Uranium, plutonium and neptunium co-recovery with high nitric acid concentration in extraction section by simplified solvent extraction process

Abstract As a part of NEXT, the behavior of Np in a simplified solvent extraction process using TBP as an extractant for U, Pu and Np co-recovery was investigated. Two approaches to Np co-recovery with U and Pu in the irradiated fast reactor core fuel using a dissolver solution in a counter current were examined. One used a feed solution with a high HNO3 concentration, and the other used a scrubbing solution with a high HNO3 concentration. The leakages of Np to the raffinate were 1.1 and 4.7% using high HNO3 concentration feed and scrubbing solutions, respectively. Simulation results based on these experiments showed that high HNO3 concentration in the feed solution is advantageous for the Np extraction because Np oxidation progresses in the feed solution before being supplied into the centrifugal contactor, and there is less effect of HNO2 at the extraction section.