Development of a Simplified Fuel Oxidation Model for Defective Nuclear Fuel

Abstract

The rare occurrence of sheath defects may lead to contact between the fuel and coolant, which may lead to fuel hyperstoichiometry, thus degrading fuel thermal performance and raising the potential for centreline melting. By simplifying a published mechanistic model, a treatment has been developed to predict fuel hyperstoichiometry using a one-dimensional oxygen transport equation coupled to a two-dimensional temperature equation, improving numerical robustness for possible implementation into fuel performance codes. The model has been validated against experimental measurements from commercial defective elements for normal operation, and has been used to predict the response of defective fuel under accident conditions.