Method for the chemical decontamination of nuclear reactor components
AssigneeKraftwerk Union Aktiengesellschaft
InventorHorst-Otto Bertholdt
Life of this patent
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Abstract
Chemical decontamination of equipment contaminated with radioactive material, such as components and systems, particularly water-cooled nuclear reactors, by pretreating with alkaline permanganate, rinsing with demineralized water, treating with a citrate-oxalate solution, rinsing with demineralized water, and post-treating with an acidified hydrogen peroxide solution containing suspended inert particles. Solutions desirably contain no sulfur. The decontamination solution with a pH of about 3.5 and other preferred operating conditions are recited.
Claims15
Method for the chemical decontamination of radioactively contaminated equipment constructed of a metal selected from the group consisting of chrome-nickel steel, nickel alloys or chrome alloy steel, which comprises subjecting the contaminated equipment to three stages of treatment with an intermediate rinsing with demineralized water between stages as follows:
- (a) pretreating the contaminated equipment with an aqueous alkaline permanganate solution at a temperature of 85.degree. C. to 125.degree. C. for about 2 hours
- (b) rinsing the equipment after treatment with the alkaline permanganate with demineralized water
- (c) treating the rinsed equipment with an aqueous decontamination solution with a pH-value adjusted to about 3.5, containing a citrate and oxalate and an inhibitor, at a temperature of 85.degree. C. to 125.degree. C. for about 2 to 20 hours
- (d) rinsing the equipment after treatment with the citrate-oxalate with demineralized water, and
- (e) post-treating the rinsed equipment with an aqueous solution of an organic acid and hydrogen peroxide containing suspended inert particles at a temperature of 20.degree. C. to 80.degree. C. for about 2 to 8 hours.
Dependencies are inferred from the claim text.