PHYSICOCHEMICAL PROCESSES OCCURRING IN STORAGE OF HIGH-LEVEL WASTES IMMOBILIZED ON SILICA-GEL

It was demonstrated experimentally that the major physicochemical proc esses occurring in the course of long-term storage of long-lived radio nuclides of high-level wastes immobilized on silica in closed tanks ar e radiation decomposition of adsorbed water and accumulation of new ad sorption centers. The former process results in hydrogen evolution int o free volume of the tank, increasing the pressure in it, and the latt er process, in adsorption of gases from the free volume, decreasing th e pressure. The limiting composition of the gas mixture and the limiti ng total pressure are estimated from the experimental data, and the po ssibility of self-ignition of a mixture of H-2 and O-2 or of nonchain thermal explosion is evaluated.