Patent Number: 047567686
Section: summary

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a method for the chemical decontamination of metallic parts of nuclear reactor installations, in which first, an oxidative treatment with a permanganate solution is applied before dicarbonic acids are used for further treatment. 2. Description of the Prior Art In the method known from German Patent No. 26 13 351 and U.S. Pat. No. 4,226,640, which has found acceptance in practice, an alkaline permanganate solution is used for the oxidative treatment of contaminated nuclear reactor components at a temperature of about 100.degree. C. The components are subsequently flushed with demineralized water (deionate) before continuing with a citrate-oxalate solution which is adjusted with ammonia to a pH-value of 3.5. The solution contains an inhibitor as well as ethylenediamine tetraacetic acid. The inhibitor is iron-III formate. The known method with its individual stages and in-between rinsing operations uses high chemical concentrations and the time of treatment is quite long. Also, the known method has not been applied to primary systems of nuclear reactors which would have to be practically emptied for this purpose and would have to be filled again after the treatment. SUMMARY OF THE INVENTION An object of the invention is to lower the radiation exposure of inspection and repair personnel by chemical decontamination of the primary system of nuclear reactors or of parts thereof, which chemical decontamination can be carried out at a lower cost. Only little secondary waste is produced in the chemical decontamination. This waste is eliminated in a radiation-proof manner. With the foregoing and other objects in view, there is provided in accordance with the invention a method for the chemical decontamination of metallic parts of nuclear reactor installations in which an oxidative treatment with a permanganate solution is applied before dicarbonic acids are used for the further treatment, characterized by the feature that permanganic acid is used for the oxidative treatment. Other features which are considered as characteristic for the invention are set forth in the appended claims. Although the invention is illustrated and described herein as embodied in a method for the chemical decontamination of metallic parts of nuclear reactor installations, it is nevertheless not intended to be limited to the details shown, since various modification may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.