The cause of the inhomogeneous swelling which was observed near to grain boundaries in irradiated materials was studied by taking account of the nucleation and diffusional growth of cavities, and the interaction of cavities with mobile interstitial clusters which were produced in collision cascades. The model demonstrated the formation of a characteristic profile of inhomogeneous swelling which exhibited features that were similar to those observed experimentally. The rate of swelling was found to be strongly dependent upon the size of the cavities; with cavities growing near to the boundary being able to attain substantially larger sizes than those growing within the interior of the grain. The distance between the peak swelling and the grain boundary was given by N-β, where N was the density of cavities and β was close to 1/3.

Inhomogeneous Nucleation and Growth of Cavities in Irradiated Materials. S.L.Dudarev: Physical Review B, 2000, 62[14], 9325-9