Thermodynamic and experimental analyses of the oxidation behavior of UO 2 pellets in damaged fuel rods of pressurized water reactors

摘要

A small leak occurring on the surface of a fuel rod due to damage exposes UO2to a steam atmosphere. During this time, fission gas trapped inside the fuel rod leaks out, and the gas leakage can be increased due to UO2oxidation. Numerous studies have focused on the steam oxidation and its thermodynamic calculation in UO2. However, the thermodynamic calculation of the UO2oxidation in a pressurized water reactor (PWR) environment has not been studied extensively. Moreover, the kinetics of the oxidation of UO2pellet?also has not been investigated. Therefore, in this study, the thermodynamics of UO2oxidation under steam injection due to a damaged fuel rod in a PWR environment is studied. In addition, the diminishing radius of the UO2pellet with time in the PWR environment was calculated through an experiment simulating the initial time of steam injection at the puncture.