Probabilistic observation of design basis ground motions of NPPS

Takada, Tsuyoshi  ; Tsutsumi, Hideaki*; Kawata, Manabu

The 2006 seismic design review guide requires results of their site-specific probabilistic seismic hazard assessment (PSHA) for setting Design Basis Ground Motions (DBGMs) to verify seismic safety of Nuclear Power Plants (NPPs). All electric utilities have submitted their results of their DBGMs to the NRA (Nuclear Regulatory Authority) together with the results of their PSHA. The AEPs (Annual Exceedance Probabilities) of DBGMs reflect not only the site-specific physical earthquake environment but also degree of design conservatisms which each electric utility wants to maintain for their NPPs. The present paper, based on the publicly available documents submitted to NRA, demonstrates the AEPs of the DBGMs of 16 NPPs in Japan and shows the regulatory requirements as well as utilities' decision by statistically analyzing the AEPs, which certainly can lead to risk-informed decision-making activities for nuclear safety assurance in Japan.