To provide a decontamination method and a decontamination agent suitable for chemical decontamination of structural parts including a copper oxide in a nuclear power plant.
Malonic acid 5 is injected as the decontamination agent in circulating lines 15, 16, and circulated through lines 15, 16 to dissolve copper oxide from a radioactive insoluble substance stuck to a decontamination object 1 (a copper removal process). Dissolved copper ions are removed by making decontamination agent liquid flow to a cation exchange resin column 3 (a metal ion removal process). After the completion of the copper removal process, ascorbic acid 5 is injected in the circulating lines 15, 16 to dissolve iron oxide remaining in the copper removal process, from the decontamination object 1 (an iron removal process). Dissolved iron ions are removed in the cation exchange resin column 3. Hydrogen peroxide 9 is injected in the decontamination agent liquid from which iron ions are removed and the decontamination agent liquid is circulated through a catalyst column 8 to decompose the decontamination agent into carbon dioxide and water, and further passed through a mixed bed resin column 4 for final purification.
YOSHIKAWA HIROO
AIZAWA MOTOHIRO
NAGASE MAKOTO
HITACHI ENG CO LTD
HITACHI LTD
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