In this research, a new index “The Resilience Index” was proposed to evaluate the capability of nuclear power plant to recover from the situation of safety function lost. Three elements assumed to evaluate the resilience index are the achievement rate, necessary time, and probability of success of each accident management activity. The resilience index is expected to visualize the improvement of safety of each nuclear power plant against severe accidents.

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Resilience index is proposed to be applied to evaluate the capability to recover safety performance of systems under severe accident of nuclear power plant. This study developed the failure probability model of equipment by low-cycle fatigue and applied the model to the reliability analysis for degradation of static components in resilience index.

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The ultrasonic examination personnel are required to have high-level abilities such as defect detection, classification of detected echoes and so on, in the ISI of nuclear power plant in Japan. For that purpose, the examination personnel of the inspection companies are trained to learn and maintain these abilities. In general, the importance of education and training for the ultrasonic examiners is recognized. However, the effectiveness of education and training to enhance the abilities of the ultrasonic examiners has not been clarified. This study investigates the advantages of education and training for the ultrasonic examiners using the defect detection test in austenitic stainless steel piping welds specimen. From the analysis and evaluation of examination results, the major improvement of the defect detection capabilities after education and training was shown. Therefore, the effectiveness of education and training to improve the abilities of the ultrasonic examiners was demonstrated in austenitic stainless steel piping welds.

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