WIMS
WIMS – Lattice Modelling (morning - half day)
WIMS is a multi-purpose reactor physics code that uses deterministic and Monte Carlo methods, developed by the ANSWERS Software Service of Wood. It has been successfully used in support of the design and operation of a wide range of nuclear reactors worldwide. Due to its open modular structure, WIMS can be used in a wide variety of modes. This means that almost all types of reactor physics calculation can be specified within WIMS.
This workshop covers the use of WIMS for lattice-scale modelling for LWR and fast-spectrum systems, with the intent of generating data for use in subsequent whole-core analysis. Descriptions of cross-section preparation and flux solution methods will be given, as well as the construction of WIMS calculation routes using its modular input scheme. The functionality of the WIMSBUILDER and Visual Workshop software for the pre- and post-processing of WIMS calculations will be discussed. Recent code developments have included the implementation of an uncertainty quantification toolkit for WIMS. Details of the application of this toolkit for assessing uncertainties in lattice calculations and the propagation of uncertainties from lattice to whole-core codes will be presented.
MONK is an advanced, 3D, continuous energy Monte Carlo code for criticality safety and reactor physics analyses. The workshop will demonstrate how to build a MONK model of LWR fuel assemblies, for benchmarking the deterministic WIMS calculation. It will also show how a continuous energy Monte Carlo MONK calculation can be used to generate resonance-shielded cross-sections for use in WIMS. The use of the uncertainty quantification tools in Visual Workshop and MONK will be demonstrated, including the use of Bayesian updating for validation/data assimilation and the use of a similarity index for the selection of appropriate validation data.
WIMS – Whole-Core Modelling (afternoon - half day)
Historically, the WIMS reactor physics code has been used as a tool for lattice calculations to generate data for use in separate whole-core codes (i.e. traditional two-step analysis). Recent work by the ANSWERS Software Service of Wood has considered the extension of WIMS to a whole-core code with a multiphysics capability.
This workshop covers the new whole-core capabilities within WIMS, currently targeted at steady-state and transient analysis for SMRs. A description of the framework to simplify the setup and execution of whole-core LWR problems will be presented. Details of new flux solvers that include functionality to target specific issues associated with whole-core solutions will be given. Thermal-hydraulic feedback is modelled by the use of a new, fully-integrated subchannel solver. Functionality to couple WIMS to other codes via a Fortran-C-Python interface has been developed. This provides a route for including fuel performance analysis within the calculation scheme.
It will be shown how the MONK model of the LWR fuel assembly, developed during the WIMS lattice modelling workshop, can be used hierarchically in building a whole-core MONK model, and a MONK steady state, clean core calculation will be used for benchmarking the WIMS whole-core calculation.