Development of a Promising Membrane-Sorption Technology for Radionuclide Removal from Liquid Radioactive Waste at NPP with Next-Generation WWER-1200/TOI Reactor Units

This article presents the experimental results on the development of a low-waste technology designed to process liquid radioactive waste (LRW) from the operation of new-generation WWER-1200/TOI NPP. It specifies the chemical, radionuclide and phase-dispersion composition of several LRW streams from drain water and special laundries of Novovoronezh NPP-2 and Leningrad NPP-2. It presents data on the removal of the main dose-contributing radionuclides, i. e., 125Sb, 137,134Cs and 60Co, from LRW via sorption, membrane and precipitation methods. Based on these data, the paper proposes a comprehensive membrane-sorption processing technology for NPP LRW involving the following stages: separation of suspended particles; nanofiltration treatment; sorption post-treatment using the Termoksid-35 sorbent and reverse osmosis post-treatment to produce a salt melt of the VLLW category. Based on the proposed comprehensive flowchart, conditioned solid radioactive waste volume was reduced by 3.6 times compared to the basic one, which may considerably reduce both capital and operating costs.