Recent Advances in the Treatment of Nuclear Wastes by the Use of Diamide and Picolinamide Extractants

TLDR

The SPIN(ACTINEX) program evaluates combustible diamides and picolinamides for partitioning and transmutation of actinides in nuclear fuel reprocessing effluents. The study investigates picolinamides as potential extractants for separating An(III) from Ln(III). DMDBTDMA, a N,N‑dimethyl N,N‑dibutyl tetradecyl malonamide, was selected as the reference diamide for extraction studies. Actinides(III) can be extracted from concentrated nitric acid effluent and readily stripped from the loaded solvent, with limited third‑phase formation due to long alkyl chains and varied amide substituents.

Abstract

Abstract In the framework of the SPIN(ACTINEX) program for the partitioning and transmutation of actinides contained in effluents generated during the nuclear fuel reprocessing cycle, diamides and picolinamides, extractants which have the common characteristic of being totally combustible, were evaluated. Among the diamides, N,N-dimethyl N,N-dibutyl tetradecyl malonarmide (DMDBTDMA) was chosen as the reference extractant. It has been shown that actinides(III) may be extracted from concentrated nitric acid effluent; the actinides(III) may be readily stripped from the loaded solvent. There is restricted third-phase formation. Long alkyl groups (R″) and different R and R' on the amide nitrogen limit the extent of third-phase formation. The second class of extractants studied, the picolinamides, seem to have potential for the separation of An(III)/Ln(III).