Proceedings of the Public Security S&T Summer Symposium 2009

CRTI 07-0103RD

Full-Scale Radiological Dispersal Devices Experiments and Models

Project Lead: Department of National Defence – Director General Nuclear Safety

Federal Partners: DRDC Valcartier, DRDC Suffield, Royal Military College of Canada, Natural Resources Canada, Health Canada, Environment Canada

Industry Partners: International Safety Research Inc., New England Complex Systems Institute

Other Partners: Acadia University, Sandia National Laboratories, Atomic Weapons Establishment

Objectives

The CRTI Consolidated Risk Assessment (CRA) identifies terrorist deployment of a radiological dispersion device (RDD) as a significant threat to Canadian security. RDD response planning is currently based on valuable but incomplete experimental evidence, models, and simulations. This project improves Canada’s threat intelligence and consequence management capability by developing models that more thoroughly characterize the distribution of radiological material from an RDD event.

In the experimental stream, project researchers are performing highly controlled indoor experiments with non-radioactive material, progressing to outdoor experiments using short half-life radioisotopes. These experiments will produce the most accurate simulation yet of an actual RDD detonation. In the modelling stream, the researchers are developing, refining, and verifying models of RDD detonations. They will refine and combine existing RDD algorithms or create new ones to produce the new model. The model will be verified and refined in an iterative manner using the results from the experimental stream.

Relevance

Strategies and decisions to protect responders, the public, and critical infrastructure against the effects of a detonated RDD must be made in the planning stage, not in the period after an attack. By the time it is known that an attack has occurred, there will likely have been casualties from the explosion, all the radioactive material will have been released, plume growth and particle deposition will be progressing, and there will be no time for evaluating possible countermeasures. The development of emergency response procedures and guidelines for first responders in dealing with radiological terrorism incidents requires experimentally verified data on the behaviour of RDDs, benchmarked with reliable, accurate modelling tools.

Recent Progress and Results

Following a meeting at Sandia National Laboratories with domestic and international partners, initial explosive design and composition as well as an appropriate short-lived isotope were chosen to replicate the project’s experimental “terrorist RDD.” With knowledge of the isotope to be used, the project researchers have identified several other key elements of the experimental stream. These include the isotopic activity, which, in turn, has allowed planning for isotope production, transport, and integration to begin. The researchers have written preliminary field-trial plans, an environmental assessment plan, safety plans, and a radiation management plan. An initial modelling attempt is needed to proceed with these plans.

Researchers have also been proceeding with the modelling stream according to the project schedule. DRDC Ottawa has retained a software engineer to assess the existing algorithms as they pertain to the disparate regimes subsumed within the RDD event framework (e.g., aerosolization, rise, transport, etc.). The researchers have decided to use the Autodyne Eulerian method, which may later be changed, and to create a bridge program to the United States (US) Defense Threat Reduction Agency’s Hazard Prediction and Assessment Capability program. The result of this work is a physics-based modelling toolkit capable of accurately modelling each distinct regime of the event individually and together as a whole. The primary application of this toolkit is in pre-event consequence assessment.

Acadia University has staffed a laboratory capable of performing the morphological analysis that will be required once the indoor experiments are running. The New England Complex Systems Institute is also ready to begin an agent-based modelling approach that will supplement the physics-based model described above. The agent-based modelling toolkit will be able to run in (near) real-time during an actual event. The benchmarking of the simulated RDD event will give confidence to the predictions of the consequences of employing different isotopes, chemical composition, device yield, location, and so on.

Impact

By identifying the scenarios of greatest concern, and experimentally verifying data on simulated RDD behaviour (i.e., explosion, isotope fragmentation, plume formation, isotope distribution, etc.), Canada’s emergency preparedness and response communities will be more able to properly prepare for such incidents. Using these data and models, first responders and decision makers will be better able to quantify the probability and impact for known and emerging RDD threats and update CRTI’s CRA. The involvement of United Kingdom and US partners brings significant additional knowledge to Canada from their complementary programs and promulgates to our allies the knowledge generated by this project.

Authors

Lorne Erhardt, DRDC Ottawa, lorne.erhardt@drdc-rddc.gc.ca

Scott Noel, International Safety Research Inc., scottnoel@i-s-r.ca

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