METHOD FOR ALLEVIATING START OR SPREADING OF CRACK ON SURFACE OF METAL CONSTITUENT PART OF WATER-COOLING TYPE NUCLEAR REACTOR OR RELATED INSTALLATION,AND METAL CONSTITUENT PART HAVING CRACK ON SURFACE THEREOF

摘要

PURPOSE: To reduce the start and development of crack at the surface of a metallic constituent of a water-cooled nuclear reactor or related equipment by injecting the solution of compounds containing noble metal into the water of the nuclear reactor. CONSTITUTION: This method is a field technique by which the inside of a crack in the surface of the constituent part of a nuclear reactor is coated or doped with a noble metal by injecting the solution of compounds containing a noble metal such as palladium into the inside of the high-temperature water of the nuclear reactor. In the nuclear reactor, feed water is fed into the pressure vessel 10 through a feed- water inlet 12 and a feed-water sparger 14. The solution of the noble metal compounds is preferably injected at the upstream point of the feed-water inlet 12. The high- temperature inside the core 20 and the radiation of gamma-rays and neutrons act so as to dissolve the compounds of the noble metal. Thereby, the ions or atoms of the noble metal become free and adhere to the circumference of the opening part of the crack and the inside thereof at the surface of the oxide film of the metallic constituent part. Thus, the growth of crack can be restrained.