Stability of Tungsten Crucible against Uranium, Rare Earth, Cadmium, and Chlorides for Cathode Process in Pyroprocessing

The stability of W against U, rare-earth (RE) elements, Cd, and various chlorides was evaluated by melting and distillation testing. Three runs were performed with a W crucible to examine its reactivity: (i) RE melting by induction heating, (ii) salt distillation test of U-dendrite and various chlorides, and (iii) Cd distillation test from U–Cd alloy. The W crucible remained stable after the RE melting test using induction melting, exhibiting its applicability for induction heating systems. The salt distillation test with the W crucible at 1050°C exhibited the stability of W against U and various chlorides, showing no interaction. The Cd distillation test with the W crucible at 500°C showed that the crucible was very stable against Cd, maintaining a shiny surface. These results reveal that the W crucible is stable under operation conditions for both salt and Cd distillation, suggesting the high potential utility of W as a crucible material for application in cathode processes in pyroprocessing.

Composition and Pressure Estimation on Salt Distillation Process after Electrorefining for Spent Nuclear Fuel

A pyroprocessing technology has been developed to process spent nuclear fuels with decreased waste and increased proliferation resistance. A main process of the pyroprocessing is an electrorefining which requires a post-treatment for recovered uranium. A distillation approach is adopted to remove an electrolyte salt residue on the uranium. In this work, the vapor composition of the distillation process and the total pressure were estimated to obtain basic data for process design and integration. Six chlorides including KCl, LiCl, UCl3, PuCl3, CeCl3, and YCl3 were considered to understand the behavior of the representative components of actinides and lanthanides. It was found that small amount of the actinides and lanthanides would be accompanied by the electrolyte salts (KCl and LiCl) during the distillation under high vacuum.