Development of a semi-empirical cladding oxidation model and verification by BWR & VVER type CORA tests

The high temperature oxidation with cladding damaged is complicated and the accurate simulation model needs to be developed. In this study, a non-parabolic and semi-empirical oxidation model is proposed for cladding high temperature oxidation with different damage regimes. Moreover, five past out-of-pile severe fuel damage experiments CORA-18, CORA-28, CORA-31, CORA-W1, and CORA-W2 (ISP36) are employed as cases for verification. Then, the hydrogen generation rates predicted by this semi-empirical model and several previous parabolic oxidation models are compared and analyzed. The total weight of hydrogen predicted by this new model can be in accordance with the related experiment values. This model considers the early cladding failure since 1473 K. The most conservative form of this model can be used as a replacer for Baker-Just model. Additionally, the suitable value of coefficients in this model may roughly represent the oxidation and damage status of the whole bundle.