A stochastic program for interdicting smuggled nuclear material

Abstract

This paper describes a stochastic network interdiction model for identifying locations for installing detectors sensitive to nuclear material. A nuclear material smuggler selects a path through a transportation network that maximizes the probability of avoiding detection. An interdictor installs sensors to minimize that maximum probability. This problem is formulated as a bi-level stochastic mixed-integer program. The program is stochastic because the evader's origin and destination are unknown at the time the detectors are installed. The model is reformulated as a two-stage stochastic mixed-integer program with recourse and is shown to be strongly NP-Hard. We describe an application of our model to help strengthen the overall capability of preventing the illicit trafficking of nuclear materials.