Anodic behaviour of U-Pu-Zr alloy in LiCl-KCl eutectic melt

In molten salt electrorefining of U-Pu-Zr alloy, uranium and plutonium are recovered at solid cathode and liquid cadmium cathode, respectively. Rate of dissolution of alloy in LiCl-KCl eutectic melt and the corresponding rate of deposition of uranium and plutonium are few parameters that influence the electrorefining operation. Important design aspects of anode include ease of dissolution of U-Pu-Zr alloy, retention of loose zirconium metal powder and complete drainage of melt after it is lifted up from the melt. In this paper, we report on first design aspect i.e. determining if the rate of dissolution of U-Pu-Zr is facile or sluggish by estimating its exchange current density in LiCl-KCl eutectic melt. A three-electrode assembly with graphite as counter electrode and Ag+|Ag as reference electrode was used for the measurements. The working electrode was U-Pu-Zr alloy (Electrode area: 3.2 cm²) as shown. LiCl-KCl eutectic melt was purified by chlorination prior to measurements. The same melt was used to prepare LiCl-KCl-UCl₃ electrolyte by equilibrating uranium and cadmium chloride at 500 °C