Processing of fast neutron reactor fuel by electrorefining:Thematic overview

International Journal of Energy Research, 2020; P. 1–20

Alexander Y. Galashev

Abstract — This work provides basic knowledge on the spent fuel management on thebasis of the published literature data on electrorefining. This review examinesthree main areas of work devoted to electror efining. These are electrodeposition and electrodissolution using solid and liquid electrodes, as well as masstransfer in phases present during electrorefining. As part of this research, thecomposition of the irradiated metallic fuel was estimated. Due to the greatpotential difference between solid cathodes, it is possible to separate actinidesfrom lanthanides. The co-deposition of metallic Pu and U in the eutectic LiCl-KCl melt containing UCl₃ and PuCl₃ indicates stable co-precipitation of U and Pu at U³⁺ concentration less than ~0.2 wt. Periodically performed electricaltransport of ions to liquid (Cd) and solid cathodes in the galvanic mode madeit possible to deposit preferentially U on the solid cathode, and Pu and Am onthe liquid cathode. Oxidation of these metals caused fluctuations in the anodepotential. The electrode processing after electrorefining is investigated. This process consists of oxidizing the actinides remaining in the liquid electrode byadding CdCl₂ and removing the associated chloride by high-temperature distil-lation. During the electrorefining of irradiated met allic fuel, the fission prod-ucts accumulate in the molten salt. Reduction of uranium on a solid cathodefrom a spent molten salt using a liquid Cd-Li anode is considered. A modelthat describes electrorefining with a liquid metal anode, solid cathode, andmolten LiCl-KCl salts, is presented. The formation of plutonium at the surfaceof a solid cathode is analyzed. In a one-dimensional model of an electrorefiner,it is shown that the concentration of Pu at the cathode cannot be predictedfrom the Cm concentration in the melt.

PDF file