Radiation effects in nuclear waste materials. 1997 annual progress report

'The objective of this multidisciplinary, multi-institutional research effort is to develop a fundamental understanding at the atomic, microscopic, and macroscopic levels of radiation effects in glass and ceramics. This research will provide the underpinning science and models for evaluation and performance assessments of glass and ceramic waste forms for the immobilization and disposal of high-level tank waste, plutonium residues and scrap, and excess weapons plutonium. Studies will focus on the effects of ionization and elastic collision interactions on defect production, defect interactions, diffusion, solid-state phase transformations, and gas accumulation using actinide-containing materials, gamma irradiation, ion-beam irradiation, and electron-beam irradiation to simulate the effects of a-decay and p-decay on nuclear waste glasses and ceramics. This program will exploit a variety of structural, optical, and spectroscopic probes to characterize the nature and behavior of the defects, defect aggregates, and phase transforma-tions. Computer simulation techniques will be used to determine defect production, calculate defect stability, defect energies, damage processes within an a-recoil cascade, and defect/gas diffusion and interactions. A number of irradiation facilities and capabilities will be used, including user facilities at several national laboratories, to study the effects of irradiation under different conditions.