INVESTIGATION OF METAL ION EXTRACTION AND AGGREGATE FORMATION COMBINING ACIDIC AND NEUTRAL ORGANOPHOSPHOROUS REAGENTS

摘要

Advanced nuclear fuel cycles are dependent on successful chemical separation of the various elements present in the used fuel. Numerous extraction systems have been developed for the recovery and separation of the various metal ions present in the used fuel. In these solvent extraction systems for the purification of spent nuclear material, aggregation phenomena can interfere with the efficiencies of the processes and decrease the successfulness of the separation. The predictability of these phenomena have been challenging due to the lack of a fundamental understanding of the mechanism that drives these aggregate formations. To increase our understanding we have studied extraction systems of combined solutions oftri-n-butyl phosphate (TBP) and dibutyl phosphate (HDBP) in n-dodecane, representative of solvents used for nuclear fuel reprocessing.Distribution ratios of metal ionswere studied combined with wateruptake to help determine the physicochemical properties of the investigated system. Additionally, X-ray absorption behavior of these organic solutions wasinvestigated to shed light on the macromolecular structures created by the extractants.