Gas release and swelling in oxide fuel; modeling of the kinetics of gas porosity development

A quantitative model of gas porosity development, gas release and gas swelling in oxide fuel is proposed. In the model the gas porosity evolution is supposed to be caused by the collision and coalescence of moving gas bubbles. The suppression of small gas bubble mobility is taken into account too. For oxide fuel, calculation results are in a reasonably good agreement with the data available on swelling, gas release and gas bubble size distribution. Besides, the model calculations enable one to reveal the dependence of these phenomena on various physical characteristics of the material under consideration and on its operation conditions. (orig.)