Year End Progress Report on Rattlesnake Improvements

Wang, Yaqi¹  DeHart, Mark David¹  Gleicher, Frederick Nathan¹  Ortensi, Javier¹  Schunert, Sebastian¹ 

[1] Idaho National Lab. (INL), Idaho Falls, ID (United States)

关键词: LEAST SQUARE FIT;    PROGRESS REPORT;    FINITE ELEMENT METHOD;    DISCRETE ORDINATE METHOD;    EIGENVALUES;    MONTE CARLO METHOD;    RADIATION TRANSPORT;    SPHERICAL HARMONICS;    APPROXIMATIONS;    DENSITY;    DIFFUSION;    COMPUTERIZED SIMULATION;    CROSS SECTIONS;    NONLINEAR PROBLEMS;    STEADY-STATE CONDITIONS;    ACCELERATION;    COOLANTS;    SERIES EXPANSION;    FEEDBACK;    NUCLEAR FUELS;    TEMPERATURE DISTRIBUTION;    INVENTORIES;    TRANSIENTS;    MULTIGROUP THEORY;    ADJOINT FLUX Finite Element;    MOOSE;    Rattlesnake;   

DOI  :  10.2172/1245688
RP-ID  :  INL/EXT--15-36639
PID  :  OSTI ID: 1245688
Others  :  TRN: US1601243

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来源: SciTech Connect

【 摘 要 】

Rattlesnake is a MOOSE-based radiation transport application developed at INL to support modern multi-physics simulations. At the beginning of the last year, Rattlesnake was able to perform steady-state, transient and eigenvalue calculations for the multigroup radiation transport equations. Various discretization schemes, including continuous finite element method (FEM) with discrete ordinates method (SN) and spherical harmonics expansion method (PN) for the self-adjoint angular flux (SAAF) formulation, continuous FEM (CFEM) with SN for the least square (LS) formulation, diffusion approximation with CFEM and discontinuous FEM (DFEM), have been implemented. A separate toolkit, YAKXS, for multigroup cross section management was developed to support Rattlesnake calculations with feedback both from changes in the field variables, such as fuel temperature, coolant density, and etc., and in isotope inventory. The framework for doing nonlinear diffusion acceleration (NDA) within Rattlesnake has been set up, and both NDA calculations with SAAF-SN-CFEM scheme and Monte Carlo with OpenMC have been performed. It was also used for coupling BISON and RELAP-7 for the full-core multiphysics simulations. Within the last fiscal year, significant improvements have been made in Rattlesnake. Rattlesnake development was migrated into our internal GITLAB development environment at the end of year 2014. Since then total 369 merge requests has been accepted into Rattlesnake. It is noted that the MOOSE framework that Rattlesnake is based on is under continuous developments. Improvements made in MOOSE can improve the Rattlesnake. It is acknowledged that MOOSE developers spent efforts on patching Rattlesnake for the improvements made on the framework side. This report will not cover the code restructuring for better readability and modularity and documentation improvements, which we have spent tremendous effort on. It only details some of improvements in the following sections.