A coupled neutronics shock physics solver: implementation of an SN neutron transport module

Abstract: A multiphysics finite volume method (FVM) solver, coupling neutronics and shock physics, is under development at Politecnico di Milano for the analysis of shock imploding fissile materials [1]. The proposed solver can be a useful tool to make preliminary safety assessment of subcritical plutonium experiments [2] and, more in general, to perform criticality safety evaluations in case of strongly energetic events (such as chemical explosions) involving fissile materials [3]. To this aim, a multi-group SP3 neutron transport model is coupled with a hydrodynamic shock physics model [4], suitable to describe the propagation of strong shockwaves in solid materials. The shock physics module implements a dynamic mesh to reproduce material deformations and its governing equations are written in an Arbitrary Lagrangian Eulerian (ALE) formulation to preserve the mesh quality in case of large distortions.