An Experimental Study of Molten Salt Electrorefining of Uranium Using Solid Iron Cathode and Liquid Cadmium Cathode for Development of Pyrometallurgical Reprocessing.

Abstract

Electrorefining of uranium was studied for developing pyrometallurgical reprocessing technology of metal fuel cycle. After concentration dependence of polarization curve was measured, uranium was electrodeposited either on solid iron cathode or in liquid cadmium cathode. Design and operational conditions of the cathode were improved for obtaining much greater quantity of deposit, resulting in recovery of 732g of dendritic uranium on a single solid cathode, and of 232 g of uranium in 2,344 g of a liquid cadmium cathode. The behaviors of electro-codeposition of rare earth elements with uranium were observed for liquid cadmium cathode, and were found to follow the local equilibrium between salt electrolyte and cathode. The decontamination factors of FP simulating elements from uranium were tentatively determined as >2,000 for deposition to solid cathode and as >7 for deposition to liquid cadmium cathode, respectively. KEYWORDS: nuclear metal fuels, molten salts, electrorefining, pyrometallurgy, uranium, FBR type reactors, fuel cycle, pyroprocess, partition, Concentration dependence, electrodepositionand the noble FPs such as ruthenium and palladium are not oxidized from the spent fuels and are retained in the anode basket as a sludge or fall into cadmium pool.The original concept of this type electrorefiner was first proposed by Miller et al. of ANL at 1986'"). In the beginning, they studied the deposition behaviors of uranium and plutonium by using laboratory scale elec-

Countercurrent Extraction Test with Continuous Flow of Molten LiCl-KCl Salt and Liquid Cd for Pyro-Reprocessing of Metal FBR Fuel

“…1,2) This technique is also available for the partitioning of long-lived transuranic elements (TRUs). 3) In the pyrometallurgical reprocessing, actinides dissolve from the spent metal fuel and simultaneously deposit on a solid iron cathode or in a liquid cadmium cathode by electrolysis in a molten salt bath.…”

Integrated Experiments of Electrometallurgical Pyroprocessing Using Plutonium Oxide

“…These cathode assemblies were designed to be used each other. An Ag/ LiCl-KCl-1 wt.%AgCl electrode assembled in a pyrex glass tube 19) was used as the reference. The cathode processor shown in Fig.…”

“…High PuCl 3 /UCl 3 concentration ratio of more than 2 as well as the total heavy metal concentration of more than 1 wt.% in the salt electrolyte are thought to be necessary to deposit both Pu and U in the liquid Cd cathode. 19,20) Hence, the electrorefining tests were carried out in the following way. The first two tests, RUN-ER1 and RUN-ER2, were carried out without recovering Pu in the liquid Cd cathode.…”

Analyses of Anodic Behavior of Metallic Fast Reactor Fuel Using a Multidiffusion Layer Model

“…Uranium, which has the highest redox potential among the actinides, is preferentially reduced and collected on the solid steel cathode. 6) Plutonium and other transuranium elements are recovered into the liquid cadmium cathode together with the remaining uranium since their activities are drastically reduced in liquid cadmium. [7][8][9] The most fundamental behavior of every element in the electrorefining step, such as the electrode reactions of the actinides and separation performance of FPs, has been clarified.…”