RECOVERY OF NEPTUNIUM FROM HIGHLY RADIOACTIVE-WASTE SOLUTIONS OF PUREX ORIGIN USING CMPO

The partitioning and recovery of Np-237 from three types of simulated high level waste solutions originating from PUREX processing of spent nuclear fuels such as sulfate bearing high level waste (SB-HLW), HLW f rom a pressurised heavy water reactor (PHWR-HLW) and from a fast breed er reactor (FBR-HLW) have been carried out using a mixture of 0.2M CMP O and 1.2M TBP in dodecane. Quantitative extraction of neptunium was p ossible by either oxidizing it to the hexavalent state keeping K2Cr2O7 at 0.01M concentration or by reducing it to tetravalent state keeping Fe2+ at 0.02M concentration. Stripping of neptunium was carried out u sing different reagents, such as dilute nitric acid, oxalic acid and s odium carbonate. Almost quantitative recovery of neptunium has been ac hieved during these studies.