Application of square wave voltammetry to on-line monitoring of lanthanide ions in LiCl-KCl molten salt at 773K

Molten salt based pyrochemical process has received attention as a possible future separation technique for reprocessing. Recently, the technology has attracted much attention due to a possibility to be able to prepare metallic nuclear fuels for sodium-cooled fast breeder reactor. In general, pyroprocess consists of three subsequent steps. First, uranium oxide is electrochemically reduced at the cathode to create a metal ingot containing uranium and oxygen gas is generated at the anode in electrolytic reduction process. Next, the metal ingot is transferred to an electrochemical cell of a LiCl-KCl molten salt at 773K for electrorefining process, where pure uranium metal is recovered through an electrochemical reduction route. Finally, uranium and TRU remained after the electrorefining process is completely recovered in electrowinning process, where uranium and TRU are co-deposited at liquid cadmium electrode to make cadmium-based alloy for nuclear nonproliferation. In order to practically use the recovered actinides as a fuel of SFR, it is necessary to protect co-deposition of lanthanide elements. In case of a lanthanide contaminated fuel, the neutron flux for transmutation of the actinides is significantly decreased due to the some lanthanide elements with large neutron capture cross sections. So, it is quite needed to measure the concentration of lanthanides in the molten salt to efficiently avoid the co-deposition of lanthanide elements and further to improve the efficiency of the electrowinning process