NPP decontamination

Decontamination methods for NPP with LWGR and WWER reactors are considered. Circuits iof NPP with LWGR are decontaminated with solutions on the basis of oxalic acid and hydrogen peroxide with addition of nitrate-ions, whereas WWER with complexones followed treatment with strong oxidizers. As a result of decontamination γ-background of the equipment decreases 5-100 fold. The instruments and room surfaces are decontaminated using vapour-ejecting sprayers, hydromonitors and special baths with solutions on the basis of mineral acids and complexones with various additions, which can be used for stainless and carbon steels, coatings of epoxide enamels and plastifiers. Methods of dry decontamination using easily peeled off coatings on the basis of polyvinyl alcohol and other materials lately are widely used for NPP room decontamination. Small metallic parts of surface are decontaminated by electrochemical method. Different mixtures of mineral and organic acids, as well as caustic potash and boric acid, are used as electrolytes