Physical protection of nuclear facilities against unmanned aerial threats: Performance limits under identification timing constraints

Nuclear physical protection systems (PPS) have traditionally been designed against ground-based adversaries delayed by physical barriers. Unmanned aerial systems (UAS) bypass this design assumption through three-dimensional approach paths that no ground barrier can interrupt, compressing the defender response window to UAS flight time. Counter-UAS (C-UAS) response at nuclear sites is further constrained by site-specific conditions. Broadband RF jamming, widely deployed elsewhere, is disfavored due to electromagnetic compatibility requirements for instrumentation and control systems and the risk of uncontrolled UAS descent near radiological areas. Intelligent soft-kill neutralization (ISN), the preferred alternative, cannot be initiated until the UAS type is identified. This identification prerequisite introduces a timing constraint not yet quantitatively assessed in the nuclear physical …