Pu-Th separation studies employing di(2-ethylhexyl)isobutyramide (D2EHIBA) as extractant from nitric acid medium

Summary An attempt has been made to explore the use of di(2-ethylhexyl)isobutyramide (D2EHIBA) as an extractant for the recovery of Pu from the (proposed) AHWR fuel fabrication scrap solution. The extraction of Pu in the hexavalent state has been found to be distinctly more efficient than that in the tetravalent state. Distribution studies have been carried out by maintaining Pu as Pu(VI) employing AgO as the oxidant. Scrubbing at 5M HNO3 has been proposed to reduce the interference due to the co-extracted Th(IV). Quantitative stripping of the extracted Pu was achieved using Hydroxyl Ammonium-Nitrate (HAN) as reductant. Ion exchange studies have been carried out for the final purification of Pu. It is proposed to employ the cation exchanger, Biorad AG 50X8 for the final purification of Pu from the stripped solution, keeping Pu as Pu(III).