Evaluating glasses for high-level radioactive waste immobilization

The factors affecting the chemical durability of HLW glasses are identified and discussed. The science and technology underlying the development an optimization of such glasses are reviewed. Specific tests presently used to measure the leaching and dissolution rates for purposes of absolute rate determination and comparative evaluation of different glasses are shown to be less than satisfactory. The present criteria used for the evaluation of HLW glasses may be incomplete and unlikely to lead to the development of better materials. Arguments for specific procedures and techniques which will lead to better understanding of mechanisms and more meaningful evaluation of performance, are presented. (Auth.)