Actinides recovery by solvent extraction in NEXT process

Concerning the advanced aqueous reprocessing system named NEXT process, the behavior of actinide elements was investigated in main two extraction processes of NEXT process, i.e. the simplified PUREX process for U, Pu and Np recovery, and SETFICS process for Am and Cm recovery. For optimizing the simplified PUREX flowsheet, counter current experiments with centrifugal contactors were carried out under the condition with high HNO3 concentration in the feed solution or scrubbing solution. These experimental results showed the large contribution of HNO3 concentration at the extraction section to Np oxidation and extraction, and the effectiveness of high HNO3 concentration in the feed solution, which might bring the acceleration of the Np oxidation in the feed solution as well as at the extraction section in the centrifugal contactors. In the SETFICS process of a high-loading flowsheet, Am and Cm could be recovered as An(III) product solution. Although Cs was decontaminated well, the decontamination factor of Nd was less than that in the past experiment. (author)