Abstract
Electric power generating utilities have devoted increasing attention to problems associated with corrosion and deposition in raw water systems. Various approaches to control of raw water corrosion have included water treatment, mechanical and chemical cleaning, and the use of alternate materials. In 1989, Duke Power Company constructed a test stand in a sidestream off the service water system of their Catawba nuclear station to evaluate the corrosion resistance of reference alloys (carbon steel, Admiralty, and Type 304 stainless steel) and candidate alternate materials (Type 316 stainless steel, AL–6XN(1), and Sea–Cure(2) in the plant’s untreated service water environment. The effects of flow (stagnant, intermittent, and continuous flow) and seasonal variations in temperature, water chemistry, etc. on general and localized corrosion were evaluated in a nominal one year exposure. The results of electrochemical measurements of corrosion are summarized. These results are compared to corrosion coupon data and microbiological characterizations.
While carbon steel showed a constant level of general corrosion and Admiralty exhibited susceptibility to pitting, especially early in the exposure, all stainless steels exhibited good resistance to general corrosion and no indication of pitting. Microbiological effects on corrosion behavior did not appear to be significant over the duration of the exposure.
