An experimental study for Li recycling in an electrolytic reduction process for UO2 with a Li2O–LiCl molten salt

Abstract

If Li is excessively produced in an electrolytic reduction process for UO2 with a Li2O–LiCl molten salt, a part of Li2O will be lost in the form of Li as deposited on the cathode, and the Li can cause negative effects on a post process. To solve these problems, a method for Li recycling was investigated in this study. A series of experiments were carried out consisting of four runs. In the first run, UO2 fragments were electrochemically reduced at 3.2V of cell voltage. The excess Li was then recovered by transferring to another electrode at 0.3V of cell voltage. The recovered Li was then utilized as the source for the reduction of fresh UO2 fragments. Finally, the remaining UO2 was electrochemically reduced at 3.2V of cell voltage. The concentration of Li2O was reasonably maintained as a result of the Li recycling without a significant loss. Consequently, the potential problems by Li could be disregarded using the recycling method. The electrolytic reduction process for UO2 will be more efficient and sustainable by combining the technology for Li recycling and the conventional electrolytic reduction process.