Nuclear Technology / Volume 163 / Number 3 / September 2008 / Pages 366-372
Technical Paper / Molten Salt Chemistry and Technology
The results from a study of U and Pu metal electrodeposition from molten eutectic LiCl-KCl on a solid inert cathode are presented. This study has been conducted using ~50 g of U-Pu together with rare earths (mostly Nd) and 1.5 kg of salt. The introduction of a three-electrode probe with an Ag/AgCl reference electrode has allowed voltammetric measurement during electrolysis and control of the cathode potential versus the reference. Cyclic and square-wave voltammetric measurements proved to be very useful tools for monitoring the electrolysis as well as selecting the cathode versus reference potential to maximize the separation between actinides and rare earths. The voltammetric data also highlighted the occurrence of back reactions between the cathode deposit and oxidizing equivalents formed at the anode that remained in the molten salt electrolyte. Any further electrolysis test needs to be conducted continuously and followed by immediate removal of the cathode to minimize those back reactions.