Selective separation of Am(Ⅲ) from PUREX Raffinate with a TODGA-based solvent using innovative hydrophilic complexing agents

摘要

Americium is the main contributor to the longtermradiotoxicity and to the heat generation of glassesused for HLW conditioning. To decrease these impactsand to avoid the difficult recycling of curium, the selectiveseparation and recovery of a pure americium productdirectly from PUREX raffinate is envisaged in this study.The new approach is based on the co-extraction oflanthanide(Ⅲ) and actinide(Ⅲ) cations from a PUREXraffinate into an organic phase containing N,N,N’,N’-tetraoctyl-diglycolamide (TODGA) as extractant,followed by the subsequent selective stripping of Am(Ⅲ)and separation from Cm(Ⅲ) and lanthanides. Threewater-soluble selective ligands were studied: H4TPAENdeveloped at the CEA Marcoule, TS-BTPhen developed atthe University of Reading, and SO_3-Ph-BTBP developedat KIT. Very promising results were achieved for allsystems with a quite high Cm(Ⅲ)/Am(Ⅲ) selectivitybetween 3-4 to carry out the difficult separation atreasonably high process relevant nitric acid acidities.Numerous batch experimental data were acquired for thedevelopment of the extraction model. Finally, tests onsingle centrifugal contactors were conducted to getinformation on the kinetic and hydraulic performance ofthe system. Finally, tests on single centrifugal contactorswere conducted to get information on the kinetic andhydraulic performance of the system.