IRRADIATION EFFECTS IN CERAMICS FOR PLUTONIUM DISPOSITION

Understanding the effect of radiation damage and noble gas accommodation in potential ceramic hosts for plutonium disposition is important for determining long-term behaviour during geological disposal. Polycrystalline samples of zirconolite and Nd-doped zirconolite were irradiated ex-situ with 2 MeV Kr+ ions to simulate plutonium nuclei recoil which occurs during alpha decay. The microstructural and chemical modifications induced by the irradiation were investigated by Transmission Electron Microscopy (TEM) on thin sections prepared by Focused Ion Beam (FIB). During this study, the feasibility of TEM section preparation from pristine and irradiated ceramics by FIB was demonstrated. After Kr+ irradiation, the samples were observed to be amorphous at the surface and an interface between the pristine and irradiated parts of the specimen was identified. No significant chemical modification was observed.