A Methodology for Safety Inspection Analysis Based on Risk Insight and Defense-in-Depth Concept for APR1400 Nuclear Power Plant

Abstract

To confirm the safety of Nuclear Power Plants (NPP) several regulatory safety inspections based on defense in depth criteria were conducted. However, once the plant is put into service the regulatory safety inspection must be focused on whether to minimize the risk of accident using defense-in-depth concept and risk insight obtained from probabilistic safety analysis. The regulatory oversight of accident prevention can be strengthened by requiring that safety improvements be considered through the use of deterministic and probabilistic approaches (such as probabilistic risk assessments (PRA). Hence, the incorporation of DID concept and risk insight into deterministic-based safety inspection has not been well studied so far since the regulatory safety inspection was developed depending on each country’s specific regulation. The aim of this study is to propose a methodology using APR1400 Large LOCA as a case study to develop Safety Inspection Methodology using AIMS-PSA as an analysis platform to develop Event tree and fault trees and analyze how to secure the success path and how to block the failure path in a specific event tree. This study will help to improve accident anticipation, high reliability, and risk assessments to maintain the operability of all safety systems and to ensure the long-term ability to mitigate any extreme accident scenarios