Application of Binary Ga-Al Alloy Cathode in U Separation from Ce: the Possibility in Pyroprocessing of Spent Nuclear Fuel

Abstract To study the application perspectives of binary Ga-Al alloy electrodes in pyroprocessing, the utilization of Ga-Al alloy electrode for the separation of U from Ce was studied in this work. Specifically, the reduction behaviors of U (III) on Ga, Al and Ga-Al alloy electrodes was first explored in LiCl-KCl eutectic at 773 K. The cathode peak potential of U (III) at the Ga-Al alloy electrode was 0.44 V (vs. Li/Li3Bi), and less affected by the Ga/Al ratio. Moreover, potentiostatic electrolysis at 0.55 V (vs. Li/Li3Bi) was conducted on the Ga-Al alloy electrode for 4 h to separate U from Ce. X-ray diffraction (XRD) analysis indicated the co-existence of Al3U and Ga3U with an identical crystal structure in the deposits. Scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) illustrated a good diffusion of U metal in Ga-Al alloy electrodes. Inductive coupled plasma optical emission spectrometry (ICP-OES) determinations exhibited an excellent separation performance of the Ga-Al alloy electrode.