Use of the Termoxid-3K sorbent for the removal of 90Sr from high-salinity liquid radioactive waste
摘要
An assessment was carried out of the efficiency of removing the radionuclide 90Sr from model solutions simulating liquid radioactive wastes of various origins and salt compositions using the inorganic sorbent Termoxid-3 K. The highest distribution coefficients for strontium were obtained in low-salinity neutral media and reach 1.4 × 105 mL/g. Increasing the boric acid concentration in the solution to 0.5 mol/L has little effect on the sorption properties of T-3 K: the distribution coefficient for strontium remains at least 1.4 × 104 mL/g. Increasing the sodium concentration in the solution above 0.1 mol/L leads to a tenfold decrease in the distribution coefficient. A decontamination of alkaline high-level radioactive waste (HLW) from spent nuclear fuel (SNF) reprocessing for 90Sr was performed under dynamic (flow-through) conditions. The influence of sorbent mass and of the filtration rate of the liquid radioactive waste on removal efficiencies was established. At a flow rate of the simulated HLW solution of 60 mL/h, the volume of filtrate processed before reaching 1% breakthrough amounted to 127 bed volumes (BV); at 10 mL/h it was 200 BV which indicates a significant effect of filtration rate on the overall purification efficiency. Based on the results of the dynamic experiments, a sorption method for extracting 90Sr from alkaline HLW using the Termoxid-3 K sorbent is proposed.