Multiphysics Simulations for LWR Analysis

Abstract

Accurate prediction of the neutron and temperature distributions within an operating nuclear reactor requires the solution of multiple coupled physics equations. In a light water reactor (LWR), there is a very strong coupling between the power distribution (governed by the radiation transport equation) and the temperature and density distributions (governed by a thermal diusion equation in combination with a fluid flow model). This study aims to begin to quantify the impact of such feedback mechanisms as well as identify numerical diculties associated with such multiphysics problems. A description of the multiphysics model and current solution strategy within the Exnihilo code package will be presented, along with numerical results for a representative 3 3 PWR mini-assembly.