Radiation Effects in Nuclear Waste Materials

The objective of this multidisciplinary, multi-institutional research effort is to develop a fundamental understanding of radiation effects in glasses and ceramics at the atomic, microscopic, and macroscopic levels. Current research addresses many of the scientific issues identified in the reports of two recent DOE panels (Weber et al. 1997, 1998). The goal of this effort is to provide the underpinning science and models necessary to assess the performance of glasses and ceramics designed for the immobilization and disposal of high-level tank waste, plutonium residues, excess weapons-grade plutonium, and other highly radioactive waste streams. Studies are focused on the effects of ionization and elastic collisions 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 b-decay on nuclear waste materials. This program exploits a variety of structural, optical, and spectroscopic probes to characterize the nature and behavior of defects, defect aggregates, and phase transformations. Computer simulation techniques are also used to determine defect production processes, defect energies, and defect/gas diffusion and interactions. A number of irradiation facilities and capabilities are used, including user facilities at other national laboratories, to study the effects of irradiation under different conditions