Behavior of plutonium and americium at liquid cadmium cathode in molten LiCl-KCl electrolyte

The effects of the electrochemical conditions on the behavior of plutonium and proper conditions for plutonium recovery at the liquid cadmium cathode (LCC) used in the pyrometallurgical reprocessing were studied by the electr otransport experiments with small, not stirred electrodes. Plutonium was su ccessfully collected up to 7.75 wt% without disturbance by solid phase form ation at the surface. Plutonium collected beyond saturation formed intermet allic compound PuCd6 and accumulated at the bottom of the LCC. The cathodic current density adequate for plutonium collection was proportional to the concentration of plutonium in the molten salt. The behavior of americium wa s reasonably explained by a local equilibrium model between plutonium and a mericium at the surface of the LCC, although thermodynamic study and quanti tative analysis are needed for further understanding. The plutonium collect ion rate in practical electrorefiner was estimated to be 324 g/h for one LC C by extrapolation of the experimental results. (C) 2001 Elsevier Science B .V. All rights reserved.