VERA 3.3 Release Notes
Contents
1. 28 CTF The following unit tests COBRA_TF_run_par_quarter_cross_pets and COBRA_TF_run_multistate_par_cross_par have been observed to time out on virtual machine installations of VERA both CentOS 6 6 and Ubuntu 14 04 1 It is likely that these observed CASL U 2015 0042 000 11 Consortium for Advanced Simulation of LWRs VERA 3 3 Release Notes BI 3 timeouts are related to the lack of computational resources on the virtual test machines i e 2 cores and 4 GB of memory but this hypothesis has not been confirmed as of the time of release 29 BISON The number of processors used by the libmesh build process within MOOSE is controlled by the CASL environment variables MOOSE_JOBS and LIBMESH_JOBS If building on less than 8 cores it is MOOSE advisable to set these environment variables equal to the number of available processors 10 REFERENCES Godfrey A VERA Core Physics Benchmark Progression Problem Specifications CASL Technical Report CASL U 2012 0131 004 2014 Brendan M Kochunas B S Collins D R Jabaay T J Downar and W R Martin Overview of Development and Design of MPACT Michigan Parallel Characteristics Transport Code International Conference on Mathematics amp Computational Methods Applied to Nuclear Science amp Engineering M amp C 2013 Sun Valley Idaho May 5 9 2013 Schmidt R K Belcourt R Hooper R Pawlowski K Clarno S Simunovic S Sla2. R AJANNoL r CASL U 2015 0042 000 p A DOE ergy Innovation Hub VERA 3 3 Release Notes April 20 2015 ae N U S DEPARTMENT OF NERGY Nuclear Energy VERA 3 3 Release Notes REVISION LOG CASL Revision Date Affected Pages Revision Description 0 All Initial Release Document pages that are Export Controlled None IP Proprietary NDA Controlled None Sensitive Controlled Requested Distribution To Copy None Consortium for Advanced Simulation of LWRs CASL U 2015 0042 000 GI 3 VERA 3 3 Release Notes 1 GENERAL REMARKS The CASL software components provided in this release are under active development and are subject to change They have not been fully validated or assessed and should be used primarily for test evaluation and research purposes only The Virtual Environment for Reactor Applications components included in this distribution include selected computational tools and supporting infrastructure that solve neutronics thermal hydraulics fuel performance and coupled neutronics thermal hydraulics fuel performance problems The infrastructure components provide a simplified common user input capability and provide for the physics integration with data transfer and coupled physics iterative solution algorithms Neutronics analysis can be performed for 2D lattices 2D core and 3D core problems for pressu
3. stochastic expansions polynomial chaos and stochastic collocation Optimization calibration gradient based local derivative free local pattern search global genetic algorithms direct etc local least squares surrogate based local methods Surrogate models polynomials Gaussian process Kriging neural network Parameter types all are mature except discrete string and categorical types Interfaces system fork and direct The following features are considered to be Stable Design and analysis of computer experiments DDACE grid random orthogonal array OA LHS FSU quasi Monte Carlo Halton Hammersley centroidal voronoi tessellation PSUADE Morris one at a time Uncertainty quantification global reliability probability of failure methods adaptive stochastic expansions importance sampling including adaptive and surrogate based Probability of Failure Darts epistemic interval uncertainty Dempster Shafer Bayesian inference QUESO DREAM incremental LHS Optimization NOMAD directional search surrogate based global including EGO hybrid and pareto optimization Surrogate models MARS Taylor TANA hierarchical and multi fidelity Interfaces Matlab and Python interfaces work directory and parallel interface scheduling features refactored recently The following features are considered to be Experimental or Weakly Tested Design and analysis of computer experiments DDACE Box Behnken central composite designs Cons
4. 1 8 8 38 77 s 2j inp 1 8 8 39 75 s 2k inp 1 8 8 24 75 s 2l inp 1 8 8 96 80 s 2m inp 1 8 8 96 92 s 2n inp 1 8 8 104 30 s 20 inp 1 8 8 40 76 s 2p inp 1 8 8 40 53 s 2q inp 1 8 8 39 47 s 3a inp 4 4 41 58 2 98 m 3b inp 4 4 41 58 3 19 m 4a inp 33 4 05 522 8 40 m 4a 0 inp 33 4 05 522 11 15 m 4a 10 inp 33 4 05 522 12 92 m 4a 100 inp 33 4 05 522 11 98 m 4a 20 inp 33 4 05 522 8 73 m 4a 2d inp 33 4 05 522 8 16 m 4a 30 inp 33 4 05 522 7 94 m Consortium for Advanced Simulation of LWRs 14 CASL U 2015 0042 000 CASL VERA 3 3 Release Notes 4a 40 inp 33 4 05 522 8 45 m 4a 50 inp 33 4 05 522 8 68 m 4a 60 inp 33 4 05 522 8 88 m 4a 70 inp 33 4 05 522 7 49 m 4a 80 inp 33 4 05 522 7 61 m 4a 90 inp 5 4 44 12 0 81 m 4b 2d inp 5 4 44 12 0 92 m 4c 2d inp 5 4 44 12 0 90 m 5a 0 inp 29 4 00 464 336 25 m 5a 1 inp 29 4 00 464 345 33 m 5a 10 inp 29 4 00 464 279 42 m 5a 2 inp 29 4 00 464 348 03 m 5a 3 inp 29 4 00 464 339 02 m 5a 4 inp 29 4 00 464 324 90 m 5a 5 inp 29 4 00 464 376 57 m 5a 6 inp 29 4 00 464 386 93 m 5a 7 inp 29 4 00 464 348 78 m 5a 8 inp 29 4 00 464 384 77 m 5a 9 inp 29 4 00 464 389 10 m 5a 2d inp 37 4 05 584 4 23 m 5b 2d inp 37 4 05 584 4 42 m 5c 2d inp 37 4 05 584 4 41 m p6 inp 4 4 41 58 11 31 m p7 inp 29 4 00 464 7 06 h Appen
5. Data Transfer Kit A Geometric Rendezvous Based Tool for Multiphysics Data Transfer International Conference on Consortium for Advanced Simulation of LWRs 12 CASL U 2015 0042 000 GI 3 VERA 3 3 Release Notes Mathematics amp Computational Methods Applied to Nuclear Science amp Engineering M amp C 2013 Sun Valley Idaho May 5 9 2013 CASL U 2015 0042 000 13 Consortium for Advanced Simulation of LWRs VERA 3 3 Release Notes BI 3 APPENDIX A COMPUTE RESOURCES REQUIRED TO EXECUTE THE CASL CORE SIMULATOR BENCHMARK PROGRESSION PROBLEMS The following CPU memory and execution time metrics were recorded during acceptance testing of the VERA 3 3 Release Candidate Problems were executed on the EPRI Phoebe cluster an industry class 8 9 teraflop high performance computer with 784 Intel Xeon compute cores 84TB of mass storage and 3TB of memory Input files are provided in the verain Progression_ Problems directory Appendix A 1 With MPACT Requested Actual Input Nodes Memory GB core Cores Time s la inp 1 8 8 176 87 s 1b inp 1 8 8 178 04 s lc inp 1 8 8 179 60 s 1d inp 1 8 8 178 96 s le inp 1 8 8 179 30 s 2a inp 1 8 8 39 78 s 2b inp 1 8 8 35 53 s 2c inp 1 8 8 35 41 Is 2d inp 1 8 8 34 32 s 2e inp 1 8 8 38 84 Is 2f inp 1 8 8 37 49 s 2g inp 1 8 8 42 57 s 2h inp 1 8 8 41 73 s 2i inp
6. Denovo Sy solver are also integrated into other radiation transport codes The Exnihilo component Insilico is a 2D and 3D transport code based on the discrete ordinates Sn and simplified PN SPN methods to solve the transport equation Both methods can be executed in parallel to reduce overall run times Cross section processing is based on a unit cell approach using the XSProc capability from the SCALE code package and includes a 252 group cross section library Exnihilo in VERA currently contains the following source code packages e Nemesis Infrastructure components This collection of utilities should be applicable to most scientific codes Included are Design by Contract utilities communication libraries containers and algorithms HDF5 and Silo interface wrappers template based serialization utilities and the unit testing harness e Transcore Tranport core components These components are specific to radiation transport and multiphysics codes Included are cross section storage classes libraries for reading and writing cross sections quadrature sets Trilinos solver wrappers Monte Carlo samplers and Python interface wrappers Consortium for Advanced Simulation of LWRs 4 CASL U 2015 0042 000 Z CASL VERA 3 3 Release Notes e Geometria Geometry packages The geometries in this class are used for meshing deterministic problems for transporting Monte Carlo particles on and for tallying Geometries include mesh and cylindri
7. Simulation of LWRs 2 CASL U 2015 0042 000 KG CASL VERA 3 3 Release Notes Critical Boron Search Equilibrium Xenon Calculation Direct Coupling with COBRA TF Simplifed Internal T H Model Modeling of Control Rod Banks Fission Chamber Detector Response Separate B 10 Depletion of soluble Boron Semi Explicit modeling of grid spacers Simulated Control Rod movement between states Checkpoint files Isotopic Restart Files Cycle to Cycle Fuel Shuffling Rotational Symmetry Improved Transport Corrected PO Approximation 2 D 1 D Transport Capability NEM Diffusion SANM Diffusion SP1 SP3 and SP5 1 D Nodal Kernels 47 group Cross Section Library Data The following features are considered to be Stable Footnotes refer to the Known Issues listed in Table 1 of Section 9 below Support for Windows OS 32 bit and 64 bit Support for Linux OS 32 bit and 64 bit Parallel Spatial Decomposition with MPI Parallel Angular Decomposition with MPI User defined Macroscopic Cross Sections 47 group Macroscopic Cross Section Library Data Transport Corrected POf Export of Mesh to Legacy VTK file for visualization 2 D MOC Transport Kernel Coarse Mesh Finite Difference CMFD Acceleration 1 D Nodal Kernels based on NEM Diffusion and SPn 2 D 1 D Full Core Solution Multi State Calculation Capability Depletion and Decay Critical Boron Search Equilibrium Xenon Calculation Direct Coupling with COBRA TF Simplified Internal T H General P
8. global 2D and local effects 3D modeling and Utilizes high performance computing platforms to achieve the massively parallel performance and scalability required to perform coupled multi physics simulations of full length 3D representations of the fuel rod components Consortium for Advanced Simulation of LWRs 6 CASL U 2015 0042 000 GI 3 VERA 3 3 Release Notes The BISON CASL fuel rod performance code architecture uses the finite element method for geometric representation and a Jacobian free Newton Krylov JFNK scheme to solve systems of partial differential equations The fuel rod performance capability includes models for e Clad stress strain and strain rate e Clad oxidation hydrogen pickup and hydride formation e Pellet stress strain and strain rate e Fission gas release transient and pseudo steady state e Pellet densification swelling and fission product evolution e Pellet restructuring and high burnup rim thickness e Pellet cracking and relocation e Thermal expansion including pellet hour glassing e Thermal and irradiation creep e Thermal conductivity effects due to clad oxidation and fuel microstructure evolution e Material strength and ductility effects due to irradiation thermal cycling hydriding fission product evolution e Pellet cladding gap evolution and local stress due to partial contact e Pellet stack growth and fuel rod growth e Explicit modeling of duplex and triplex clad desi
9. has been extended to use the axisymmetric 2D R Z fuel rod modeling functionality of BISON CASL to produce a three way coupled neutronics thermal hydraulics and fuel performance capability known as Tiamat This distribution is intended to be used for testing and evaluation of the released components of VERA Testing within CASL has focused specifically on Westinghouse four loop reactor geometries and conditions with example problems included in the distribution 2 SYSTEM REQUIREMENTS Linux platforms with functioning gcc g and gfortran compilers and X11 libraries are supported 32 cores or greater are recommended Detailed system software and third party library requirements are specified in the provided VERA Installation Guide CASL U 2015 0042 000 1 Consortium for Advanced Simulation of LWRs VERA 3 3 Release Notes BI 3 This distribution has been tested and verified to install and execute on the following OS distributions e CentOS 6 6 e Ubuntu 14 04 1 e SUSE Linux Enterprise Server 11 SP3 e Fedora 21 e CrayOS Appendix A provides a summary of the compute resources required to execute each of the CASL Core Simulator Benchmark Progression Problems 1 1 7 during acceptance testing on the EPRI Phoebe cluster These resource measurements should be taken as a guide only system configuration and resource variations can significantly impact the performance for other systems 3 INSTALLATION Detailed installation instructi
10. satisfies its internal convergence criteria on eigenvalue and fission source 6 7 7 3 Tiamat Tiamat uses PIKE and DTK to couple Insilico CTF and BISON CASL into a single executable application 8 9 The Tiamat code is being developed as an integrated tool for predicting pellet clad interaction and improving the high fidelity core simulator Tiamat solves a transient problem where each time step is sub cycled using Picard iteration to converge the fully coupled nonlinear system 8 INFRASTRUCTURE COMPONENTS 8 1 DataTransferKit DTK Software library for parallel data transfer algorithms for physics code coupling 10 8 2 LIME The Lightweight Integrating Multiphysics Environment LIME was well suited to the requirements of VERA and was used as the initial basis for coupling of capabilities in VERA It was specifically designed for integration of existing components already exist to solve different parts of a multiphysics problem LIME provides the key high level software written in C a well defined approach and interface requirements to enable the assembly of multiple physics codes into a single executable coupled code multiphysics simulation capability In order to create a new multiphysics application using LIME physics codes are required to support a minimal software interface Depending on the structure and design of the original physics codes some degree of code refactoring may be required CASL U 2015 0042 000 9 Consorti
11. E heat transfer models are encountered in validation tests but no validation of models done o Droplet entrainment de entrainment models encountered in validation tests but droplet field is not validated Channel splitting and coalescing Channel flow area variations rod ballooning Grid directed cross flow modeling Boron tracking model with consideration of boron precipitation O O 0 0 6 4 BISON CASL VERA includes the capability to predict fuel rod performance utilizing 3 D coupled multi physics and represents a significant advancement for the modeling analysis capabilities in LWR fuel rod behavior The capability is being constructed within the MOOSE BISON computational framework from Idaho National Laboratory that supports Statics with elasticity plasticity with strain hardening creep large strains large displacements and smeared plus explicit cracking Unsteady transient heat transfer including conduction convection and radiation with time and spatial axially radially and potentially azimuthally in a cylindrical fuel element dependent internal heat generation 2D axisymmetric plane strain and plane stress representations including contact and friction interactions between pellets and between the pellet and cladding 3D statics and dynamics with contact and friction and heat transfer Mixed dimensional coupling via multipoint constraint equations etc e g combined 2D and 3D numerical representations for coupled
12. WR Geometry Modeling o IFBA o Control Rods and Control Rod Banks CASL U 2015 0042 000 3 Consortium for Advanced Simulation of LWRs VERA 3 3 Release Notes BI S o Burnable Poison Inserts o Fission Chamber Detectors o Grid spacers Nozzles Plenum Baffle etc e Checkpoint File e Isotopic Restart File 41516 17 The following features are considered to be experimental and are not mature e Separate B 10 Depletion of soluble Boron e Semi Explicit modeling of grid spacers e Rotational Symmetry This feature should work without issue in most cases but has not yet been extensively tested e Cycle to Cycle Fuel Shuffling This feature should work without issue in most cases but has not yet been fully verified o One known issue is that the assm_map in the input must match the shuffle_label card o Shuffle by assembly serial number is not supported o Changing the axial mesh is not supported for shuffle e 3 D MOC Kernels e Processing of AMPX Working Cross Section Libraries e 1 D Nodal Kernels based on SANM diffusion 6 2 Exnihilo Exnihilo is a modern radiation transport framework that implements a variety of advanced solvers and solution methodologies enabling it to solve a wide variety of nuclear engineering and applications problems with the scalability to run on both desktop machines and leadership class supercomputers It supports stand alone execution using its internal front ends but its components such as the
13. ation CASL U 2015 0042 000 Document ID Document Title CASL U 2015 0082 000 VERA Installation Guide CASL U 2015 0083 000 VERA Configure Build Test and Install Quick Reference Guide CASL U 2014 0014 002 VERA Common Input User Manual CASL U 2015 0054 000 CTF Theory Manual CASL U 2015 0055 000 CTF User s Manual CASL U 2015 0056 000 CTF Preprocessor User Manual CASL U 2014 0169 000 CTF Validation Manual CASL U 2015 0078 000 MPACT Theory Manual CASL U 2015 0077 000 MPACT User s Manual CASL U 2015 0043 000 MPACT VERA Common Input User s Manual CASL U 2014 0038 000 User Guidelines and Best Practices for CASL VUQ Analysis Using Dakota CASL U 2015 0090 000 DAKOTA Theory Manual CASL U 2015 0087 000 DAKOTA User s Manual CASL U 2015 0089 000 DAKOTA Reference Manual CASL U 2015 0088 000 DAKOTA Developer s Manual CASL U 2015 0080 000 Exnihilo Methods Manual CASL U 2015 0079 000 Exnihilo User Manual BISON Theory Manual https inlportal inl gov portal server pt document 164359 theory1_1_pdf BISON User s Manual https inlportal in gov portal server pt document 164360 users1_1_pdf 17 Consortium for Advanced Simulation of LWRs
14. cal mesh Reactor ToolKit geometry MCNP geometry using the Lava wrapper SCALE geometry and DagMC geometry e Physica Physics packages These are geometry agnostic physics engines used for Monte Carlo transport Currently included are continuous energy and multigroup physics packages e Denovo Deterministic transport solvers Denovo contains advanced transport solvers for fixed source and eigenvalue problems with discrete ordinates Sy and simplified spherical harmonics SPw using Cartesian grids with the KBA decomposition e Shift Monte Carlo solver The Shift Monte Carlo framework is based on geometry and physics agnostic transport routines These routines include advanced parallel algorithms flexible tallies and extensible source definitions e Insilico Neutronics front end The Insilico front end couples Denovo and Shift with cross section processing depletion and thermo hydraulics feedback for reactor analysis This component is integrated into VERA the Virtual Environment of Reactor Applications 6 3 CTF CTF COBRA TF is a subchannel thermal hydraulics code that uses a two fluid three field i e fluid film fluid drops and vapor modeling approach Both sub channel and three dimensional 3D Cartesian forms of nine conservation equations are available for LWR modeling CTF includes a wide range of thermal hydraulic models important to LWR safety analysis including flow regime dependent two phase wall heat transfer in
15. dix A 2 With Insilico Requested Actual Case Nodes Memory GB core Cores Time s la inp 1 64 1 24 76 S 1b inp 1 64 1 17 46 S lc inp 1 64 1 8 22 S Id inp 1 64 1 8 22 S le inp 1 64 1 19 48 S 2a inp 2 8 16 27 45 S 2b inp 2 8 16 29 99 S 2c inp 2 8 16 32 15 S 2d inp 2 8 16 21 96 S 2e inp 2 8 16 21 25 S CASL U 2015 0042 000 Consortium for Advanced Simulation of LWRs VERA 3 3 Release Notes 2f inp 2 8 16 21 25 S 2g inp 2 8 16 21 10 S 2h inp 2 8 16 26 08 S 2i inp 2 8 16 21 33 S 2j inp 2 8 16 21 32 S 2k inp 2 8 16 22 21 S 2l inp 2 8 16 32 27 S 2m inp 2 8 16 50 48 S 2n inp 2 8 16 37 53 S 20 inp 2 8 16 23 93 S 2p inp 2 8 16 24 30 S 2q inp 2 8 16 30 76 3a inp 4 4 00 64 348 22 s 3b inp 4 4 00 64 346 17 s 4a 90 inp 1 4 00 16 73 48 S 4b 2d inp 1 4 00 16 70 71 S 4c 2d inp 1 4 00 16 72 17 S 5a 2d inp 4 4 00 64 127 96 5b 2d inp 4 4 00 64 133 63 s 5c 2d inp 4 4 00 64 134 45 s 6p inp 4 4 00 64 1238 40 s Consortium for Advanced Simulation of LWRs CASL U 2015 0042 000 APPENDIX B VERA 3 3 DOCUMENTATION The following documentation is being made available with the VERA 3 3 release and can be viewed or downloaded at www casl gov docs document id pdf or at the URL indicated below Other CASL technical reports and presentations are available at http www casl gov publications shtml Table 1 VERA 3 3 Component Document
16. ed calculation is run and the coupled iteration produces a temperature beyond the range of the library Note that the latter typically happens if the solution contains very high peaking and power which may also indicate the specification of an unphysical STATE 4 MPACT When using TCPO it has been observed that in some cases that this correction can drive the solution negative Consortium for Advanced Simulation of LWRs 10 CASL U 2015 0042 000 GI 3 VERA 3 3 Release Notes WORKAROUND Use P2 scattering is recommended at the expense of longer run times The LTCPO option may also be used however the solution may not as accurate 5 MPACT When exporting the Flat Source Region mesh of the full core gaps between and or overlapping of the mesh at assembly boundaries is present 6 MPACT The number of azimuthal divisions in the Flat Source Region mesh of a fuel pin or guide tube in the visualization file is not representative of the computational mesh The visualization contains extra divisions to approximate a curved surface as a series of line segments 7 MPACT When linking against some versions of BLAS notable differences in the computed k eff have been observed 10 39 pcm 8 MPACT For some 2 D 1 D cases with TCPO SP3 may have convergence issues WORKAROUND Use the NEM nodal kernel or a different scattering treatment 9 MPACT Not all values of state variables are carried forward or processed in subse
17. gns The VERA fuel rod performance subcomponent calculates on a 3D basis fuel rod temperature fuel rod internal pressure free gas volume clad integrity and fuel rod waterside diameter These capabilities allow simulation of power cycling fuel conditioning and deconditioning high burnup performance power uprate scoping studies and accident performance It is important to note that these tools are built around the known performance of existing zirconium based clad with UO fuel and predictions for other fuel types may not be accurate Estimates for the global effects of minor modifications to the fuel or clad may be possible for example chromia doped pellets may be simulated with user supplied models for several of the pellet performance characteristics or steel based clad may be simulated with similar user supplied models Materials such as silicon carbides that do not fit the system paradigm can be simulated but are likely to provide inaccurate results 6 5 Dakota The Dakota package http dakota sandia gov manages and analyzes ensembles of simulations to provide broader and deeper perspective for analysts and decision makers In its simplest mode Dakota can automate typical parameter variation studies through a generic interface to a physics based computational model This can lend efficiency and rigor to manual parameter perturbation studies already being conducted by analysts Dakota also delivers advanced parametric analysis techn
18. ion Subsequent STATE blocks should specify depletion points 17 MPACT Changing the mesh is not supported for restarts 18 Dakota Command line redirection may entangle output when running in parallel 19 Dakota Some tests fail running in parallel with MPICH 20 Dakota Message passing errors with discrete string variables of variable lengths 21 Dakota Some methods that write intermediate files e g LHS err can t be run as concurrent iterators 22 Dakota dprepro doesn t support the full range of permitted variable descriptors or string variable values Right now it accepts w which is a zA Z_ 23 Dakota Incremental LHS does not support mixed continuous discrete sampling and output tabular data file mis ordered 24 Dakota Support for categorical variables missing from several methods 25 Dakota Importing tabular files into Matlab no longer works straightforwardly due to presence of interface ID 26 Dakota Separate work directories not created for concurrent iterators 27 MPACT The following unit tests MPACT_libsNodal_testNodalSweeper_MPI_4 and MPACT_libsCMFD_testParCMFD_MPI_4 have been observed to fail on virtual machine installations of VERA both CentOS 6 6 and Ubuntu 14 04 1 It is likely that these observed failures are related to the lack of computational resources on the virtual test machines i e 2 cores and 4 GB of memory but this hypothesis has not been confirmed as of the time of release
19. iques enabling design exploration optimization model calibration risk analysis and quantification of margins and uncertainty with such models It directly supports verification and validation activities Dakota algorithms enrich complex science and engineering models enabling an analyst to answer crucial questions of e Sensitivity Which are the most important input factors or parameters entering the simulation and how do they influence key outputs CASL U 2015 0042 000 7 Consortium for Advanced Simulation of LWRs VERA 3 3 Release Notes BI 3 Uncertainty What is the uncertainty or variability in simulation output given uncertainties in input parameters How safe reliable robust or variable is my system Quantification of margins and uncertainty QMU Optimization What parameter values yield the best performing design or operating conditions given constraints Calibration What models and or parameters best match experimental data A CASL Technical Report providing user guidelines and best practices for CASL VUQ analysis using Dakota CASL U 2014 0038 SANDIA Report SAND2014 2864 is available at https dakota sandia gov sites default files documents SAND Cas lDakotaManual pdf The following features are considered to be mature and robust Parameter studies list vector centered multi dimensional Uncertainty quantification Monte Carlo and Latin hypercube sampling local reliability probability of failure methods
20. ons are provided in the VERA Installation Guide located in the distribution tarball under the VERA doc installation_guide folder and at www casl gov docs CASL U 2015 0082 000 pdf 4 DOCUMENTATION A detailed list of documentation provided with this release is given in Appendix B Pointers to additional software documentation are provided in the README lt component gt files found in the VERA doc directory Additional documentation in the form of CASL technical reports and publications is available at http www casl gov publications shtml 5 SUPPORT Questions issues bugs and suggestions should be reported to support casl gov Every effort will be made to respond to any requests within a reasonable period of time Due to active development efforts users may experience some delays 6 PHYSICS COMPONENTS INCLUDED IN VERA 3 3 6 1 MPACT MPACT 2 0 0 is based on the Method of Characteristics transport approach for 2D problems with cross section weighting based on the subgroup methodology 2 The code can be executed in parallel to reduce overall run time For 3D problems MPACT uses the 2D 1D method which uses 2D MOC in a radial plane and diffusion or SP in the axial direction A 47 group library with subgroup parameters is provided New features implemented since MPACT 1 0 0 are e Multi State calculation capability e Depletion and Decay o Direct coupling with ORIGEN o Alternative internal capability Consortium for Advanced
21. opment and are subject to rapid change They have not been fully validated or assessed and should be used for test evaluation and research purposes only e Users who are evaluating VERA for commercial or institutional use should be aware that not all components in this release will be supported long term by CASL Specifically the LIME coupled Insilico CTF coupled physics driver provided in this release will be deprecated in future releases since the capabilities it provides are superseded by Tiamat and other coupled codes under development e When using BISON CASL through Tiamat users should run 1 MPI process per MOOSE fuel pin The following issues have been identified during development and testing of this release package Table 1 Known Issues Issue ID Component Issue 1 MPACT In full core models with jagged boundaries the decomposition algorithm fails WORKAROUND specify the spatial decomposition with an explicit partition file 2 MPACT It has been observed that on some platforms in particular Eos that depletion cases run with spatial and angular decomposition will fail WORKAROUND Use threading instead of angle decomposition 3 MPACT If the code iterates to a material temperature beyond the range of the data in the cross section library the code segfaults This can happen either if a material temperature is specified in the input beyond the range of normal operating conditions of the reactor or if a coupl
22. ortium for Advanced Simulation of LWRs 8 CASL U 2015 0042 000 GI 3 VERA 3 3 Release Notes e Uncertainty Quantification Topology based adaptive sampling e Optimization Genie Opt Darts Genie Direct e Surrogate models moving least squares radial basis functions e Interfaces Scilab and grid e Responses field data and experimental data capabilities are in refactoring flux e Other active subspace methods for dimension reduction string categorical variable support is limited Known Limitations of Dakota 6 1 are listed in Section 9 Table 1 items 18 26 7 COUPLED PHYSICS EXECUTABLES 7 1 Insilico CTF Coupled Insilico CTF uses the neutronics and thermal hydraulics capabilities described above with the LIME and DTK coupling infrastructure to support data transfers and perform coupled iterations using Picard iteration to arrive at a converged solution 3 5 7 2 MPACT CTF MPACT has the ability to call CTF to obtain fuel temperatures and moderator density This is done by directly calling the CTF solver every outer iteration and passing the power distribution After CTF converges on a given power shape the temperatures and densities are passed back to MPACT and applied to the cross sections A conditional check on the change in temperature and density is performed to determine if the subgroup calculation needs to be rerun to obtain new shielding parameters for the cross section generation This procedure continues until MPACT
23. quent states The xenon tinlet modden and tfuel cards are not properly processed for multiple states 10 MPACT When using units of HOURS in the deplete card the hours are not cumulative between STATE blocks The time always restarts to 0 11 MPACT For smaller problems lattices or pins the MOC rays typically need to be refined if IFBA is present to obtain an accurate result If rays are not refined the azimuthal meshing of the IFBA layer may be reduced If this occurs a warning is printed to the log file 12 MPACT Support for the depletion of absorbing materials in control rods is not yet implemented The absorber material in a control rod should be defined in the CONTROL block to ensure rod materials are not depleted If the materials are placed elsewhere they may be flagged as depletable 13 MPACT Symmetry unfolding is not yet supported for restarts 14 MPACT State variables are not read from the restart file and must be entered in the STATE block when a restart is performed otherwise default values are used 15 MPACT It has been observed that in cases modeling start up the restarted solution does not match the solution of the state where the restart file was written 16 MPACT If the deplete card appears in the same state block as a restart_read then issues might be encountered WORKAROUND If restarting a calculation it is best to explicitly define the first state as ONLY the restart state and no deplet
24. rized water reactor geometries that can be used to calculate criticality and fission rate distributions by pin for input fuel compositions Two neutronics capabilities are provided in this distribution including MPACT from the University of Michigan that supports 2D lattices and Insilico from Oak Ridge National Laboratory that supports 2D lattices 2D core planes and 3D core geometries Both codes include integrated cross section capabilities that provide problem specific cross sections for the problems defined A thermal hydraulics capability is provided with CTF an updated version of the COBRA TF code developed by the Pennsylvania State University that allows thermal hydraulics analyses for single and multiple assemblies using the simplified VERA common input This distribution also includes an initial coupled neutronics thermal hydraulics capability to allow calculations of single assemblies using Insilico or MPACT coupled with CTF The VERA fuel rod performance subcomponent BISON CASL calculates on a 3D basis fuel rod temperature fuel rod internal pressure free gas volume clad integrity and fuel rod waterside diameter These capabilities allow simulation of power cycling fuel conditioning and deconditioning high burnup performance power uprate scoping studies and accident performance Specifically targeted at VERA s core simulator functionality VERA CS the existing VERA subchannel neutronics capability based on CTF and Insilico
25. ter phase heat transfer and drag droplet breakup and quench front tracking Due to its 3D capabilities and extensive array of reactor thermal hydraulic modeling capabilities CTF has found much use in modeling of LWR rod bundle transient analysis and Pressurized Water Reactor PWR whole vessel Loss Of Coolant Accident LOCA analysis Stable features e Solid modeling capabilities o Radial conduction o Nuclear fuel rod models pellet gap and clad regions and UO2 and zircalloy material properties e Fluid modeling capabilities o Solid to fluid heat transfer single phase convection subcooled saturated boiling o Critical heat flux Departure from Nucleate Boiling o Two phase flow with droplets o Closure models Wall drag and form loss modeling Turbulent mixing and void drift Fluid equation of state o Incorporation of PETSc solvers o Variable size axial meshing CASL U 2015 0042 000 5 Consortium for Advanced Simulation of LWRs VERA 3 3 Release Notes BI 3 o Grid heat transfer enhancement modeling The following features are considered to be experimental or developmental and are not mature Solid modeling capabilities o Fuel rod axial azimuthal conduction o Axial mesh refinement quench front tracking o Dynamic gap conductance model pellet relocation and pellet clad interaction o Zircalloy water thermal reaction o Fuel pellet cracking sintering Fluid modeling capabilities o Non condensable gas effects o Post CH
26. ttery J Turner and S Palmtag An approach for coupled code multiphysics core simulations from a common input Annals of Nuclear Energy in press doi 10 1016 j anucene 2014 11 015 2015 Palmtag S K Clarno G Davidson T Evans J Turner K Belcourt R Hooper and R Schmidt Coupled Neutronics and Thermal Hydraulic Solution of a Full Core PWR Using VERA CS Proceedings of PHYSOR 2014 Kyoto Japan September 28 October 3 2014 on CD ROM Palmtag S Coupled Single Assembly Solution with VERA Problem 6 CASL Technical Report CASL U 2013 0150 000 2013 Kochunas B D Jabaay B Collins and T Downar Demonstration of Neutronics Coupled to Thermal Hydraulics for a Full Core Problem using COBRA TF MPACT CASL Technical Report CASL U 2014 005 1 000 2014 Kochunas B D Jabaay B Collins and T Downar Coupled Single Assembly Solution with COBRA TF MPACT Problem 6 CASL Technical Report CASL U 2013 0230 000 2013 Pawlowski R K Clarno and R Montgomery Milestone L1 CASL P9 03 Demonstrate Integrated VERA CS for the PCI Challenge Problem CASL Technical Report CASL I 2014 0153 000 Clarno K T Evans B Collins R Pawlowski R Montgomery B Kochunas and D Gaston Design of a High Fidelity Core Simulator for Analysis of Pellet Clad Interaction CASL Technical Report CASL U 2015 0036 000 2015 Slattery S R R P Pawlowski and P P H Wilson The
27. um for Advanced Simulation of LWRs VERA 3 3 Release Notes BI 3 8 3 PIKE PIKE short for Physics Integration KErnels is an open source software library for coupling and solving multiphysics applications It provides basic interfaces and utilities for performing code to code coupling such as simple black box Picard iteration methods for solving a coupled systems of equations including Jacobi and Gauss Seidel solvers The PIKE library builds on concepts and capabilities first deployed in other open source multiphysics coupling libraries including LIME AMP and MOOSE The principal differentiating features in PIKE are simplified interfaces no overarching framework requirements and an emphasis on user extensibility relying more heavily on the Trilinos software stack and capabilities especially the Teuchos package for memory management parameter handling and error handling utilities PIKE is being used now as the successor to LIME for coupling physics components in VERA 8 4 VERAIn The VERA Common Input VERAIn is a PERL script which converts the ASCII common input file to the intermediate XML used to drive all of the physics codes in the VERA Core Simulator VERA CS VERA component codes either input the VERA XML format directly or provide a preprocessor which can convert the XML into native input COBRA TF and BISON CASL 9 CAVEATS AND KNOWN ISSUES e The CASL codes provided in this release are still under active devel
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