Hydrothermal reprocessing of liquid radwastes from nuclear power plants

Abstract

Selective removal of radionuclides from the bottoms residue of evaporation equipment used in nuclear power plants has an enormous advantage over the conventional methods currently being used to condition liquid radwastes (cementing, bituminization). The advantage is primarily due to the decrease in the volume of the conditioned wastes put into solid radwaste repositories. Selective purification was first used at the Lovisa nuclear power plant (Finland) [1], but the quality of this operation was too low to consider the purified bottoms residue as being nonradioactive. The removal of radionuclides of corrosion origin, primarily cobalt, remained unsolved. The only currently used technology for completely cleaning bottoms reside to NRB-99 requirements is ion-selective purification used at the Kola nuclear power plant [2]. However, it has limitations associated with ozonization, which is used to oxidize the organic component. The objectives of the present work were to develop a new technology for reprocessing bottoms residue, which does not use ozonization, and to test it on real wastes from nuclear power plants with different types of reactors.