Electrochemical transient techniques for determination of uranium and rare-earth metal separation coefficients in molten salts

Kuznetsov, S. A.*; Hayashi, Hirokazu ; Minato, Kazuo ; Gaune-Escard, M.*

Electrochemical experiments were carried out at 723-823K in order to estimate separation coefficients in LiCl-KCl eutectic melt containing uranium and lanthanum trichlorides. The diffusion coefficients of U(III) were determined by electrochemical methods. The standard rate constants of charge transfer for electroreduction of uranium U(III) +3e=U were calculated by the impedance spectroscopy method. It was shown that for the calculation of uranium and lanthanum separation coefficients it is necessary to determine the voltammetric peak potentials of U(III) and La(III), their concentration in the melt and the kinetic parameters relating to U(III) discharge such as transfer and diffusion coefficients, and standard rate constants of charge transfer.