Electrode reaction of Pu3+/Pu couple in LiCl-KCl eutectic melts: Comparison of the electrode reaction at the surface of liquid Bi with that at a solid Mo electrode

The electrode reaction of Pu3+/Pu couple at the interface between LiCl-KCl eutectic melt containing PuCl3 and liquid Bi phase was investigated by cycl ic voltammetry at 723, 773 and 823 K. For comparison, the system was also s tudied using a solid Mo electrode in place of the liquid Bi electrode. It w as found that the electrode reaction of Pu3+/Pu couple at the Bi electrode was almost reversible. The redox potentials of Pu3+/Pu couple at the liquid Bi electrode in the LiCl-KCl eutectic melt containing 0.87 wt% PuCl3 (0.00 14 mole fraction) at 723, 773 and 823 K were observed to be more positive b y 0.575, 0.572 and 0.566 V, respectively, than those at the Mo electrode, T hese differences in potential were thermodynamically analyzed by assuming a lowering of the activity of Pu in Bi phase according to the alloy formatio n of PuBi2.