| 摘要 |
The invention relates to a method for chemically decontaminating the surface of a metal component of the primary circuit of a pressurized-water reactor, said surface comprising an oxide layer. The method is divided into two process stages and is further implemented as follows: - in the first process stage, at least one treatment cycle is performed, comprising an oxidation step, a reduction step, and a subsequent first decontamination step, wherein the component is treated in the oxidation step with an aqueous solution comprising an oxidizing agent, which converts trivalent chrome present in the oxide layer into hexavalent chrome; the component is treated in the reduction step with an aqueous solution comprising a reducing agent for reducing excess oxidation agent from the oxidation step; the component is treated in the first decontamination step with an aqueous solution comprising exclusively or predominantly at least one decontamination acid that forms no antisoluble deposits with metal ions present in the solution, in particular bivalent metal ions; and the solution is fed through an ion exchanger for removing metal ions present in the solution, which metal ions originate from the oxide layer and/or the base metal of the component, - in the second process stage, at least one treatment cycle is performed, comprising a second decontamination step, wherein the component is treated with an aqueous solution comprising exclusively or predominantly oxalic acid as a decontamination acid.
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