An approach to model stress corrosion cracking in nuclear fuels containing a graphite coating

This work builds on existing fuel models developed at RMCC using the COMSOL Multiphysics platform. The fuel parameters relevant to Stress Corrosion Cracking (SCC) for in-reactor conditions are being modelled to develop an improved tool to predict SCC. The model will incorporate a critical sheath stress to initiate cracking of the protective oxide layer and the impact of CANLUB on iodine concentrations with burnup. Modelling of a stress-dependant critical crack depth to initiate sheath rupture is also being explored. The model will be benchmarked against a large database of SCC power reactor and experimental test reactor data available from the open literature. This paper will outline the proposed methodology for development and implementation of the model. (author)