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

Abstract

The three-stage countercurrent extraction test with molten LiCl-KCl and liquid Cd was carried out for the development of spent salt treatment process in pyrometallurgical reprocessing of metal FBR fuel. Both salt and Cd solvent were supplied successively from each feed tank into the extractor at a constant flow rate and recovered separately into individual recovery tanks. Uranium, transuranic elements, and rareearth elements were substituted by Ce, Gd, and Y, respectively. More than 98% of Ce and 93% of Gd were recovered, and 27% of Y was corecovered in the Cd solvent. The separation factors of Gd and Y against Ce were evaluated to be 0.28-0.29 and 0.0057-0.0073, respectively. The former is almost equal to and the latter is better than that in the equilibrium. As the connecting part between each stage had a simple structure, a small amount of Cd in each stage mixed with that in the neighboring stage, which made the separation efficiency lower than expected. A calculation study showed the relationship between the Cd mixing rate and recovery yield or separation factor, and it showed that the recovery yield and separation efficiency were expected to be much improved by the modification of the connecting part to prevent Cd from mixing.

Actinides draw down process for pyrochemical reprocessing of spent metal fuel

“…This is in line with the results of Kurata et al [4]. Equilibration studies reported by Kurata et al [4] revealed that distribution coefficient of actinides between salt and cadmium alloy is dependent on lithium concentration in the cadmium phase. For 10% excess of lithium above the required stochiometric concentration in cadmium phase, the equilibrium distribution coefficient is two orders of magnitude or higher.…”

“…This is done by reductive liquid-liquid extraction using cadmium-lithium alloy. Earlier Kinoshita et al [3,4] have reported studies on the reductive extraction of Ce, Gd and Y from the salt using single stage and three stage continuous extractors by considering the Ce and Gd are surrogates for the actinides. As part of the development efforts on pyrochemical reprocessing, an experimental facility has been installed inside an argon atmosphere glove box for carrying out studies on the actinide draw down process.…”

(Invited) Pyrochemical Reprocessing of Used Nuclear Fuels

“…An electrorefiner equipped with a concentrically configured anode/solid cathode module and a mechanism for scraping off cathode deposits was developed to increase the uranium recovery rate. Figure 11 shows the anode/solid cathode module installed in Ar atmosphere glove box (18). Stalling of the anode and scraper rotation due to the interference by the cathode deposits was completely diminished by the modifications in the design of the anode basket and scraper mechanism.…”