Risk-Informed Assessment Methodology Development and Application

Abstract

Westinghouse Electric Company (WEC) has been working with Korea Power Engineering Company (KOPEC) on a US Department of Energy (DOE) sponsored Nuclear Energy Research Initiative (NERI) project through a collaborative agreement established for the domestic NERI program. The project deals with Risk-Informed Assessment (RIA) of regulatory and design requirements of future nuclear power plants. An objective of the RIA project is to develop a risk-informed design process, which focuses on identifying and incorporating advanced features into future nuclear power plants (NPPs) that would meet risk goals in a cost-effective manner. The RIA design methodology is proposed to accomplish this objective. This paper discusses the development of this methodology and demonstrates its application in the design of plant systems for future NPPs. Advanced conceptual plant systems consisting of an advanced Emergency Core Cooling System (ECCS) and Emergency Feedwater System (EFWS) for a NPP were developed and the risk-informed design process was exercised to demonstrate the viability and feasibility of the RIA design methodology. Best estimate Loss-of-Coolant Accident (LOCA) analyses were performed to validate the PSA success criteria for the NPP. The results of the analyses show that the PSA success criteria can be met using the advanced conceptual systems and that the RIA design methodology is a viable and appropriate means of designing key features of risk-significant NPP systems.