CHALLENGES FOR PHYSICS-BASED MODELS OF A RADIONUCLIDE DISPERSAL DEVICE

A “dirty bomb” is a type of hypothetical radiological dispersal device (RDD) that has been the subject of significant safety and security concerns given the disruption that would result in a postulated terrorist attack. Reliable and accurate predictions of dispersion of radiological material from an RDD are absolutely necessary for first responders and emergency decision makers to plan effective response strategies. Development of high-fidelity, mechanistic models of a dirty bomb are complicated because dispersion over areas with the greatest risk of contamination is highly sensitive to the source of contaminant particles, and this source term is governed by processes over much smaller temporal and spatial length scales than the dispersion. New work on accelerating high-fidelity models of RDDs has been initiated that looks to incorporate the multiscale aspects of the problem and enhance predictive capabilities that may assist in anti-terrorism activities.