Nuclear reactor decontamination
AssigneeAtomic Energy of Canada Limited
InventorJohn Torok
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Abstract
Heat transfer and associated surfaces in nuclear reactors are decontaminated by treating the surface with ozone to oxidize acid-insoluble metal oxides to a more soluble state, removing oxidized solubilized metal oxides, and removing other surface oxides using low concentrations of decontaminating reagents. Ozone treatment has been found very effective with alloys having surface metal oxides rendered more easily dissolved by ozone oxidation especially with chromium or chromium-nickel containing alloys.
Claims19
A method of decontaminating and removing corrosion products at least some of which are radioactive, from nuclear reactor surfaces exposed to coolant or moderator, said surfaces containing acid-insoluble metal oxides, including chromium oxide, rendered more soluble by oxidation, comprising:
- (a) contacting the contaminated surfaces with ozone to an extent sufficient to oxidize insoluble surface metal oxide or oxides, oxides of said metals being thereby rendered more soluble in water or acidic decontaminating solutions;
- (b) dissolving the solubilized surface metal oxides in an aqueous liquid;
- (c) dissolving or detaching the remaining surface oxides into aqueous liquid containing oxide-removing acidic decontaminating reagents;
- (d) removing insoluble particulate material from the resulting aqueous liquids;
- (e) removing dissolved metals from the resulting aqueous liquids;
- and
- (f) removing both residual dissolved metals and reagents from the reactor system to complete the decontamination.
Dependencies are inferred from the claim text.