Evaluating the NESC-I test and the integrated approach to structural integrity assessment

The NESC-I spinning cylinder test was designed to simulate selected conditions associated with an ageing reactor pressure vessel (RPV) subjected to severe pressurised thermal shock (PTS) loading and containing hypothetical flaws. It formed the focal point of the first project of the Network for Evaluation of Structural Components (NESC), with the objective of validating the combination of non-destructive inspection and structural mechanics assessment procedures for evaluating the integrity of such an aged structure containing postulated flaws. The huge amount of data generated over the seven-year project has been evaluated and is now available to the international community. The test demonstrated that, for the specific conditions considered, defects of up to 74 mm depth in material related to that of an ageing RPV would not propagate to cause catastrophic failure under a severe PTS-type thermal shock. This outcome was fully in line with the pre-test analysis forecasts, which combined the defect-size information supplied from blind inspections trials, a comprehensive materials data set, and a range of structural analysis tools