RADIATION-INDUCED STORED ENERGY IN ROCK-SALT

A review is given of experimental and theoretical research on radiation damage in NaCl. The emphasis in this review is put on the decomposition of NaCl into metallic Na colloids and gaseous aggregates of Cl2 centers. This decomposition process leads to the formation of stored energy which can be released if the metallic sodium and gaseous chlorine recombine. Detailed knowledge of the decomposition process is needed for a proper risk evaluation of disposal of radioactive waste in geological rock salt formations. It is shown that, although many details of the radiation damage processes in alkali halides are not completely understood yet, phenomenological models have been developed which adequately describe the main processes of formation of Na colloids and Cl gas as observed in experiments. Some findings of these models are used to formulate disposal policy recommendations which may lead to a further reduction of the risks related with radiation damage in rock salt repositories.