Risk-informed Physical Security Assessment for Nuclear Power Plants

The concept of risk-informed physical security for nuclear power plants (NPPs) has recently been extensively explored across various stakeholders, including the nuclear industry, the Department of Energy, the Nuclear Energy Institute, the Nuclear Regulatory Commission (NRC), and researchers at national laboratories and universities. Risk-informed physical security holds promise for advanced assessment and optimization of NPP physical security postures, leading to safer, more efficient, and more economical plant operations. Recently NRC issued a revision to Regulatory Guide 5.76, transitioning from the prescriptive regulatory requirements for physical security to newer guidance based on a reasonable assurance of protection time. The new NRC guidance paves the way for physical security performance assessments to be tied-in with existing risk-based plant safety approaches and associated metrics (e.g., time to core damage) through timeline. This paper presents a novel computational framework for risk-informed physical security, aimed at performing various types of analyses such as security design optimization, armed-guard reduction, and the crediting of plant mitigating strategies in security postures.