Development of extraction and separation method of total actinides using TODGA (Contract research)

Sasaki, Yuji  ; Sugo, Yumi; Suzuki, Shinichi; Kitatsuji, Yoshihiro  ; Kimura, Takaumi 

As a separation step of an innovative chemical separation process (ARTIST process) for treatment of spent nuclear fuel, the condition to extract TRU using TODGA was studied. TODGA has strong affinity with trivalent and tetravalent actinides. The oxidation state of Np and Pu can be changed quantitatively to Np(IV) and Pu(III) using ascorbic acid. After extraction of TRU, it is important to know the appropriate condition of stripping TRU from the organic phase. Tetramethyl-diglycolamide (TMDGA) has high affinity with An(III) and An(IV) in the aqueous phase. The chemical separation flow-sheet for actinides and Sr was designed. The flow rate of aqueous and organic phases, and stage number of mixer-settler were determined in order to obtain the optimum condition for TRU and Sr separations. The TRU extraction process was discussed from the viewpoints of the amount of metal oxide, heat generation and radioactivities.