Reasons for Corrosion and Perforation of Domestic Water System Pipeline in Fuqing Nuclear Power Plant

The domestic water system of Fuqing Nuclear Power Units No. 1-4 suffered multiple perforation and leakage. The reasons for corrosion and perforation of the pipeline were analyzed through macroscopic inspection and microscopic inspection of the inner surface corrosion status of the pipeline after disassembly, in combination with the operating condition, material and protective measures of the pipeline. The results show that the fundamental cause of pipeline corrosion were as following: the carbon steel material selected for the pipeline of the domestic water system had bad corrosion resistance and no corrosion measures; the pipeline operated in the water environment rich in oxygen and chloride for a long time. Oxygen concentration corrosion of corrosion nodules was the direct cause of pipeline perforation. Chloride in water had a certain promoting effect on pipeline perforation. Finally, some improvement suggestions for pipeline perforation were proposed.