Sheath Hydriding Model for Defective Fuel

Abstract

A thermodynamic model for the Zr-H binary system at temperatures of 550°C and lower has been developed using the Gibbs energy minimization technique. This model is intended to provide terminal solubility concentrations of hydrogen in the α-Zr phase in a fully mechanistic model for sheath hydriding of defective fuel now under development. The fundamental equations of the distribution of hydrogen in α-Zr and (α+δ)-Zr, first introduced by Sawatzky, have been solved for and serve as a foundation for mechanistic model construction.