Development of SELECT process using CHON extractants for partitioning and transmutation

Matsumura, Tatsuro  ; Ban, Yasutoshi  ; Suzuki, Hideya*; Hotoku, Shinobu ; Tsutsui, Nao  ; Toigawa, Tomohiro   ; Morita, Keisuke ; Tsubata, Yasuhiro   

PUREX process was established for industrial scale reprocessing plant. The several separation processes were developed for partitioning of minor actinides from high level liquid waste, and demonstrated by the continuous extraction test using genuine high level liquid waste. Although the extractants for the processes, such as TBP, CMPO and DIDPA, have excellent performance for recovery of U, Pu or MA, the molecules contain phosphorus which could be cause for the secondary waste. To minimize the radioactive waste from nuclear fuel cycle, we have been developing many extractants in accord with CHON principle, and proposed a hydrometallurgical process called SELECT (Solvent Extraction from Liquid-waste using Extractants of CHON-type for Transmutation) aiming at recycle use of nuclear materials and separating actinides for transmutation. The separation performances of the flowsheets were evaluated by continuous extraction tests using simulated or genuine spent fuel and high level liquid waste. The all flow sheets were worked effectively. Over 99.9% of Am in genuine HLW was recovered by An(III)+RE recovery process using TDdDGA and 95% of Am was separated from rare earth elements by An(III)/RE separation process using HONTA. Furthermore, development of new extractants for simplification and improvement of robustness of the processes have been carried out.