Year
2007
Abstract
Sandia National Laboratories and the Japan Atomic Energy Agency are cooperating to develop an advanced transparency framework capable of assessing diversion risk in support of overall plant transparency. The diversion risk quantifies the risk of a host nation diverting nuclear materials from a civilian fuel cycle facility. For demonstration purposes we are calculating the risk of diversion at a facility similar to the Monju Fast Breeder Reactor in Tsuruga, Fukui Prefecture in Japan. The diversion risk has two components under the transparency framework: the probability that nuclear materials have been diverted and the consequence of such a diversion. The diversion risk is defined as the product of the two. The Monju facility is a fully automated reactor, and all process steps are monitored with a set of sensors. A set of expected signals from the sensors for normal operations has been developed, and a fundamental component of the probability calculation is the comparison of these expected signals with the observed signals from actual operations. These comparisons, the probabilities that diversions will be attempted at individual process steps, and the probabilities that sensors will malfunction are the inputs that are used to evaluate that likelihood that a diversion has actually occurred. When the observed signals differ from the expected signals, the probability that radioactive materials have been diverted increases. This paper details the mathematical model that has been developed to quantify the probability component of diversion risk for the transparency framework.