Vacancy cluster evolution and swelling in irradiated 316 stainless steel

A recently developed master equation and Fokker–Planck method for cluster-nucleation and growth simulations is applied to a model of impurity-free type-316 stainless steel under irradiation. The evolution of the void size distribution is treated in full generality, although the dislocation density is held constant versus time and temperature. The simulations reproduce several observed characteristics of irradiation swelling, involving a brief incubation delay followed by quasi-steady swelling. The predicted incubation period shows a clear dose-rate response – lower irradiation flux requires less total fluence to complete the incubation process. This trend is consistent with some recent experimental reports.