Improvement of probabilistic fracture mechanics evaluation code PEDESTRIAN for piping. Implementation of evaluation methods for crack propagation

Probabilistic fracture mechanism (PFM) is recently featured as a promising technology for quantitative and reasonable structural integrity evaluation method for nuclear components. United States of America is leading the scene from code development to its implementation into regulatory requirement. U. S. Nuclear Regulatory Commission and EPRI are developing a PFM code named 'xLPR' for evaluation of leak-before-break of primary water stress corrosion cracking. The xLPR has recently been released for institutions outside the US, but its computation speed is slow. A PROLOCA code consists almost the same modules as the xLPR and calculates faster than the xLPR. These codes were developed in accordance with U. S. regulatory requirement. CRIEPI has developed a PEDESTRIAN code for structural integrity assessment of piping in Japanese plants. In order to apply PFM to structural integrity assessment, an analysis code is necessary to establish Japanese evaluation system with reference to leading U. S. perception. In this study, we investigated the evaluation methods on the xLPR, and implemented the methods, which are considered to be important, on the PEDESTRIAN. The deterministic and probabilistic analyses were conducted by using the updated PEDESTRIAN, and then these results were compared with those obtained by PROLOCA. Consequently, the deterministic and probabilistic results were in good agreement with each other. (author)