RELIABILITY ASSESSMENT OF PLR PIPING BASED ON DOMESTIC SCC DATA

摘要

This paper describes effects of a probability of detection (POD) of a stress corrosion crack on the reliability of the piping in a nuclear power plant (NPP). Various POD curves were proposed using the results of Japanese study on the detection for the stress corrosion crack which is frequently observed in austenitic stainless steel piping of boiling water reactor (BWR). Based on the proposed POD curves, the reliability of a flawed pipe was analyzed using probabilistic fracture mechanics (PFM) code. The results suggest that the detectable crack depth and, oversight probability (e.g. human error) is important on the reliability of piping with the stress corrosion crack. The reliability of piping depends on the detectable crack depth rather than the oversight probability when the detectable crack depth is larger than 3mm. Meanwhile, it depends on the oversight probability, when the detectable crack depth is 3mm or less.