Integrating Human Reliability Analysis With Dynamic Modeling of Physical Security Effectiveness

The overall cost for protecting nuclear power plants (NPPs) accounts for approximately 7% of the total cost of power generation, with labor accounting for half the operation and maintenance cost [1]. In the current physical security research being conducted under the Department of Energy’s Light Water Reactor Sustainability Program, interaction with utilities and other stakeholders enabled the determination that physical security forces account for nearly 20% of the entire workforce at several NPPs. Ongoing research into the dynamic modeling of risk-informed physical security has successfully demonstrated the integration of plant mitigation strategies such as Diverse and Flexible Mitigation Capability Strategies (FLEX) with assessments of plant physical security effectiveness [1, 6]. This modeling and simulation (M&S) approach evaluates the excessive margin inherent in many security postures, providing a means of maintaining overall security effectiveness while increasing efficiencies and lowering costs. This paper presents the integration of human reliability analysis in dynamic modeling of plant mitigation strategies with physical security force-on-force (FOF) models. Plant mitigation strategies and procedures consist of multiple human actions that strongly impact the outcome of the overall strategy. Accurate, realistic modeling of these human actions is critical for achieving a reliable, robust M&S framework. This work leverages current research in human reliability analysis in order to model actions, timelines, and errors associated with human actions, integrating it with the current dynamic modeling framework in order to obtain accurate, realistic assessments of physical security effectiveness. The resulting dynamic modeling framework enhances the realism of physical security assessments and can potentially steer the industry away from its current prescriptive posture on risk-informed decision making.