Seismic Safety Margin Assessment for NPP Utilizing Full-Scale Tests: Overview

Seismic safety margin assessment is discussed for structural systems and components of nuclear power plants (NPP). Emphasis is placed on utilizing full-scale test results. This paper presents an overview of the ongoing project at Japan Nuclear Energy Safety Organization (JNES). It proposes a conceptual framework of the issue, and provides a basis for the three companion papers that will present application examples on actual NPP equipments. Discussion is focused on 1) motivation of the project arising from the Kashiwazaki-Kariwa NPP earthquake experience in 2007, 2) problem identification with varying targets (verification of experienced plant performance, seismic risk assessment, etc.), 3) formulation of seismic safety margin, 4) needs for realistic assessment of seismic safety margin by incorporating full-scale test results, and 5) activities of the JNES project.