A rate-theory model for the radiation-induced amorphization and crystallization of U3Si during ion bombardment was generalized so as to treat the other materials. The generalized model provided an explanation for the temperature variation of the dose which was required to amorphize the material. It also explained the bombardment-induced nanoscale polycrystallization of these materials at temperatures above the critical temperature for amorphization, as well as the role which was played by small crystallites in retarding amorphization. An alternative mechanism for the evolution of recrystallization nuclei was described for the bombardment-induced recrystallization of UO2; where the stored energy was concentrated in a network of sink-like nuclei that decreased with dose, due to interactions with bombardment-generated defects. The sink-like nuclei were identified as being cellular dislocation structures that changed relatively early during bombardment. The complicated kinetics which were involved in the formation of a cellular dislocation network were approximated by the formation and growth of sub-grains, due to the interaction of shock waves that were produced by fission-generated damage to the oxide.

J.Rest: Journal of Nuclear Materials, 1997, 240[3], 205-14