Removal and Recovery of Ruthenium and Cesium from Spent Nuclear Fuel by Using Tungsten Molybdophosphate Novel Inorganic Ion Exchanger

抄録

Novel inorganic ion exchangers, tungsten molybdophosphate (WMP) and its silica-supported type (WMP-Si) were synthesized for the removal and recovery of elements from spent nuclear fuel. Both of ion exchangers were synthesized by vacuum impregnation method using a vacuum evaporator from phosphomolybdic acid and ammonium tungstate. The adsorption properties were evaluated by batch experiment in both HNO₃ and HCl, as well as small-scale column test which carried out using Muromac® S-size column, and simulated high-level nuclear waste as feed in HNO₃. The element concentrations before and after batch experiment and column test were evaluated using ICP-MS. In batch experiment results, it was confirmed that both WMP and WMP-Si had high selectivity towards ruthenium in low concentration of HNO₃ and HCl, also strongly adsorbed cesium regardless of the acid concentrations. Small-scale column test also confirmed the adsorption of ruthenium and cesium at low concentrations of HNO₃. On this test, it was confirmed that ruthenium was eluted and cesium remained in WMP-Si after washing with high concentration of HNO₃, which means removal of cesium and recovery of ruthenium is possible by using WMP-Si. Furthermore, the adsorption capacity of ruthenium and cesium in were 0.65 mg Ru/g WMP and 2.38 mg Cs/g WMP respectively.