A Theoretical Method to Predict Wear of Plugged Tubes of Steam Generators

Wear of steam generator tubes has been focused on in nuclear power industries for a long time. In case a certain amount of a steam generator tube wall is revealed to be worn out, which is usually caused by flow induced vibrations, by nondestructive tests, the tube is required to be plugged to avoid leakage of primary water into the secondary side and possible serious sequences. Recently, the question about the integrity of plugged tubes has been issued. This is because the tube might experience the wear even after the plugging, therefore, in a worst situation the plugged tube could be ruptured and then give mechanical impacts on neighboring tubes. If this scenario happens the plugged tube should have been stabilized by an appropriate method. In order to decide whether the stabilizer is necessary for the plugged tube, we need to evaluate the wear of the tube after the plugging. This paper proposes a theoretical and practical method to predict wear of plugged tubes, which is based on actual measurement data from some PWR plants in service