Rethinking the encounter probability for direct-to-target nuclear attacks for aviation security

Abstract

The threat of nuclear terrorism has become an important issue for national security. A critical component in preventing a nuclear attack is to prevent nuclear material from being smuggled into the United States via any mode of transportation, including commercial air transportation. Screening baggage on incoming international commercial flights for nuclear material after the flights arrive in the United States makes the system vulnerable to a direct-to-target attack. A direct-to-target attack uses an aircraft to transport a nuclear bomb directly to a particular target prior to United States border screening. The encounter probability has been proposed for capturing the fraction of baggage that has been screened, which indirectly captures screening device utilization. This paper compares and analyzes potential performance measures for analyzing baggage screening systems given the impact of a direct-to-target attack. Seven discrete optimization models are formulated for determining how to screen checked baggage for nuclear material on incoming international flights given the performance measures, including four singleobjective models and four goal programming models that analyze the tradeoffs across two performance measures. The models are compared to analyze the tradeoffs across the various performance measures. The results suggest that the encounter probability can be improved by considering one of the proposed performance measures, particularly the performance measure that focuses on targets. The goal programming model results suggest that multiple performance measures can be optimized with minimal trade-offs.