Assessment of steam generator tube flaw size and leak rate models

The Canadian Nuclear Safety Commission (CNSC) recently developed the CANTIA methodology for probabilistic assessment of inspection strategies for steam generator tubes as a direct effect on the probability of tube failure and primary-to-secondary leak rate. In an effort to improve the CANTIA, a steam generator tube integrity assessment code, relevant survey of the literature on discharge of subcooled water from cracks and critical flow models, steam generator tube cracks, leakage and probabilistic assessment methodologies was carried out. The original CANTIA and ANL/CANTIA code models for the flaw opening leakage rate models were reviewed. The crack opening area and the leakage flow rate models were compared with experimental measured data from a steam generator tube crack.