Modelling the Behaviour of UO2+x During Melting

Abstract

A model is being developed to simulate melting UO_2+x. The existence of the first order phase change from solid to liquid makes this a moving boundary, Stefan problem. The model presented here numerically solves a system of coupled nonlinear differential equations by the Finite Element Method using commercial software. Included in the treatment are the effects of non-stoichiometry. Material properties at high temperatures are taken from recent published literature. The current model compares well with published experiments. The goal of this research is to model centerline melting in operating CANDU fuel.