Simulation of High-Temperature, Non-Congruent Phase Transitions in UO₂+x

Abstract

A detailed model of UO₂+x undergoing non-congruent melting at very high temperature is being developed to help support the design and analysis of experimental work being conducted as part of nuclear safety research. This work includes the simulation of nuclear fuel under upset conditions where centreline melting may occur. The Phase Field model has been implemented for this purpose using recently published material properties and compares well with experimental data. The versatility and robustness of this modelling technique is demonstrated with a simulation of centreline melting as a consequence of fission heating.