超音波探傷試験員の力量向上が配管破損リスクの低減に及ぼす影響の評価
Effect of Ultrasonic Testing Examiners’ Capability Improvements on Reduction of Piping Failure Risk
著者:
小嶋 正義 高橋 秀治 木倉 宏成 （東工大）
発刊日:
公開日:
Capability Improvement of UT ExaminerCumulative Failure ProbabilityIn-Service InspectionPiping Failure RiskProbabilistic Fracture MechanicsProbability of DetectionUltrasonic Testing
概要
Ultrasonic testing (UT) is a part of maintenance program for essential equipment of nuclear power plants in in-service inspection (ISI). Analyses of probabilistic fracture mechanics (PFM) for welds of class 1 piping have been studied to evaluate piping failure risks. Probability of detection (POD) is one of the important input conditions in the PFM analysis. The POD is closely related to a capability of UT examiners; therefore it is anticipated that the capability improvement of UT examiners is related to the piping failure risk. The objective of this paper is to demonstrate effects of the capability improvement of UT examiners on the reduction of piping failure risk. A blind test was conducted twice at 11 week intervals by 2 examiners. The experimental results of PODs and cumulative failure probabilities were compared to evaluate relationships between the capability improvement of the 2 examiners and the piping failure risks. The results showed that the POD and the cumulative failure probability are useful for evaluating the capability improvement of UT examiners. In addition, it was demonstrated that the capability improvement affects the reduction of piping failure risk.
