Dealing with highly active wastes formed in nuclear-fuel regeneration

Abstract

At present, highly active liquid wastes are concentrated by boiling down in standard evaporation units and sent for temporary storage in special stainless-steel holding tanks of volume ranging from a few tens to a few hundreds of cubic meters. The tanks are fittted with spiral cooling units, which maintain a temperature of no more than 50-60~ in the wastes throughout storage. The complex chemical composition of the wastes results in a set of radiation-chemical transformations, which may lead to the release of gaseous products and deposition of solid phase. Hazardous concentrations of hydrogen in the gas space of the tank are prevented by continuous blowing of air above the level of the liquid radioactive wastes, with subsequent purification of the air from aerosols in special filters. The pH values of the liquid wastes are continuously monitored and corrected here, in order to exclude the deposition of solid phase. With the aim of increased reliability and prevention of escape of the wastes into the environment, the tanks are fitted with double walls and special drip pans for collecting any leakage and returning it rapidly to the tank.