An advanced model for the grain face transport of gas atoms, self-consistently

taking into consideration the effects of atom diffusion over the grain surface, their

trapping by and irradiation induced resolution from intergranular bubbles was

presented. The model allows prediction of a noticeable gas release from UO2 fuel

without visible interlinkage of grain face bubbles, i.e. at very low grain face

coverage, below the critical value manifested by formation of bubble channels on

grain faces interconnected with open porosity, in accordance with experimental

observations of UO2 and MOX fuel behaviour under various irradiation conditions.

An Advanced Model for Grain Face Diffusion Transport in Irradiated UO2 Fuel,

Part 1: Model Formulation. M.S.Veshchunov, V.I.Tarasov: Journal of Nuclear

Materials, 2009, 392[1], 78-84