Maintaining robust physical protection at commercial nuclear power plants requires effective compensatory measures when security systems become degraded or inoperable. Current industry practices often rely on labor-intensive approaches that may not consistently account for the actual risk posed by system failures. Ongoing research and development efforts at INL are aimed at developing a risk-informed framework that enables utilities to implement proportionate, defensible responses aligned with the security posture while meeting regulatory requirements. The framework will leverage risk assessment methodologies to differentiate between low- and high-risk degradations, reducing unnecessary resource expenditures while maintaining regulatory compliance and safety.

This paper outlines the technical scope, modeling and simulation activities, and key findings from ongoing research, culminating in a risk-informed, cost-efficient framework designed to align compensatory actions with quantitative and qualitative risk metrics. It delivers a comprehensive evaluation of prevailing industry practices and protective strategies, identifies deficiencies in site-specific assessments, and examines the effectiveness of previously implemented compensatory measures. Additionally, technology-driven solutions, such as temporary sensor deployment and advanced surveillance capabilities, are analyzed to optimize resource utilization.