Review of self-irradiation effects in Pu-substituted zirconolite

Self-irradiation effects due to alpha decay in Pu-substituted zirconolite (CaPuTi/sub 2/O/sub 7/) have been assessed by dilatometry, TEM, microindentation testing, and differential thermal analysis. The crystalline material became metamict as a result of accumulation of alpha recoil tracks, with accompanying swelling, reduction of hardness, and increase in fracture toughness. Storage at elevated temperature partially or wholly suppressed metamictization. Studies of recovery from the metamict state showed that ease of crystallization depends on extend of prior damage and that heavy damage reduces the amount of stored energy. These results are interpreted in terms of competition between damage accumulation and annealing, variations within the metamict state, and the role of a heterogeneous microstructure.