Feasibility study of a CHON-UNEX process

Simonnet, M.   ; Muller, L.*; Sittel, T.*; Wessling, P.*; Mullich, U.*; Geist, A.*

Reaching a sustainable nuclear waste management is one of the major challenges to gain public acceptance. The most commonly accepted solution is to process the spent fuel to recover useful isotopes, along with removing the highest heat emitters. Several processes were designed to achieve the separation of the actinides to be potentially re-used as nuclear fuel, and of Sr and Cs to decrease the heat load of the final nuclear waste to be disposed of. Most of these processes consist in a step-by-step methodology, requiring the use of many stages, except for the UNEX process that aimed at co-extracting An(III), Ln(III), Cs(I) and Sr(II) from the PUREX raffinate. Unfortunately, none of the extractants are CHON-compatible, nor the diluent that is also toxic. The present study shows the feasibility of a CHON-UNEX process, where An(III), Ln(III), Cs(I) and Sr(II) are co-extracted and then selectively stripped, allowing to merge several processes into one.