Multischeme transport with upwinding for Rattlesnake code

Abstract

This report describes efforts at INL to incorporate full support for a multischeme transport capability in Rattlesnake, the MOOSE-based multigroup radiation transport application. Specifically, this report details all five types of interface conditions for coupling six available discretization schemes within Rattlesnake using the upwinding method. These discretization schemes include S N (discrete ordinates method), P N (spherical harmonics expansion method) and diffusion for angular discretization, and continuous finite element method (CFEM) and discontinuous finite element method (DFEM) for spatial discretization. Another type of method based on Lagrange multipliers for coupling schemes with CFEM has been studied in [1]. In addtion to simple test problems, a more realistic application of multischeme transport for experiment simulations within the Transient Reactor Test Facility (TREAT) are presented. Several enhancements are reviewed at the end which could potentially be useful in the future.

Integrated Modeling and Simulation Capability For Full Scale Multi-Physics Simulation and Visualization of Microreactor Concept

“…The latter can be particularly efficient for multiphysics coupling where a fully heterogeneous for all physics may not be tractable. Another unique feature offered by MAMMOTH is the so-called multischeme capability, where various parts of the domain can be discretized with a different numerical scheme [12]. This allows to focus the computational resources towards the regions of the problem where precision is most desired.…”