Corrosion of steam generator tubing in operating pressurized water reactors

Corrosion of steam generator tubing has been observed in all but three PWR's that have been in operation for more than one year. The history of this experience with both stainless steel and Inconel-600 tubing is reviewed. Both intergranular stress corrosion cracking and localized, transgranular wastage have been observed with Inconel-600 tubing. The wastage can be attributed to a localized concentration, or ''hideout'' of phosphates in limited flow areas. A model is proposed for this wastage phenomenon which is consistent with operating experience. 33 references. (auth)