELAP5 MOD3 2 0 0 e3o3 jqueadgnoo 0 0 3168 eonpea adu GO H SS0 9 90 BTS Sg04386811 6 90 BTS SO HH860L 8 90 BTS GO HETI8T S 90 BTS SOFH6LLHS L 90 BTS G0 966S8L 9 90 BTS SO HOLE98 S 90 BTS GO HSEFI9 F 90 Aqq S043081S8 2 90 Aqq GO H9FP9TO T1 90 3sy asy sy 38 3S4 3su 3s 3S4 sy 38 3sy T T MOTJ3 00 3000 0 puoo uo OESLT 90 v6TZT 90 S L816 SO 0 L2c08 SO T 989L SO v 8c9L SO v LL69 SO S L8 tS SO v 69ovt SO 8 T9LT SO 65095 1oden SprouAewx 00 I u oTqeqs Aqttenb Ayttenb 00 H000 0 00 H000 0 00 3000 0 00 H000 0 00 H000 0 00 H000 0O 00 H000 0 00 H000 0 00 H000 0 00 H000 0 00 H000 0 00 H000 0 00 H000 0 00 H000 0 20 3vZL 20 3010 2 c0 3t16 20 3t 8 20 392L 20 3019 20 aL9v 20 SLVT 0 H6vv G 0 3690 2 0 388L 0 480S 0 d9 0b 0 3SE v 0 0 0 0 303 11p3 queanoo uru TN86lLTI I Tdv699 G TdS6vct G T4L6SLC S 4759000 S HE060T S 3L8998 v TSIILLOS vV TALSCII 40S9 S T308TvS HGL720 T 9019951 6 HH9EZ0 8 WH9TSLV L 386c08 9 TICLOEE S 4 86S0 v T3c1868 c T46S8L8L T1 8LZ09 prnbrT AN gt
87. 38 3 62 3 06 7000 23000 0 23001 0 0 0 0 0 1 0 0 0 15 0 05 0 24 0 8 0 3 0 96 0 4 0 98 4 17 NUREG CR 5535 V2 RELAP5 MOD3 2 Table 4 2 1 Input data for a sample problem to test pump generator and shaft Continued 23002 0 6 0 97 0 8 0 9 0 9 0 8 0 96 0 5 1 0 1 0 23100 0 23101 0 0 17 0 0001 017 0 0006 0 0 0 1 0 0 0 15 0 05 23102 0 24 0 56 0 8 0 56 0 96 0 45 1 0 0 0 30000 loop2 pipe 30001 19 30101 0 0376 19 30201 0 0376 6 0 01 7 0 0376 18 30301 2 0 19 30601 0 0 4 90 0 9 0 0 14 90 0 19 30801 0 0 19 31001 0 19 31101 0 6 100 7 0 18 31202 3 2265 780 540 0 0 0 0 19 31301 0 0 0 18 40000 loop2 pump 40101 0 0468 0 0 1600 0000 40108 3010000 0376 00 0 40109 3000000 0376 0 0 0 40200 3 2244 78 540 0 0 40201 0000 40202 0000 403012220 15011 40302 3560 0 0 0 180 0 192 0 34 8 38 3 62 3 35 06 7000 46001 1440 1 00 2160 1 10 2880 1 50 46002 3526 2 80 3672 2 70 4320 1 90 46003 5040 1 20 5760 1 05 6480 1 00 46004 7200 0 98 end of first case two loops with pumps using shaft component 20301 10 2 1 101 20302 3560 0 0 66573 180 0 192 0 34 8 37 0 62 3 06 7000 20309 20 40301222 1 100 40302 3560 0 0 0 180 0 192 0 34 8 38 0 62 3 06 7000 NUREG CR 5535 V2 4 18 RELAP5 MOD3 2 Table 4 2 1 Input data for a sample problem to test pump generator and shaft Continued 40309 10 46001 46002 46003 46004 20500100 mtr trq function 47
88. 4 Differentiation DIFFERNI or DIFFERND dV 1 _ Y S t Or Y s SsV s 4 2 14 Use of DIFFERNI is not recommended and if possible any differentiation should be avoided See the discussion in Volume I of this manual 4 2 1 15 Proportional Integral PROP INT A t 2 Y s A v A v at Or Y s da 2 s 4 2 15 4 2 1 16 Lag LAG t SV Yi 1 Y A dt or Y s ism s 4 2 16 0 NUREG CR 5535 V2 4 8 RELAP5 MOD3 2 4 2 1 17 Lead Lag LEAD LAG 1 Ass t A SV SV I Y lt Ais oom dt or Y s S Vi s 4 2 17 Each control component generates an equation and together the components generate a system of nonlinear simultaneous equations The solution of the simultaneous equations is approximated by simply evaluating the equation for each component in order of increasing component numbers and using the currently available information Evaluation of algebraic control components uses only currently defined values but evaluation of components involving integration and differentiation use both old V and new yn values For time advanced variables other than control variables both the old and new quantities are available If a control variable is defined by appearing on the left side of an equation before it appears on the right side the correct old and new variables are available If a control variable appears on the right side before it is defined or
89. 4536282 0 0 20500101 entrlvar 10 10 20500200 trip tripunit 1 0 1 00 20500201 501 20500300 torque mult 0 7375621495 0 0 20500401 cntrlvar 3 20501000 shaft4 shaft 1 0 0 0 0 20501001 3 0 3 0 0 pump 4 20201000 reac t 0 0 10471975512 1 0 20201001 1440 0 1 00 2160 0 1 10 2880 0 1 50 20201002 3528 0 2 80 3672 0 2 70 4120 0 1 90 20201003 5040 0 1 20 5760 0 1 05 6480 0 1 00 20201004 7200 0 098 20502200 shaft2 shaft 1 0 2370 0 1 20502001 0 1 0 0 0 pump 2 generatr 20 20502006 1800 0 2370 0 0 3 0 0 501 0 end of job 4 19 NUREG CR 5535 V2 RELAP5 MOD3 2 NUREG CR 5535 V2 4 20 RELAP5 MOD3 2 5 REACTOR KINETICS The reactor kinetics capability can be used to compute the power behavior in a nuclear reactor The power is computed using the space independent or point kinetics approximation which assumes that power can be separated into the product of space and time functions This approximation is adequate for those cases in which the space distribution remains nearly constant Reactor kinetics data may be entered for new or restart problems In restart problems reactor kinetics data completely replaces previous reactor kinetics data 1f present thus all needed data must be entered even if they duplicate existing data 5 1 Power Computation Options Data for the six generally accepted delayed neutron groups are built into the code Optionally yield ratios and decay constants for up to 50 groups may be entere
90. 9 Single phase vapor convection or supercritical pressure with the void fraction greater than Zero Mode 10 Condensation when the void is less than one Mode 11 Condensation when the void equals one If the noncondensable quality is greater than 10 20 is added to the mode number If the structure is a reflood structure 40 is added Thus the mode number can vary from 0 to 71 Generally the hydrodynamic volume will not be a time dependent volume Caution should be used in specifying a time dependent volume since the elevation and length are set to zero and the velocities in an isolated time dependent volume will be zero Note that the current version of the code does not allow an isolated standard or time dependent volume Users now have the option to be more specific about the type of hydraulic cell a heat slab is next to Most of the default heat transfer coefficients originate from data taken inside vertical pipes Users can now specify that the fluid is flowing in a vertical or horizontal rod or tube bundle or below a flat plate When modelling a vertical bundle the rod or tube pitch to diameter ratio should be input This has the effect of increasing the convective part of heat transfer such that users can input the true hydraulic diameter and get reasonable predictions Other boundary condition options that can be selected are setting the surface temperature to a hydrodynamic volume temperature obtaining the surface temperature from
91. 90 3c0IvVI cC 90 H0CS0C S 90 J0vvvc c 90 dIv6S7 C 90 HELIIT TS 90t dv8SL2 7 90 465198Z Z 90 H6v8672 Z 90 H69ETE Z QO HZETEE T QO HEEESE TS 90 49006 Z 90 H8SPER TS 90 H40Z218D Z 90 HE7009 S 90 H07P6S 2 90 H7668S C 90 HS9S8S 7 90 H7808S 4 90 H868LS5 C 90 4LE68S Z 90 3L0c09 2 90 388vI9 7 90 HTZLE9 Z 90 HLOZS9I Z 90 HSLPS9 S 90 499959 C 90 8901859 90 468859 Z 90 H8TSS9 TS 90 H88SE9 2 90 H8086SS C 90 HTTODO Z 90 H90S506 90 H00000 L ed 000001 90 6SS 8 TI 90 ZSL8 T 90 30S1 6 T 90 H88SL6 T 90 4T0S00 C 90 HE9870 S 90 36LcS0 2 90 HE Z980 Z 90 H9PZHT Z 90 HOEEZZ Z 90 H68 6Z Z 90 HZL9OTE Z 90 HLOBEE Z 90 HEZDLE Z 90 HS99ED Z 90 H9THZS Z 90 HZT6ES Z 90 055099 0 9044228296 90 6 LZLS Z 90 S LI8S Z 90 H98L8S C 90 8 TI 8S TS 90 36vL8S C 90 3LLT6S c 90 3L2c6S8 c 90 498L8S Z 90 3 ECV8S C 90 31186S8 2 90 H0Z8T9 Z 90 H698 9 Z 90 38L85S9 2 904 3908S89 c7 90 47S6S59 C 90 H00099 Z 90 H4826659 Z 90 4809659 Z 90 490919 Z 90 H6T08 Z 90 H6 v6b T 90 39106S8 G 90 H00000 L ed 0000S0 90 388928 1 90 H8SSL8 T 90 HS67E6 I 90 HE08L6 T 90 488500 Z 90 HS7870 S 90 3688v0 2 90 HZLL90 Z 90 468L60 Z 90 49089T Z 90 HL980 Z 90 HSTOOS ZS 90t d6LLIS c 90 d39vcES C 90 HE997S C 90 H98TSS ZS 90 31009S8 7 90 WOT LS Z 90 0066 9 904 388c8S8 C 90 30v98S 7 90 400065 Z 90 H0 Z85 Z 9O HEEIBS TS 90 H8
92. Aetpdtz4 uqoujpas pu jzjjJIp Terbequt TUS1JJITO ATP 3Inu 6lv G vT ZOS 91 Z0S LT ZOS LT ZOS 8T Z0S 8T Z0S 8T Z0S 8T Z0S 81 c0S 81 0S 139 b z 0 9 r c 7619 9 SQ ZUS OT ZOS ET 20S ST OS 91 c0S LT ZOS LT OS LT ZOS LT ZOS LT ZOS Z OU 31001 u93314M 601 ou 1I18IS89Y v0 H000005 Z 119p993 l39peej 505 wee ys vov 0 4000000 T T3odund Tqodund 805 20402 205 00 4000000 0 3ueisuoo uoo TO 06732 506 8 6 89 0 ber peer 0 T32 0 06132 ZOE 000ST Z 3ur doad TOETIO TOE 06132 00 00000 0 xzemod LOZl39 LOZ 02132 9028 00000Z 0 T1Smod S0Z2139 soz 02132 voc 00 4000000 0 qundaq 02139 EOZ 00132 208 00000 uor3aoung TOZTID TOZ 66132 66 10 3000000 I TUSIJITP STT ST PITH vI 0 H000000 S Tezp qur ETTI I ZIT ZI 96Z00 T ATP 01132 TE 01132 OT LG9 8ZZ 3Tnu 6732 S pT v 90 HZ0 985 Z uns TT T oes 000001 0 9uTA 3e 13708 e qeraeA TOIJUOD 00 800000 0 06955 65108 989L 8 901 6 86I2 6 100 002 81 20G6 S8 TOS 6 TOS 8v 00G 88 86v 9b 96b 020 0 81 20G S6 TOS 8S 10S 6L 00G 62 66v S8 96v 610 0 81 20G Z0 70S bL TOS 80 10S ZL 66P EE L6b 810 0 81 20G 80 Z0S 88 TOS SE TOs 9T 00S 98 L6v LTO 0 81 Z0S ZI ZOS 86 T0S 6S TOS T9 00S LV 865 910 0 81 20G vl cO0G So 20S 6L TOS v0 I0G Ll1 66V SI0 0 81 20G SI 20S 01 Z20G S6 TOS LV 10G 00 00S v10 0 81 ZOS 91 c0S ZI ZOS 0 ZOS 6L TOS
93. E6 OT ZES TZ 06v 6686 9v 8 Z 0006 8S00 T SEPTETO 68 9 c 9v9 6L 198 I 016 T 8601 T 8601 L8 z88 9E GEB 78 60S S9 GcG 21 88v S6 8v 99 LE9 69 069 LT TL8 I cI6 801II 9 LOTT v8 88 GS SE8 T6 LCS TL EZS 20 98 v8 l8v 01 6S9 06 2v6 S vLOT 89 v8L 8v lcGS 8L 6Lv SB 699 2 CS6 L TEOT EZ v8L ES 6TS S9 LLV 96 vL9 9v vL6 6 0SOT 16 L Te LTS T9 SL ev 089 ZE 66 8 LSOT 76 L ve SIS OP ELT 15069 9T0I Z LZOI 20 969 PU EES Sv ILV 00 L69 6 ZEOT O ETOT L v69 9I IIGS 62 69v M seanaeaedue43 qurod useu Tetxe soejans 8162 T9DZ E CELTE 81S9 c 8828 I VLEL I OvvI6 0 96cc8 0 c0091 0 688v1 0 vooc e 09S c 69569 cSTIEL O 9ILET O LESTE 689v c SPOS STE 800079 0 ELSZT O 060T E FELCE G 0695 1 v98vS 0 O vII O L8201 0 ZO 400bbT 6 20 300100 8 20 300888 9 c0 300SIL S ZO H00ZLS b cO 3006cv 20 300982 c ZO H00 PT T 00430000070 00 400000 0 u uorarsod du qa 3T19 w woz OG ST 0 0 vT S9L PE SSS OD OD duea3 duea3 buraa n a 99S ZO 4918955 9 Teorarzo Vl OIG 1 duis 31608 Trog euc3 Je 3708 poorgeu 65 EST umurxeu OUT 4equnu s pou erxe JUSTA T9 33 T I9 eprs pue ou uoeb us u erxe jo uorarsod quesoala T9 ou uoeb Figure 8 3 3 Example of reflood major edit NUREG CR 5535 V2 8 19 RELAP5 MOD3 2 Str no side penetration depth m 2
94. EMENTS oo cee eeccsecseceseceseceseeeseeeaeecsecesecsseceseesaeeeaeeeaecaeenseenseesaes A 1 APPENDIX B EXAMPLE OF A DIAGNOSTIC EDIT enn enne B 1 vii NUREG CR 5535 V2 RELAP5 MOD3 2 NUREG CR 5535 V2 viii RELAP5 MOD3 2 FIGURES 2 1 1 Possible volume orientation specifications 2 4 2 1 2 Volume schematic showing face numbers 2 5 2 1 3 Sketch of possible coordinate orientation for three volumes and two JUDICES asus cte Causa Su nas a qon eua S musasasa Dated 2 7 2 1 4 Sketch of possible vertical volume connections 2 7 2 2 1 A 90 degree tee model using a crossflow Junction 2 14 2 2 2 Tee model using a branch component 2 14 2 2 3 Typical branching junctions e oce a coena ts riadas idoneidad 2 15 2 2 4 Plenum model using a branch 2 1 e e cesscacasveccevenndceds nota ados 2 16 2 2 5 Leak path model using the crossflow Junction 2 17 2 2 6 High resistance flow path model 2 18 2 3 1 Four quadrant head curve for Semiscale MOD1 pump ANC A 2083 2 36 2 3 2 Four quadrant torque curve for Semiscale MODI pump ANC A 3449
95. G 98 0L vL89 yv ST 89D LTIZ 1 19997 91c8 79 E90 ELIP E 08 99rv IS8v 66 2LVv 6 8 TT v8 0F 68 L86 4 tes dd z 6 v 9 90 HT6LSE E vE Lv9 90 HZ6EZD E 8L 099 90 39888v 98 EL9 90 HZ99DS T S89 90 H07T09 LL 069 90 322689 S8 POL 90 318cL9 CE LOL 90 dSvvVL6 V 98l vc 90 3L902L c 8 LEST dppusp s onsr 00 400000 0 00 300000 0 EE 60 1988 0 0 S3PSLOT I 004300000 0 ZO HESSOL E 0 L 6 0000 606660 00 H00000 0 00 00000 0 0 L 6 ZTL98 0 v0 4LS090 6 00 4300000 0 ZO H8TOLL 67D ZZ 0000 6726660 004300000 0 00 4300000 0 60500 Ss89L8 0 F0 d L9F L 00 300000 0 ZO H6ZZ 8 eee 61 0000 6 666 0 00 4300000 0 00 400000 0 BEE ST 65 88 0 70 009 80 9 004300000 0 20 392 68 vVIZ 81 0000 cS8666 0 00 300000 0 00 4300000 0 PTZ 81 68006 0 FT0 36cSI8 Fv 00 4300000 0 ZO HLTOS6 666 vl 0000 19666 0 004300000 0 00 00000 0 666 vI 6vPII6 0 Fv0 3S89L8 00 300000 0 2Z0 3S9766 SE L9 8 0000 L666 0 00 4300000 0 00 400000 0 SELJE 00660 PO HGZLES Z 00 8400000 0 20 30 0 6 Tp 96 0000 6666 0 00 300000 0 00 300000 0 Ty 96 6L086 0 SO0 H6Z60Z L 00 H00000 O0 CO APEDSL C CL ODT 0 dS667S 6 7S066 0 004300000 0 00 4300000 0 cl 9vI Sc002 0 0 SIvE9v 6 00 300000 0 Z0 HSE697Z S 00 300000 0 vOSST 0 00 300000 0 00 H00000 O0 00 00000 0 00 300000 0 00 H00000 0 0000 1 ouozoq eubrs ouqop renb bpr
96. It is assumed that each plot must be uniquely identified and hence the run time date and code version is written in the plot margin oriented to appear on the edge that would be placed in a notebook binder The plot heading and title are written at the top of the plot and the axes labels and titles are written parallel to the left hand and bottom axes In addition the curves plotted must lie within the axes extremities and yet span as much of the axes as possible The axes labeling subdivisions are also rounded to the first significant digit in order to produce simple labels Results can be plotted for any NEW or RESTART run In addition a PLOT run can be performed for which plots can be made of any variable stored in the plot record on the restart plot file Plot input is analogous to the component input for NEW and RESTART problems in that once plot requests have been input the resultant plot records and plot comparison data records are written to the restart plot file Hence only input to delete replace insert or add plot requests is required for successive RESTART or PLOT runs In addition undefined results are not plotted for components added or deleted by renodalization Some user inconvenience is apparent for input of plot comparison data tables because this input must be in an 80 character card image and must be part of the user input stream If each data table is reasonably small the user may manually produce the card images on a t
97. L T CATAT ZOST Tl VESZT vLOO T vVSIVL O 6186F 0 018Sc 0 26974 Teal BTT oO O S QO 0 0 Q CO GO OO SO o c O oo OO Oo Q O O QO 000 O OO oO o o0 oo cu 00010 S 0000c 00061 00081 000L1 00091 000SI 000v1 OOOET E 000ZT OOOTT 00001 00060 00080 000L0 00090 000S0 000F0 000 0 000Z0 lO oq er TI TE I Ooo0oo000 s vo Z0000Z 000000 b unfious Apqaua 200061 00006T 200081 000081 ZOOOLT 0000LT ZO009T 00009T ZOOOST E 0000SI ZOOOPT E 0000vI ZOOOET E 0000 T 2000c1 0000ZT ZOOOTT 0000TT ZO000T 00000T 200060 000060 Z00080 000080 2000L0 0000L0 200090 000090 ZO00SO0 0000S0 ZOO00PO E 0000v0 ZOOOEO E 0000 0 Z000Z0 0000Z0 ZO00TO 0000TO edid s paewpe TOA 40234 ou unp x 9UOUX I u aqas s 0 000010 S 0 00000c 0 00006T 0 00008T 0 0000LT 0 00009T 0 0000ST 0 0000vI OOOOET E 6 0000ZT S OOOOTT c 000001 T 000060 0 000080 0 0000L0 0 000090 0 0000S0 0 0000v0 0 0000 0 Figure 8 3 1 Example of major edit Continued 8 8 NUREG CR 5535 V2 RELAP5 MOD3 2 00 400000 0 I c0S Z TES 00 400000 0 6L80T 00 400000 0 I c0S L9 vv9 00430
98. OCSIV v0 3S582c6 cC v0 38 8Sv C v0 369vv0 c v0 3 80L9 T v0 36c2 0 T1 00 H00000 0 00 300000 0 00 H00000 0 000010 sTenb 90 H9867L T 90 H7986L T 90 3907v8 1 90 320868 1 90 3Lv0LG6 T 9O HLEISO TS 90 HS99ZT Z 90 H8vE9T Z 90 H7908T ZS 90 59061 lt 90 dv 66T c 904 398807 2 90 39281c 7 90 HDZLZZ Z 90 3L SEZ C 90 439 2vc 7 90 dE 8v2 C 90 dcSt S2 C QO HLT8SC C 90 H08797 C 90 HS8L9Z Z 90 HL6ZLZ Z 90 HZG6LZ Z 90 4pLT18Z Z 90 32616c c 90 3v8162 c 90 32810 c 90 36cLTE 7 90 46 92 2 QO HPVEESE ST 9O HSE9LE TS 90 0 6F ZS 90 4088TS Z 90 Wp0S S Z 90 3908 S 2 90 dv9S2S8 C 90 4SL86b Z 90 HZ6S9D Z 90 H9TZSD Z 90 HLTLTS Z 90 H0ESZI Z 90 400000 L ed 000002 90 3L2 6L 1 90 3cECV8 T 90 3 E9888 T1 90 HSS6E6 T 90 468866 T 90 3866S0 2 90 HTEZZT Z 90 H999LT Z 90 H6P90Z Z 90 HLLOZZ Z 90 HPZ6ZZ Z 90 8SL Z C 90 LF9P2Z Z 90 380SS2 C 90 HP9E9Z Z 90 H4S8TLZ Z 90 3vS6L7 C 90 3 60L82 2 90 3EE v6cC 7 90 HSSTOE S 90 32601 7 90 30 vcE C 90 3vLTIVE C 90 3LIc9 7 90 36196 7 90 H06ESD Z 90 HOSE6b Z 90 HLTZO9 Z 90 36 L6S8 2 90 3v6c09 2 90 3 6c9 c 90t 369vv9 7 90 3S8G6S879 C 90 3L8vV9 c 90 3819v9 2 90 HLOTS9 Z 90 HTOSS9 Z 90 3LvGG9 C 90 3189v9 C 90 H00SES Z 90 HO0P9E9 Z 90 H00000 L 60 0000STE 90 4 8bT8 T 90 H8L0L8 T 90 3E8916 T 90 310896 1 90 318700 c 90 HE TODO Z 90 3c0 80 2
99. RELAP5 MOD3 2 NUREG CR 5535 INEL 95 0174 Formerly EGG 2596 Volume ll RELAP5 MOD3 CODE MANUAL VOLUME Il USER S GUIDE AND INPUT REQUIREMENTS The RELAP5 Code Development Team Manuscript Completed June 1995 Idaho National Engineering Laboratory Lockheed Idaho Technologies Company Idaho Falls Idaho 83415 Prepared for the Division of Systems Research Office of Nuclear Regulatory Research U S Nuclear Regulatory Commission Washington DC 20555 Under DOE Idaho Field Office Contract No DE AC07 941D13223 FIN W6238 NUREG CR 5535 V2 RELAP5 MOD3 2 NUREG CR 5535 V2 RELAP5 MOD3 2 ABSTRACT The RELAPS code has been developed for best estimate transient simulation of light water reactor coolant systems during postulated accidents The code models the coupled behavior of the reactor coolant system and the core for loss of coolant accidents and operational transients such as anticipated transient without scram loss of offsite power loss of feedwater and loss of flow A generic modeling approach is used that permits simulating a variety of thermal hydraulic systems Control system and secondary system components are included to permit modeling of plant controls turbines condensers and secondary feedwater systems RELAP5 MOD3 code documentation is divided into seven volumes Volume I provides modeling theory and associated numerical schemes Volume II contains detailed instructions for code application and input data pr
100. S 9 G 66 IvvLS O 6SGcv 0O 0000LT 00 3000 0 0 4HEZZ T 20 3209 08660 9I1LSS 0 v8cvv O 000091 E 00 3000 0 0 46SZL Z ZO 4HTE9 80019 Z89 5 0 eTe9vb 0 0000ST E 00 4000 0 0 HSL7 6 20 3899 SO HT9Z00 Z 0605 0 L606b 0 0000pT 00 H000 O0 ZO HETO Z 20 30cL S0 3c8800 2 SS6 v 0 Sv09S 0 0000 ET 00 3000 0 20 309L c 20 3996 90615 9029c 0 V6L L 0 0000ZT 00 H000 0 EELU c0 UHS9L v CEL ST 8S TI IO vVvc88 0 0000TT 00 H000 0O LLl O Z O H8LE E GILER S6201 0 S0L68 0 00000T 00 H000 0 cIC 0 c0 HE8V ESIS E 20 309v18 8 S8116 0 000060 00 H000 0 9 2 0 Z20 SvVS Lt V0 9 20 3ISEST 8 91916 0 000080 00 3000 0 6vc 0 20 S3vC9 E 69S TL 20 30 0 7v 8 OLST6 O 0000L0 00 H000 0 Ero Oo Z20 SdSCL E EV STE 20 3L0 82 6 LILOG O0 000090 00 4000 0 2Z 0 20 3c98 66865 SI601 0 98068 0 0000S0 00 3000 0 8722 0 ZO 4LLO p TOL IE 9c671 0 VLOL8 O 0000F0 00 H000 0 5900 ZO H4E0P 1 999 81 16980 69 98 0 0000 0 00 8000 0 VSZ O ZO 4LZ9 p L6S vv ILOII O 62688 0 0000Z0 00 H000 0 867 0 ZO0 HLS0 9 180 LL9ZT O c L8 0 000010 qu zs u Junf y tereng C3Tem3 Cty oppos 3proaA ou unp Figure 8 3 1 Example of major edit Continued NUREG CR 5535 V2 8 9 RELAP5 MOD3 2 98 8 TES eb ss L9 8L 88 86 90 c TLS CES aes ETZ OS OS 0S 09 OS 0S 09 OS 0S OS OS 0S 005
101. S68S C 90 HS026S 7 90 H9768S C 90 3LLS8S C 90 36996GS 2 90 HLZITI Z 90 H6LSE9 Z 90 H7 2959 7 90 H9 099 Z 90 J0vvV99 c7 90 3965899 2 90 HLZELI Z 90 HTEGLI Z 90 3 0919 2 90 H8TT96 T 90 JIvVLE T 90 S6S60 9 904 300000 ed 000010 000066 0 000086 0 000016 0 000006 0 000062 0 000082 0 0000L2 0 000092 0 0000S2 0 0000b2 0 000060 0 000000 0 000016 0 000008 0 000061 0 00008 0000L 00009 00009 00005 0000 00008 00001 00000 20 3000000 6 20 3000000 8 20 3000000 L 0 3000000 9 20 3000000 S Z0 4000000 b 0 3000000 20 3000000 c 20 3000008 I Z0 4000009 T 20 300000v I 20 3000002 I Z0 4000000 T 0 3000000 8 0 4000000 9 0 4000000 P 0 3000000 2 007300000070 QO QUO GO OQ O 0 10 GO oes eura Figure 8 3 6 Example of minor edit 8 22 NUREG CR 5535 V2 RELAP5 MOD3 2 UF noncondensable quality QUALA liquid void fraction VOIDF and vapor void fraction VOIDG Further information on the specifics of the thermodynamic property failure such as in which phase the failure occurred is usually printed This particular printout using the semi implicit hydrodynamic scheme 1s located between the EQFINL and STATE diagnostic printouts No MASS ERROR diagnostic occurs for this failure Failures that result in a diagnostic edit with HELP 1 can be grouped into two cases The first case occurs when the user is responsible The thermodynamic property erro
102. Section 2 1 The junction coordinate direction is from one volume end to another volume end and the input description use the words FROM and TO to identify the connections If a junction is reversed the sign of the vector quantities associated with the junction are reversed To maintain the same physical problem no further changes are needed in other components The initial velocities in reversed system junctions or time dependent velocities in time dependent junctions should also be reversed 2 27 NUREG CR 5535 V2 RELAP5 MOD3 2 Two quantities the junction area and the junction area ratio are defined from the user supplied junction area These are printed in the major edit as JUN AREA and THROAT RATIO Junctions can connect two volumes with possibly different volume flow areas and the junction can also have a different flow area Two options are provided for calculating area change effects as the fluid flows through the upstream volume flow area the junction flow area and the downstream volume flow area The smooth area change option uses only the stream tube form of the momentum equation that includes spatial acceleration and wall friction terms This option should be used when there are no area changes or when the area changes are smooth such as in a venturi There are no restrictions on the user supplied junction area for smooth area changes and the junction area may be smaller than larger than or between the adjacent volume flow area
103. UE pump octant number OCTANT and torque generated from the pump motor MTR TORQUE These terms are discussed in Volume 1 For an accumulator four additional quantities are printed These are the volume of liquid in the tank standpipe surge line LIQ VOLUME the mass of liquid in the tank standpipe surge line MASS the liquid level of water contained in the tank standpipe surge line LEVEL and the mean tank wall metal temperature WALL TEMP These terms are discussed in Volume 1 and in Section 2 of this volume For a turbine four additional quantities are printed In the normal operating mode these are the power extracted from the turbine POWER the torque extracted from the turbine TORQUE the turbine rotational speed SPEED and the efficiency factor used to represent nonideal internal processes EFFICIENCY These terms are also discussed in Volume 1 and in Section 2 of this volume ipump pump rpm 125 22 rad sec head 0 5911SE 06 pa torque 0 10090E 06 es octant 2 mtr torque 0 10090E 06 n m snglaccm accum lig volume 24 404 m3 mass 24167 kg level 19 028 m wall temp 322 18 K stage3 turbine power 1 75174E 08 watt torque 0 30571E 06 n m speed 573 00 rad sec efficiency 0 62945 Figure 8 3 2 Example of additional output for pumps turbines and accumulators 8 3 2 5 Hydrodynamic Volume Information Second Section This information appears in every major edit if noncondensable species we
104. a control variable The time dependent volume is connected to the system through a normal junction thus inflow or outflow will result depending upon the pressure difference Several precautions are needed when specifying a pressure boundary since flow invariably accompanies such a boundary First the time dependent volume conditions must represent the state of fluid that would normally enter the system for an inflow condition Second there are implied boundary conditions for a time dependent volume in addition to the specified values Third only the static energy of an incoming flow is fixed by a time dependent volume The total energy will include the inflow Kinetic energy that increases with increasing velocity The additional boundary conditions represented by a time dependent volume concern the virtual viscosity terms inherent in the numerical formulation of the momentum equation see Section 3 in Volume I for a detailed discussion For this purpose the derivative of velocity across the time dependent volume is zero and the length and volume are assumed to be zero regardless of the specified input The fact that the energy of inflow increases with velocity can lead to a nonphysical result since the stagnation pressure also increases and for a fixed system pressure an unmitigated increase in inflow velocity can result This effect can be avoided by making the cross sectional area of the time dependent volume large compared to the junction s
105. a nuclear plant analyzer Specific applications have included simulations of transients in LWR systems such as loss of coolant anticipated transients without scram ATWS and operational transients such as loss of feedwater loss of offsite power station blackout and turbine trip RELAPS is a highly generic code that in addition to calculating the behavior of a reactor coolant system during a transient can be used for simulation of a wide variety of hydraulic and thermal transients in both nuclear and nonnuclear systems involving mixtures of steam water noncondensable and solute The MOD3 version of RELAPS has been developed jointly by the NRC and a consortium consisting of several countries and domestic organizations that were members of the International Code Assessment and Applications Program ICAP and its successor organization Code Applications and Maintenance Program CAMP Credit also needs to be given to various Department of Energy sponsors including the INEL laboratory directed discretionary funding program The mission of the RELAP5 MOD3 development program was to develop a code version suitable for the analysis of all transients and postulated accidents in LWR systems including both large and small break loss of coolant accidents LOCA s as well as the full range of operational transients The RELAP5 MOD3 code is based on a nonhomogeneous and nonequilibrium model for the two phase system that is solved by a fast partially imp
106. a temperature versus time table obtaining the heat flux from a time dependent table or obtaining heat transfer coefficients from either a time or temperature dependent table For the last option the sink temperature can be a hydrodynamic volume temperature or can be obtained from a temperature versus time table These options are generally used to support various efforts to analyze experimental data A factor must be entered to relate the one dimensional heat conduction representation to the actual heat structure Two options are available for entry either a heat transfer surface area or a geometry NUREG CR 5535 V2 3 4 RELAP5 MOD3 2 dependent factor For rectangular geometry the factor is the surface area there is no difference in the options In cylindrical geometry the heat structure is assumed to be a cylinder or a cylindrical shell and the factor is the cylinder length For a circular pipe where a hydrodynamic volume represents the flowing part of the pipe and a heat structure represents the pipe walls the factor equals the hydrodynamic volume length For a hydrodynamic volume representing a core volume with fuel pins or a heat exchanger volume with tubes the factor is the product of the hydrodynamic volume length and the number of pins or tubes In spherical geometry the heat structure is assumed to be a sphere or a spherical shell and the factor is the fraction of the sphere or shell For a hemisphere the factor would be 0 5 Except
107. accumulate unrealistically since it cannot leave the system In a simple pipe modeling application a time dependent volume and junction can be used to specify the inlet flow Likewise a time dependent volume and junction can model the feedwater flow into a reactor steam generator Controlling the fluid flow out of the pipe or controlling the water steam flow out of the steam generator through a time dependent junction is not recommended If a system junction flows computed by the simulation rather than specified as boundary conditions connected to a time dependent volume is not sufficient perhaps a servo valve can provide the required simulation 2 3 4 Single Volume Component A single volume component is simply one system volume A single volume can also be described as a pipe component containing only one volume This single volume component uses fewer input cards and fewer data items than does a pipe component However if the single volume might be divided into several volumes for nodalization studies we suggest the pipe component since such changes are quite easy for pipes 2 3 5 Single Junction Component A single junction component is simply one system junction It is used to connect other components such as two pipes Initial junction conditions can be phasic velocities or phasic mass flow rates 2 31 NUREG CR 5535 V2 RELAP5 MOD3 2 2 3 6 Pipe A pipe component is a series of volumes and interior junctions the number of junctio
108. acts both as an actuation set point for opening a closed valve and as a closing force for closing an open valve For the flow controlled valve the back pressure acts only as an actuation set point for opening a closed valve 2 3 10 2 Trip Valve The trip valve is also an on off switch that is controlled by a trip such that when the trip is true 1 e on the valve is on 1 e instantly and fully open Conversely when the trip is false i e off the valve is off i e instantly and fully closed Since trips are highly general functions in RELAPS and since trips can be driven by control systems the on off function of a trip valve can be designed in any manner the user desires The user should remember however that trips control systems and valves are explicit functions in RELAPS and hence lag the calculational results by one time step 2 3 10 3 Inertial Swing Check Valve The inertial valve model closely approximates the behavior of a real flapper type check valve To direct the model to neglect flapper mass and inertial effects the user simply inputs the flapper mass and moment of inertia as small numbers Flapper open angles are positive in the positive junction flow direction The code assumes that gravity always acts in the vertically downward direction so that gravity can act to either open or close the valve depending on the implied junction direction The minimum flapper angle must be greater than or equal to zero 2 3 10 4 Moto
109. added to VAR2 before comparison and either L or N is used to indicate a latched or unlatched trip TIMEOF is the optional initialization value A special form NULL O is used to indicate that no variable is to be used VAR2 must be NULL O if VARI is to be compared only to the constant Either VARI or VAR2 may also be TIMEOF trip number The trip number may refer to either a variable or a logical trip Three examples of variable trips are 501 P 3010000 LT NULLO 1 545 N 502 P 5010000 GT P 3010000 2 045 N 510 TIME O GE NULL 0 100 0 L Trip 501 Is the pressure in volume 3010000 1 5 bar 1 bar 10 Pa Trip 502 Is the pressure difference between volumes 5010000 and 3010000 2 0 bar Trip 510 Is the current advancement time gt 100 s Use of the equal EQ or not equal NE operator should be avoided because fractions expressed exactly in decimal notation may not be exact in binary notation As an example assume a time step of 0 01 After ten advancements the time should be 0 10 but an equality test of time equal to 0 10 would probably fail An analogous situation is dividing 1 by 3 on a three digit decimal calculator obtaining 0 333 Adding 1 3 three times should give 1 000 but 0 999 is obtained NUREG CR 5535 V2 4 2 RELAP5 MOD3 2 4 1 2 Logical Trips A logical trip evaluates a logical statement relating two trip quantities with the operations AND OR inclusive or XOR exclusive Table 4 1 1 defines the logical operations
110. al processing A pump component includes data defining pump head and torque characteristics for single phase and two phase conditions as a function of pump angular velocity A pump component requires additional processing to advance the differential equation defining pump angular velocity A valve component requires additional data defining its characteristics and additional processing to calculate the junction flow area as a function of valve position Components are numbered with a three digit number 001 999 Components need not be in strictly consecutive order so that changes to a model of a hydrodynamic system requiring addition or deletion of NUREG CR 5535 V2 2 24 RELAP5 MOD3 2 components are easily made Volumes and junctions within a component are numbered by appending a six digit number to the component number cccxxyyzz The ccc is the component number At present yyzz are zeros and xx is numbered consecutively starting at 01 for the volumes and junctions in the one dimensional components presently defined 2 3 1 Common Features of Components Each volume s flow area length and volume must be supplied as input As noted above each one dimensional volume has a x coordinate direction along which fluid flows in a positive or negative direction and may have y and z coordinate directions if crossflow connections are made to the volume The x volume flow area 19 the volume cross sectional area perpendicular to the x coordinate directi
111. all system modeling capability a control system model is included This model provides a way to perform basic mathematical operations such as addition multiplication integration and control components such as proportional integral lag and lead lag controllers for use with the basic fluid thermal and component variables calculated by the remainder of the code This capability can be used to construct models of system controls or components that can be described by algebraic and differential equations The code numerical solution includes the evaluation and numerical time advancement of the control system coupled to the fluid and thermal system 1 1 NUREG CR 5535 V2 RELAPS MOD3 2 The hydrodynamic model and the associated numerical scheme are based on the use of fluid control volumes and junctions to represent the spatial character of the flow The control volumes can be viewed as stream tubes having inlet and outlet junctions The control volume has a direction associated with it that is positive from the inlet to the outlet Velocities are located at the junctions and are associated with mass and energy flow between control volumes Control volumes are connected in series using junctions to represent a flow path All internal flow paths such as recirculation flows must be explicitly modeled in this way since only single liquid and vapor velocities are represented at a junction In other words a countercurrent liquid liquid flow cannot be re
112. an example of a strip input file Data for all the parameters listed in the input file will appear on an ASCII file called STRIPF These data must then be processed to put them into a format that is acceptable to the users plotting software XMGR could be used to plot data from the STRIPF file The INEL usually uses XMGR5 an INEL extension to XMGR that adds features to conveniently plot information from restart plot files or STRIPF files If users plan on using external plots they should make up their strip input file before generating the RSTPLT file because some parameters they may desire are on the RSTPLT file only if they are specifically requested with 208 cards 8 4 2 Internal Plots This code feature designed at the INEL for the CDC 176 has currently not been made compatible with the CRAY and the workstations The following discussion of this capability is printed so that it will be available after the capability is restored A plot package has been provided in RELAPS so that the user may produce graphs of calculational results However because each user may have a different use for the plots many options are provided so that the user may design and vary the quality of plots as desired In addition since it is often necessary to compare the results to experiments or other calculations a means to input plot comparison data tables has also been provided 8 23 NUREG CR 5535 V2 RELAP5 MOD3 2 LL6S 9 Lv 9LV L898 G I9 ELY 99 2
113. ancement reaching the final time on the last time step control card Minor and major edits are printed and a restart record is written at termination Since trips can be redefined and new time step cards can be entered at restart the problem can be restarted and continued Transient termination can also occur based on two tests on the CPU time remaining for the job One test terminates if the remaining CPU time at the completion of a requested time step is less than an input quantity The second test is similar but the comparison is to a second input quantity and is made after every time advancement The input quantity for the first test is larger than for the second test because the preferred termination is at the completion of a requested time step In either case the termination can be restarted Failure terminations can occur from several sources including hydrodynamic solution outside the range of thermodynamic property subroutines heat structure temperatures outside of thermal property tables or functions and attempting to access an omitted pump curve Attempting to restart at the point of failure or at an earlier time without some change in the problem input will only cause another failure Problem changes at restart may allow the problem to be successfully restarted Additional information on terminating calculations is presented in Section 3 of Volume V 8 7 Problem Changes at Restart The most common use of the restart option is simply
114. aphics package could be developed to show isometric views of the system as an aid in model checking Such a graphics package is not included in the MOD3 version The horizontal angle is checked to verify that its absolute value is less than or equal to 360 degrees but no further use is made of the quantity The volume vertical angle specifies the vertical orientation of the volume This quantity would also be used in the graphics package and in addition specifies the vertical orientation of the volume coordinate direction The vertical angle must be within the range 90 to 90 degrees The angle 0 degrees means the x coordinate direction is in the horizontal plane a positive angle means that the coordinate direction is directed upward a negative angle means it is directed downward Slanted vertical orientation such as an angle equal to 45 degrees is permitted Note that as the vertical angle changes from zero the y coordinate is always in the horizontal plane and that the x and z coordinates and their associated faces move out of their original horizontal and vertical planes respectively The coordinate direction implies the position of the inlet and outlet ends of the volume The terms inlet and outlet are convenient mnemonics relative to the coordinate direction but do not necessarily have any relation to the fluid flow The direction of fluid flow is indicated by the sign of the velocity relative to the coordinate direction For input convenie
115. appearance of noncondensable gas or water packing The modifications to the hydrodynamic advancement algorithm are described in Volume I in the section entitled Special Techniques In addition if in the time step in which noncondensable gas first appears in a volume the pressure change in that cell is too large the time step is repeated with a smaller time step size to reduce the pressure change in that cell The same advancement may be repeated several times with smaller and smaller time steps until the pressure change criterion is satisfied Like the quantities under the REDUCE headings the quantity under the REPEAT DEL PRES heading is incremented only after the pressure change criterion is satisfied 8 3 2 9 Hydrodynamic Junction Information First Section This section of output is not optional and always appears in a major edit This section is printed in Figure 8 3 1 As with the first section of the hydrodynamic volume information quantities are grouped by system For each system the label SYSTEM the system number 1 2 3 etc and the system name optional are printed on the first line The first printed quantity for each junction is the junction number Labeled JUN NO it denotes the component number CCC and the six digit junction subfield number XX YY YZZ within the component These numbers are separated by a hyphen The next two quantities are the volume numbers for the from and 70 volumes associated with the junction labe
116. art with the values at restart It is possible to delete all trip definitions and enter completely new definitions Individual trips can be deleted or redefined and new trips can be inserted Individual trips can be reset to false At 4 1 NUREG CR 5535 V2 RELAP5 MOD3 2 restart a latched trip can be reset Detailed discussions and examples of the use of trips are presented in Section 4 of Volume V of this code manual 4 1 1 Variable Trips A variable trip evaluates a comparison statement relating two variables and a constant using one of the relationships equal EQ not equal NE greater than or equal GE greater than GT less than or equal LE or less than LT The variables currently allowed are listed in the Input Requirements Appendix A Most variables advanced in time are allowed and any variable that is permanently stored can be added to the list The only restriction on the two variables is that they have the same units Thus a hydrodynamic volume temperature can be compared to a heat structure temperature but a pressure cannot be compared to a velocity The variable trip statement is L NUM VARI OP VAR2 CONSTANT ls TIMEOF 4 1 1 where NUM is the card number VAR1 and VAR2 each consist of two words that identify a variable the first word being alphanumeric for the variable type the second word being a number associated with the particular variable OP is the comparison operation CONSTANT is a signed number to be
117. ason why they should be different In particular a very large forward and small reverse loss factor should not be used to simulate a check valve This approach can cause code failure A typical leak path model between vertical volumes is illustrated in Figure 2 2 5 Minor flow paths having extreme area variations or flow splits in which the minor flow is a small fraction of the main flow 0 1 can also be modeled using the standard junction by the following special procedures The smooth area change option is used for the junction the efvcahs flag with a 0 and the junction area is allowed to default the minimum area of the adjoining volume areas It may be necessary for the user to input a more reasonable flow area if the default area is too large With this specification it is necessary to enter user input form loss coefficients normalized to the default area in order to give the proper flow rate and pressure drop relationship The loss factor to be input can be estimated using the following equation NUREG CR 5535 V2 2 16 RELAP5 MOD3 2 Figure 2 2 5 Leak path model using the crossflow junction K 2APA E 2 2 4 m where K loss factor AP nominal pressure drop Pa A Junction area m2 p fluid density kg m m nominal mass flow rate kg s The value computed for K in this way may be very large because the default area is much larger than the actual flow area Also critical flow would not
118. ast time step set to 1 if it was set to O if it was not The subheading EDIT lists the number of times the choking model was applied since the last major edit the subheading TOTAL lists the number of times the choking model was applied for the entire problem As with the first section of the hydrodynamic volume information quantities within each system are grouped by component with the component name and type printed above the quantities 8 3 2 10 Hydrodynamic Junction Information Second Section This section of output is optional and can be skipped by setting bit two in the ss digits of Word 4 W4 on the time step control cards Cards 201 through 299 This section is printed in Figure 8 3 1 As with the second section of the hydrodynamic volume information no system information is printed no component label information is printed no additional component quantities are printed and all quantities are printed in numerical order within each system The junction number JUN NO and twelve other quantities are next printed out on each line These are printed out in numerical order within each system The quantities are VOIDFJ liquid junction void fraction VOIDGJ vapor junction void fraction a FIJ interphase drag coefficient C 2 FWF Ax forward and reverse flow energy loss coefficients FJUNF and FJUNR corresponds to 2 HLOSSF v and 2 HLOSSG FWALFJ and FWALGJ dimensionless liquid and vapor wall f
119. ation of shock waves downstream from a choked junction Sometimes it is necessary to remove the choking option at junctions near a known internal choked junction in order to avoid oscillations 2 2 3 Branching A fundamental and vital model needed for simulation of fluid networks is the branched flow path Two types of branches are common the tee and the plenum The tee involves a modest change in flow area from branch to branch and a large change in flow direction while the plenum may involve a very large change in flow area from branch to branch and little or no change in flow direction In PWR simulations a tee model would be used at pressurizer surge line connections hot leg vessel connections and cold leg connections to the vessel inlet annulus A plenum model would be used for modeling upper and lower reactor vessel plenums steam generator models and low angle wyes Two special modeling options are available for modeling branched flow paths These are a crossflow junction model and a flow stratification model in which the smaller pipe at a tee or plenum may be specified as connected to the top center or bottom of a larger connecting pipe When stratified flow is predicted to exist at such a branch vapor pullthrough and or liquid entrainment models are used to predict the void fraction of the branched flow The use of these models for simulating tees plenums and leak paths are discussed in greater detail below 2 2 3 1 Tees The simp
120. be detected with this approach Both the forward and reverse loss coefficients should be equal unless there is a reason why they are physically different In this case Equation 2 2 4 should be used to calculate the effective loss factor for both the forward and reverse flow conditions i e assume AP and m also correspond to the reverse flow case The geometric relationship between the actual situation and the model is illustrated schematically in Figure 2 2 6 In the case of minor flow paths that connect at branches having large main flows a similar approach can be used In this case let the junction area default to the minimum of the adjoining volumes presumably the area of the minor flow path and use the smooth option efvcahs with a 0 The determination of the loss factor may require some experimentation because of the possible large 2 17 NUREG CR 5535 V2 RELAP5 MOD3 2 Abrupt area change efvcahs 0000100 Ajunction up pora Aqown Athroat Throat ratio Athroat Ajunction Physical situation with a loss factor K ctual Smooth area change efvcahs 0000000 p Ajunction y Adown 2 Keffective a Kactual CAjunction Athroat Equivalent model with effective loss factor for the same pressure drop flow relation Figure 2 2 6 High resistance flow path model momentum flux effect which is ignored in the derivation of Equation 2 2 4 If one of the volumes is
121. btainable from the limited data available to the user In particular the stage group nozzle throat area Aj and the nozzle velocity v are not always easily obtained A steady state turbine heat balance usually contains the representative stage group pressures the enthalpies and the mass flow rates From the mass flow rate and state properties the product v A is easily obtained but the actual value of v or A requires more information If a geometric description of the turbine is available then A is known and v can be calculated This is the proper way to obtain the input data If no geometric data are available then the following procedure can be used to crudely estimate the needed input data A reasonable estimate must be made for one junction area Then knowing v A gives the corresponding v The turbine momentum equation 1 1 2 3 24 2 55 NUREG CR 5535 V2 RELAP5 MOD3 2 along with the stage pressures can then be used to estimate the neighboring junction velocity The mass flow along with this new velocity gives the neighboring junction area In this way all the velocities and junction areas can be estimated if any one junction area A or junction velocity v is known or estimated Note that turbines are usually designed to run with large velocities in the nozzles The turbine may be the component that gives the maximum Courant number in the system For this reason the turbine component may limit
122. c edit when a failure occurs 8 24 8 3 8 Example of printout buried in the diagnostic edit when a failure occurs 8 25 8 4 1 Sip input file aida di ias FORI Ue eR 8 26 ix NUREG CR 5535 V2 RELAP5 MOD3 2 NUREG CR 5535 V2 RELAP5 MOD3 2 TABLES 2 1 1 Flow regime letters and numbetrs encoder tere io Quaices 2 8 2 1 2 Bubbly slug flow regime numbers for vertical Junctions 2 9 2 2 1 Values of m c and cg for Tien s CCFL correlation form 2 23 2 3 1 Pump homologous curve definitions eene 2 38 4 1 Logical Operas cid iia 4 3 4 1 2 Truth table example S u pu DS Sinus q f Ea asa 4 5 4 1 3 Boolean algebra identities ioo oce o nu S a na iderc littus ub pelis 4 5 4 2 Input data for a sample problem to test pump generator and shaft 4 16 8 3 1 LOW MAD 106 BHO TIEES a as 8 4 xi NUREG CR 5535 V2 RELAP5 MOD3 2 NUREG CR 5535 V2 xii RELAP5 MOD3 2 EXECUTIVE SUMMARY The light water reactor LWR transient analysis code RELAPS was developed at the Idaho National Engineering Laboratory INEL for the U S Nuclear Regulatory Commission NRC Code uses include analysis required to support rulemaking licensing audit calculations evaluation of accident mitigation strategies evaluation of operator guidelines and experiment planning analysis RELAP5 has also been used as the basis for
123. c internal energy vapor specific internal energy void fraction and noncondensable quality For Options 0 through 6 the boron concentration is assumed to be zero If 10 is added to the above option numbers a boron concentration is required See Section 3 of Volume I for a complete description of the boron transport model Boron is assumed to be only present in and to be convected by liquid water If a volume with liquid and boron has the liquid water removed by convection the boron is also removed If the liquid water is evaporated the boron remains This is analogous to boron precipitating out as water is evaporated Infinite solubility of boron in water is assumed and boron remains in solution regardless of its concentration until all of the liquid water disappears Boron instantly redissolves the instant the quality becomes less than 1 Boron concentrations are computed using only a boron continuity equation for each volume Boron is assumed to have no momentum no internal energy and to have no effect on the equation of state Junctions connect two volumes by specifying a connection code for each volume The connection code specifies both the volume and a specific face of the volume Except for a pipe component current components have only one volume and a component reference is essentially a volume reference The connection codes for each component type are described in the beginning of the input description for that component as well as in
124. can be obtained from plant data or reactor physics calculations As discussed in Volume 1 a data point must be entered for each combination of coordinate values Accurate reactivity data need only be entered for points near zero reactivity Once the shutdown reactivity decreases below 2 0 dollars 11016 change in fission energy release occurs with further decreases in reactivity Thus in sections of the multidimensional table where reactivity is known to be very much shut down data can be determined from extrapolation and need not be accurate Similarly some parts of the table may contain large values of reactivity The user does not expect the transient to use this portion of the table but the code input requires all tabular points to be entered Again accurate data need not be entered if the transient should enter this area the large power rises will be evident and the user can investigate the modeling difficulty In some instances a coordinate value is introduced to ensure accuracy in one section of a table but the detail is not needed in other parts of the table Where the detail is not needed data could be obtained at a more coarse mesh and the user can interpolate to meet the input requirements of the code Usually several hydrodynamic volumes are used to represent the coolant channels in a reactor core and several heat structures represent the fuel pins Weighting factors are input to specify the reactivity contribution of each hydrodynam
125. cept that 40 is added see Section 3 2 2 2 5 Noncondensables The noncondensable model has the ability to be applied at every hydrodynamic volume in a system model While in operation the model affects interface mass and heat transfer wall heat transfer and the output of several variables that may cause discontinuities in plotted output The purpose of this discussion is to clarify the operation of the noncondensable model and its affect on the calculated results and to give guidance for its use in system calculations In order to properly understand the operation of the noncondensable model the fundamental assumptions used in the model need to be discussed First the steam noncondensable mixture is assumed to be in thermal equilibrium Second the total pressure is the sum of the partial pressures of the steam and 2 19 NUREG CR 5535 V2 RELAP5 MOD3 2 the noncondensable Next the specific vapor internal energy is the mass weighted sum of the steam specific internal energy and the noncondensable specific internal energy Last the saturation properties of the liquid and steam are assumed to be a function of the partial pressure of the steam One of the effects of these assumptions is to force the phasic temperatures and the saturation temperature to the same value This causes a reduced driving potential for the interface mass and heat transfer models The interface heat transfer coefficients are reduced in the presence of noncondensables
126. ch as controls or instrumentation in which the process can be defined in terms of system variables through logical algebraic differentiating or integrating operations These models do not have a spatial variable and are integrated with respect to time The control system is coupled to the thermal and hydrodynamic components serially and implicitly The control system advancement occurs after the heat conduction transfer hydrodynamic and reactor kinetics advancements and uses the same time step as the hydrodynamics so that new time thermal and hydrodynamic information is used in the control model advancement However the control variables are fed back to the thermal and hydrodynamic model in the succeeding time step 1 e they are explicitly coupled NUREG CR 5535 V2 1 2 RELAP5 MOD3 2 A system code such as RELAPS contains numerous approximations to the behavior of a real continuous system These approximations are necessitated by the finite storage capability of computers by the need to obtain a calculated result in a reasonable amount of computer time and in many cases because of limited knowledge about the physical behavior of the components and processes modeled For example knowledge is limited for components such as pumps and separators processes such as two phase flow and heat transfer Examples of approximations required because of limited computer resources are limited spatial nodalization for hydrodynamics heat transfer and kinet
127. condensable 16 present in a volume all temperatures are set to equal values and are a function of the gas energy As a fluid is injected into the volume the temperatures the partial pressure of steam and possibly the vapor energy will abruptly change to new values based on the calculated thermodynamic conditions Additionally the liquid and saturation temperature may appear at the fluid triple point value if the partial pressure of the steam is calculated to be lower than the minimum fluid property table value As an example a checkout problem used for development 2 3 consisted of 322 K liquid water being injected into 436 K helium The liquid temperature and saturation temperature both changed from 436 to 273 K in one time step as the volume changed from a pure noncondensable state to a steam noncondensable mixture state As more water was injected the liquid transitioned to the correct value Selecting noncondensable input consists of specifying type and concentration of species on the system cards and by selecting Options 4 5 and 6 on the volume initial condition cards Option 4 which consists of pressure temperature and equilibrium quality is the easiest to use A restriction on the temperature is that it has to be less than the saturation temperature as a function of pressure Little experience has been obtained in using Option 5 and it has not been checked out Option 6 is generally used to renode system models from Pygmalian decks 2
128. ctures can be attached to the same hydrodynamic component such as fuel pins and a core barrel attached to a core volume the G portion can be used to distinguish the different types of heat structures The combined field CCCG is the heat structure geometry number and input data are organized by this heat structure geometry number Up to 99 individual heat structures may be defined using the geometry described for the heat structure geometry number The individual heat structures are numbered consecutively starting at 01 this number is the subfield NN of the heat structure number The heat structure input requirements are divided into input common to all heat structures with the heat structure geometry number Cards 1CCCG000 through 1CCCG499 and input needed to uniquely define each heat structure ICCCG501 through 1CCCG999 3 0 1 Reference 3 0 1 C M Allison and E C Johnson eds SCDAP RELAP5 MOD3 1 Code Manuals Volumes I IT III NUREG CR 6150 EGG 2720 October 1993 3 1 Heat Structure Geometry Temperature distributions in heat structures are assumed to be represented adequately by a one dimensional form of the transient heat conduction equation in rectangular cylindrical or spherical coordinates The spatial dimension of the calculation is along any one of the coordinates in rectangular geometry and is along the radial coordinate in cylindrical or spherical geometry The one dimensional form assumes no temperature variations along
129. d The total reactor power is the sum of immediate fission power and the power from decay of fission fragments The immediate power is that released at the time of fission and includes power from fission fragment kinetic energy prompt gammas and neutron moderation Decay power is generated as the fission products undergo radioactive decay The user can specify one of three options for computing reactor power fission power only fission and fission product decay product power or fission fission product decay and actinide decay power Actinide decay power is the power resulting from production of 239U by neutron absorption in 238U and subsequent two stage beta decay to 239pu Two sets of fission product decay data are built into the code The default set is the eleven group ANS standard proposed in 1973 5 1 The other set of data is from the 1979 ANS Standard for Decay Heat Power in Light Water Reactors 12 The 1979 standard specifies data for three isotopes 235U 2380 and 239py using 23 groups for each isotope To use the three isotope data the user must furnish the fraction of power produced by each isotope An option exists to use only the SU isotope data from the 1979 standard Actinide data are from the 1979 standard An input fraction is applied to both the fission product and actinide yield data For fission products the factor is usually 1 0 for best estimate calculations and 1 2 has been used for conservative calculations with the 197
130. d moderator temperature coefficient is not the usually quoted quantity Assume the moderator feedback is a function of density and temperature r p T NUREG CR 5535 V2 5 2 RELAP5 MOD3 2 and density is a function of temperature p T The usual temperature coefficient is the total derivative dr E The input requires partial derivatives The moderator density feedback is or the temperature dT P Ir or coefficient is S Ti The three and four dimensional table lookup and interpolation option uses three or four quantities as the independent variables The four dimensional table includes the effects of boron the three dimensional table does not include boron effects Two suboptions allow a choice of independent variables One choice is reactivity as a function of moderator density void weighted moderator temperature volumetric average fuel temperature and boron density This option uses the same variables as the separable option plus boron effects if four variables are used The other option uses void fraction liquid moderator temperature volume averaged fuel temperature and boron concentration as independent variables Feedback effects in light water power reactors are usually expressed in terms of these quantities The multidimensional interpolation allows nonlinearities and interaction of feedback effects but burdens the user with obtaining a larger amount of reactivity data As with the separable option required data
131. d to the outlet and is called the discharge junction The pump head torque and angular velocity are computed using volume densities and velocities The head developed by the pump 19 divided equally and treated like a body force in the momentum equations for each junction With the exception of the head term the hydrodynamic model for the pump volume and junctions is identical to that for normal volumes and junctions NUREG CR 5535 V2 2 32 RELAP5 MOD3 2 2 3 8 1 1 Pump Performance Modeling Interaction of the pump and the fluid is described by empirically developed curves relating pump head and torque to the volumetric flow and pump angular velocity Pump characteristic curves frequently referred to as four quadrant curves present the information in terms of actual head H torque t volumetric flow Q and angular velocity or N These data are generally available from pump manufacturers For use in RELAPS the four quadrant curves must be converted to a more condensed form called homologous curves which use dimensionless quantities The dimensionless quantities involve the head ratio torque ratio volumetric flow ratio and angular velocity ratio where the ratios are actual values divided by rated values The rated values are also required pump component input and correspond to the design point or point of maximum efficiency for the pump The homologous curves are entered in tabular form and the dependent variable is obtained as a
132. d with respect to a heat structure geometry all heat structures with the heat structure geometry number are affected Composition and general table data can also be added deleted or replaced at restart A transient or steady state problem terminated by a heat structure temperature out of range of the thermal property data can be restarted at the restart prior to the termination by replacing the thermal property data 3 5 NUREG CR 5535 V2 RELAP5 MOD3 2 3 5 Heat Structure Output and Recommended Uses Up to six sections of heat structure output are printed at major edits The first section prints one line of heat transfer information for each surface of each heat structure Each line provides the heat structure number a left or right surface indicator the connected hydrodynamic volume or if none zero surface temperature the heat transfer rate the heat flux the critical heat flux the critical heat flux multiplier the mode of heat transfer and the heat transfer coefficient The first line for each heat structure also includes the heat input to the structure the net heat loss from the structure and the volume average temperature for the structure The critical heat flux multiplier is the value used to multiply the value from the CHF table The second section prints the mesh point temperatures for each heat structure This section can be suppressed by an input option The other optional sections include output on metal water reaction
133. de input and initialization process for a new problem For a restart problem the values are established from the previous calculation For restart with renodalization or problem changes the initialization will result from a combination of the two processes and care must be exercised to ensure that the input values are compatible with those from the restart especially if an initial steady state is to be simulated Boundary conditions may be required for hydrodynamic models heat structures or control components if these parameters are governed by conditions outside of the problem boundaries Examples of these could be mass and energy inflows or an externally specified control parameter Obtaining a desired simulation is very dependent upon proper specification of initial and boundary conditions The purpose of this section is to summarize recommended approaches for these specifications 7 1 Initial Conditions All variables of the problem that are established by integration require initial values in order to begin a calculation or simulation Problem variables related to the integration variables through quasi steady relationships do not require initial conditions since they can be established from the initial values required for the integration variables An example is the pump head which is related to the pump flow and speed both of which are obtained by integration Thus the initial conditions for pump flow and speed must be specified 7 1
134. ds Cards 201 through 299 This section is printed in Figure 8 3 1 As with the previous section no system or component label information is printed no additional component quantities are printed and all quantities are printed in volume numerical order within each system All quantities are presented in two columns The EDIT column contains the number since the previous major edit the TOTAL column is over the entire problem The numbers under LRGST MASS ERR give the number of times a volume had the largest mass error The numbers under MIN COURANT give the number of times a volume had the smallest time step based on the Courant stability limit One volume under each of the headings is incremented by one for each successful advancement The columns under REDUCE indicate volumes that have caused time step reductions The MASS and PROPTY columns are for reductions resulting from mass error and out of range thermodynamic properties The MASS column is for time step size reduction resulting from local mass error it does not include reductions resulting from overall global mass error The QUALITY column is for reductions resulting from problems with void fraction 06 noncondensable quality X g and X being slightly less than 0 0 or slightly greater than 1 0 are allowed and the variable is reset to 0 0 or 1 0 Advancements that result in values much less than 0 0 or much greater than 1 0 are considered an error and the time step is repeated Th
135. e are as follows For a break nozzle venturi geometry a discharge coefficient of nearly 1 0 should be used For an orifice geometry the discharge coefficient depends on the break configuration and may be somewhat less than 1 0 The throat dA dx used in subcooled choking which is denoted by dA dx in Volume 1 of this manual is calculated differently for the normal junction abrupt area option the normal junction smooth area option and the crossflow junction only uses smooth area option For the recommended abrupt area change option the following formula is used aA DAS t abrupt EN 11000 2 2 1 where 2 11 NUREG CR 5535 V2 RELAP5 MOD3 2 Ak the upstream volume flow area Ay the throat or junction area minimum physical area Dx the upstream volume diameter It is recommended the user input the actual physical values for Ax Aj and Dx This formula is empirical and the data base is limited It was developed primarily to obtain the proper subcooled discharge at the break for the LOFT Wyle Blowdown Test WSB03R 22 1 which is one of the developmental assessment separate effects test problems In addition it has been used successfully in many Semiscale test comparisons for the break flow 2 2 2 following formula If the user selects the smooth area change option the code uses the da s uid 2 2 2 dX u smooth 0 5Ax where Ak the upstream volume flow area Ay the throat or junction area minimum
136. e a junction at the inlet or outlet normal junctions or at the side of a volume crossflow junctions The stream wise variation of the fluid passage is specified through the volume cross sectional area the junction areas and through use of the smooth or abrupt area change options at the junctions The smooth or abrupt area change option affects the way in which the flow is modeled both through the calculation of loss factors at the junction and through the method used to calculate the volume average velocity Volume average velocity enters into momentum flux boiling heat transfer and wall friction calculations The abrupt area change model should be used to model the effect of reducers orifices or any obstruction in which the flow area variation with length is great enough to cause turbulence and flow separation Only flow passages having a low wall angle 10 degrees including angle should be considered smooth An exception to this rule is the case where the user specifies the kinetic loss factor at a junction and uses the smooth option This type of modeling should only be attempted for cases where the actual flow area change is modest less than a factor of two The hydrodynamic boundaries of a system are modeled using time dependent volumes and junctions For example a reservoir condition would normally be modeled as a constant pressure source of mass and energy a sink in the case of an outflow boundary The reservoir is connected to the
137. e appropriate junction void fraction the junction density donored quantities the junction velocity and the junction flow area For orifices and valves the actual flow velocity is higher at the minimum area which is the junction area multiplied by the junction area ratio The junction area ratio is used to compute the velocity at the minimum area when needed such as in the choked flow model For user convenience if the user supplied junction area is zero it is set to the minimum of the adjacent volume flow areas regardless of the area change option This is the proper default value for most junctions and only smooth area changes where there is an area change and orifices need nonzero user supplied junction areas Junction loss coefficients can be entered when additional losses above the wall friction and area change losses are needed These losses could arise from pipe bends irregularly shaped volumes entrance or exit losses or internal obstructions Two coefficients are entered one for forward positive flow the other for reverse negative flow The coefficients are applied to the junction dynamic pressure Zero coefficients mean no additional losses are computed It is important to note that MOD3 computes interfacial drag at junctions rather than within volumes This has important implications with respect to modeling reactor core bundles and steam generator bundles In these instances the user should invoke the bundle interfacial d
138. e cutoff points are based on a functional relationship This relation is tied and mixture density from the phasic continuity equations Pm Advancements that result in a to the mass error upper limit 8 x 10 Advancements that result in Pm being lt 0 are also counted in the QUALITY column The final cause of a QUALITY column reduction relates to the one phase to two phase appearance case discussed in Volume 1 of this manual If too much of one phase appears more than a typical thermal boundary layer thickness an error is assumed to have occurred the time step is NUREG CR 5535 V2 8 14 RELAP5 MOD3 2 halved and repeated and the QUALITY column counter is incremented The EXTRAP column is for reductions when extrapolation into a metastable thermodynamic state causes problems see Section 8 of Volume 1 for a discussion of metastable thermodynamic conditions These problems are vapor density Pg lt 0 0 vapor temperature T lt 274 K liquid density pp lt 0 0 liquid temperature Tf gt saturation temperature T 50 K and vapor temperature Tj saturation temperature T 50 K The COURANT column is for reductions resulting from the material Courant limit check When the semi implicit numerical scheme is used the time step is reduced to the material Courant limit When the nearly implicit numerical scheme is used the time step is reduced to 20 times the material Courant limit for the TRANSNT option and to 40 times
139. e performance The fully degraded performance and the single phase performance data are used to form two phase difference homologous performance curves for head or torque The pump performance is then expressed in terms of the single phase data and the difference data using a two phase multiplier that is a function of void fraction The pump head is expressed as H Hyg My 0 AH 2 3 13 where AH is the head difference obtained from the single phase to two phase difference homologous curve The function My is the two phase multiplier defined such that it is zero for the void fraction g equal to 0 0 and 1 0 The pump torque is expressed in a similar way Very little advice can be offered with respect to scaling of the two phase performance data Generally it is assumed that the same similarity principles used for single phase performance also hold for two phase performance A complete set of data was generated for a Semiscale pump and these data are widely used for predicting two phase performance of other pumps 2 3 8 1 5 Pump Velocity Modeling The pump computation for a time step begins by computing pump head and torque from the homologous data using pump angular velocity and volume conditions at the beginning of the time step The head is used in the momentum equations The remaining pump calculation determines the pump angular velocity at the end of the time step The logic for computing pump angular velocity is complex since stop logic
140. e retried with a halved time step SUCCESSFUL ADV is the number of accepted advancements REQUESTED ADV is the number of advancements with the specified requested maximum time step These are presented in two columns The TOT column is over the entire problem the EDIT column contains the number since the previous major edit MIN DT MAX DT and AVG DT are the minimum maximum and average time step used since the last major edit REQ DT is the requested maximum time step used since the last major edit This quantity may not be the requested time step entered on the card if the major edit is for the final time value on the card LAST DT is the time step used in the last advancement CRNT DT is the time step limit based on the Courant stability criterion for the last advancement ERR EST is the estimate of the truncation mass error fraction at the last advancement Entering 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 or 31 for the time step control option will reduce or double the time step to keep this quantity between the limits of 8 0 x 10 and 8 0 x 10 if the mass error criterion is controlling the time step In Figure 8 3 1 the problem is running at the requested maximum time step and the ERR EST is below the lower limit CPU is the CPU time for the entire problem up to the time of the major edit TOT MS is the total mass currently contained in the hydrodynamic systems and MS ERR is an estimate of the cumulative error in the t
141. e shaft and other connected components are forced to the synchronous speed The other mode is tripped and the rotational velocity then responds to the torques applied to the shaft When the generator is connected to the grid the torque necessary to maintain synchronous velocity is computed and the generator power is that torque times the synchronous velocity If the torque is negative the generator is in its normal mode of generating electricity If the torque is positive the generator is acting as a synchronous motor and power is being drawn from the grid to maintain the synchronous velocity When the generator is tripped the generator torque is zero A generator can be connected to a pump through the shaft component This allows a synchronous motor pump combination which is yet another pump motor option that can yield results identical to the pump without a shaft using an implied motor 4 2 3 5 Pump Generator and Shaft Sample Problem Table 4 2 1 shows input data for a sample problem to test pump generator and shaft components The test problem consists of two identical but separate loops Each loop has a pump and a pipe connecting the pump discharge to the pump suction The normal wall friction model is used and an orifice is included for additional dissipation The loops are filled with subcooled water at zero velocity The two pumps are driven differently The first pump uses an implied pump motor operating at normal speed The water is acc
142. eady state runs using the previous steady state results This results in reduced calculational times for the subsequent runs and at the same time maintaining a complete set of steady state initializations The steady state initialization calculation is an open loop calculation unless control functions are defined such that active control systems are used to obtain desired operating points Active control is achieved using controlled variables such as pressure flow rate etc The user must design and implement such control functions and only a limited number of system parameters can be controlled independently In this regard the model behaves exactly as a real system and if a resistance to flow must be varied to achieve the desired steady state then a valve must be used with a controller The use of a controller to achieve a desired steady state can save considerable time compared to the process of open loop control in which a resistance or other parameter is varied from run to run until the desired steady state is achieved In providing control systems and trips to drive the solution to steady state two rules of thumb must be considered both of which revolve around the basic purpose of the steady state run The first rule is that if the run is to simulate the real behavior of a plant in achieving steady state then control systems and trips simulating real plant controls or control procedures should be designed However the second rule of thumb i
143. ection about the ordinate divides each quadrant into two octants Each of these eight octants is named according to the convention listed in Table 2 3 1 for the purpose of constructing the homologous representation The four quadrant pump head and torque maps in Figure 2 3 1 and Figure 2 3 2 can be reduced to the homologous representation curves in two steps First the maps are made dimensionless by using the rated head Hp flow Qp speed Ng and torque Tp to form corresponding dimensionless parameters h H Hg v Q Qp amp N Np and B T Tp respectively Second the data are plotted in terms of the homologous parameter h a or h v v a or a v and Bla or p The parameter used depends upon the octant in which the curve is being plotted The choice is made so that the values are bounded i e the denominators never vanish and in the case of the capacity parameter the range of variation is confined between plus and minus 1 0 Figure 2 3 3 is the homologous head curve that is obtained from the head map in Figure 2 3 1 Note that not all points fall on a single curve This is a result of the inexact nature of the similarity theory Real pumps do not perform exactly according to the similarity relations due to 2 35 NUREG CR 5535 V2 RELAP5 MOD3 2 Homologous states Dissipation Normal HVN HVD 5 200 f110 x 150 ft Volumetric flow 200 100 GPM HVT HVR Reverse Turbine HAT HAR Figure 2 3 1 Four
144. ects balance If no wall friction options are selected for the loop piping and no area losses are present the water will accelerate until the pump head is zero When steady state is reached and the pump trip is then set true the pump will begin to decelerate because the pump friction torque and the torque exerted by the water on the pump are no longer balanced by the pump motor torque The water also begins to decelerate owing to loss effects The interaction between the water and pump depends on the relative inertias and friction losses between the two If the water tends to decelerate more rapidly than the pump the pump will use its rotational kinetic energy to maintain water velocity If the pump tends to decelerate more rapidly than the water the pump depending on its design as reflected in the homologous data may continue to act as a pump or the kinetic energy of the water may tend to maintain pump angular velocity The second example is similar to the first example except that the initial pump angular rotational velocity is zero and a pump motor torque curve for an induction motor is used From the curve the torque is positive at zero angular velocity and increases slowly as the velocity increases to a value slightly below the synchronous speed Then the torque decreases sharply to zero at the synchronous speed and continues to negative torque At the initial conditions the net torque is positive the pump angular velocity increases and the wa
145. ed since the default method can apply a time delay and the other cannot 2 3 3 Time Dependent Junction Time dependent junctions can be used whenever the phasic velocities or phasic mass flow rates are known as a function of time or other time advanced quantity Time dependent junctions can connect any two system volumes or a system volume and a time dependent volume Phasic mass flow rates are converted to phasic velocities using the upstream phasic densities Examples of their use would be to NUREG CR 5535 V2 2 30 RELAP5 MOD3 2 model a constant displacement pump in a fill system a pump or a valve or both by using an associated control system or measured experimental data Time dependent junctions are also used frequently in test problems to check code operation The phasic velocities or mass flows in the time dependent junction as a function of time or the time advanced quantity are entered as a table with time or the time advanced quantity as the independent or search variable The requirements interpolation and trip logic are identical to that for time dependent volumes The capability of using time advanced quantities as search arguments can be used to model pressure dependent water injection systems If the injection flow is a function of the pressure at the injection point the volume pressure at that point is used as the search argument A trip is defined to be true when the injection system is actuated One entry of table da
146. eduction and increased computer cost Eliminate minor flow paths that do not play a role in system behavior or are insignificant compared to the accuracy of the system representation This can not usually be done until some preliminary trial calculations have been made that include all the flow paths Care must be used here because in certain situations flow through minor flow paths can have a significant effect on system behavior An example is the effect of hot to cold leg leakage on core level depression in a PWR under small break loss of coolant accident conditions Establish the flow and pressure boundaries of the system beyond which modeling is not required and specify appropriate boundary conditions at these locations 2 1 NUREG CR 5535 V2 RELAP5 MOD3 2 2 1 Basic Flow Model The RELAPS flow model is a nonhomogeneous nonequilibrium two phase flow model See Section 3 of Volume I for a detailed description of the model and the governing equations However options exist for homogeneous equilibrium or frictionless models if desired These options are included to facilitate comparisons with other homogeneous and or equilibrium codes Generally the code will not run faster if these options are selected The RELAPS flow model is a one dimensional stream tube formulation in which the bulk flow properties are assumed to be uniform over the fluid passage cross section The control volumes are finite increments of the flow passage and may hav
147. elerated to near steady state velocity within a few seconds A true steady state is not possible since there is no provision for removing dissipation heat The pump is then tripped the pump coasts down and flow velocities diminish The second pump uses a pump motor torque table representing an induction motor with the rotational velocity initially zero The pump accelerates to near the synchronous velocity and in turn the water velocity is accelerated similarly to the first loop The second loop is tripped similarly to the first loop In the second problem the pumps are driven identically but using a different mechanism The first pump uses a shaft and a generator acting as a motor The second pump uses a shaft and control system to 4 15 NUREG CR 5535 V2 RELAP5 MOD3 2 develop the torque A general table duplicates the motor torque table and a unit trip applies the trip action Identical results are obtained in the two cases Table 4 2 1 Input data for a sample problem to test pump generator and shaft two loops with pumps This problem has two loops each with friction an orifice and a pump Built in pump data are used The first loop is similar to the pump problem The second loop uses pump motor torque data to represent an induction motor The pump is initially at rest The pump accelerates to near synchronous speed and fluid is accelerated Reaching near steady state pump trip and decreasing pump speed and
148. eparation Volume III provides the results of developmental assessment cases that demonstrate and verify the models used in the code Volume IV presents a detailed discussion of RELAP5 models and correlations Volume V contains guidelines that have evolved over the past several years through the use of the RELAP5 code Volume VI discusses the numerical scheme used in RELAPS and Volume VII is a collection of independent assessment calculations FIN W6238 Code Maintenance RELAPS5 and NPA lii NUREG CR 5535 V2 RELAP5 MOD3 2 NUREG CR 5535 V2 1v RELAP5 MOD3 2 CONTENTS ABSTRACT A tee te edite d t ON ED Paes iii CONTEN TS exse hte ee h au u gu S Qu a a e ia u ua q Sh PI uh aaa v FIGURES 4 aida AVE eia derer eit i o data dde ix TABLES isc a gan ta e ee et n ERE EUR a t de dae e ERE Eo o ih rate xi EXECUTIVE SUMMARY yuana tere ER ea aa esti xiii ACKNOWLEBDGMBNIS 5 55 gue Cuin tre pere t teque etre teruel xvii 1 INTRODUCTION t mapa dt e ete edite Be A 1 1 1 1 Generali uy as deter E eh M e eie ete de need sss 1 1 1 2 Areas ot Application ito Ep Ho I ete p EEG Ue e dett 1 1 1 3 Modeling Philosophy een ia ate e a Ua 1 1 2 HYDRODYNAMIGCS ne ep eec ic 2 1 2 1 Basic Plow Model u na ner ien f e E roten eet ot eee ld 2 2 2 2 Process Models iii ete eer eee ae ee SG E kuk RP E C E A 2 10 2 2 1 Abrupt Area Change eai eat qae etm di oie 2 10 2 22 iChoked BLOW ete v aasma anu has A an ue EH 2 11 2 2 3 Branching iiec n de
149. er components use that data This holds true for built in data since built in data are treated as input data and stored in the pump component data when requested There are no component ordering restrictions when one pump component references tables in another pump component Thus a pump component may reference a pump component numbered higher or lower than itself Also a pump component may reference another pump component that references another pump component as long as a pump component with data entered is eventually reached 2 43 NUREG CR 5535 V2 RELAP5 MOD3 2 2 3 8 4 Pump Edit Parameters Major output edits include pump performance information in addition to the quantities common to all volumes and junctions Pump angular velocity head torque octant number and motor torque are edited Pump angular velocity head torque motor torque and inertia are available as minor edit variables The pump torque is the sum of torque from homologous data and friction effects Pump motor torque is zero if the motor is tripped or if no motor is directly specified or implied 2 3 9 Jet Pump A jet pump is modeled in RELAPS using the JETMIXER component In a jet pump the pumping action is caused by the momentum mixing of the high speed drive line flow with the slower suction line flow Figure 2 3 5 contains a schematic showing the typical nodalization used for a jet pump mixing section Suction region KS Q Vks j Vs M
150. erminal The tables may then be stored for future use with RELAPS runs or be made part of each problem input stream as desired To produce plot comparison data tables from other restart plot files the RELAP5 STRIP option may be used to retrieve results and build plot comparison data tables If the data are contained on user tapes or disk files the user can provide programs to build plot comparison data tables in the format required by RELAPS NUREG CR 5535 V2 8 26 RELAP5 MOD3 2 8 5 RELAP5 Control Card Requirements When run under the Unix operating system the code includes processing of the command line that initiates RELAPS execution This processing permits specification of some options and the names of the files such as input output and restart plot files needed for execution Unix is an operating system available on Cray computers and most workstations The command line for execution under Unix is documented in the last section of the Input Data Requirements Appendix A 8 6 Transient Termination The transient advancement should not abort terminate by operating system intervention except for exceeding available disk space Other program aborts such as floating point errors illegal address or segmentation faults are indications of programming errors and should be reported to the RELAPS development staff The user may optionally specify one or two trips to terminate a problem Normal termination is from one of these trips or the adv
151. essing and error flags are set to terminate the problem if input errors are encountered Error messages are also printed to inform the user that the data entered were in error The specific input description is detailed in Appendix A 2 3 11 Separator Figure 2 3 7 contains a schematic showing the typical nodalization used for a separator and the adjoining bypass and downcomer regions If there is any possibility of recirculation flow through a bypass region we recommend that this flow path be included In general there will be a mixture level at some location in the downcomer volumes The RELAPS separator model can be looked on in the following way The flux through the liquid outlet is all water when the volume fraction of liquid is above a critical value Below that critical value a mixture of steam and water are fluxed out the liquid outlet A similar thing occurs for the steam outlet When the volume fraction of steam is above a critical value only steam is fluxed through the steam outlet When the volume fraction of steam is below this critical value a mixture of steam and water is fluxed through the seam outlet The critical values are given names VUNDER for the water outlet and VOVER for the steam outlet This behavior can be shown in Figure 2 3 8 The volume on the bottom furnishes a mixture of steam and water to the separator For the separator water outlet notice that 1f the water level drops below the outlet baffle on the left steam
152. flow map and the corresponding number printed out under the label Flow Map Table 8 3 1 Flow map identifiers Number Flow Map Input Edit Vertical 1 Horizontal 2 Annular 3 Pump ECC Mixer 5 NUREG CR 5535 V2 8 4 RELAP5 MOD3 2 Depending on the type of data input is edited in only one of the last two edits or in both of them Error diagnostics can be issued during either phase even if no editing for the erroneous data is done in a phase When an error is detected possible corrective actions are disregarding the data which usually leads to other diagnostics inserting benign data or marking data as being entered but useless for further processing These actions are taken so that input processing continues despite severe errors other than on problem type and options Regardless of errors all data are given preliminary checking Severe errors can limit cross checking Correcting input errors diagnosed in a submittal may lead to other diagnostics in a subsequent submittal as elimination of errors allow more detailed checking Except for exceeding requested computer time disk limits and printed output limits any abnormal termination is considered a programming error and even exceeding computer time limits is prevented during transient execution The final message of input processing indicates successful input processing or that the problem is being terminated as the result of input errors 8 3 2 Major
153. grid spacer For area changes the donor diameter for the normal flow direction is recommended For orifices the actual diameter is recommended 2 2 Process Models In RELAPS process models are used for simulation of processes that involve large spatial gradients or which are sufficiently complex that empirical models are required The flow processes for an abrupt area change a choked flow a branch reflood noncondensables water packer CCFL level tracking and thermal stratification are all simulated using specialized modeling These particular processes are not peculiar to a component and will be discussed as a group Some components such as pumps and separators also involve special process models these models will be discussed with the component models The use of the process models is specified through input and proper application is the responsibility of the user As a general rule we recommend that the user not mix process models e g we recommend the user not use the choking model at either the inlet or outlet side of a volume where the abrupt area change is activated and more than one junction is connected The purpose of this section is to advise the user regarding proper application of the process models 2 2 1 Abrupt Area Change The abrupt area change option should generally be used in the following situations 1 Sharp edged area changes 2 Manifolds and plena connecting parallel flow passages 3 At break locations For
154. h the nonequilibrium noncondensable state input option value of 6 for the volume initial conditions control word t The users employ the following method For a given total pressure P gas temperature Ts liquid temperature Tg void fraction Qo and noncondensable gas quality X M M M first calculate the steam quality X 1 X The partial pressure of steam P is determined from the relation P X e P which is true only if both steam and noncondensable are ideal gases obey Dalton s mixture law and have similar molecular weight Using steam tables to get the steam energy Us from the known values of P and T then calculate the noncondensable energy U from Equations in Volume I of the code manual The mixture gas energy Ug is then calculated from Equations in Volume I of the code manual Finally the liquid energy Up is determined using steam tables from the known values of P and Ty Option 4 with quality 1 0 is recommended for containment volumes 2 2 6 Water Packing The volume control flag p is used to activate the water packing mitigation scheme The scheme is invoked if the detection criteria are met The number of partial time step repeats is shown in the hydrodynamic volume statistics block time step control information in the major edit Both the number of repeats since the last major edit and for the whole calculation are shown 2 2 7 Countercurrent Flow Limitation Model The countercurrent
155. hases forced to have equal temperatures calculation is used Generally we recommend that wall friction be computed in the x direction and usually not in the y direction and that the nonequilibrium equation of state be used System volumes require initial thermodynamic state conditions and time dependent volumes require state conditions as a function of time or a time advanced quantity Seven options numbered 0 through 6 are available to specify state conditions Options 0 through 3 specify water only conditions and do not allow a noncondensable gas Option 0 requires pressure liquid specific internal energy vapor specific internal energy and void fraction Options 1 and 2 always specify saturation conditions Option 1 requires saturation temperature and equilibrium quality Option 2 requires saturation pressure and equilibrium quality Two phases are present if the quality is neither 0 nor 1 Option 3 always specifies single phase conditions and requires pressure and temperature Options 1 through 3 can only specify equilibrium conditions even if the nonequilibrium equation of state is requested The next three options can specify the presence of a noncondensable gas Option 4 requires pressure temperature and equilibrium quality Equilibrium conditions are assumed and the vapor consists of air and water vapor at 100 humidity Option 5 requires temperature equilibrium quality and noncondensable quality Option 6 requires pressure liquid specifi
156. he initial processing of data Input data are moved and expanded into dynamic arrays sized for the problem being solved and default options are applied Processing and error checking is local to the data being processed That is when processing a single junction component no checking is performed regarding the existence of connected volumes Similarly hydrodynamic volumes connected to heat structure surfaces are not checked during processing of heat structure boundary data At the end of this phase all data cards should have been used Unused cards are considered errors and are listed Asterisks following the card number indicate that the card number was bad that an error was noted in the card image listing and that the number is the sequence number rather than the card number The third phase completes input processing and performs requested initialization Once the second phase has been completed data specifying linkages between various blocks of data can now be processed and checked Examples of error checking are junction connections made to nonexisting volumes heat structure surfaces connected to nonexisting hydrodynamic volumes specified thermal properties and power data not entered Solution of steady state heat conduction for initial temperature distribution in heat structures is an example of initialization The flow map used for a particular volume is printed out during the input editing of the hydrodynamic volumes Table 8 3 1 shows the
157. he nonhomogeneous choking model at all junctions Specifically it has been demonstrated that the nonhomogeneous model produces unrealistically low mass fluxes at low pressure below 30 bar and low static upstream quality below 0 5 This in turn causes choking to remain on down to very low pressure ratios 1 1 Consequently the current recommendation is to invoke choking c 0 only where it is expected to occur i e breaks relief valves etc and to select the homogeneous flow option h 2 for these junctions All other junctions in the model should be specified as nonhomogeneous h 0 with choking turned off c 1 Using the homogeneous junction option produces mass fluxes that closely agree with the homogeneous equilibrium critical flow model In identifying the junctions where choking should be invoked the user should not overlook the possibility of choking occurring at locations internal to the system for example the upper core support plate in a PWR The recommendation for such locations is to invoke choking with the nonhomogeneous junction option This allows slip to occur and does not preclude countercurrent flow When specifying the choking option at internal junctions the user should carefully monitor calculated results for nonphysical choking particularly at low pressure If this occurs the user should turn choking off for the remainder of the calculation Guidelines for the discharge coefficients subcooled and two phas
158. he program If closure is not within the error criterion of 0 0001 m an input error will result The horizontal flow regime map is used rather than the vertical flow regime map when is less than or equal to 45 degrees Horizontal flow calculations include a horizontal stratified flow capability and a horizontal stratified entrainment model Wall friction effects are computed from pipe roughness and hydraulic diameter data entered for each volume If the input hydraulic diameter Dj is zero it is computed from the volume flow area A D Y 2 3 2 The thermal stratification t level model 1 water packer p vertical stratification v and equilibrium e flags can be entered only for the x coordinate direction The friction f flag can be entered for the x y and z coordinate directions NUREG CR 5535 V2 2 26 RELAP5 MOD3 2 A check is made that the pipe roughness is less than half the hydraulic diameter Most volumes allow seven control flags tlpvbfe the t flag is the thermal stratification flag the 1 flag is the level model flag the p flag is the water packer flag the v flag is the vertical stratification flag the b flag is the bundle interphase friction flag recommended for cores and steam generators the f flag determines whether wall friction from the volume is to be included or neglected the e flag controls whether a nonequilibrium two phases permitted to have unequal temperature or an equilibrium two p
159. ic volume and heat structure to the total Reactivity feedback is usually defined such that the weights for volumes and heat structures each should sum to one The code does not check that the weights sum to one The use of the weights is different between the separable and table options In the separable option a reactivity effect is first computed for a volume or for a heat structure Then its contribution to the total reactivity is obtained by multiplying the effect by the weighting factor This order is reversed for the table option Weighted averaged independent variables for table lookup and interpolation are obtained by using volume or heat structure values and the weighting factors Table evaluation for total feedback uses the averaged values It is possible to define a table equivalent to the separable data However slightly different transient results would be obtained using the equivalent data owing to the difference in application of the weighting factors In steady state problems the user usually wishes to specify reactor power If reactivity feedback data are entered reactor power will vary as the reactor system moves toward a steady state condition To 5 3 NUREG CR 5535 V2 RELAP5 MOD3 2 prevent this a control system could be defined to adjust reactivity to maintain constant power A simpler alternative is to omit reactivity feedback in steady state and the reactor power will remain constant at the input value At the restart
160. ics and density of thermodynamic and property tables In general the accuracy effect of each of these factors is of the same order thus improving one approximation without a corresponding increase in the others will not necessarily lead to a corresponding increase in physical accuracy At the present time very little quantitative information is available regarding the relative accuracies and their interactions What is known has been established through applications and comparison of simulation results to experimental data Progress is being made in this area as the code is used but there is and will be for some time a need to continue the effort to quantify the system simulation capabilities 1 3 NUREG CR 5535 V2 RELAP5 MOD3 2 NUREG CR 5535 V2 RELAP5 MOD3 2 2 HYDRODYNAMICS The hydrodynamics simulation is based on a one dimensional model of the transient flow for a steam water noncondensable mixture The numerical solution scheme used results in a system representation using control volumes connected by junctions A physical system consisting of flow paths volumes areas etc is simulated by constructing a network of control volumes connected by junctions The transformation of the physical system to a system of volumes and junctions is an inexact process and there is no substitute for experience General guidelines have evolved though application work using RELAPS The purpose here is to summarize these guidelines In selecting a
161. inertia friction and torque and has storage for its rotational velocity For example the pump model allows cubic expressions for inertial and friction The friction expression shown in Equation 4 2 25 is used for the shaft itself and the generator component Each component also has a disconnect trip number If zero no trip the component is always connected to the shaft If a trip is specified the component is connected when false and disconnected when true Any disconnected component is advanced separately and thus can have a different rotational velocity than the shaft All connected components have the same rotational velocity The shaft equation is advanced explicitly by roue 0 2 Ye 4 2 26 where superscripts indicate time levels Inertias torques and friction are evaluated using old time information The torque from the control system T would be in terms of new time values for quantities other than control variables and would use new or old time values for control variables depending on their component numbers relative to the shaft component number Except when a generator component is involved the shaft component calculations consist of solving Equation 4 2 26 for ont separately for each component disconnected from the shaft if any and for the shaft and the connected components as one system For separated components the new rotational velocity is stored with the component data and the summations are only over
162. instantaneously and fully and the switch is on Once the valve is opened the fluid is accelerated flow through the valve begins and the dynamic pressure aids in holding the valve open Since the valve cannot close until the closing back pressure PCV exceeds the junction static and dynamic pressure there is a hysteresis effect both with respect to the opening and closing pressure differential and with respect to the fluid flow These hysteresis effects are also determined by the sign of PCV as input by the user If PCV is input as positive positive or forward flow through the valve will be allowed and negative or reverse flow will be restricted In this sense the valve performs as a check valve However if PCV is input as negative it will aid in opening the valve and significant negative or reverse flow must occur before the valve will close In this sense the valve will not perform as a check valve In addition valve actuation lags one time step behind the pressure and flow calculations in the numerical scheme 2 47 NUREG CR 5535 V2 RELAP5 MOD3 2 2 3 10 1 4 Check Valve Closing Back Pressure Term PCV In Section 3 in Volume 1 the term PCV is used in the input requirements this term is designated as the closing back pressure However to be precise PCV 16 a constant representing an actuation set point If positive PCV behaves as a back pressure acting to close the valve In both the static and dynamic pressure controlled valves PC V
163. interpolating when needed If the table is missing the pump motor is implied and torque is assumed to be such that the net torque is zero This is implemented in the program by simply setting the pump angular velocity at the end of the time step equal to that at the beginning of the time step This latter option is usually used when the problem starts with the pump at its normal steady state velocity the pump is assumed to remain at this velocity until the pump trip and the trip once true remains true for the rest of the problem NUREG CR 5535 V2 2 42 RELAP5 MOD3 2 2 3 8 2 Pump Modeling Examples Two examples are discussed to illustrate pump operation Consider a pump in a closed loop filled with liquid water At the start of the transient all the water in the loop is at zero velocity but the pump is rotating in the positive direction No pump motor torque table is used the pump trip is initially false and thus the pump angular velocity is constant at the initial value until the pump trip becomes true With the pump rotating at a constant angular velocity but the water at rest the head is high and the water is accelerated As the velocity of the water increases wall friction and area change losses increase because of the dependence of these losses on water velocity At the same time the pump head obtained from the homologous data will decrease as the volumetric flow increases A steady state will be reached when the pump head and the loss eff
164. ion should also be connected to the separator inlet side CCC000000 NUREG CR 5535 V2 2 52 RELAP5 MOD3 2 4 the type of separator desired is specified on Card CCC0002 If the mechanistic separator or dryer options are chosen additional input data may be entered on the CCCOSOX cards for the mechanistic separator model and on the CCC0600 card for the dryer model Default data are provided for both the mechanistic separator and dryer models 3 a word W7 R is added to the SEPARATR component junction geometry Cards CCCNI01 for the simple separator option For the vapor outlet Word W7 R specifies VOVER For the liquid fall back junction Word W7 R specifies VUNDER No input should be entered for Word W7 R on the separator inlet junction 2 3 11 2 Recommendations for the Simple Separator Option The smooth or abrupt junction option can be used for the separator Separators in general have many internal surfaces that lead to flow resistances above that of an open region For this reason additional energy loss coefficients may be required at the appropriate separator junctions These should be obtained from handbook values or adjusted to match a known pressure drop across the separator In some cases it is necessary to use large loss coefficients 2100 in order to remove void oscillations in the separator volume In addition we recommend that choking be turned off for all three junctions The nonhomogeneous options should be used for the vapor
165. ion will stop This method is often used by the development staff in debugging the code An example of a diagnostic edit for one time step when HELP 3 is presented in Appendix B Another way a diagnostic edit can occur is to set HELP 2 with a debugger in any of the hydrodynamic subroutines This will force out the diagnostic edit for the remainder of the hydrodynamic subroutines in this time step Then the time step will be repeated with HELP set to 2 and IWRITE set to 1 in the heat transfer subroutines As a result the entire time step will be repeated with the diagnostic edit obtained for the hydrodynamic and heat transfer subroutines After this the code continues the calculation with HELP reset to 0 resulting in no further diagnostic edits The final way a diagnostic edit can occur is when a code failure occurs This does not occur for every code failure but it does occur for a large number of them When this occurs HELP will be set to 1 in most cases When it is set to 1 the diagnostic edit will be forced out for the remainder of the time step Then the time step will be repeated with HELP set to 1 and IWRITE set to 1 in the heat transfer subroutines As with the previous case the entire time step will be repeated with diagnostic edit obtained for the hydrodynamic and heat transfer subroutines For this case however the calculation terminates and a final major edit plus a minor edit are printed out There are two added printouts for
166. ip number for the table 16 trip number 605 the third entry indicates that the time values are to be used as entered 1 6 multiplied by 1 0 the last entry indicates that the power values that are input should be scaled by 50 0 6 1 e 50 MW The search logic is determined by the trip input A nonzero trip number specifies the following logic when the trip is false the table is interpolated using a search argument of 1 0 resulting in a power of zero up to the trip time t when the trip is true the table is interpolated with search argument t t effectively shifting the origin of the table to time t This is analytically equivalent to the application of a unit step function and delay If a zero trip number is specified current time is always the search argument The remaining input defines the time history The data are input as x y pairs of time and power The tabular data show two data points having the same time value zero but having different power values This allows entry of step changes as shown on the graph The graph also illustrates that when search arguments are beyond the range of entered data endpoint values are used rather than extrapolation Entry of a nonzero trip number in general tables is valid only when time is the independent variable Time dependent volumes time dependent junctions and pump angular velocity tables are examples of component tables These tables provide for entry of a trip number and in the default
167. iquid discharge line from a dryer to the downcomer should be modeled as a separate volume or set of volumes so that the liquid removed by the dryer may be injected into the downcomer at the correct elevation below the two phase mixture level in the downcomer The void fraction within the dryer component can also be adjusted by use of the liquid discharge junction form loss coefficient The separator component may represent any number of physical separators It is required that the geometry i e volume and junction flow areas of the separator component be the volume and flow areas of all of the physical separators represented by the RELAPS separator components and that the number of separators represented by the RELAPS separator component be specified in Word 2 on Card CCC0002 in the separator component input data 2 3 12 Turbine A steam turbine is a device that converts thermal energy contained in high pressure high temperature steam to mechanical work Three different stage group types can be implemented a a two row impulse stage group which is normally only used as the first stage of a turbine for governing purposes b a general impulse reaction stage group with a fixed reaction fraction needed as input and c a constant efficiency stage group to be used for very simple modeling or as a preliminary component during the model design process A simple efficiency formula for each of the turbine types is given in Volume I where all the terms a
168. itial calculations result in unphysical results because of unanticipated numerical idiosyncrasies Only the algebraic sign is needed in the one dimensional hydrodynamic components to indicate the direction of vector quantities i e the volume and junction velocities Both the volumes and the junctions have coordinate directions that are specified through input Each hydrodynamic volume has three coordinate directions named x y and z and each coordinate direction has an associated inlet and outlet face The coordinate direction is positive from the inlet to the outlet The normal one dimensional flow is along the x coordinate Normal volume connections are to the inlet and outlet faces associated with the x coordinate Cross flow connections are to the inlet and outlet faces associated with coordinates orthogonal to the x coordinate that is the y and z coordinates Which faces of a volume are the inlet or outlet faces depend upon the specifications of the volume orientation For a positive vertical elevation change the inlet is at the lowest elevation whereas for a negative vertical elevation change the inlet is at the highest elevation of the volume For a horizontal volume whether the inlet is at the left or right depends upon the azimuthal angle A zero value implies an orientation with the inlet at the left This orientation of a horizontal volume is not important as far as hydrodynamic calculations are concerned but is important if one
169. ixer section 0 Vr Drive line Vp KD 0 Vxp Section 1 Section 2 Figure 2 3 5 Schematic of mixing junctions 2 3 9 1 Input Requirements The input for a JETMIXER component is the same as that for a BRANCH component with the following modifications 1 for a BRANCH component the Junctions connected to that branch can be input with the branch or as separate components For a JETMIXER three and only three Junctions representing the drive suction and discharge must be input with the JETMIXER component i e NJ 3 If NJ is not equal to 3 an input error message is printed 2 the three junction card sequences must be numbered as follows Cards CCC1101 and CCC1201 represent the drive junction Cards CCC2101 and CCC2201 represent the suction junction Cards CCC3101 and CCC3201 represent the discharge junction in the mixing section NUREG CR 5535 V2 2 44 RELAP5 MOD3 2 3 The drive and suction junctions must have their TO connection codes referring to the JETMIXER volume and the discharge junction must have its FROM connection code referring to the JETMIXER volume If this is not the case an input error message 18 printed The drive and suction junctions must be connected to the inlet side of the JETMIXER volume and the discharge junction must be connected to the outlet of the JETMIXER volume If this is not the case an input error message is printed 2 3 9 2 Recommendations Although the junction and volume areas f
170. junction If no card is entered but the CCFL flag f is set to 1 then default values of the four quantities will be used Presently the default values are D UAYT B 0 1 m 1 This corresponds to a Wallis CCFL correlation with a gas intercept of 1 and a slope of 1 which 2 2 5 according to Wallis is the case for turbulent flow m 1 and when end effects are minimized c 1 The input was made general so that the user can input CCFL correlations for the particular geometry of interest Wallis 75 Bankoff et al 2 2 6 and Tien et al 22 7 discuss numerous examples and these along with other references should be consulted in order to justify the use of a particular correlation for a given geometry Wallis suggests m 1 for a turbulent flow c 0 725 for tubes with sharp edged flanges and c 0 88 to 1 0 for tubes when end effects are minimized Bankoff suggests D tanh yk D where the critical wave number k 27 t corresponds to the maximum wavelength that can be sustained on a interface of length t the plate thickness and Y is the perforation ratio fraction of plate area occupied by holes Bankoff suggests m 1 and c of the form c 1 07 4 33 x 10 D D 200 2 2 5 c 2 D gt 200 where D is a Bond number defined as D nIID g pr p o 2 2 6 and n is the number of holes Tien uses the Kutateladze form B 1 but the form of c allows the Wallis form also to be invoked for small
171. led FROM VOL and TO VOL A minus sign will be printed in front of the from volume number if it is not the outlet end of the volume Similarly a minus sign will be printed in front of the to volume number if it is not the inlet end of the volume Next are the liquid n 1 junction velocity and vapor junction velocity LIQ J VEL and VAPJ VEL v and Vii In single phase the velocities are equal This is followed by MASS FLOW the mass flow rate n 1 n 1 Cae De Ve JA The next two quantities are JUN AREA junction area A and 8 15 NUREG CR 5535 V2 RELAP5 MOD3 2 THROAT RATIO throat ratio A5 A where Ar is the junction area at the throat For the smooth area option Aj is the physical area full open area if a valve For the abrupt area option Aj is the minimum area of the two connecting volumes The throat ratio is the ratio of the actual junction area to the defined junction area This quantity may be less than one for orifices and valves The velocities are based on the junction area A The next quantity is the junction control flag JUNCTION FLAGS which 16 the seven digit packed number efvcahs that the user inputs for each junction The next quantity is the junction flow regime FLOW REGI see Section 2 1 of this volume of the manual for the meaning of the flow regime label The last three columns are a choking summary NO ADVS CHOKED The subheading LAST indicates whether the choking model was applied on the l
172. led SYSTEM followed to the right by the system number 1 2 3 etc and the name of the system optional none if no name is input on Cards 120 through 129 To the right of this are the labels MASS MASS ERROR and ERR EST for this system followed immediately by the actual value and unit These three quantities correspond to the TOT MS MS ERR and ERR EST listed in the Time Step Summary except that these are only for the particular system whereas the Time Step Summary quantities are the sum for all the systems In Figure 8 3 1 there is only one system SYSTEM 1 and thus the MASS MASS ERROR and ERR EST are the same as the corresponding quantities in the Time Step Summary The largest error estimate labeled ERR EST for all the systems is used for the error estimate labeled ERR EST of the entire configuration As Figure 8 3 1 illustrates quantities are grouped by component within each system Each component is first labeled with the component name supplied by the user and the component type Underneath this are the values for each volume within the component The first items printed in this section are the abbreviated labels and units for the quantities to be printed out The first label is VOL NO which is the component number CCC and the six digit volume subfield number XX Y YZZ within the component These numbers are separated by a hyphen Next is PRESSURE which is the pressure Pr used in the hydrodynamic equa
173. lest tee is the 90 degree tee in which all branches have the same or comparable diameters The recommended nodalization for this flow process is illustrated in Figure 2 2 1 The small volume at the intersection of the side branch with the main flow path should have a length equal to the pipe diameters Generally this length will be shorter than most other hydraulic volumes and will have a relatively small material Courant limit The code however has a time step scheme that permits violation of the material Courant for an isolated volume for the semi implicit scheme Thus this modeling practice may not result in a time step restriction User experience has shown that if the code runs too slowly and is Courant limited in the small volume it is possible to increase the length of the volume to allow faster running without adversely affecting the results The Junction J3 is specified as a half normal junction and half crossflow junction The half of Junction J3 associated with Volume V4 is a normal junction whereas the half associated with Volume V2 is a crossflow junction The junction specification is made using the junction flag efvcahs which for a single junction is Word W6 I of Cards CCCO101 through CCCO109 As noted in previous crossflow discussions the same momentum equation options are used available in both normal and crossflow Both flow types allow ignoring of momentum flux and wall friction terms through the use of volume and junction flags
174. licit numerical scheme to permit economical calculation of system transients The objective of the RELAP5 development effort from the outset was to produce a code that included important first order effects necessary for accurate prediction of system transients but that was sufficiently simple and cost effective so that parametric or sensitivity studies are possible The code includes many generic component models from which general systems can be simulated The component models include pumps valves pipes heat releasing or absorbing structures reactor point kinetics electric heaters jet pumps turbines separators accumulators and control system components In addition special process models are included for effects such as form loss flow at an abrupt area change branching choked flow boron tracking and noncondensable gas transport The system mathematical models are coupled into an efficient code structure The code includes extensive input checking capability to help the user discover input errors and inconsistencies Also included are free format input restart renodalization and variable output edit features These user conveniences were developed in recognition that generally the major cost associated with the use of a system transient code is in the engineering labor and time involved in accumulating system data and developing system models while the computer cost associated with generation of the final result is usually small The
175. mixing of high velocity parallel streams Application of this model is discussed in Section 2 3 9 A branch component consists of one system volume and zero to nine junctions The limit of nine junctions is due to a card numbering constraint Junctions from other components such as single junctions pumps other branches or even time dependent junction components may be connected to the branch NUREG CR 5535 V2 2 14 RELAP5 MOD3 2 component The results are identical whether junctions are attached to the branch volume as part of the branch component or as part of other components Use of junctions connected to the branch but defined in other components is required in the case of pump and valve components Any of these may also be used to attach more than the maximum of nine junctions that can be described in the branch component input A typical one dimensional branch is illustrated in Figure 2 2 3 The figure is only one example and implies merging flow Additional junctions could be attached to both ends and any of the volume and junction coordinate directions could be changed The actual flows may be in any direction thus flow out of Volume V3 through Junction J and into Volume V5 through Junction J is permitted Ji y V1 0 j Aii V3 Y 03 Ja V4 O J i E vgVa V5 O Aja V3 Figure 2 2 3 Typical branching junctions The volume velocities are calculated by a method that ave
176. n Eds SCDAP RELAP5 MOD2 Code Manual Volume I RELAPS Code Structure System Models and Solution Methods and Volume III User s Guide and Input Requirements NUREG CR 5273 EGG 2555 June 1989 c To be published in 1996 xv NUREG CR 5535 V2 RELAP5 MOD3 2 Volume IV contains a detailed discussion of the models and correlations used in RELAP5 MOD3 It provides the user with the underlying assumptions and simplifications used to generate and implement the base equations into the code so that an intelligent assessment of the applicability and accuracy of the resulting calculations can be made Thus the user can determine whether RELAP5 MOD3 is capable of modeling his or her particular application whether the calculated results will be directly comparable to measurement or whether they must be interpreted in an average sense and whether the results can be used to make quantitative decisions Volume V provides guidelines for user that have evolved over the past several years from applications of the RELAPS5 code at the Idaho National Engineering Laboratory at other national laboratories and by users throughout the world Volume VI discusses the numerical scheme in RELAP5 MOD3 and Volume VII is a collection of independent assessment calculations NUREG CR 5535 V2 xvi RELAP5 MOD3 2 ACKNOWLEDGMENTS Development of a complex computer code such as RELAPS is the result of team effort and requires the diverse talents of a large numbe
177. n be made in the transient mode In this case all initial conditions for the transient are supplied from the steady state calculation It is also possible to restart in either the transient or steady state mode from either a prior transient or steady state run The user should be aware that use of the steady state option provides a more optimum solution than simply running the problem as a transient and monitoring the results This occurs because the code monitors results for the entire system including the effects of calculational precision Also thermal inertia for the heat structures is generally quite large so that for the transient option the heat structure temperature distribution will not achieve steady state in the time that a hydrodynamic steady state can be achieved Hence use of the steady state option will provide the user with a precise steady state including a precise heat structure steady state NUREG CR 5535 V2 7 2 RELAP5 MOD3 2 It is still necessary to supply input specifying initial conditions for a steady state run However the accuracy of the input data is less critical since they are simply used as a starting point for convergence to a steady state The values used should be reasonable however since the closer they are to the actual steady state the shorter the calculation will be to achieve steady state Once an initial steady state is calculated the user can save the RESTART PLOT file and perform subsequent new st
178. n of single junctions its common use is to crosslink adjacent volumes of parallel pipes Because the junctions linking pipe volumes tend to be similar N junctions crosslinking N volumes per pipe can be entered with the amount of input comparable to one junction A sketch showing a series of three horizontal volumes connected by two junctions is shown in Figure 2 1 3 to illustrate some of the possible coordinate orientations that result from combinations of the connection codes and the volume orientation data In Figure 2 1 4 two possible combinations are illustrated for the connection of two vertical volumes Figure 2 1 4a shows the two volumes unconnected Figure 2 1 4b shows the result when the outlet of Volume 1 is joined to the inlet of Volume 2 and Figure 2 1 4c shows the result when the inlet of Volume 1 is connected to the inlet of Volume 2 In particular note that the geometry can be modified from a straight passage to a manometer configuration by simply reversing the inlet outlet designator in the junction connection code NUREG CR 5535 V2 2 6 RELAP5 MOD3 2 Figure 2 1 4 Sketch of possible vertical volume connections When systems of volumes or components are connected in a closed loop the summation of the volume elevations must close when they are summed according to the junction connection codes and sequence or an unbalanced gravitational force will result RELAPS has an input
179. n of two volumes from two vertically stacked volumes to a U tube configuration Input for a volume includes the elevation change in a volume For a straight pipe the elevation change Az is related to the volume length Ax and the vertical angle 0 by Az Ax sing 2 3 1 Note that the elevation change associated with the x coordinate has the same sign as the vertical angle To allow for irregularly shaped and curved volumes the input elevation change is used for gravity head calculations Input checks are limited to the following the magnitude of the elevation change must be equal to or less than the volume length and for the x direction the elevation change must be zero if the vertical angle is zero and the elevation change must be nonzero and have the same sign as the vertical angle if the vertical angle is nonzero The volume input does not need the elevation height of a volume relative to an arbitrary base The elevation change data performs the same function in determining gravity heads If the hydrodynamic system has one or more loops the user must ensure that the sum of the elevation changes of the volumes in each loop is zero A loop is any hydrodynamic flow path starting at a volume passing through one or more other volumes and returning to the starting volume If the net elevation change in a loop is not zero an incorrect gravity head exists this is comparable to having an undesired pump in the loop This error is checked by t
180. nal flow regime number iregj in the minor edits and plots that is associated with a particular geometry flow and correlation that is used in the interphase drag If not in bubbly or slug flow and not a vertical function the number will be zero Table 2 1 2 shows the number used for each regime In the transition regions 11 and 15 a fraction is added to the number between 0 and 1 that indicates how far the junction conditions are between churn turbulent bubbly and Kataoka Ishii based on the dimensionless vapor superficial velocity gs The interphase friction model for bundles i e core and steam generator can be activated with a volume control flag b The model is based on a correlation from EPRI as discussed in Volume I of this Manual When in bubbly or slug flow the flow regime number is 2 as indicated in Table 2 1 2 otherwise it is O The user should be aware that all plant or experimental facility geometries that are not circular should have an input junction hydraulic diameter to specify the necessary information required for the code calculated interphase friction For bundles and steam generators the junction hydraulic diameter should match the volume hydraulic diameter including grid spacers which should use the volume hydraulic diameter at the junction In addition for grid spacers the volume flow area should be used at the junction and the user input loss should be multiplied by ratio of squared areas of the volume and the
181. namic calculational results by one time step In order for the user to more fully use the valve models some characteristics and recommendations for each valve are discussed in the following subsections 2 3 10 1 Check Valves Check valves are on off switches and the on off action is determined by the formulation presented in Volume 1 of this manual In turn it is the characteristic of these formulations that determines the kind of behavior modeled by each type of check valve 2 3 10 1 1 Static Pressure Controlled Check Valve The check valve logic in Section 3 of Volume I describes the operation of a static pressure controlled check valve If the equation is positive the valve is instantaneously and fully opened and the switch is on If the equation is negative the valve is instantaneously and fully closed and the switch is off If the equation is zero an equilibrium condition exists and no action is taken to change the existing state of the valve Hence in terms of pressure differential there is no hysteresis However because the valve model is evaluated explicitly in the numerical scheme the actual valve actuation will lag one time step behind the pressure differential In terms of fluid flowing through the valve in a transient state it is obvious that if the valve is closed and then opens the flow rate is zero but when a pressure differential closes the valve the flow rate may be either positive negative or zero Hence with respect to
182. nce or ease in output interpretation the coordinate direction should be an easily remembered direction such as the normal flow direction as opposed to the flow in an accident situation As noted in the discussion of Figure 2 1 4 and described further below a junction connects a specified end of one volume to the specified end of another volume This in turn establishes relative 2 25 NUREG CR 5535 V2 RELAP5 MOD3 2 positioning of the volumes Because of gravity heads the relative position is important to any volume with a nonzero vertical component of a volume coordinate direction If the coordinate direction in a volume with a vertical component is reversed but no other changes are made the inlet and outlet ends of the volumes are also reversed The physical problem is changed since the relative vertical positions of the volumes are changed If appropriate changes are made to junctions connecting the reversed volume such that the physical problem remains unchanged the only change in the problem results would be a reversal in the sign of the vector quantities associated with the volume Furthermore given a stack of vertically oriented volumes the proper gravity head is computed whether the direction coordinates are all upward all downward or any random distribution This assumes that junction connections are such that a vertical stack is specified As shown in Figure 2 1 4 a change in junction specification can change the relative positio
183. nd boundary conditions If a good temperature guess is not known setting the temperature of any surface connected to a hydrodynamic volume equal to the volume temperature assists the convergence of the boundary conditions The iteration process is not very sophisticated and convergence to 0 01 K occasionally is not obtained Input of a better initial distribution especially surface temperatures usually resolves the problem 3 2 Heat Structure Boundary Conditions Boundary condition input specifies the type of boundary condition the possible attachment of a heat structure surface to a hydrodynamic volume and the relating of the one dimensional heat conduction solution to the actual three dimensional nature of the structure Each of the two surfaces of a heat structure may use any of the boundary conditions and may be connected to any hydrodynamic volume Any number of heat structure surfaces may be connected to a hydrodynamic volume but only one hydrodynamic volume may connect to a heat structure surface When a heat structure is connected to a hydrodynamic volume heat transferred from or to the heat structure is added to or subtracted from the internal energy content of the volume For both left and right surfaces a positive heat transfer rate represents heat flow out of the surface A symmetry or insulated boundary condition specifies no heat transfer at the surface that is a zero temperature gradient at the surface This condition should be
184. nd has already been discussed The h flag controls the type of momentum treatment two velocity or one velocity models The two velocity model is recommended except as indicated above The s flag controls whether the momentum flux is to be used System junctions require initial velocities and time dependent junctions require velocities as a function of time Two options are available to specify the velocities One option requires the velocities the other requires mass flow rates from which the velocities are computed If the flow is single phase the velocity of the missing phase is set to that of the flowing phase This matches the transient calculation that computes equal phasic velocities when one phase is missing The velocity conditions also require an interface velocity This input is for future capability involving moving volume interfaces For now the interface velocity must be set to zero 2 29 NUREG CR 5535 V2 RELAP5 MOD3 2 2 3 2 Time Dependent Volume A time dependent volume must be used wherever fluid can enter or leave the system being simulated The geometry data required are similar to system volumes but during input processing the volume s length elevation change and volume are set to zero With the staggered mesh the pressure boundary would be applied in the center of the time dependent volume Setting these quantities to zero moves the boundary to the edge of the system volume The state conditions as a function of time o
185. nn cana ayaka S 5 2 6 GENERAL TABLES AND COMPONENT TABLES eene 6 1 7 INITIAL AND BOUNDARY CONDITIONS etre nete ren rennen 7 1 7 1 Initial Conditions iter tre e EE he ERE TE e e Reged 7 1 Tl Input Initial Values ee IE Ree deen 7 1 7 1 2 Steady State Initialization eese eren 7 2 7 2 Boundary Conditions idiota iii Peek tert eere up leet 7 3 7 2 Mass Sources or Sinks uide ine e ere re ere Re Mean 7 3 1 2 2 Pressure Boundary een Sot ere dle t Ger Eee et eo OPERIS avec 7 4 8 PROBLEM CONTROL orita ett ree ete e E R E a de 8 1 8 1 Problem Types and Options ip tede e ep oe ete des 8 1 HB BEN CULA 8 1 8 2 Time Step ConttroLl i eru te bm aet He ert eot oet 8 1 8 3 Printed Output asas 2 5 uu s u em cin HR dee 8 4 9 3 1 Input Editing cia centenis eiie ordena 8 4 8 3 2 Major Edits ii e aman u aa sticks rene i em Fe tant 8 5 NUREG CR 5535 V2 vi RELAP5 MOD3 2 5 2 29 Minor Edits ue eee ete tee ciet et eh eren 8 18 8 3 4 Diagnostic Edite alasan em eere cte pee espe Bp ede 8 18 8 4 Pl tted Outp t vendia pi seas esteet 8 23 s 4 1 External Plots dd de e a u te Na ER ees 8 23 9 4 2 Internal Plot nete e eA Ls 8 23 8 5 RELAPS Control Card Requirements eese ener 8 27 8 6 Transient Termitiatlori tt ort hetero rt ret e e e guste u Qu o anes 8 27 8 7 Problem Changes at Restart a iecore eee la 8 27 APPENDIX A INPUT REQUIR
186. ns being one less than the number of volumes and the junctions connect the outlet of one volume to the inlet of the next volume Pipe components can be used for those portions of the system without branches Pipe components offer input conveniences since most characteristics of the volumes and junctions in a pipe are similar or change infrequently along the pipe and input data requirements can be reduced accordingly Because of the sequential connection of the volumes junctions are generated automatically rather than being individually described Although the input is designed to assume considerable similarity in volume and junction characteristics any of the volume and junction features such as flow area orientation pipe roughness or control flags can be changed at each volume or junction 2 3 7 Branch Branch components are provided to model interconnected piping networks The branching model is based on one dimensional fluid flow which is adequate for most cases of branching and merging flow Such situations include wyes parallel flow paths from upper and lower plenums and any branch from a vessel of large cross section For branching situations where phase separation effects caused by momentum or gravity are important an approximate mapping technique can be used to map the two dimensional situation into the one dimensional space of the fluid model A branch component consists of one system volume and zero to nine junctions The limit of
187. ns must be specified for each control component used even if the option to compute the initial condition is selected As stated above only the integral functions should require initial conditions However since control components are initialized using a sequential single pass solution scheme and since some control variables may be specified as arguments for other control variables it is possible for some to be initially undefined Hence the initial value for all control variables must be specified Also the code does not check whether initial values are needed nor whether they are reasonable thus the user should always supply an accurate initial value The reactor kinetics model requires specification of an initial power and reactivity Previous power history data may also be entered 7 1 2 Steady State Initialization RELAPS contains an option to perform steady state calculations This option uses the transient hydrodynamic kinetics and control system algorithms and a modified heat structure thermal transient algorithm to converge to a steady state The differences between the steady state and transient options are that a lowered heat structure thermal inertia is used to accelerate the response of the thermal transient and a testing scheme is used to check if steady state has been achieved When steady state is achieved the run is terminated thus saving computer time The results of the steady state calculation are saved so that a restart ca
188. ntaining a time limit minimum time step requested maximum time step control option minor edit plot frequency major edit frequency and restart frequency The time limit must increase with increasing card numbers The information on the first card is used until the problem time exceeds the card limit then the next card is used and so on In restart problems these cards may remain or may be totally replaced Cards are skipped if necessary until the problem time at restart is properly positioned with regard to the time limit values The control option is a packed five digit ssdtt word containing a major edit select option ss a debug output option d and the time step control tt The major edit select option ss allows sections of major edits for the hydrodynamic volumes and junctions heat structures and statistics to be skipped The debug output option d forces any combination of plot minor edits or major edit output to be written at 8 1 NUREG CR 5535 V2 RELAP5 MOD3 2 each successful advancement rather than at just the completion of advancement over a requested time step The time step control option tt allows the user to change the time step control logic All options can be changed with each time step control card Specifically digit tt allows the user to select several time step control options This time step control option is represented by a number between O and 31 that can be thought of as a five bit number Entering
189. ntum flux options attached to the same coordinate direction Even though the momentum flux is ignored in one junction its velocity contributes to the average velocity in that coordinate direction and thus other junctions using momentum flux terms use that average volume velocity The current crossflow model requires input information for the y and z coordinates similar to that entered for the x coordinate Default data for the y and z coordinates are obtained from the x coordinate data by assuming the volume is a section of a right circular pipe Optional input data may be entered when this assumption is not valid In major edits and similar input edits the junction connection code is edited in the new format Note that the new logic allows branching and merging flow 1 6 multiple junctions at a face at any volume including interior pipe volumes The primary reason for this change is to permit crossflow to all volumes in a pipe Now it is possible to use pipe volumes to represent axial levels in a vessel and to use multiple pipe components to represent radial or azimuthal dependence Single junctions can crosslink any of the pipe volumes at the same axial level A simpler method to crosslink volumes is to use the multiple junction component This component describes one or more junctions with the limitation that all volumes connected by the junctions must be part of the same hydrodynamic system Although this component can be considered a collectio
190. o BVDG e 9 BVN 9 Turbine Q N BAT e 9 9 9e aa e BVT j Reverse Q N BAR e BVR 1 0 0 5 9 gt e 1 0 d ee m 0 Denotes torque B Denotes division by a or a A j v or v V Denotes quadrant N D T R Figure 2 3 4 Homologous torque curve which are only approximate In all cases the rated conditions must correspond to the same specific speed as the pump used to produce the data However the operating point does not have to correspond to the rated conditions In such a case the pump will operate at off design conditions and efficiency will be less than the design value Such off design adjustments may be desirable to better match the modeled pump head flow characteristics at the system operating point 2 3 8 1 4 Two Phase Performance Representation The discussion above applies to a pump operated with a single phase fluid of constant density When pump performance operation with a two phase fluid is considered the homologous representation of performance data has a less firm basis An NUREG CR 5535 V2 2 40 RELAP5 MOD3 2 empirical modification of the homologous approach has therefore been developed The RELAPS5 two phase pump model 16 the same as that developed for RELAP4 23 2 The approach is one in which the two phase performance data are plotted and a lowest performance envelope is constructed This curve 16 called the fully degraded two phas
191. o that the volume velocity of the time dependent volume is small and thus the total energy of the inflow is constant When a large area ratio exists between the time dependent volume and the junction connecting it to the system a reservoir or plenum is simulated As a general rule all pressure boundary conditions having either inflow or outflow should be modeled as plenums for stability and realism In particular when an outflow is choked the critical flow model more closely approximates the conditions at a large expansion 1 6 little or no diffusion occurs Thus this assumption is consistent with the choked flow model and is therefore recommended NUREG CR 5535 V2 7 4 RELAP5 MOD3 2 8 PROBLEM CONTROL 8 1 Problem Types and Options RELAPS provides for four problem types NEW RESTART PLOT and STRIP The first two are concerned with simulating hydrodynamic systems NEW starts a simulation from input data describing the entire system RESTART restarts a previously executed NEW or RESTART problem PLOT and STRIP are output type runs using the restart plot file written by NEW or RESTART problems NEW and RESTART problems require an additional option to be selected STDY ST or TRANSNT A RESTART problem may restart from any restart record A note indicating the restart number and record number is printed at the end of the major edit whenever a restart record is written The restart number is equal to the number of attempted advancements and
192. oA uodoq erenb uqop sienb FPTOA T dteu 16667 qunoou 1 0 99856 061 1P Z0 30L6L9GG 9 p aeuruas a Bur q quetsuez ST T6S 8 019 29 99 c8 6cL c8 6c8 BOT TIG 68 166 T ELOT 6 v801 P SOTI O LOTT E LSOT L LOOT LE TOG 89 TE6 ET GES 8S CEL ZE 969 vS 696 8v z0S SIT z8 0 29 c8 6 8 6 89 T 68 T TEL 6 v8 v 80 0 LO LG L LO E T 89 T LIS 8S c cE 796 8v c 4 6S 9 99 cL c8 6 66 01 OT E OT OT 96 6 8 L S89 9G 0S qnoqutad bnqep _ 43474 pea3eedea buteg queueoueApe 3seT 0 ST T6S ST T6S 28 019 28 019 c9 99 c9 99 28 6cL 28 6cL 28 678 28 678 89 TT6 89 TT6 68 166 68 166 T ELOT T ELOT 6 780T 6 780T 78011 78011 0 LOTT 0 LOTT LS0T LS0T L LOOT L LOOT LE T96 L T96 B9 TEG 89 TE6 LT SE8 LT S 8 8S ZEL 8S ZEL ZE 969 ZE 959 vG 69G vG 69G 8v c0S 8v c0S s znaez du q jutod useu ou 90 H9EDLL 0 46650 8 Z 000060900 90 H08599 0 dASSOE8 C 90 H08599 0 4650 8 Z 000080900 90 H700LS 0 3S8GS80 8 C 90 3v00LS e 0 46650 8 Z 000010900 90 31818rv 0 38G80 8 2 90 4T818D 0 46650 8 Z 000090900 90 31L86 0 dASSOE8 C 90 31L86 0 38G80 8 2 000050900 90 HTZDZE 0 H46650 8 Z 90 HTZPZE e 0 46650 8 Z 000070900 90 H0089C 0 ASSOE8 2 904300892 0 SS0 8 Z 0000 0900 90 H6867E 0 dASSOE8 SC 90 H6867E 0 38S80 8 2
193. oble and the current monitor W Rettig The technical editing of the RELAPS5 manuals by D Pack and E May is greatly appreciated Finally acknowledgment is made of all the code users who have been very helpful in stimulating timely correction of code deficiencies and suggesting improvements xvii NUREG CR 5535 V2 RELAP5 MOD3 2 RELAP5 MOD3 2 1 INTRODUCTION The purpose of this volume is to help educate the code user by documenting the modeling experience accumulated from developmental assessment and application of the RELAPS code This information includes a blend of the model developers recommendations with respect to how the model is intended to be applied and the application experience that indicates what has been found to work or not to work Where possible approaches known to work are definitely recommended and approaches known not to work are pointed out as pitfalls to avoid 1 1 General The objective of the user s guide is to reduce the uncertainty associated with user simulation of light water reactor LWR systems However we do not imply that uncertainty can be eliminated or even quantified in all cases since the range of possible system configurations and transients that could occur is large and constantly evolving Hence the effects of nodalization time step selection and modeling approach are not completely quantified As the assessment proceeds there will be a continual need to update the user guidelines document
194. observed when specifying the nonhomogeneous choking model at all junctions Specifically it has been demonstrated that the nonhomogeneous model produces unrealistically low mass fluxes at low pressure below 30 bar and low static upstream quality below 0 5 This in turn causes choking to remain on down to very low pressure ratios 1 1 Consequently the current recommendation is to invoke choking c 0 only where it is expected to occur i e breaks relief valves etc and to select the homogeneous flow option h 2 for these junctions All other junctions in the model should be specified as nonhomogeneous h 0 with choking turned off c 1 Using the homogeneous junction option produces mass fluxes that closely agree with the homogeneous equilibrium critical flow model In identifying the junctions where choking should be invoked the user should not overlook the possibility of choking occurring at locations internal to the system for example the upper core support plate in a PWR The recommendation for such locations is to invoke choking with the nonhomogeneous junction option This allows slip to occur and does not preclude countercurrent flow When specifying the choking option at internal junctions the user should carefully monitor calculated results for nonphysical choking particularly at low pressure If this occurs the user should turn choking off for the remainder of the calculation The a flag is for the area change option a
195. of restart to the end of the transient Minor edit internal plot input data and expanded edit plot variables 2080xxxx cards can be changed at restart If any of the minor edit cards are entered all previous cards are deleted New cards must define all desired minor edit quantities The internal plot request data and expanded edit plot variables 2080xxxx cards are handled in the same manner Trip cards can be entered at restart The user can specify that all previous trips be deleted and can then define new trips The user can also specify that the previously defined trips remain but that specific trips be deleted be reset to false be redefined or that new trips be added Existing hydrodynamic components can be deleted or changed and new components can be added An especially useful feature is that the tables in time dependent volumes and junctions can be changed If a component is changed all of the cards for the component must be entered Control system components can be deleted changed or added Heat structures general tables and material properties can also be deleted changed or added Heat structures can only be changed at the level of heat structure geometry When the heat structure geometry is changed all heat structures referencing that heat structure geometry are affected Individual general tables and material properties can be added deleted or changed Reactor kinetics can be added or deleted on restart A complete
196. ol flag is set the major edit will print out parameters associated with the mixture level in the hydrodynamic volume The parameters are voidla i the void above the level voidlb i the void below the level vollev i the location of the level in side the volume and vlev i the velocity of the level movement The parameters voidla i voidlb i and vollev i can also be written to the restart plot file if a 2080xxxx card is used One can use control system cards 205CCCNN or 205CCCCN to construct the level in the component 2 2 9 Thermal Stratification Model The volume control flag t in tlpvbfe is used to turn on the subcell resolution scheme in the model The model is invoked if the detection criteria are satisfied The model is intended for one dimensional components only 2 23 NUREG CR 5535 V2 RELAPS MOD3 2 The thermal stratification model should be used to improve the accuracy of calculations where there is a warm fluid layer appearing above a cold fluid in a vertical stack of cells A complete description of the model is presented in Section 3 of Volume I 2 2 10 Energy Conservation at an Abrupt Change The junction control flag e in efvcahs is used to activate the modification to the energy flux term described in Volume I This model is recommended for break junctions that connect to containment volumes that are modeled using regular volumes not time dependent volumes 2 2 11 References 2 2 1 V H Ransom et al RELAPS MOD2
197. omponent RELAPS treats control system variables as dimensionless quantities No unit conversion of the input scaling factors or multiplier constants is done when British input units are specified and no unit conversion is done on output when British output units are specified All dimensioned variables are stored within the program in SI units and the units for variables that can be used in control components are stated in the input description The user may assume any desired unit for each control variable It is the user s responsibility to enter appropriate scale factors and multiplier constants to achieve the desired units and to maintain unit consistency Two card formats are provided for input of control system data but only one format may be used in a problem The default format uses Card 205CCCNN where CCC is the control component number and NN is a card sequence number The card format limits the number of control components to 999 The alternate format using Card 205CCCCN can be selected by entering Card 20500000 With the alternate format only one digit is used for card sequencing and up to 9999 control components can be used with the 4 9 NUREG CR 5535 V2 RELAP5 MOD3 2 four digit CCCC Control variables are printed in major edits can be specified for minor edits and can be plotted 4 2 2 Control System Examples Two examples of control system use are given See Section A 14 of Appendix A for input format descriptions Input f
198. omposition placement and source space distribution are common to all the heat structures defined with the heat structure geometry number and only one copy of this information is stored If a heat structure geometry has this data in common with another heat structure input NUREG CR 5535 V2 3 2 RELAP5 MOD3 2 preparation and storage space can be saved by referencing the data in the other component There are no ordering restrictions as to which heat structure geometry may reference another one heat structure geometry may reference another which in turn references a third etc as long as a defined heat structure 1s finally reached An initial temperature distribution may be entered for each heat structure geometry This initial distribution is common to all heat structures defined with the same heat structure geometry number but storage space for temperatures is assigned to each heat structure Referencing initial temperature distributions in other heat structure geometries is allowed Optionally an initial temperature distribution may be entered for each heat structure The input temperature distribution can be used as the initial temperature distribution or initial temperatures can be obtained from a steady state heat conduction calculation using initial hydrodynamic conditions and zero time power values The input temperature distribution is used as the initial temperature guess for iterations on temperature dependent thermal properties a
199. on The x volume length is the length along the x coordinate direction and similarly for the y and z coordinate directions The hydrodynamic numerical techniques require that the volume be equal to the volume flow area times the length for each coordinate direction This requirement is easily satisfied for constant area volumes but poses difficulties for irregular shaped volumes Since it is very important that such a systems code as RELAPS conserves mass and energy with momentum being an important but lesser consideration we recommend that an accurate volume be used that the volume flow area be the cross sectional area averaged over the actual length of the volume and the volume length be the quotient of the volume and the flow area The component input routines permit the volume flow area and length of each volume to be entered as three nonzero positive numbers or two nonzero positive numbers and a zero If three nonzero quantities are entered the volume must equal the flow area times length within a relative error of 0 000001 If one quantity is zero that quantity is computed from the other two The user need not be concerned with x or y coordinate data unless crossflow connections are made and even then only if the default data for those coordinates are not satisfactory The volume horizontal angle specifies the orientation of the volume in the horizontal plane The code numerics have no requirement for this quantity they were entered so a gr
200. on is 7 1 NUREG CR 5535 V2 RELAP5 MOD3 2 valid only for single phase nonsaturated conditions When air 16 specified it is best to use conditions of humid or saturated air at the initial pressure and temperature of the system The specification of dry air can cause numerical difficulties when mixing with water or water vapor occurs If air is the only system component and mixing with water or water vapor does not occur the specification of pure air will cause no problems Heat structure initial temperatures must be input Depending upon the initialization option selected these temperatures are either used as the initial temperatures or as the initial guess for an iterative solution for a steady state temperature profile The iteration solution will attempt to satisfy the boundary conditions and heat sources sinks that have been specified through input Some care is needed since an indeterminate solution can result from specification of some boundary conditions e g a two sided conductor with specified heat fluxes If the initial temperature of a heat structure is unknown it is generally safer to use the steady state option and supply as a first guess a uniform temperature distribution equal to the temperature of a hydrodynamic volume to which it is connected In the case of a two sided structure either side may be selected The steady state solution algorithm will rapidly converge to a steady state temperature distribution Initial conditio
201. operator action may also be used The time variation of the boundary conditions is specified by input tables that can also be varied dynamically by using trips 7 2 4 Mass Sources or Sinks Hydrodynamic mass sources or sinks are simulated by the use of a time dependent volume with a time dependent junction The thermodynamic state of the fluid is specified as a function of time by input or by a control variable The thermodynamic state is needed for inflow because the densities and energies 7 3 NUREG CR 5535 V2 RELAP5 MOD3 2 are needed in the donored flux terms in the density and energy equations The time dependent junction flows or velocities are also specified This approach can be used to model either an inflow or an outflow condition however care is required in modeling outflows A time dependent junction is analogous to a positive displacement pump in that the flow is independent of the system pressure In the case of outflow 1t is possible to specify a greater outflow than inflow to a volume or even outflow that will exhaust the volume In this case a numerical failure will result when the equivalent of a negative density 16 calculated For this reason modeling outflows using a time dependent junction is not recommended 7 2 2 Pressure Boundary A pressure boundary condition is modeled using a time dependent volume in which the pressure and thermodynamic state variables are specified as a function of time through input by tables or by
202. or a JETMIXER are not restricted the JETMIXER will properly model a jet pump only 11 the drive and suction junctions flow areas sum to the JETMIXER volume area The drive and suction junctions can be modeled with smooth or abrupt area changes If they are modeled as smooth junctions then the appropriate forward and reverse loss coefficients must be input by the user They should be obtained from standard references for configurations similar to those of the jet pump being modeled The use of smooth junctions gives the user more explicit control over the resistance coefficients In either case 1t should be remembered that the turning losses associated with reverse flow through the suction junction are automatically included in all code calculations The JETMIXER component volume is intended to represent the mixing region of the jet pump The diffuser section of a jet pump normally follows the mixing section The diffuser section is not an integral part of the JETMIXER component and must be modeled using one or more additional volumes Several volumes with slowly varying cross sections and the smooth junction option can be used to model the diffuser region 2 3 9 3 Additional Guidelines It has been customary to identify jet pump operations in terms of two dimensionless parameters These are the M and N parameters defined as follows The M ratio flow ratio is the suction flow rate Ws divided by the drive flow rate Wp M WyWp 2 3 17 The
203. or the examples are shown except that symbols enclosed in parentheses are sometimes used where the actual input would need a number Also all examples use control component numbers beginning with one The first example is the computation of total flow rate in a volume from W AP Op ev A 4 2 18 where aq is void fraction p is density v is velocity A is flow area the subscript g denotes vapor and the subscript f denotes liquid Two multiplication components and one addition subtraction component are used The time advanced quantities 0 p and v are specified as V4 V and V3 respectively in the two multiplication components one for each phase The area A is entered as the scaling factor An addition subtraction component adds the results from the multiplication components with A 0 Ay A5 S 1 0 and V and V are the control variables defined by the multiplication components For the present numerical scheme the products should be defined first This control system is assumed to generate a quantity for plotting only so initial values are entered as zeros and initialization is selected For volume number 123010000 input data using the default format would be the following 20500100 FFLOW MULT A 0 0 1 20500101 VOIDF 123010000 RHOF 123010000 20500102 VELF 123010000 20500200 GFLOW MULT A 0 0 1 20500201 VOIDG 123010000 RHOG 123010000 20500202 VELG 123010000 20500300 TFLOW SUM 1 0 0 0 1 20500301 0 0 1 0 CNTRLVAR 1 1
204. or volume average velocity vii SOUNDE isentropic sonic velocity for single phase or homogeneous equilibrium isentropic sonic velocity for two phase b QUALITY MIX CUP mixing nal cup or equilibrium quality that accounts for slip X QUALITY STATIC static quality x and n l QUALITY NON COND noncondensable quality X 8 3 2 7 Hydrodynamic Volume Information Fourth Section This section prints whenever the third section prints This section is printed in Figure 8 3 1 Following the volume number is TOT HT INP the total wall heat transfer rate to the liquid and vapor Qj e Vi VAP HT INP wall heat n transfer rate to the vapor Q e Vi VAPOR GEN bulk vapor generation rate per unit volume wg L os WALL FLASHING the direct wall liquid flashing positive mass transfer s LIQ INT HTC liquid to saturation interfacial heat transfer coefficient times area per unit volume Hi DS VAP INT HTC vapor to saturation interfacial heat transfer coefficient times area per unit volume Ho MASS FLUX volume average mass flux G REYNOLDS LIQUID liquid Reynolds number REYNOLDS VAPOR vapor Reynolds number and finally FLOW REGI flow regime See Section 2 1 of this volume for the meaning of the flow regime label 8 3 2 8 Hydrodynamic Volume Time Step Control Information This section is also optional and can be skipped by setting bit four in the ss digits of Word 4 W4 on the time step control car
205. ortioned to the shaft The one exception noted above is that with an implied pump motor no motor torque table entered and no pump trip entered trip number is zero the implied motor torque is always zero This same situation without the shaft generates motor torque sufficient to maintain constant velocity This option with the shaft forces the pump motor torque always to be zero It would be used when a turbine is attached to the shaft or the torque is computed by the control system The pump and shaft components offer several options and in some cases the same model can be specified in more than one manner Some general application recommendations follow For motor driven pumps that are either on or off untripped or tripped use the pump component without a shaft For a variable speed pump where the speed is computed by the control system use a pump component with a one to one velocity table The one to one table is a stratagem for forcing pump velocity to be equal to a control variable Specify the search variable to be the control variable containing the velocity and enter a two point velocity table The independent and dependent variable for each point are the same The first point is for the minimum possible velocity the second point is for the highest velocity expected The output from the table lookup and interpolation is just the input search argument For a motor driven variable speed pump where the torque is computed by the control sy
206. otal mass owing to truncation error M RATO is the NUREG CR 5535 V2 8 5 RELAP5 MOD3 2 00 3000 0 0 3Uv6S T 00 3000 0 0 4906 T 00 3000 0 0 3L0 2 00 3000 0 E0 UZSH Z 00 3000 0 0 39 6 I 00 3000 0 0 3LS2 C puoo uou pt3ae3s A3tTenb AatTenb 000110 90 389090S Z 000000 90 4Z966S Z 000000 90 H6Y66S Z 000000 90 4Z966S Z 000000 90 H6L66S Z 000000 90 3 0009 2 000000 90 31 009 2 000000 90 46S009 Z 000000 90 H66009 Z 000000 90 HEET09 Z 000000 90 4TTI09 Z 000000 90 49ZT09 Z 000000 90 387P109 Z2 000000 90 319109 c2 000000 90 319109 2 000000 90 H8STO9 Z 000000 90 31S109 c2 000000 90 3vvI109 c7 000000 90 307P109 Z2 000000 90 H0YTO9 Z 000000 90 H6ETO9 Z 66073 64 0 unToA bn oes 000001 0 v0 S3SP06Tvl1 I bx 6TOT TT 84 0 83L81L8L l 0 4ZT6 S v 9c 8997 T 0 4pL8 S 88b 9Z 981860 0 3288 G 928 9c 89089 0 0 S3I9 G Lc9 9c cILV O 0 38 S G 8E9 97 16856 0 S LI8 9C 8eezzT 0 dno x Tu S s u S s u AatTenb epunos ZTOdeA TSA SO HLODLT D c8L cLE TEL ELE GO HOTP6E 6 982 c6v 91 c6v GO HS670b 6 ott 267 877 C67 SO WZSLIV 6 82L c6V T9S C67 GO H0SSEP 6 L80 67 6v6 cov SO 0FPLSPE 6 TES E67 tvv t6v S0 3LO0IST 6 L60 v6v 90 v6v GO H7LE0S 6 796 D6 S6 60 GO HPTOLS 6 82h 967 ECP IGE GO HSL9L9 6 0S 867 ILV 867 GO H68S7L 6 9T8 867 FL9 867 GO HZOTSL 6 6L6 860 S88 860 GO HP7T9SL 6 Sv0 66v 0 66b SO 80LSL 6 870 66v T60 667 GO HETLGL 6 800
207. outlet and liquid fall back junctions An important parameter that influences the operation of any heat exchanger separator combination is the equivalent mixture level in the downcomer region This level is primarily determined by the rate of flow in the liquid return junction which in turn is affected by the water level in the separator and the vapor flow out of the separator The liquid return flow and water level in the separator are affected by the user input void limits VOVER and VUNDER that determine the range of ideal separation Because of the simple black box nature of the separator these limits should be adjusted to obtain the desired operating mixture level in the downcomer region The default void limits VOVER 0 5 and VUNDER 0 15 for ideal separation are intended to be preliminary The black box nature of the separator along with the use of VOVER and VUNDER may result in some changes to the user input initial conditions If the user inputs a mass flow rate for both the vapor outlet and liquid fall back junctions the code will in many cases alter the mass flow rates so that they no longer match those inputted This is due to the use of the piecewise linear donor junction voids used see Volume 1 of this manual Depending on the relations of yk and VOVER as well as otc and VUNDER it may be necessary to scale back the mass flow rates to achieve the desired input mass flow rates Once the transient calculation begins the mass flow rate
208. output is optional and can be skipped by setting bit one in the ss digits of Word 4 W4 on the time step control cards Cards 201 through 299 As in the first heat structure section the individual heat structure number STR NO is printed in the first column Then all the mesh point temperatures MESH POINT TEMPERATURES for the individual heat structure are printed starting with the left side and proceeding toward the right side read from left to right across the page In Figure 8 3 1 11 mesh point temperatures are printed out 8 3 2 13 Heflood Information This section of output is not optional and always appears in a major edit when heat structures are present and the reflood model is turned on Once the model is turned On it stays on and this section continues to be printed out Figure 8 3 3 shows an example of this section preceded by the normal heat structure printouts The section begins with the label REFLOOD EDIT and the time The first quantity printed is the heat structure geometry number CCCG labeled GEOM NO Following this are two columns providing information about the number of axial nodes AXIAL NODES NUMBER The first of these columns is the assigned maximum number of axial nodes MAXIMUM This number is computed at input time and it is the theoretical maximum number of heat structures with this geometry maximum number of axial intervals 1 when the user requests 2 4 or 8 maximum number of axial intervals Owing
209. presented by a single junction For flows in pipes there is little confusion with respect to nodalization However in a steam generator having a separator and recirculation flow paths some experience is needed to select a nodalization that will give correct results under all conditions of interest Nodalization of branches or tees also requires more guidance Heat flow paths are also modeled in a one dimensional sense using a finite difference mesh to calculate temperatures and heat flux vectors The heat conductors can be connected to hydrodynamic volumes to simulate a heat flow path normal to the fluid flow path The heat conductor or heat structure is thermally connected to the hydrodynamic volume through a heat flux that is calculated using heat transfer correlations Electrical or nuclear heating of the heat structure can also be modeled as either a surface heat flux or as a volumetric heat source The heat structures are used to simulate pipe walls heater elements nuclear fuel pins and heat exchanger surfaces A special two dimensional heat conduction solution method with an automatic fine mesh rezoning is used for low pressure reflood Both axial and radial conduction are modeled and the axial mesh spacing is refined as needed to resolve the axial thermal gradient The hydrodynamic volume associated with the heat structure is not rezoned and a spatial boiling curve is constructed and used to establish the convection heat transfer boundary
210. quadrant head curve for Semiscale MOD1 pump ANC A 2083 leakage viscous effects etc however the correspondence is surprisingly close as evidenced by the tight clustering of points The homologous curve for the torque data of Figure 2 3 2 is shown on Figure 2 3 4 Since the data do not form a single curve the design operating usual approach is to use least squares or other smoothing techniques to obtain curves passing through the point 1 0 1 0 These curves must also be continuous at the point v amp or amp v equal to 1 0 The legends on Figure 2 3 3 and Figure 2 3 4 have a key indicating which of the homologous parameters are used in each octant All combinations of head flow speed and torque can now be located on a corresponding segment of the homologous curve Note that the impeller diameter parameter that appears in the dimensionless similarity parameters is not used in the homologous reduction of the four quadrant representation thus special considerations are necessary for application of the data to a larger but geometrically similar pump The advantage of using the homologous pump performance data representation in a computer code is obvious Two dimensional data arrays and two dimensional interpolation are avoided and only two parameter tables and one dimensional interpolation are required NUREG CR 5535 V2 2 36 RELAP5 MOD3 2 9 a Line of copstant Q N Dissipation N BAD E ELE Normal BVD BVN E Vol
211. r and Servo Valves The interaction of both motor and servo valves with fluid flow are identical but the means of positioning the valves are different Both valves use a normalized stem position to position the valve The normalized stem position ranges between 0 0 for the closed position to 1 0 for the fully open position The flow area corresponding to a normalized stem position is determined from the normalized flow area which also ranges from 0 0 for fully closed to 1 0 for fully open A general table can be used to describe the normalized flow area for a given normalized stem position If the general table is not used the normalized flow area is set to equal the normalized stem position Two models are provided to effect flow changes based on valve flow area If the abrupt area change flag is set the abrupt area change model is used to determine flow losses and the valve flow area is treated as the orifice area in the abrupt area change model If the abrupt area change flag is not set a CSUBV table must be entered This table contains forward and reverse flow coefficients as a function of normalized valve area The model using CSUBV coefficients should usually be used when the valve is designed for regulating flow The motor valve assumes that the valve stem is positioned by a motor The valve position can be stationary or the valve can be moving at a constant rate in the opening or closing direction The rate is a user input quantity in terms of no
212. r junction is zero It is further assumed that the standpipe surgeline is initially full of liquid and that the tank liquid level is as defined by the user These assumptions are also true for RESTART runs if the user renodalizes the accumulator Hence the user must be careful to define the initial accumulator pressure lower than the injection point pressure including elevation head effects The tank geometry may be either cylindrical see Figure 2 3 11 or spherical see Figure 2 3 12 In the input description Appendix A the standpipe surgeline inlet refers to the end of the pipe inside the tank itself see Figure 2 3 13 Also the noncondensable nitrogen used in the accumulator is that defined for the entire system being modeled Hence the user must be sure to input the correct noncondensable name nitrogen on Card 110 as discussed in Appendix A No other junctions except the accumulator junction should be connected to an accumulator volume There are 4 possible accumulator configurations as shown in Figure 2 3 14 The inclination angle W5 and elevation change W6 in Cards CCCO101 CCCO109 can be either positive or negative but both must have the same sign The elevation drop of the surgeline and standpipe W4 in Card CCC2200 is positive NUREG CR 5535 V2 2 56 RELAP5 MOD3 2 Steam and nitrogen Lrk Liquid water Y Fill ATK p Standpipe g surgeline Figure 2 3 11 Schematic
213. r mentioned above and shown in Figure 8 3 7 and Figure 8 3 8 can occur as a result of this This can occur when the user inputs state properties that are undetected in input processing and thus get into the transient calculation Thermodynamic property errors are the same as when either the REDUCE PROPTY or REDUCE EXTRAP flags are set in the major edit hydrodynamic volume time step control information block see Section 8 3 2 8 Another example of a user caused failure is when material property data are out of range Two more user caused failures can occur in the case of valves If both motor valve trips become true at the same time a failure will result In addition if the control system is set up incorrectly and this results in the servo valve stem position not being between 0 and 1 a failure will result Another example is when a divide by 0 occurs in a control variable The second case occurs as the result of a coding failure which can be caused by a programming error or a model deficiency Such a failure should be reported to the development staff through the RELAPS User Services Such errors often result in negative densities bad viscosities bad thermal conductivities or thermodynamic property errors 8 4 Plotted Output The two methods normally used to obtain time plots of computed information are described below 8 4 1 External Plots The STRIP option on Card 100 may be used to obtain ASCII data from the RSTPLT file Figure 8 4 1 shows
214. r of people Special acknowledgment is given to those who pioneered and continue to contribute to the RELAP5 code In particular V H Ransom J A Trapp and R J Wagner A number of other people have made and continue to make significant contributions to the continuing development of the RELAP5 code Recognition and gratitude is given to the other current members of the RELAPS team V T Berta C E Lenglade R A Riemke K E Carlson M A Lintner R R Schultz C D Fletcher C C McKenzie A S L Shieh E E Jenkins G L Mesina R W Shumway E C Johnsen C S Miller C E Slater G W Johnsen G A Mortensen S M Sloan J M Kelly P E Murray M Warnick H H Kuo R B Nielson W L Weaver N S Larson S Paik G E Wilson The list of contributors is incomplete as many others have made significant contributions in the past Rather than attempt to list them all and risk unknowingly omitting some who have contributed we acknowledge them as a group and express our appreciation for their contributions to the success of the RELAPS effort The RELAPS Program is indebted to the technical monitors from the U S Nuclear Regulatory Commission and the Department of Energy Idaho Operations Office for giving direction and management to the overall program Those from the NRC include Drs W Lyon Y Chen R Lee R Landry H Scott M Rubin and the current monitor D E Solberg Those from DOE ID include Dr D Majumdar N Bonicelli C N
215. r some time advanced quantity are entered as a table with time or the time advanced quantity as the independent or search variable The table must be ordered in increasing values of the search variable and each succeeding value of the search variable must be equal to or greater than the preceding value Linear interpolation is used if the search argument lies between search variable entries End point values are used if the search argument lies outside the search variable entries If constant state values are desired only one set of data consisting of any search value and the associated constant data needs to be entered The program recognizes when only one set of data is entered and computer time is saved since the equation of state is evaluated only once rather than every time advancement Step changes can be accommodated by entering two adjacent sets of data with the same time or an extremely small time difference The default search argument is time If no trip number is entered or if the trip number is zero the current advancement time is used as the search argument When a nonzero trip number 16 entered a unit step function based on the time the trip was last set is applied If the trip is false the search argument is 1 0 When the trip is true the search argument is the current advancement time minus the last time the trip was set Thus the search argument is always 1 0 when the trip 16 false and can range between zero and the problem time
216. rag model by specifying b 1 on the pipe volume control flags data card see Section A7 6 20 in Appendix A In addition in modeling grid NUREG CR 5535 V2 2 28 RELAP5 MOD3 2 spacers as junctions within the core or steam generator bundle the user should specify the junction area and hydraulic diameter as equal to that for the bundle rather than those characteristics of the grid spacer The reason for this is that the bundle interfacial drag model was formulated on the basis of bundle geometry In order to achieve the correct pressure drop at each grid spacer junction the user should input a loss coefficient that is adjusted for the difference between specifying bundle geometry rather than grid geometry For example if the loss coefficient associated with the grid spacer is k then the adjusted loss coefficient would be computed as k k 2 3 3 where A is the flow area of the grid spacer and Ay is the flow area of the bundle Seven control flags are associated with junctions efvcahs The e flag is the energy correction flag recommended at break junctions into a containment The f flag is the CCFL model flag recommended for tie plates downcomer annulus etc The v flag is the horizontal entrainment model flag recommended at break junctions connected to horizontal volumes The c flag controls applications of the choking model The current recommendation regarding the choking model is based on circumventing problems that have been
217. rages the phasic mass flows over the volume cell inlets and outlets The volume velocities of Volume Vs are used to evaluate the momentum flux terms for all junctions connected to Volume V3 The losses associated with these junctions are calculated using a stream tube formulation based on the assumption that the fraction of volume flow area associated with a junction stream tube is the same as the volumetric flow fraction for the junction within the respective volume Also using the junction flow area the adjacent volume flow areas and the branch volume stream tube flow area the stream tube formulation of the momentum equation is applied at each junction However if the smooth area change is specified large changes in flow can lead to nonphysical results Therefore it is normally recommended that the abrupt area change option be used at branches Plenums are modeled using the branch component Typical LWR applications of a plenum are the upper and lower reactor vessel regions steam generator plenums and steam domes The use of a branch to model a plenum having four parallel connections is illustrated in Figure 2 2 4 The flows in such a configuration can be either inflows or outflows The junctions connecting the separate flow paths to the plenum are ordinary junctions with the abrupt area change option recommended It is possible to use crossflow junctions at a branch for some or all of the connections A wye is modeled as illustrated in Figu
218. re 2 2 3 using the branch component The flow can either merge or divide Either the smooth or the abrupt area change option may be used If the smooth area 2 15 NUREG CR 5535 V2 RELAP5 MOD3 2 J2 To Figure 2 2 4 Plenum model using a branch change is specified large changes in flow can lead to nonphysical results Therefore it is normally recommended that the abrupt area change option be used at wyes 2 2 3 3 Leak Paths An application that may or may not involve branching but which is frequently a source of problems is the modeling of small leak paths These may be high resistance paths or may involve extreme variations in flow area The approximation of the momentum flux terms for such flow paths is highly uncertain and can lead to large forces resulting in numerical oscillations Modeling of small leak paths was one of the primary motivations for developing the crossflow connections As needed the momentum flux and wall friction can be omitted and the flow resistance could instead be computed from a user specified kinetic loss factor In applying the crossflow junction to leak path models the actual area of the leak path is used as the junction area A kinetic loss factor is input based on the fluid junction area velocity for the forward and reverse loss factors The forward and reverse loss factors should be equal unless there is a physical re
219. re ERE So ee Re RES eds 2 13 2 2 4 Retlood Model 5 eere eee ree ee be oe eae 2 19 2 2 5 Noncondensables 4 e coe Pe aee ea ee 2 19 2 2 0 Water Packing tege uude etes 2 21 2 2 1 Countercurrent Flow Limitation Model 2 21 2 2 5 Level Tracking Model 2 23 2 2 9 Thermal Stratification Model essent 2 23 2 2 10 Energy Conservation at an Abrupt Change eene 2 24 22511 References ato ari e ete et tte ERU Ce till 2 24 2 3 Hydrodynamic Components u u G aG i s ea e 2 24 2 3 Common Features of Components esee ene 2 25 2 3 2 Time Dependent Volume ntt e eate inttr Lege Lp ihe 2 30 2 3 3 Time Dependent Junction tete eiecti eee jer aee ie 2 30 2 3 4 Single Volume Componetnt tren rennen 2 31 2 3 5 Single Junction Component 2 31 2 9 0 PIDE eee eee D PUR ea POOR RI URS e rdiet s 2 32 2 31 Branch sas e M e rre Ur Mi ien ER ce sa 2 32 2 3 8 P mpiu su pee etie itd ec I guter etie dd 2 32 23 9 Jet Pumpin u ene eie eet ete e em ee ete 2 44 2 3 10 81969 A E APR ERA EE te ee Ee ES 2 46 23 11 SEPA Lilia ege 2 49 2 3 12 Turbine saisie mta qp dde due 2 54 23 13 Aceumulator nN it epe eee e Pa eoe e Ure one 2 56 2 3 14 Annulu
220. re defined The mean stage radius needed in the efficiency formulas may not be known from the actual turbine design diagrams We recommend the mean stage radius R be obtained from the efficiency formulas If the turbine model is used with a constant efficiency factor the stage radius is not needed except for startup and 1 0 can be entered If the turbine stage is a general impulse reaction stage then the maximum efficiency No is obtained when MM 2 3 20 v 1 Using v RO and the input values v r and at the design operating point Equation 2 3 20 gives for R _ 05v R cp 2 3 21 This is the recommended mean stage radius that is consistent with the assumed efficiency formula For a two row impulse stage the maximum efficiency occurs when 0 25 2 3 22 NUREG CR 5535 V2 2 54 RELAP5 MOD3 2 Expressing v as Ro gives 2 3 23 as the mean stage radius consistent with the efficiency formula For a TURBINE component the primary steam inlet junction must be input with the TURBINE component as the first junction If a steam extraction bleed junction is desired it must be input with the TURBINE component as the second junction Thus NJ must be either 1 or 2 Cards CCC1101 and CCC1201 represent the steam inlet junction and Cards CCC2101 and CCC2201 represent the steam extraction bleed junction if desired The TO connection for the steam inlet junction must refer to the inlet of the TURBINE CCC00000
221. re specified in the input In this section no system or component label information is printed The volume number labeled VOL NO and four to eight other quantities are printed on each line These are printed out in numerical order within each system The n 1 quantities are PART PRESS the partial pressure of steam P SOLUTE MASS the mass of soluble n 1 n 1 species Mz NONCOND VAPOR MASS noncondensable mass M and the mass fraction of each of the noncondensable species a labeled by the element name and NCOND QUAL The noncondensable qualities X sum to 1 0 in each volume 8 3 2 6 Hydrodynamic Volume Information Third Section This section of output is optional and can be skipped by setting bit three in the ss digits of Word 4 W4 on the time step control cards Cards 201 through 299 This section is printed in Figure 8 3 1 In this section no system information and no component label information is printed Furthermore no additional component quantities are printed out Instead just the volume number VOL NO and ten other quantities are printed out on each line These are printed out in numerical order within each system The quantities are RHOF n l n 1 liquid density p i RHOG vapor density p RHO MIX void averaged mixture density 0 8 13 NUREG CR 5535 V2 RELAP5 MOD3 2 n 1 RHO BORON boron density pg VEL LIQUID liquid volume average velocity vr 2 VEL VAPOR vap
222. riction Vr and 2 FWG Axy v in most cases user specified dimensionless and the dimensionless abrupt area change liquid and vapor loss coefficients FORMFJ and FORMGJ 2 e HLOSSF v and 2 HLOSSG v in most cases The previous six quantities were all made dimensionless so that the relative importance of each in the momentum equations could be determined from the major edits The last three quantities are a countercurrent flow limitation CCFL model summary NO ADVS CCFL The subheading LAST indicates whether the CCFL model was applied on the last time step set to 1 if it was or set to O if it was not the subheading EDIT lists the number of times the CCFL model was applied since the last major edit the subheading TOTAL lists the number of times the CCFL model was applied for the entire problem n n Ve j Vaj n n Ve j Ve j 8 3 2 11 Heat Structure Heat Transfer Information This section of output is not optional and always appears in a major edit when heat structures are present Quantities in this section are printed in numerical order The first printed quantity for each heat structure is the individual heat structure number STR NO denoting the heat structure geometry number CCCG and the three digit individual heat structure subfield number ONN These numbers are separated by a hyphen Following this nine quantities are printed out for both sides of the heat
223. rmalized position change per second The motor is controlled by an open trip and a closed trip The valve stem position is stationary when both trips are false when the open trip is true the valve stem moves in the open position when the close trip is true the valve moves in the closing direction The code terminates if both trips are simultaneously set true Section 4 1 4 shows trip logic for the open trip that could be used to position a valve to regulate flow such that an upstream pressure is held within a set range NUREG CR 5535 V2 2 48 RELAP5 MOD3 2 The servo valve uses the value of a control variable to indicate the normalized valve stem position A typical application would be regulating steam flow to the turbine to maintain a desired quantity such as primary system temperature or secondary side steam generator pressure The control system perhaps using a STEAMCTL specialized proportional integral controller would compare the current value of the primary temperature or steam generator pressure to the desired value and from the difference of the values compute an appropriate valve position The servo valve using the control output would position the valve and thus regulate the flow 2 3 10 5 Relief Valve A scheme was designed to input the terms required to define a typical relief valve geometry and dynamic parameters This scheme is consistent with the RELAPS input philosophy in that extensive checking is performed during input proc
224. rossflow model only three momentum flux terms are used the momentum 10 each direction convected by velocity in the same direction The code input provides junction flags to ignore momentum flux effects in either the from volume the to volume both volumes or to include momentum effects in both volumes the default Intuitively including momentum effects is more accurate modeling and momentum effects should be included in junctions attached to the normal faces In previous versions of the code a restricted form of the momentum equation was used that omitted momentum flux wall friction and gravity terms One reason was that the geometric information necessary for computing these terms was not available and average volume velocity terms in the crossflow directions were not computed The earliest motive for the crossflow model was to treat recirculation flows in the reactor core and these restrictions were acceptable since velocities were low and there were no elevation changes The crossflow model was subsequently used for tees since the crossflow model even with the restrictions was a better model than previous approaches for tees The current recommendation is to include the momentum flux terms for crossflows but remove them if computational difficulties involving crossflow junctions are encountered The crossflow model 16 currently under developmental assessment A more definite recommendation is not to have multiple junctions with differing mome
225. rupture and axial location and temperature of fine mesh nodes For the heat structure additional boundary cards 1CCCG801 through 1CCCG899 and 1CCCG901 through 1CCCG999 it is suggested to use zero for the heat transfer hydraulic diameter Dr i e the heated equivalent diameter When zero is used the heat transfer hydraulic diameter is set the same as the hydraulic diameter Dj at the boundary volume which should be determined by the user from flow area D 4x ul j X wetted perimeter 3 5 1 Because the heat transfer coefficient in RELAPS is obtained from the correlations developed from tube and parallel channel tests for consistency the same scaling method used in the hydraulic calculation should be used in the heat transfer calculation If the heat structure does not represent the pipe walls the default should not be taken The heat transfer hydraulic diameter should be determined by the user from flow area Penia heated perimeter fn NUREG CR 5535 V2 3 6 RELAP5 MOD3 2 4 CONTROLS 4 1 Trips Extensive trip logic has been implemented in RELAPS Each trip statement is a single logical statement but because trip statements can refer to other trip statements complex logical statements can be constructed There are two aspects to trip capability a to determine when a trip has occurred and b to determine what to do when a trip occurs In the modular design of RELAPS these two aspects have been
226. s u an Ee CR t HEREDI eaten isa 2 57 2 3 15 ECC MIRED zen n Du ee ee o a e eta 2 57 v NUREG CR 5535 V2 RELAP5 MOD3 2 2 3 16 Referente Sro aeaiee ere e tbe ede A k A 2 58 3 HEAT STRU CTURDBS econtra en t eO Ie E ee nene pupas B 3 1 3 0 1 A re en e ep bi O ge 3 1 3 1 Heat Structure Geometry depende te eint ripe eee er deep ee inpr See iR 3 1 3 2 Heat Structure Boundary Conditions esee 3 3 3 3 Heat Structure SOU eti e ee c RD RR ede Sas 3 5 3 4 Heat Structure Changes at Restart sese 3 5 3 5 Heat Structure Output and Recommended Uses a 3 6 4 CONTROLS Sasu Nah riens cde dq epi po rede tended en 4 1 4 1 MTP Siecle teen etti tod e hte ett A qa E aa T A ood a nick ed 4 1 ALL Variable IrIpS ie ete pete e ebd 4 2 4 12 Logica TDS eme te etii eate isnt 4 3 4 13 Trip ExecutoM NER 4 3 4 1 4 TnpEosgicExample cie ee eee edt 4 4 4 2 Control Componients 1 o dd den te te eL in Le rd e eR Ee dino 4 6 4 2 1 Basic Control ComponentSs ua nennen nennen nenne 4 6 4 22 Control System Examplesa uu n Leto re e per et ieee ee 4 10 4 23 Shaft Control Component s espies 1 eere eire tere citro dina 4 12 5 REACTOR KINETICS 00 e Reni e eid S uum adi 5 1 5 1 Power Computation Options l asnus an sa tD Ia ua pha 5 1 Dll References sos eoe nta D rre n He 5 2 5 2 Reactivity Feedback Options sess u usa c
227. s The junction flow area is set to the user supplied flow area and the junction area ratio is set to 1 0 The abrupt area change option provides for additional losses resulting from abrupt expansions abrupt contractions orifices and vena contracta effects The user supplied junction area must be equal to or less than the minimum of the adjacent volume flow areas for an abrupt area change The junction area is set to the minimum of the adjacent volume flow areas and the junction area ratio is set to the ratio of the user supplied junction area to the minimum of the adjacent volume flow areas When the user supplied flow area equals the minimum of the adjacent volume flow areas the junction area ratio is 1 0 and the junction is a contraction expansion Program logic checks flow direction and an expansion with flow in one direction is treated as a contraction when flow reverses and vice versa If the user supplied junction area is less than the minimum of the adjacent volume flow areas an orifice is indicated and the junction area ratio is less than one Specifying the abrupt area change option when there is no area change gives the same result as specifying the smooth area change option but slightly more computer time is required Valve junctions using either area change option vary the junction area ratio as the valve opens and closes Junction velocities correspond to the junction flow area Thus the flow rate of a phase is the product of th
228. s and voids will most likely change from the initial value and some adjustment of VOVER and VUNDER may be required The final recommendation concerns the use of a bypass volume If there is any possibility of a recirculation flow through a bypass like region we recommend such a flow path be included The inclusion of such a flow path has generally improved the performance predictions The use of a crossflow junction between the separator plenum and a bypass plenum instead of a normal junction generally provides a better model for the recirculation flow 2 3 11 3 Recommendations for the Mechanistic Separator and Dryer Options The mechanistic separator and dryer models are new in RELAP5 MOD3 They are intended to model the centrifugal separator and chevron dryer components in a BWR reactor Until a base of user experience is obtained we recommend default input data for the models be used The user should explicitly model the separator standpipe as a separate volume or set of volumes because the separator component volume is 2 53 NUREG CR 5535 V2 RELAP5 MOD3 2 intended to model the volume within the separator barrel and discharge passages Likewise the dryer volume should encompass the physical volume inside the dryer skirt between the elevations of the dryer inlet and outlet elevations The separator inlet quality can be adjusted to the desired operating point by modifying the form loss coefficient in the separator liquid discharge junction The l
229. s on a page nine of the selected quantities per page with time printed in the leftmost column on each page Minor edits can print selected quantities at frequent intervals using much less paper than major edits Section 4 of Appendix A of this volume indicates how to request minor edits and what the user specified quantities represent 8 3 4 Diagnostic Edit During a transient TRANSNT on Card 100 or steady state STDY ST on Card 100 problem additional tables of variables can be printed out by inputting Words 4 and 5 on Card 105 or the tables often will be printed out when a failure occurs These tables will be discussed in this section This printout contains key variables from the hydrodynamic and heat transfer subroutines The main variable in the code NUREG CR 5535 V2 8 18 RELAP5 MOD3 2 ES SOL v 8sot S 001 L0 8S9 L6 80S 8S ETL 9 LOT 2 800T 969 999 L6 90S c 90 0982 c 9TL T OcLSv O 09645 Ov IcL L S90T 91 186 EL 19 08 v0S LS 18S STOEL S 6L0T 66 v86 LE ETS 8L 20S 9LS9 9410 9v6T Z z08z T 9LS9 0 L0 68S EL SPL 0 ELOT 8 8S6 0 TLS 9 00S OV T6S 9T SSL v S80T 8 196 08 69S 65 867 CIGS E 81L6 c TEOT Z L88T T ctvLc O T8 86S vc 89L S S80T 85 06 S0 8 S 9v 96v EZ 109 81 08L f LOOT L6 9v6 67 9 S Ov v6r LVLV T926 c LTTO Z L60 l 88281 0 05809 OTSTE 08601 Te 0 6 66 EES 60 COV 90 TT9 0z 0 8 0 60TT TT Z
230. s that if the run is simply to achieve a steady state initialization of the system model then controls not representative of the actual system may be designed that will drive the solution to steady state in the fastest manner possible The only restriction is that stability of the calculations must be maintained There is also an option Word 4 digits tt on the time step control cards 201 through 299 which allows the user to select part of the steady state calculation to be used The thermal inertia of the heat structures is lowered but the testing scheme to check the derivatives of variables to determine a steady state is not used This gives a user the advantage of using the artificially accelerated thermal steady state in the heat structures while allowing use of either a set end time or else the user s own choice for a variable to monitor for a steady state through a simple control system 7 2 Boundary Conditions Boundary conditions are required in most transient calculations In reality boundary conditions take the form of the containment atmosphere operator actions or mass and energy sources that are not explicitly modeled as part of the system Such boundary conditions are simulated by means of time dependent volumes for specified sources or sinks of mass time dependent junctions for specified flows or specified heat structure surface heat fluxes and energy sources Specified variation of parameters in control components to simulate an
231. separated The term trip logic refers only to the first aspect and includes the input processing of the trip statements and the transient testing to set trip status The action to be taken when a trip occurs is considered to be part of a particular model and that aspect of trip coding is associated with the coding for the model Examples of the second aspect of trips are the effects of trips on pump models and check valves Trip capability provides for variable and logical trips Both types of trips are logical statements with a false or true result A trip is false that is off not set or has not occurred if the result is false A trip is true that is on is set or has occurred if the result is true Trips can be latched or unlatched A latched trip once true set remains true set for the remainder of the problem execution even if conditions change such that the logical statement is no longer true An unlatched trip is tested at each time step and the conditions can be switched at any step A TIMEOF quantity is associated with each trip This quantity is always 1 0 for a trip with the value false When a trip is switched to true the time at which it switches replaces the value in TIMEOF For a latched trip this quantity once set to other than 1 0 always retains that value An unlatched trip may have several TIMEOF values other than 1 0 during a simulation Whenever an unlatched trip switches to false TIMEOF becomes 1 0 when true again
232. set of reactor kinetics data must be input i e individual sections of kinetics data may not be specified as replacement data NUREG CR 5535 V2 8 28 RELAP5 MOD3 2 In summary all modeling features in RELAPS can be added deleted or changed at restart 8 29 NUREG CR 5535 V2 RELAP5 MOD3 2 NUREG CR 5535 V2
233. sing flow with decreasing pressure possibly up to a maximum flow rate The source 6 1 NUREG CR 5535 V2 RELAP5 MOD3 2 1 0 Pi 0 0 1 0 20201000 20201001 20201002 Figure 6 0 1 Input data for a power type general table and graph 0 0 Power 1 0 0 0 0 0 0 5 0 0 0 0 1 0 1 0 1 0 1 0 2 0 50 0 6 of injection water is usually a time dependent volume This technique would not add pump work to the injected fluid Some approximation of the pump work could be made by also specifying the injection point pressure as the independent variable of the time dependent volume and entering appropriate thermodynamic conditions as dependent variables NUREG CR 5535 V2 RELAP5 MOD3 2 7 INITIAL AND BOUNDARY CONDITIONS All transient analysis problems require initial conditions from which to begin the transient simulation Usually the initial conditions will correspond to a steady state with the transient initiated from a change of some boundary condition In general the initial conditions required are a determinate set of the dependent variables of the problem The hydrodynamic model requires four thermodynamic state variables in each volume and the velocities at each junction Heat structures require the initial temperature at each node control systems require the initial value of all control variables and kinetics calculations require initial power and reactivity All of these parameters are established through the co
234. steel stainless steel uranium dioxide and zirconium are stored within the program The data were entered to demonstrate the capability of the code and as a user convenience and should not be considered recommended values Input editing includes the thermal properties and a list of the built in data can be obtained by assigning the built in materials to unused composition numbers in any input check run The thermal property data must span the temperature range of the problem Problem advancement is terminated if temperatures are computed outside the range of the data Heat structures can have an internal volumetric heat source that can be used to represent nuclear gamma or electrical heating The source S x t is assumed to be a separable function of space and time S x t P Q x P t 3 1 1 where P a scaling factor Q x a space distribution function P t E power The space function is assumed to be constant over a mesh interval but may vary from mesh interval to mesh interval Only the relative distribution of the space function is important and it may be scaled arbitrarily For example given a heat structure with two zones the first zone having twice the internal heat generation of the second the space distribution factors for the two zones could be 2 0 and 1 0 200 0 and 100 0 or any numbers with the 2 to 1 ratio Zeros can be entered for the space distribution if there is no internal heat source The mesh point spacings c
235. stem use the shaft component For a turbine driven pump use a shaft with the pump and turbine stages attached NUREG CR 5535 V2 4 14 RELAP5 MOD3 2 4 2 3 3 Turbine Component A turbine component is a hydrodynamic component consisting of one volume and has additional modeling to compute torque based on volume conditions and rotational velocity One junction may connect to the turbine volume inlet to represent the steam line Multiple junctions may connect to the outlet to represent steam exit extraction steam for regenerative heating of feedwater and drain lines to remove liquid A small turbine such as might be used to drive a pump is usually modeled by one turbine component The turbine used to drive the electrical generator typically has steam extraction points and drain lines and thus is usually modeled by two or more turbine components The shaft component is the only mechanism for providing the rotational velocity common to each turbine component and summing the torque developed in each turbine component The shaft is also the only mechanism to couple the turbine to a pump or generator 4 2 3 4 Generator Component The generator component consists of the minimum model to load a turbine Because of the simple model and its small input data requirements it has been made an option of the shaft component The generator model allows two operating modes One mode is having the generator connected to a large electrical grid the generator th
236. structure geometry composed of 1 to 99 heat structures as a reflood unit As there is no input specification for the length of a structure except for the heat structure surface such length is inferred from the length of the boundary volume connected to the heat structure It is the user s responsibility to make certain that the length of a heat structure corresponds to the length of its connected volume for reflood calculations Additional suggestions concerning the use of the reflood model are listed below 1 the appropriate user specified maximum number of axial fine mesh intervals is 8 to 32 No significant differences have been found in using 16 to 128 axial nodes for 0 18 m 0 6 ft long heat structures 2 the appropriate length of hydrodynamic volumes is 0 15 to 0 61 m 0 5 to 2 0 ft 3 the maximum user specified time step size is 0 01 to 0 05 s 4 each reflood unit should have its own flow channel and parallel flow channels should be connected by crossflow junctions The number of heat structure geometries that can be specified for a reflood calculation is limited only by computer storage capacity Once the reflood model is activated for a particular heat structure geometry only the structures where the critical heat flux are located will have a value in the critical heat flux column of the output The heat transfer modes that appear in the mode column of the major edit are the same as those that appear when reflood is not activated ex
237. system pressure is greater than the time dependent volume pressure In particular any energy dissipation associated with a real pumping process is not simulated The flow work done against the system pressure is approximated by work terms in the thermal energy equation In RELAPS any volume that does not have a connecting junction at an inlet or outlet is treated as a closed end Thus no special boundary conditions are required to simulate a closed end NUREG CR 5535 V2 2 2 RELAP5 MOD3 2 The fluid properties at an outflow boundary are not used unless flow reversal occurs In this respect some caution is necessary and is best illustrated by an example In the modeling of a subatmospheric pressure containment saturated steam is often specified for the containment volume condition This will result in the outflow volume containing pure steam at low pressure and temperature If in the course of calculation a flow reversal occurs even a very minute one possibly caused by numerical noise a cascading result occurs The low pressure or low temperature steam can rush into a volume at higher pressure and rapidly condense The rapid condensation leads to depressurization of the volume and increased flow Such a result can be avoided by using air or superheated steam in the containment volume A general guide to modeling hydrodynamic boundary conditions is to simulate the actual process as closely as possible This guideline should be followed unless in
238. t input On restarted problems the trip printout at the restart time shows input values for new and modified trips and the values from the original problem for the unmodified trips Trip computations are the first calculation of a time step Thus trip computations use the initial values for the first time step and the results of the previous advancement for all other advancements Because trips use old values they are not affected by repeats of the hydrodynamic and heat structure advancements 4 3 NUREG CR 5535 V2 RELAP5 MOD3 2 Trips are evaluated in order of trip numbers thus variable trips are evaluated first then logical trips refer to the discussion of trips in Volume D Results of variable trips involving the TIMEOF quantity and logical trips involving other trips can vary depending on their position relative to other trips As an example consider 6XX 650 OR 650 N which just complements Trip 650 Also assume Trip 650 switches to true this time step and thus 650 was false and 6XX was true previous to trip evaluation At the end of trip evaluation 6XX is true if 6XX is lt 650 and false if 6XX is gt 650 If Trip 650 remains true for the following time step Trip 6XX with 6XX lt 650 becomes false one time step late Similarly TIMEOF quantities can be one time interval off This can be minimized by ordering TIMEOF tests last and defining logical trips before they are used in logical statements 4 1 4 Trip Logic Example
239. ta with a negative pressure and zero flows causes the flow to be zero when the trip is false The remaining table entries define the injection flow as a function of positive pressures The source of injection water 19 a time dependent volume The pressure of the water supplied by the time dependent volume could also be a function of the pressure at the injection volume to represent the work of pumping the water into the system If the injection flow is a function of a pressure difference the pressure difference can be defined by a control system variable and that control variable is then defined as the search argument Some uses of time dependent junctions can cause modeling difficulties When using a time dependent junction to specify flow from a time dependent volume into the system the incoming phasic densities void fractions phasic velocities phasic mass flow and phasic energies can be specified But when using a time dependent junction to specify flow out of a system the densities void fractions and energies of the fluid leaving the system are not known in advance Thus use of time dependent junctions to control outflow is not recommended The following is one example of a modeling problem The user anticipates that a volume will contain only vapor and accordingly sets a time dependent junction to a nonzero vapor flow and zero liquid flow If the user anticipated incorrectly and liquid condenses or is carried into the volume the liquid will
240. ter is accelerated If the pump torque is sufficiently high the pump velocity increases to slightly below the synchronous speed where the developed torque matches the frictional torque and the torque imposed by the water As the water accelerates the angular velocity decreases slightly to meet the increased torque requirements The angular velocity decrease is very small owing to the steep slope of the torque versus angular velocity near the synchronous speed Thus once the pump approaches the synchronous speed the transient behavior of the second example is similar to the first example 2 3 8 3 Built in Pump Data RELAPS contains built in single phase homologous data for a Bingham Pump Company pump with a specific speed of 4200 and a Westinghouse Electric Corporation pump with a specific speed of 5200 Two phase difference homologous data are also associated with these pumps but the data curves are identical and were obtained from two phase tests of the Semiscale pump The data curves are stored as data statements in subroutine RPUMP No built in two phase multiplier tables are entered Specification of built in single phase homologous data does not require specification of the built in two phase difference homologous data or vice versa If multiple pump components are used and some tables are common to more than one component then user effort and computer storage can be saved by entering the data for only one component and specifying that oth
241. terms within the component Each component has only one term except the pump motor component which has two terms For the shaft and the connected components the new rotational velocity is stored as the rotational velocity of the shaft and each connected component The following sections discuss the components that can be connected to a shaft NUREG CR 5535 V2 4 12 RELAP5 MOD3 2 4 2 3 1 Motor Component No separate motor component exists in RELAPS A motor capability is an optional feature of a pump component and input describing the motor features are entered as part of the pump input Specifying a pump as being connected to a shaft includes the motor if it is described in the pump input A motor model can also be described though the control system and its torque applied to the shaft through a control variable t in Equation 4 2 26 4 2 3 2 Pump Component A pump need not be connected to a shaft since the pump component optionally includes a model for advancing the angular velocity equation A review of the pump when not associated with a shaft follows so that the pump with a shaft can be described by their differences 4 2 3 2 1 Pump Not Associated with Shaft A pump rotational velocity table and associated trip may be entered If a rotational velocity table is entered its use depends on the optional trip If the trip 19 not entered the table is always used if the trip is entered the table is used when the trip is true and not
242. that control variables be used to set up the M and N parameters for minor edit purposes and that these parameters be printed with every edit 2 3 10 Valves In RELAPS eight valves are modeled that are of six types The types of valves provided are check valves trip valves inertial swing check valves motor valves servo valves and relief valves A single model for each type of valve is provided except for the check valves For check valves three models are provided each of which has different hysteresis effects with respect to the opening closing forces Of the six types of valves the check valves and trip valves are modeled as instantaneous on off switches That is if the opening conditions are met then the valve is instantly and fully opened if the closing conditions are met the valve is instantly and fully closed The remaining four types of valves are more realistic models in that opening closing rates are considered In the case of the inertial swing check valve and the relief valve the dynamic behavior of the valve mechanism is modeled Fundamentally a valve is used to regulate flow by varying the flow area at a specific location in a flow stream Hence in the RELAPS scheme a valve is modeled as a junction component that gives the NUREG CR 5535 V2 2 46 RELAP5 MOD3 2 user a means of varying a junction flow area as a function of time and or hydrodynamic properties Valve action is modeled explicitly and therefore lags the hydrody
243. the material Courant limit for the STDY ST option Columns under the first four REDUCE headings are incremented only after a successful advancement following one or more successive reductions Quantities are incremented only for those volumes that caused the last reduction More than one column and row quantity can be incremented in a time step Because of this characteristic quantities in the first four REDUCE headings do not necessarily equal the REPEATED ADV quantity in the Time Step Summary at the top of a major edit Since the REDUCE COURANT column is for a reduction that occurs before the advancement takes place it does not cause the time step to be repeated and thus does not increase the REPEATED ADV quantity New items have been recently added to this section that are not shown in Figure 8 3 1 Columns under the REPEAT headings are incremented if an advancement is repeated for several different reasons If noncondensable gas first appears in a volume during an advancement the quantity under the REPEAT AIR APP is incremented and the advancement repeated with the same time step size If water packing is detected in a volume the quantity under the heading REPEAT PACKING is incremented and the time step is repeated with the same time step size In either of these situations the time advancement and the time step is repeated with the same time step size In either of these situations the time advancement algorithm is modified to accommodate the
244. this is a recent addition to RELAPS3 and is still under assessment Several improvements have been made to the nearly implicit advancement but use of that option is also still under assessment Use of option 15 is recommended for steady state runs and slow transients and users are encouraged to use option 19 but with the same caution as option 7 The minor edit major edit and restart frequencies are based on the requested time step size A frequency n means that the action is taken when a period of time equal to n requested time steps has elapsed The edits and the restart record are written at time zero and at the specified frequencies up to the time limit on the time step control card The maximum time step is reduced if needed and the edits and restart record are forced at the time limit value Actions at the possibly new specified frequencies begin with the first advancement with a new time step control card A restart forces a major and minor edit to be written and a major edit forces a minor edit to be written Plot information is written to the internal plot and restart plot files whenever a minor edit is written Note that minor edits are produced only if minor edit requests are entered an internal plot file is written only if internal plot requests are entered and plot and restart data are written on the restart plot file only if the file is requested An option d used for program testing can force a plot print minor edit major edit or
245. through 6 and or junction flags could specify a crossflow connection The limited momentum equation ignored momentum flux wall friction and gravity terms Now crossflow means only that the connection is to a face other than one of the normal faces Note especially that crossflow does not imply a modified form of the momentum equation The same momentum equation options are available to both normal flows and crossflows The standard one dimensional momentum equations can be applied to both normal and crossflows Optionally and only through the use of the momentum flux junctions flags the momentum flux contribution in the from or to volume can be ignored for normal and crossflow connections In view of the above paragraph what is the difference between normal and crossflow connections The answer is there is no difference in the application of the conservation equations to the two types of connections The only difference is that the term normal is applied to the flow that would occur in a strictly one dimensional volume crossflow is an approximation to multidimensional effects consisting of applying the one dimensional momentum equation to each of the coordinate directions in use To give some perspective to the approximation the three dimensional momentum equation contains nine terms for momentum flux the momentum in each of the three directions being convected by velocities in the three 2 5 NUREG CR 5535 V2 RELAP5 MOD3 2 directions In the c
246. tion of Volume 1 of this manual Next are VOIDF VOIDG and VOIDGO which are the new liquid and vapor void fraction and the previous time step vapor void fraction ary Or and Oy L used in the equations The previous time step void fraction is significant because it helped determine the wall and interfacial terms on the current edit Next are TEMPF TEMPG and SAT TEMP which are the liquid temperature Tey the 1 snl vapor temperature T5 and the saturation temperature T used in the equations For single phase the temperature of the missing phase is set to the saturation temperature After this are UF and UG which are the liquid specific internal energy U and the vapor specific internal energy 00 used in the equations Finally the label VOL FLAG is listed which is the volume control flag tlpvbfe input by the user for hydrodynamic volume components Following the labels the title supplied by the user and type of component are given followed by the actual values of the quantities for each volume NUREG CR 5535 V2 8 12 RELAP5 MOD3 2 Additional information is printed in the first hydrodynamic volume section that is unique to certain components In Figure 8 3 2 additional information for a pump turbine and accumulator are given For a pump five additional quantities are printed In the normal operating mode these are the rotational velocity RPM pump head HEAD torque exerted by the fluid TORQ
247. to characterize the type of pump impeller best suited for a particular application In practice the acceleration of gravity g is omitted and the specific speed is simply defined as 1 3 N NQ H 2 3 8 where the speed N is in rpm the capacity Q is in gpm and the head H is in ft In this form N is not dimensionless but has a history of usage that still persists Two performance parameters that are used for pump modeling are the specific nondimensional capacity Q Q ND 2 3 9 and the specific head dimensional due to omission of the gravitational acceleration constant H H N D 2 3 10 The D that appears in Equations 2 3 9 and 2 3 10 is a characteristic dimension of the pump and is assumed to be the impeller diameter When scaling pump performance using homologous parameters the implication is that all pump dimensions are geometrically similar 1 e changing D implies a proportional change in impeller width leakage paths and in all linear dimensions of the pump When the pump torque performance is included one additional dimensionless parameter is obtained from dimensional analysis and is Ts v pN D 2 3 11 where T5 is the nondimensional specific torque NUREG CR 5535 V2 2 34 RELAP5 MOD3 2 Generally constant density is assumed so the dimensional specific torque used in constructing the homologous representation is reduced to t V N D 2 3 12 Homologous states are states for
248. to start the transient the original reactor kinetics data plus feedback data can be entered NUREG CR 5535 V2 5 4 RELAP5 MOD3 2 6 GENERAL TABLES AND COMPONENT TABLES General tables provide data for several models including heat structures valves reactor kinetics and control systems The general table input provides for the following tables power versus time temperature versus time heat flux versus time heat transfer coefficient versus time heat transfer coefficient versus temperature reactivity versus time and normalized valve area versus normalized stem position An input item identifies each table so that proper unit conversion and input checking can be done For example specifying a temperature table when a power table is required is detected as an error Because these tables are often experimental data or scaling may be needed for parametric studies the input provides for conversion and or scaling factors for these tables Input editing of these tables includes both the original and scaled data General tables can be entered deleted or replaced at restart The tables are linearly interpolated between table values and the end point values are used when the search arguments are beyond the range of entered data Figure 6 0 1 shows input data for a power type general table and the graph shows its time history The first entry of the first line indicates that it is a power versus time table the second entry indicates that the tr
249. to storage limitations this number is calculated by a formula that reduces the number below the theoretical maximum for 16 32 64 or 128 maximum number of axial intervals For the example in Figure 8 3 3 the user requested 16 so the theoretical maximum is 321 which is larger than the assigned maximum of 153 The next column is the actual number of axial nodes used for the last time advancement EDIT and in this case it is 59 If the EDIT column is ever larger than the MAXIMUM column the code will abort The next four quantities are used in deciding on the number of nodes needed to define the boiling curve The first three are the wall temperature at incipience of boiling INC BOIL TEMP Typ the wall temperature at critical heat flux CRITICAL TEMP Tcyp and the wall rewetting or quench temperature REWETTING TEMP To These numbers are set to 5 degrees below and 40 and 250 degrees above the saturation temperature respectively The final number is the location of the critical temperature CRIT TEMP POSITION This location is the distance from the start of the first heat structure This last output does not appear to be working but the quench position can be found by examining the next two sections Next is the axial position of all 59 nodes followed by the left and right side surface temperatures at these axial positions This axial section of output is optional and it is skipped when the heat structure temperatures are skipped As
250. to the inlet of the first pipe volume or to the outlet of the last pipe volume Crossflow meaning connections to faces associated with y or z faces cannot be specified with the old format 2 3 NUREG CR 5535 V2 RELAP5 MOD3 2 i 0 0 i Azimuthal angle 0 or 360 Azimuthal angle 180 inclination angle 0 inclination angle 0 0 0 I i Azimuthal angle 0 or 360 Azimuthal angle 180 inclination angle 30 inclination angle 30 i 0 i 0 Azimuthal angle 0 or 360 Azimuthal angle 0 or 360 inclination angle 30 inclination angle 30 Figure 2 1 1 Possible volume orientation specifications The expanded connection code assumes that a volume has six faces 1 e an inlet and outlet for each of three coordinate directions see Figure 2 1 2 The expanded connection code indicates the volume being connected and through which face it is being connected In the new format N nonzero N is the face number and VV is the volume number For components specifying single volumes VV is 01 but for pipes VV can vary from 01 for the first pipe volume to the last pipe volume number The quantity N is 1 and 2 for the inlet and outlet faces respectively for the volume s normal or x coordinate direction The quantity N is 3 and 4 to indicate inlet and outlet faces for the y direction and N is 5 and 6 to indicate inlet and outlet faces for the z direction Entering N as 1 or 2 specifies normal connections to a volume
251. tries to construct a three dimensional picture of the flow path Several possible volume orientations depending upon the input values for the azimuthal and inclination angles are illustrated in Figure 2 1 1 The junction coordinate direction is established through input of the junction connection code Words W1 and W2 of Cards CCCO101 through CCC0109 Section A 7 4 of Appendix A The junction connection codes designate a from and a to component and the velocity is positive in the direction from the from component to the 70 component The connection codes can be entered in an old or an expanded format The expanded format is recommended but the old format is still valid A connection code has the format CCCVVOOON where CCC is the component number VV is the volume number and N is the face number where zero indicates the old format and nonzero indicates the expanded format The old format N20 can only specify connections to the faces associated with normal flow that is flow along the x coordinate In the old format VV is not a volume number but instead VV 00 specifies the inlet face of the component and VV 01 specifies the outlet face of the component The volume number is only implied For components specifying single volumes currently only a pipe specifies multiple volumes normal flow as opposed to crossflow to either the inlet or outlet face can be specified For a pipe however the old format allows specification of normal flow only
252. ue avoids modeling the control system that maintains liquid level and temperature during steady state calculations when they are not needed in the transient Another reason for a problem change capability is to reduce the cost of simulating different courses of action at some point in the transient An example is a need to determine the different system responses when a safety system continues to operate or fails late in the simulation One solution is to run two complete problems An alternative is to run one problem normally and restart that problem at the appropriate time with a problem change for the second case The problem change capability could also be used to renodalize a problem for a certain phase of a transient This has not been necessary or desirable for problems run at the INEL For this reason techniques to automate the redistribution of mass energy and momentum when the number of volumes changes have not been provided The current status of allowed problem changes at restart in RELAPS are summarized below In all instances the problem definition is that obtained from the restart tape unless input data are entered for deletions modifications or additions The problem defined after input changes must meet the same requirements as a new problem Time step control can be changed at restart If time step cards are entered at restart all previous time step cards are deleted New cards need only define time step options from the point
253. umetric Flow GPM 290 300 200 100 A 00 BVT BVR 200 in Ib Turbine Reverse BAT BAR JEN VII F211 Figure 2 3 2 Four quadrant torque curve for Semiscale MODI pump ANC A 3449 2 37 NUREG CR 5535 V2 RELAP5 MOD3 2 Table 2 3 1 Pump homologous curve definitions Regime Regime Independent Dependent Dependent number mode a v va variable variable ID name variable head torque 1 HAN BAN 20 20 lt l v a h o2 8 102 Normal 2 HVN BVN gt 0 gt 0 gt 1 a v h v p Pump 3 HADBAD gt 0 0 gt 1 v a h o Bla Energy 4 HVD BVD gt 0 lt 0 lt 1 a v h v2 Biv2 Dissipation 5 HATBAT 0 lt lt 1 v a h a Bio Normal 6 HVT BVT lt 0 lt 0 gt 1 a v h v2 Biv Turbine 7 HARBAR 0 gt 0 gt 1 v a h a p o Reverse 8 HVR BVR 0 20 lt 1 a v h v B v2 Pump a amp rotational ratio v volumetric flow ratio h head ratio and B torque ratio 2 3 8 1 3 Homologous Data and Scaling In most system simulation tasks complete pump performance data are not available Usually only first quadrant data are available normal operation and sometimes only the design or rated values are known In the case of full scale nuclear power plant pumps it is difficult to test the pumps in all octants of operation or even very far from design conditions The usual approach to obtain data for such systems is through the use of scaled
254. used in cylindrical or spherical coordinates when the radius of the left most mesh point is zero though the numerical techniques impose the condition regardless of the boundary condition specified If a rectangular geometry is modeled with both surfaces attached to the same hydrodynamic volume with the same boundary conditions and having symmetry about the structure midpoint storage space and computer time can be saved by describing only half of the structure The symmetry boundary condition is used at one of the surfaces and the heat surface area is doubled This boundary condition can also be used when a surface is very well insulated When a heat structure is connected to a hydrodynamic volume a set of heat transfer correlations can be used as boundary conditions The correlations cover the various modes of heat transfer from a surface to fluid and the reverse heat transfer from fluid to the surface The heat transfer modes listed in the printed output are Mode 0 Convection to noncondensable water mixture 3 3 NUREG CR 5535 V2 RELAP5 MOD3 2 Mode 1 Single phase liquid convection at supercritical pressure with the void fraction equal to zero Mode 2 Single phase liquid convection at subcritical pressure Mode 3 Subcooled nucleate boiling Mode 4 Saturated nucleate boiling Mode 5 Subcooled transition film boiling Mode 6 Saturated transition film boiling Mode 7 Subcooled film boiling Mode 8 Saturated film boiling Mode
255. vancements are serially coupled That is the heat conduction transfer is advanced first using old hydrodynamic information and the hydrodynamics is then advanced using new heat transfer information The time step control for hydrodynamics is determined by the status of the first bit as described above If the fourth bit is set entering 8 9 10 11 12 13 14 15 24 25 26 27 28 29 30 or 31 the hydrodynamics will use the nearly implicit hydrodynamic numerical scheme The time step can be as large as 20 times the Courant limit for the TRANSNT option and 40 times the Courant limit for the STDY ST option The time step control for hydrodynamics is determined by the status of the first bit as described above NUREG CR 5535 V2 8 2 RELAP5 MOD3 2 If the fifth bit is set entering 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 or 31 control of termination of the steady state advancement is used At the end of each advancement in steady state problems an algorithm measures the approach to steady state If this bit is set advancement will not be terminated by the algorithm if the bit is not set steady state can be terminated by the algorithm when it detects steady state has been reached This control can allow the user to ensure that a steady state run always uses a defined minimum advancement time then can allow another period of advancement time for the algorithm to determine steady state and finally manually terminate the
256. variable as the search argument in the pump velocity table The motor and its control system that drives a BWR recirculation pump could be modeled using the control system with one of the control variables representing the rotational velocity of the motor The recirculation pump would be modeled as a hydrodynamic pump component The torque exerted by the water on the pump would be one of the input variables to the control system model Motor velocity would be supplied to the pump component by specifying the motor velocity as the search argument of the time dependent pump velocity table The table would relate the motor rotational velocity to the pump rotational velocity If the motor and pump were directly coupled the search variables and dependent variables would be the same Whenever the time dependent pump angular velocity table is not being used the pump angular velocity is determined by the advancement in time of the differential equation relating pump moment of inertia angular acceleration and net torque The net torque is the pump motor torque minus the homologous torque value and the frictional torque If the pump trip is false electric power is being supplied to the pump motor if the trip is true electric power is disconnected from the pump motor and the pump motor torque is zero If a table of pump motor torque as a function of pump angular velocity is entered the pump motor is directly specified and motor torque is obtained from the table
257. velocity If the pump trip is reset to false pump trip reset the rotational velocity remains at the previous time step velocity it is not reset to the initial velocity To return to the initial velocity the pump rotational velocity table can be used Optional input can prevent reverse rotation and stop the pump based on elapsed time and exceeding a maximum rotational speed in either direction 4 2 3 2 2 Pump Associated With Shaft Optional pump component input can be entered to associate the pump component with a shaft component When a pump is associated with a shaft component the rotational velocity is computed by the shaft component logic and not by the pump logic The following describes the differences in pump logic when the pump is associated with a shaft The pump speed table cannot be entered The options to prevent reverse velocity and to stop the pump based on time or velocity also cannot be used With one exception the motor torque computation using either the motor torque table or the implied motor with a shaft component is identical to that without a shaft If no components other than the pump are attached to the shaft the moment of inertia of the pump shaft combination is equal to that of the pump alone Identical results can be obtained with or without using the shaft The shaft must have a nonzero moment of inertia to have the inertia of a pump alone equal that of the pump shaft combination some of the pump inertia must be app
258. w regime letters and numbers Continued Flow regime Three letter code I Number major edits minor edits plots ECC mixer mist MMS 17 ECC mixer wavy slug transition MWS 18 ECC mixer wavy plug slug transition MWP 19 ECC mixer plug MPL 20 ECC mixer plug slug transition MPS 21 ECC mixer slug MSL 22 ECC mixer plug bubbly transition MPB 23 ECC mixer bubbly MBB 24 Table 2 1 2 Bubbly slug flow regime numbers for vertical junctions Geometry and flow conditions Correlations used Rise y plots Rod bundles EPRI 2 High up down flows in small pipes EPRI 3 Low up down countercurrent flows in small Zuber Findlay slug 4 pipes Transition regions between 3 and 4 EPRI amp Zuber Findlay slug 5 High up down flows in intermediate pipes EPRI 9 Low up down countercurrent flows in Churn turbulent bubbly 10 intermediate pipes Transition regions between 10 and 12 Churn turbulent bubbly amp 11 Kataoka Ishii Low up down countercurrent flows in Kataoka Ishii 12 intermediate pipes Transition between regions 9 and 10 11 12 EPRI amp Churn turbulent 13 bubbly Kataoka Ishii Large pipes Churn turbulent bubbly 14 Transition regions between 14 and 16 Churn turbulent bubbly amp 15 Kataoka Ishii Large pipes Kataoka Ishii 16 2 9 NUREG CR 5535 V2 RELAP5 MOD3 2 In the bubbly and slug flow regimes for vertical junctions it is possible to list an additio
259. when the trip is true A time dependent volume could have some constant condition when the trip is false When the trip is true it could follow a prescribed function of time where the time origin is the time of the trip not the start of the transient Through an input option nearly any time advanced quantity can be specified as the search argument The allowed quantities are listed in the input description The search variables in the table are assumed to have the same units as the search argument and the table lookup interpolation and treatment of out of range arguments are identical to those described for the default time argument However handling of trips is different If the trip number is zero the current value of the specified time advanced variable is used If the trip number is nonzero the time delay cannot be applied as for the default time case since the search argument may not be time Thus if the trip is false the search argument is 1 0E75 if the trip is true the current value of the specified variable is the search argument When time is the search argument the current value is the value at the end of the time step for any other variable the current value is the value at the beginning of the time step Time is the default search argument but time can also be specified as the search argument through the input option of naming a time advanced variable These two uses of time as the search argument are different if a trip is us
260. where O indicates false 1 indicates true Each trip quantity may be the original value or its complement Complement means reversing the true and false values that is the complement of true is false Table 4 1 1 Logical operations AND OR XOR 0011 0011 0011 0101 0101 0101 0001 0111 0110 The logical trip statement is L NUM TRIPI OP TRIP2 B TIMEOF 4 1 2 where NUM is the card number TRIP1 and TRIP2 are either variable or logical trip numbers OP is the logical operator L or N are for latched or unlatched trips and TIMEOF is the optional initialization value A positive trip number means the original trip value a negative number means the complement value Examples of logical trips are 601 501 OR 502 N 602 601 AND 510 N 620 510 OR 510 N Trip 602 involves a previous logical trip and illustrates the construction of a complex logical statement With the definitions given in the examples above and using parentheses to indicate the order of logical evaluations Trip 602 is equivalent to Pressure 3010000 lt 1 5 bar OR Pressure 5010000 gt Pressure 3010000 2 0 bar AND Time gt 100 s Trip 620 is the complement of Trip 510 and the AND operation in place of the OR operation would also give the same result Additional examples of trips are presented in Volume V of this code manual 4 1 3 Trip Execution The trip printout for a new problem at time equal to O s shows trips as they were entered a
261. which face the crossflow connection used The face number is now important both for elevation checking and in computing elevation effects momentum flux effects and friction We recommend that decks prepared for previous versions of the code have all crossflow connections reviewed for use with the newer crossflow model The junctions are printed out in the major edits in the hydrodynamic junction information sections see Section 8 3 2 9 and Section 8 3 2 10 The from and 70 volumes are listed for each junction In addition the flow regimes for the volumes floreg and the junctions florgj are also listed using three letters It is also possible to list the flow regime for the volumes and the junctions in the minor edits and plots where a number is used Table 2 1 1 shows the three letter code and number used for each flow regime Table 2 1 1 Flow regime letters and numbers Flow regime Three letter code I Number major edits minor edits plots High mixing bubbly CTB 1 High mixing bubbly mist transition CTT 2 High mixing mist CTM 3 Bubbly BBY 4 Slug SLG 5 Annular mist ANM 6 Mist pre CHF MPR 7 Inverted annular IAN 8 Inverted slug ISL 9 Mist MST 10 Mist post CHF MPO 11 Horizontal stratified HST 12 Vertical stratified VST 13 ECC mixer wavy MWY 14 ECC mixer wavy annular mist MWA 15 ECC mixer annular mist MAM 16 NUREG CR 5535 V2 2 8 RELAP5 MOD3 2 Table 2 1 1 Flo
262. xerted by the fluid on the pump and is negative if it tends to decelerate the pump In normal pump regimes and in steady state this torque is negative and is balanced by the positive torque from the pump motor 2 3 8 1 2 Pump Data Homologous Representation The use of pump performance data in terms of nondimensional homologous parameters is often confusing The purpose of this discussion is to briefly outline rules for a procedure to properly use the homologous data The homologous parameters for pumps are obtained from dimensional analysis that can only provide the conditions for similarity Three independent parameters are obtained from application of Buckingham s Pi theorem 23 1 They are 1 Q vD 2 3 4 1 3 T NQ gH 2 3 5 2 33 NUREG CR 5535 V2 RELAP5 MOD3 2 T3 Q ND 2 3 6 A fourth parameter that is commonly used can be obtained by a combination of m and 73 to yield t4 gH N D 2 3 7 The first parameter T4 is analogous to a Reynolds number and is the only parameter involving the fluid kinematic viscosity v Experience with pump design and scaling has shown that viscous effects caused by skin friction are small especially for high Reynolds number flows and in practice the requirement to maintain Tr constant is not used The use of 75 13 and Tr to correlate pump performance has proven quite useful The parameter 7 is called the specific speed and is often used as a single parameter

relap5/mod3 code manual volume ii: user`s guide and

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