SEPARATION OF NEPTUNIUM, PLUTONIUM, AMERICIUM AND CURIUM FROM URANIUMWITH DI-(2-ETHYLHEXYL)-PHOSPHORIC ACID (HDEHP) FOR RADIOMETRIC AND ICP-MS ANALYSIS

The possibility of using di-(2-ethylhexyl)-phosphoric acid (HDEHP) in solvent extraction for the separation of neptunium, plutonium, americi um and curium from large amounts of uranium was studied. Neptunium, pl utonium, americium and curium (as well as uranium) were extracted from HNO3, whereafter americium and curium were back-extracted with 5M HNO 3. Thereafter was neptunium back-extracted in 1M HNO3 containing hydro xylamine hydronitrate. Finally, plutonium was back-extracted in 3M HCl containing Ti(III). The method separates Pu-238 from Am-241, for alph a-spectroscopy. For ICP-MS analysis, the interferences from U-238 are eliminated: tailing from U-238, for analysis of Np-237, and the interf erence of (UH+)-U-238 for analysis of Pu-239. The method has been used for the analysis of actinides in samples from a spent nuclear fuel le aching and radionuclide transport experiment.