Extraction separation of U and Pu by -di(2-)-2,2-dimethylpropanamide (DEHDMPA) and -di(2-)butanamide (DEHBA) using mixer-settlers in the presence of degradation products of DEHDMPA and DEHBA

Ban, Yasutoshi  ; Hotoku, Shinobu ; Tsubata, Yasuhiro   ; Tsutsui, Nao  ; Matsumura, Tatsuro  

Two sets of continuous counter-current experiments using mixer-setters were performed for evaluating extraction properties of -dialkylamides toward U and Pu in the presence of their degradation products. The 1st cycle employed -di(2-)-2,2-dimethylpropanamide (DEHDMPA) for selective extraction of U(VI), and the 2nd cycle employed -di(2-)butanamide (DEHDBA) for co-extraction of U(VI) and Pu(IV). Degradation products were added to the organic phase of each cycle. Most of U was effectively extracted by DEHDMPA, and the ratio of U recovered to the U fraction was 99.57%. DEHDMPA barely extracted Pu, and the decontamination factor of U with respect to Pu in the U fraction was 1.1 10. The raffinate of the 1st cycle was used as the feed in the 2nd cycle, and the residual U and almost all Pu were effectively extracted by DEHBA. The degradation products had no detrimental effects on the two-phase separation and the operation of mixer-settlers.