Recent studies on radiation induced F-center and colloid particle formation in synthetic NaCI and natural rock salt

Abstract

Abstract Radiation induced F-center and Na metal colloid formation have been studied, at temperatures between 100 and 350°C, in melt growth synthetic NaCl crystals and natural rock salt samples, using equipment for making optical measurements during 1–3 MeV electron irradiation. In both types of NaCl the damage formation kinetics are qualitatively similar. However, there are large quantitative differences which depend on irradiation temperature, dose rate, total dose, inherent strain, strain applied prior to irradiation and other factors. Natural rock salt samples from different localities exhibit markedly different radiation induced colloid formation rates. An extrapolation of the current data to the doses expected in radioactive waste depositories indicate that natural salt immediately adjacent to the planned waste canisters could develop between 0.1 and 50 percent colloidal sodium in 50 to 400 years.