PNNL

Abstract

Operation of radiation portal monitors (RPMs) can be modeled as a two-person game, with the RPM operator attempting to detect any nuclear weapon passing through the portal, while the opponent tries to pass it through undetected. A key element in the defender’s decision strategy is the detection algorithm he employs, while a key element of the opponent’s strategy is the threat density he employs. This article constructs a game-theoretic formulation for RPM operation and calculates the “best” strategy for each player, called the Minimax strategy. This solution allows one to quantify the deterrent effect that the inspection system has on the opponent—that is, the reduction in threat density due to use of the system.