Swelling in UO2 under conditions of gas release

Abstract A model is developed to describe the kinetics of swelling in nuclear fuels during irradiation, when tunnels formed along grain edges by the coalescence of fission gas bubbles interlink with one another to form a network through which the entrained gas can escape to the surroundings. The predicted dependence of swelling on time, rating, external restraint pressure and temperature is physically acceptable and in qualitative agreement with existing observations.