A 2D map-based Vulnerability Assessment Code of a Physical Protection System

Nuclear facilities have a robust physical protection system (PPS) due to the potential threat of terrorism. A PPS includes such as detectors, door locks, fences, regular guard patrols, and a nearby military force. In order to properly design/operate a PPS, we should evaluate a PPS and figure out the vulnerability and the inefficiency. Force on force training is the most accurate way of evaluating the PPS of a nuclear facility. It is, however, costly and impossible to investigate all intrusion paths and adversary’s strategies. Thus, several computer codes (EASI and SAVI) have been developed to help assess a PPS. Existing codes, however, have limitations in representing the position of a facility because they use a simplified model of a PPS – called the adversary sequence diagram (ASD). We suggest an intuitive and accurate vulnerability assessment code using a two-dimensional map. Unlike an adversary sequence diagram, a 2D map provides a bird-eye view of a PPS, and thus an adversary’s path is easier to understand and also realistically represents relative positions between elements. For instance, it can reflect the decrease in detection probability of a passive infra-red sensor as the distance from the sensor is increased. We call this vulnerability assessment code, based on a 2D map, a systematic analysis of protection effectiveness (SAPE). The SAPE computer code finds the most vulnerable path of a 2D map as a measure of effectiveness. The SAPE code uses well known heuristic search algorithm to find the weakest path and calculates the probability of interruption. We also develop integrated code for a risk analysis called INCORIA (Integrated Code for Risk Assessment) which includes the SAPE as a part. The INCORIA evaluates the risk of a facility by several aspects; probability of interruption, probability of neutralization, material types, insider threat and consequence.