A new model of hydrogen redistribution in Zr alloy claddings during waterside corrosion in a temperature gradient

A new model for hydrogen spatial redistribution and hydride precipitation in Zr alloys during waterside corrosion extends the traditional approach, valid for consideration of a relatively low volume fraction of the precipitated hydride phase, to a more general case of heavily precipitated hydrides typical for high-burnup fuel cladding tubes of pressurized water reactors and also observed in various autoclave corrosion tests with high hydrogen supercharging. Being implemented in the SVECHA/QUENCH (S/Q) code, the new model reasonably explains various observations in corrosion tests at constant temperature and under temperature gradient as well as under in-reactor corrosion conditions. - Highlights: • A new model for Zr alloys hydriding during waterside corrosion is developed. • The model is based on consideration of mass transfer through the two-phase region. • The model is applied to analysis of and in-reactor and autoclave experiments.