Development of Structural Reliability Evaluation Method for Aged Piping Considering Uncertainty of Seismic Motions

Abstract

The purpose of this research is to establish a stmctural reliability evaluation method for aged nuclear components under seismic events from the viewpoint of long-term use of existing light water reactor nuclear power plants. For this purpose, we developed a piping failure probability evaluation code "PASCAL-SC" and seismic hazard evaluation code "SHEAT-FM" which is reported separately. In PASCAL-SC, aging such as SCC (Stress Corrosion Cracking) and fatigue crack extension by seismic load is considered. In this paper, a reliability evaluation procedure for aged piping under seismic events by combination of these codes is described. We evaluate the reliability of a welded joint of PLR (Primary Loop Recirculation system) piping using a BWR model plant under seismic events.