Trials of plutonium electrorefiningin calcium chloride

Abstract

Electrorefining of plutonium, containing gallium and other impurities, was conducted in a CaCl2 melt at 850°C Eight operations gave an average yield of 90%. Previously, NaCl-KCl at 750°C has been used for this process. Yields in NaCl-KCl are reported as 73 - 75%. The greater yield in CaCl2 relative to NaCl-KCl is attributed to the increased operating temperature and consequent later onset of solid plutonium/ gallium phases within the anode. A further three electroreftaing runs gave rise to poorly coalesced metal. In these operations, the feed metal contained a greater quantity of dross material, such as oxide.