Development and demonstration of innovative partitioning processes (i-SANEX and 1-cycle SANEX) for actinide partitioning

• Published in: Progress in nuclear energy (New series) Vol. 72; pp. 107 - 114
• Main Authors: Modolo, G., Wilden, A., Kaufholz, P., Bosbach, D., Geist, A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.04.2014
• Subjects: Actinides; Actinides(III); Hydrophilic BTP; Miniature; Nuclear engineering; Nuclear reactor components; Nuclear reactors; Partitioning; SANEX; Simulation; Solvent extraction; Stripping; TODGA; SANEX; Hydrophilic BTP; Partitioning; Solvent extraction; Actinides(III); TODGA
• ISSN: 0149-1970
• DOI: 10.1016/j.pnucene.2013.07.021

Two full continuous countercurrent processes for the recovery of trivalent actinides (An(III)) from a simulated PUREX raffinate solution (HAR) were developed and demonstrated using miniature laboratory-scale centrifugal contactors: the innovative SANEX and the 1-cycle SANEX processes. The innovative SANEX process was successfully demonstrated in a 16 + 16 stage flow sheet. In the first 16 stages, Am(III), Cm(III), and Ln(III) were quantitatively co-extracted from the HAR by a TODGA-based extractant. The decontamination factors (DFs) for the major non-lanthanide fission products were >103. The loaded extractant was then subjected to two stripping steps using the second 16 stages of the flow sheet. The first stripping step concerned the selective stripping of Am(III) + Cm(III) at fairly high acidity (0.35 ML−1 HNO3) with the new hydrophilic N-chelating selective ligand SO3-Ph-BTP. High An(III) recoveries >99.8% were achieved with high decontamination factors toward the trivalent lanthanides. In the second step, the residual stripping of Ln(III) from loaded organic phase was carried out quantitatively using 0.5 ML−1 citric acid solution at pH 3. However, Ru proved to be the only exception and remained to a large extent (12.8%) in the spent extractant. A more challenging route also studied at our laboratories is the 1-cycle SANEX process, i.e. direct An(III) separation from HAR using an extractant mixture of CyMe4BTBP and TODGA in 1-octanol/TPH diluent. A demonstration process was also successfully implemented using a 16 + 16 stage flow sheet on the above-mentioned laboratory-scale centrifugal contactor rig. It was demonstrated that a selective extraction and high recovery of >99.8% of Am(III) and >99.4% Cm(III) was achieved with low contamination of fission products. Both new processes are major contributions to the field of partitioning and important steps forward toward the industrial implementation of MA partitioning. •We report the development of two new actinide separation processes.•A selective separation of trivalent actinides from PUREX raffinate was demonstrated.•SO3-Ph-BTP shows a very high selectivity towards trivalent Actinides.•Very high recovery of An(III) from PUREX raffinate was achieved.