205.電解酸化法による二酸化プルトニウムの溶解,(I)

Dissolution behavior of refractory PuO2 was iwestigated with nitric acid solution containing such strong oxidants as Ce(IV) or Ag(II) which was electrolytically re-generated in the dissolving solution. An appropriate oxidant was selected and optimum conditions for concentrations of nitric acid and oxidant, electrolytic current, temperature, etc. were determined.A high dissolution rate was attained even at room temperature in the presence of Ag2+. The rate-determining step in the dissolution of 10g-level of PuO2 was electrolytic re-generation of Ag2+. Hydrogen evolution at cathode could be prevented by maintaining the nitric acid concentration to be sufficiently higher in catholyte and the current density to be lower at cathode. These results suggest that the method is applicable to larger scale dissolution of PuO2.