Damage related to intergranular corrosive cracking under stress was observed in austenite pipelines operated at atomic power plants (APPs). In 1986, such flaws were found for the first time at Russian APPs in welded joints of water equalizing pipelines in an PBMK drum separator. In 1997, numerous cracks were discovered in welded joints in downcomer and pressure pipes at APPs where PBMK-1000 and PBMK-1500 reactors were operated; i.e., this phenomenon acquired a mass character.