DEVELOPMENT OF GROUND MOTION CHARACTERIZATION MODEL AT THE IKATA SITE BASED ON GUIDELINES FOR SSHAC LEVEL 3

Abstract

In overseas countries, probabilistic risk assessment of nuclear power plant is based on probabilistic seismic hazard analysis (PSHA) applying the SSHAC (Senior Seismic Hazard Analysis Committee) Level 3. The Ikata SSHAC project is the first attempt in Japan to apply the SSHAC Level 3 seismic hazard analysis to a nuclear power plant, the Ikata Power Plant Unit 3. The characteristics of the Ikata site is that the Median Tectonic Line fault zone is located near the site and the hard rock site. Therefore, in order to take into account the epistemic uncertainty of the seismic motion, we introduced both ground motion prediction equation (GMPE) and fault rupture model simulation for evaluating ground motions, and analyzed the variations in ground motion near the seismic source. The results of this study are significant from the viewpoint of accurate and objective evaluation of uncertainty, and should be extended to subsequent PSHA.