Jérôme Serp

Electroseparation of Actinides from Lanthanides on Solid Aluminum Electrode in LiCl-KCl Eutectic Melts

University of Grenoble, ENSEEG, 38402 Saint Martin d’He`res, FranceThis work presents a study on the electrochemical behavior of actinides (An 5 Am and Pu! and lanthanides (Ln 5 La and Nd!onto solid aluminum cathodes in a molten LiCl-KCl eutectic at 733 K. Cyclic voltammetry of these elements onto Al workingelectrode is carried out to estimate the reduction potentials of An and Ln and to predict the efficiency of an An/Ln separation byelectrolysis. Results show that the reduction of Am

Promising Pyrochemical Actinide/Lanthanide Separation Processes Using Aluminum

Abstract Thermodynamic calculations have shown that aluminum is the most promising metallic solvent or support for the separation of actinides (An) from lanthanides (Ln). In molten fluoride salt, the technique of reductive extraction is under development in which the separation is based on different distributions of An and Ln between the salt and metallic Al phases. In this process molten aluminum alloy acts as both a reductant and a solvent into which the actinides are selectively extracted. It was demonstrated that a one-stage reductive extraction process, using a concentrated solution, allows a recovery of more than 99.3% of Pu and Am. In addition excellent separation factors between Pu and Ln well above 103 were obtained. In molten chloride media similar separations are developed by constant current electrorefining between a metallic alloy fuel (U60Pu20-Zr10Am2Nd3.5Y0.5Ce0.5Gd0.5) and an Al solid cathode. In a series of demonstration experiments, almost 25 g of metallic fuel was reprocessed and actinides collected as An-Al alloys on the cathode. Analysis of the An-Al deposits confirmed that an excellent An/Ln separation (An/Ln mass ratio = 2400) had been obtained. These results show that Al is a very promising material to be used in pyrochemical reprocessing of actinides.

Niobium Electrodeposition in Molten Fluorides Using Pulsed Electrolysis

that the nucleation pro-cess of niobium in molten LiF-NaF is instantaneous, three-dimen-sional, and closely controlled by linear diffusion. Under these con-ditions a columnar structure of coarse grains is expected. This situa-tion prevents obtaining a coating with a compact structure withoutdendrites if too high a current density is used. Consequently, indus-trial applications of the process would be hindered by the requiredslow deposition rates.However, pulsed electrolysis may be explored to improve theprocess, since pulsed electrodeposition of various metals in aqueousmedia have given good results in terms of high electrodepositionrates and smoothness of the coatings.