Risk Informed Design for System Life Cycle

摘要

Many facilty life cycle activities including design, construction, fabrication, inspectionrnand maintenance are evolving from a deterministic to a risk-informed basis. The risk informedrnapproach uses probabilistic methods to evaluate the contribution of individual systemrncomponents to total system performance. Total system performance considers both safety andrncost considerations including system failure, reliability, and availability. By necessity, a riskinformedrnapproach considers both the component’s life cycle and the life cycle of the system.rnIn the nuclear industry, risk-based approaches, namely probabilistic risk assessment (PRA) orrnprobabilistic safety assessment (PSA), have become a standard tool used to evaluate the safety ofrnnuclear power plants. Recent studies pertaining to advanced reactor development have indicatedrnthat these new power plants must provide improved safety over existing nuclear facilities and berncost-competitive with other energy sources. Risk-based approaches, beyond traditional PRA,rnoffer the opportunity to optimize design while considering the total life cycle of the plant in orderrnto realize these goals.rnThe use of risk-based design approaches in the nuclear industry is only beginning, withrnrecent promulgation of risk-informed regulations and proposals for risk-based codes. This paperrnbriefly summarizes the current state of affairs regarding the use of risk-based approaches inrndesign. Key points to fully realize the benefit of applying a risk-based approach to nuclear powerrnplant design are then presented and illustrated in a case study. These points are equallyrnapplicable to non-nuclear facilities where optimization for cost competitiveness and/or safety isrndesired.