Advance of Separation Technologies for Fission Nuclides ⁹⁰Sr and ¹³⁷Cs

The progress of separation technologies for fission nuclides ⁹⁰Sr and ¹³⁷Cs, including precipitation, liquid-liquid extraction and ion exchang method, were reviewed. The prospects of disposal technology for high-level waste were also discussed. Crown ether (DtBuCH18C6) and calixarene-crown ether (BOBCalixC6) possess highly selectivity for ⁹⁰Sr and ¹³⁷Cs respectively in the processing of liquid-liquid extraction; ionic liquids extraction and supercritical CO₂ fluid extraction technology could be applied to separating ⁹⁰Sr and ¹³⁷Cs from high-level waste. Crystalline silicotitanate (CST) and metal sulfide (KMS-1) have higher selectivity for ⁹⁰Sr and ¹³⁷Cs separately in alkaline condition. The mineralized steam reforming process could be used to immobilize ⁹⁰Sr and ¹³⁷Cs into a stable aluminasilicate mineral solid in the low-active waste solution phases. Although ⁹⁰Sr and ¹³⁷Cs could be separated from high-level waste efficiently in theory, there is still a long way to be achieved for final disposal of spent fuel waste.