Sequential Electrolysis of U-Pu Alloy Containing a Small Amount of Am to Recover U- and U-Pu-Am Products

Abstract

Sequential electrolysis testing was performed in a LiCl-KCl eutectic molten salt bath, in which variation in current efficiency, composition of product or molten salt, etc. were measured successively. Porous or dense U-Pu alloys containing a small amount of Am were dissolved one after another from the anode and, simultaneously, U dendrites or U-Pu-Am alloys were recovered on the iron rod or in the liquid cadmium cathode, respectively. The current efficiencies were mostly maintained to be 100% except for the anodic dissolution of the porous alloy and the cathodic recovery of U-Pu-Am in the liquid cadmium. The Pu and Am concentrations in the U dendrites varied in the ranges of 120–350 and 4–15 ppm, respectively. The separation factors for U/Pu and Am/Pu in the liquid cadmium varied in ranges of 1.69–1.74 and 0.66–0.78, respectively. The sum of U, Pu, and Am concentrations in the molten salt bath was maintained in the entire sequence, although the U concentration decreased or increased when using the iron rod or liquid cadmium cathode, respectively. The variation in the Pu concentration compensated for the U concentration variation. Material balance of Pu was mostly maintained at 100% with respect to the initial amount at each step of the sequence. These results indicate that the sequence used in the present study can be recycled.