PURIFICATION OF URANIUM METAL USING THE SOLID-STATE ELECTROTRANSPORT METHOD UNDER ULTRAHIGH-VACUUM

A uranium ingot was successfully purified using the solid state electr otransport (SSE) method. The concentration of impurities was dramatica lly reduced after the SSE treatment. In particular, magnetic transitio n metals such as Fe and Cu were removed almost completely. Impurities with high vapor pressure such as Mn and Zn were evaporated. The mechan ism of the impurity-reduction was qualitatively explained by three eff ects: sweeping out by the flow of the electrical current, diffusion an d evaporation. It is very important to hold the uranium ingot at a hig h temperature just below the melting point.