Recent achievements in the development of partitioning processes of minor actinides from nuclear wastes obtained in the frame of the NEWPART European programme (19961999)

Partitioning of long-lived minor actinides (americium and curium) from the nuclear wastes issuing the reprocessing of nuclear spent fuels, in order to transmute them into short-lived nuclides or to condition them into stable crystalline matrices, was the subject of intense research within the NEWPART research program of the European 4 th Frame Work Program, FWP (1996–1999). The target waste considered was the acidic raffinate (HAR) issuing the reprocessing of the used nuclear fuels by the PUREX process. A two step separation process based on liquid-liquid extraction was designed. The first step consists in the co-separation of the mixture of trivalent actinides and lanthanides from the HAR by extraction with a malonamide extractant (DIAMEX process), while the second step concerns the actinides(III)/lanthanides(III) group separation (SANEX process). Several DIAMEX and SANEX processes were developed and successfully tested with cold, spiked and genuine high active effluents. The research carried out also included basic and fundamental works in order to better understand the relationships between the structures of the extractants and their affinities for the target metal ions. The lecture highlighted both the basic and applied aspects of the research. This work will be pursued (PARTNEW program) within the 5 th FWP of the European Union during the period 2000–2003.