Development and trials of a technology for reprocessing of NPP liquid radioactive wastes

Laboratory trials of a process for sorption decontamination of real NPP bottom residues from Cs radionuclides with Termoksid-35 ferrocyanide sorbent and rig and pilot trials of the technology for reprocessing of bottom residues from a number of Russian nuclear power plants were performed. The efficiency of the Cs sorption drastically decreases in the presence of organic complexing agents (EDTA, oxalate ions). Preliminary ozonation of the bottom residue allows the working life of Termoksid-35 sorbent in the decontamination process to be increased by a factor of several tens. Rig and pilot trials showed that ozonation of bottom residues, followed by microfiltration separation of the precipitate formed, ensures efficient decontamination of the solutions from Co, Mn, and Sr radionuclides and from α-emitters. A technology was suggested for decontamination of NPP bottom residues from radionuclides, involving ozonation, microfiltration, and selective sorption of Cs radionuclides on Termoksid-35 ferrocyanide sorbent. Process and technical solutions obtained in the course of trials were implemented in an industrial installation for reprocessing of bottom residues from the Kola NPP.