Production of SCC Flaws and Evaluation Leak Behavior of Steam Generator Tubes

摘要

A forced outage due to a steam generator tube leak in a Korean nuclear power plant was reported. Primary water stress corrosion cracking has occurred in many tubes in the plant, and they were repaired using sleeves or plugs. In order to develop proper repair criteria, it is necessary to understand the leak behavior of the tubes containing stress corrosion cracks. Stress corrosion cracks were developed in 0.1 M sodium tetrathionate solution at room temperature. Steam generator(SG) tubes with short cracks were successfully fabricated with a restricted solution contact method. The leak rates of the degraded tubes were measured at room temperature. Some tubes with 100% through wall cracks showed an increase of leak rate with time at a constant pressure.