Modelling of irradiation-induced blockage of the grain boundary and its effect on the fission gas release from UO2

The new model of intergrain boundary radiation blockage under the conditions of low-temperature irradiation of nuclear fuel (UO2), conforming with physical notions on the mechanisms of athermal diffusion and gas bubbles radiation-induced resolving, is developed. The above model; makes it possible to explain experimentally sharp dependence of gas yield on the irradiation temperature, observed in the low-temperature area, in spite of prevalence of athermal radiation-induced transfer mechanisms. The model is integrated into the mechanistic code and verified through experimental data