| 摘要 |
PURPOSE:To remove approximately thoroughly the remaining metallic ion in a liquid in a titled decontaminating method of a metallic surface contaminated by a radioactive material by using a dilute aq. soln. of a sulfuric acid as an electrolyte and subjecting the liquid used for electrolytic polishing to filtering, electrolyzing and ion exchanging. CONSTITUTION:About 5vol% aq. sulfuric acid soln. 2 is filled in an electrolytic cell 1 and a decontaminating metal 3 as an anode is electrolytically polished with Ti, etc. as a cathode, by which the surface of the metal 3 is decontaminated. The suspension released in this state is passed through a filter 7 and is separated in the stage of circulating the liquid 2 by a pump 6. The decontaminated metal 3 is washed in a tank 8 and the washing water is circulated by a pump 9 and is reused through an ion exchange tank 10. The electrolyzing operation is continued in the cell 1 until the liquid 2 is used to the limit. The entire volume of the liquid 2 is then transferred by a pump 6 into an electrodeposition cell 12 and while the liquid is stirred with a circulating pump 16, the pH of the liquid 2 is adjusted by the alkali from a pipe 17 and DC is conducted to an anode 14 and a capturing electrode 13. Then the metallic ion in the liquid 2 is deposited on the electrode 13 and the liquid 2 having the radiation level decreased to a reference value or below is passed through a cation exchange tank 20 and is subjected to neutralization, dilution, etc. Such liquid is then discarded.
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