Salt clean-up for recycling by electrolysis with a cathode-perforated ceramic container assembly

摘要

Pyroprocessing is a promising way for the recovery of actinide elements from the used nuclear fuel. Electro-refining is a key technology of pyroprocessing and the electro-refining is generally composed of two recovery steps - deposit of uranium onto a solid cathode and the recovery of actinide elements by a liquid cathode. After the electro-refining process, it is necessary to remove the solutes from the molten salt for the salt regeneration. In this study, it was attempted to clean up a molten salt with a solid cathode- perforated ceramic container assembly and a glassy carbon anode. LiCl-KCl eutectic salt was used as a medium of the electrolytic bath. Uranium and cerium were used as solutes, where uranium was used as a surrogate for the actinide elements. The initial contents of uranium and cerium in the salt were varied in the range of 0-5 wt%. Electrolysis experiments were carried out by passing a constant current between the anode and cathode at 500 C. The solute contents were measured using ICP-AES spectroscopy. The initial cathode potential was about -1.6 V. This value decreased with increasing time in the salt. The solutes in the saline phase were successfully recovered onto the cathode.