| 摘要 |
<p>PURPOSE:To oxidize pentavalent Np to hexavalent one without generating secondary waste by controlling the electric potential of oxidizing electrode and electrolytically oxidizing high level waste liquid including only pentavalent Np and fission products. CONSTITUTION:In a glass made batch type electrolytic oxidation reaction device 1, an working (oxidizing) electrode 3, a counter electrode 4 and a reference electrode (saturated calomel electrode) 5 are arranged. The electrode 3 is placed in a glass tube 6 with diaphragm. Nitric acid solution 2 containing Np and U is contained in tone reaction device 1 and an electrolysis controller 9 is operated. In this process, the electric potential of the electrode 3 is controlled to suppress the generation of oxygen and hydrogen gases generated by the electrolysis of water. During electrolyzing, the electrolyte is sufficiently stirred using a stirrer 7 (stirring element 8) provided at the bottom of the reaction device 1. The nitrous acid concentration in the solution reduces with time. As the results, even with the existence of hexavalent U, pentavalent Np can be electrolytically oxidized to hexavalent one.</p> |
