Adjustment of oxide film conductivity to maintain low corrosion potential in high temperature water

摘要

A method for mitigating general corrosion and crack initiation and growth on the surface of metal components in a water-cooled nuclear reactor. A compound containing a non-noble metal such as zirconium or titanium is injected into the water of the reactor in the form of a solution or suspension. This compound decomposes under reactor thermal conditions to release ions/atoms of the non-noble metal which incorporate in or deposit on the surfaces of the components, including the interior surfaces of any cracks formed therein. The preferred compounds are zirconium compounds such as zirconium acetylacetonate, zirconium nitrate and zirconyl nitrate. Zirconium deposited in or on an oxided surface of a metal component will reduce the electrochemical potential at the surface to a level below the critical potential to protect against intergranular stress corrosion cracking.