Heuristic Vulnerability and Response Optimization Analysis of Physical Protection Systems in Nuclear Facilities

This paper analyzes the interaction among a facility's Physical Protection System (PPS), response forces, and a potential adversary using a performance-based perspective.The study introduces a heuristic method to identify the most vulnerable adversary path to a target and applies a related heuristic to estimate response force movement for both onsite and offsite teams.The onsite team is modeled primarily as the interruption element, while the offsite team is treated as reinforcement with a dominant neutralization role.The approach is anchored in the detection-delayresponse logic widely used in PPS evaluation and aligns with established single-path interruption models such as Estimate of Adversary Sequence Interruption (EASI).A simulation on a hypothetical facility layout demonstrates how detector placement, delay distribution, alarm assessment reliability, and response timing jointly influence interruption outcomes.Results show that heuristic path selection enables focused resource allocation to highest-risk corridors and that response time variability materially affects interruption probability.The study concludes that integrating pathbased vulnerability identification with response optimization improves the efficiency of PPS upgrades and supports risk-informed security design.