Evaluation Tool Regarding Crack Initiation and Growth for CANDU Pressure Tube

Abstract

For the purpose of an integrity evaluation of a pressure tube failure, flaws should be characterized into the typical form, particularly for multiple flaws. Then, crack initiation and growth should be evaluated at the end of the evaluation period to determine the end-of-evaluation-period crack dimensions. The crack growth evaluation includes fatigue and delayed hydride cracking. Based on the calculated final dimensions of the crack by the end of the evaluation period, an evaluation of a fracture initiation and a plastic collapse should be followed to confirm whether the current pressure tube satisfies the integrity requirement in terms of the fitness for service. In this study, we have been developing an evaluation tool for the crack initiation and growth of the CANDU pressure tube. Developed tool consists of not only the evaluation algorithm for the crack initiation and growth but also the evaluation module for the initiation of fracture and plastic collapse based on the latest technical requirements and procedures described in CSA N285.8-15.