Development of a new extractant and a new extraction process for minor actinide separation

Morita, Yasuji  ; Sasaki, Yuji  ; Asakura, Toshihide; Kitatsuji, Yoshihiro  ; Sugo, Yumi; Kimura, Takaumi 

The authors have developed a new type of extractant for Am and Cm, -tetraoctyl-diglycolamide (TODGA), which gives very high distribution ratio at relatively high nitric acid concentration. To apply such a new extractant to the separation process for Am and Cm from HLLW, many criteria should be investigated and satisfied; e.g., separability against fission products (FP), chemical and radiolytic stability, extraction capacity, compatibility with hydrocarbon diluents, and so on. From a viewpoint of extraction capacity, TODGA is modified to -tetradodecyl-diglycolamide (TDdDGA). Since TDdDGA extract Zr and Pd, effective masking agents for them were examined and selected. With those achievements, a counter-current extraction test with 0.1 M TDdDGA in n-dodecane was carried out using a small-scale mixer-settler and simulated solution of HLLW. As results of the test, a very high recovery of Am, more than 99.96%, was obtained and good separation from FP was observed.