DECONTAMINATION BY CHEMICAL AND ELECTROCHEMICAL METHODS AND WITH A WATER JET
Decontamination experiments have been carried out using representative samples from the primary circuit of a P.W.R. reactor, and on samples taken from the water supply pipes of the German Isar B.W.R. reactor. In the primary circuits of the P.W.R. reactors, the oxide is formed in a reducing environment; it can only be dislodged by a two stage process. The weakening stage is particularly effective using the compound sodium permanganate at a high temperature. The second stage is an erosion of the metal in the compound Nitrofluoric (acid). The latter is particularly effective at high or low temperatures when accompanied by ultrasound. Amongst the reagents used, only Oxalic acid allows effective decontamination by electrolytic process. The most effective reagents for decontaminating the samples taken from the B.W.R. (ferritic steel covered with Hematite) are: + The halogen hydric acids in mixed compound both with and without peroxide of hydrogen; + Sulphuric acid; + The compound formaldehyde / formic acid. The electrolytic decontamination in two stages (reduction then oxidation) gives satisfactory results in a sulphuric and formic medium. The erosion of the metallic supports by the high pressure jet and the effective decontamination of the samples taken from the B.W.R. reactor have enabled the application conditions of this method to be specified.
Bibliographic Reference: EUR 10043 FR (1986) FS, 79 P., BFR 250, EUROFFICE, LUXEMBOURG, POB 1003
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Record Number: 1989125037700 / Last updated on: 1987-04-01
Available languages: fr