Part of the book: Mass Transfer
The present chapter contains the results of studying electrochemical and thermodynamic properties of La, Nd, and U in “liquid metal-molten salt” systems, where liquid metals were binary Ga-Al and Ga-In alloys of various compositions. The apparent standard potentials of ternary U-Ga-In, U-Ga-Al, La-Ga-In, La-Ga-Al, Nd-Ga-In, and Nd-Ga-Al alloys at various temperatures were determined, and the temperature dependencies were obtained. Primary thermodynamic properties (activity coefficients, partial excess Gibbs free energy change, partial enthalpy change of mixing, and excess entropy change) were calculated. The influence of the bimetallic alloy composition and the nature of lanthanide on thermodynamic properties of compounds are discussed. The values of U/Nd separation factors on gallium-aluminum and U/La on gallium-indium alloys were calculated. The value of the separation factors strongly depends on the alloy composition. Uranium in this case is accumulating in the metallic phase and lanthanides in the salt melt. Analysis of the data obtained showed the perspective use of the active cathodes (Ga-Al and Ga-In instead of single Cd) in future innovative methods for reprocessing spent nuclear fuels (SNF) and high-active nuclear wastes in the future of closed nuclear fuel cycle.
Part of the book: Uranium