Electrochemical Study on the Reduction Mechanism of Uranium Oxide in a LiCl-Li₂O Molten Salt

Abstract

By means of a linear sweep voltammetry, a cyclic voltammetry and a chronopotentiometry, the electrolytic reduction of uranium oxide has been studied to establish the reduction mechanisms, which are based on a simultaneous uranium oxide reduction and a Li 2 O electrowinning, and the formation and electrolysis of lithium uranate. From the voltammograms, the reduction potentials of the uranium oxide and Li 2 O were obtained. From the chronopotentiometries based on the results of the voltammograms, the uranium oxide was reduced to uranium metal through the reduction mechanisms showing a more than 99% conversion. For a verification of the reduction mechanisms feasibility, basic data on the electrolytic reduction of the uranium oxide was obtained from the experiments and the characteristics of the closed recycle of Li 2 O were discussed.

Electrolytic reduction behavior of U3O8 in a molten LiCl–Li2O salt

“…An advanced SF conditioning process (ACP) has been developed to treat LWR SFs at the Korea Atomic Energy Research Institute (KAERI) and an electrolytic reduction process (Hur et al, 2003;Seo et al, 2006;Jeong et al, 2006a;Park et al, 2006) was adopted to transform an oxide SF into a metallic form in a LiCl--Li 2 O molten salt. The electrolytic reduction process of the ACP was developed according to a reduction mechanism similar to that of the ED method.…”

Recoveryof actinidesand fission products from spent nuclear fuel via electrolytic reduction: Thematic overview

“…The reduction of rare earth oxides, for example, Nd 2 O 3 , and Ce 2 O 3 , in this melt was not observed. The data of a linear sweep voltammetry and a cyclic voltammetry obtained for the LiCl‐Li 2 O and LiCl‐Li 2 O‐U 3 O 8 systems were presented in Reference 39.…”

“…Changes in the Li 2 O concentration in the molten LiCl salt with time according to the applied current 39 …”

Investigating microstructural evolution during the electroreduction of UO2 to U in LiCl-KCl eutectic using focused ion beam tomography

“…The reduction of spent fuel oxides may also be done chemically via the reaction of dissolved lithium in LiCl at 650°C, as described by Karell and Gourishankar [6,7]. Alternatively, spent fuel oxides may be reduced by electroplating Li metal onto the working electrode in a Li 2 O containing LiCl molten salt, currently the more favoured route [8][9][10][11]. A further, fully electrochemical, technique is also under investigation: pyroelectrochemical processing.…”