Preliminary Dose Assessment for Emergency Response Exercise at Disaster City Using Unsealed Radioactive Contamination
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The Department of Nuclear Engineering at Texas A&M University currently supports emergency response exercises at Disaster City, a mock community used for emergency response training that features full-scale, collapsible structures designed to simulate various levels of disaster and wreckage. Several times a year, sealed radioactive sources are used at Disaster City to create radiation fields in which emergency responders can become more familiar with dose rates and how to use their radiation detection equipment. This research seeks to enhance emergency response exercises by using unsealed radioactive sources to simulate a more realistic response environment following an incident involving the dispersion of radioactive material. Limited exercises are performed worldwide using unsealed radioactive sources, and most of that information is not published. This research compiles that information and presents the process for selection of a short-lived radionuclide for use at Disaster City. Historically-used radionuclides were considered, as well as other short-lived radionuclides commonly utilized or capable of being produced at Texas A&M. A preliminary dose assessment for the exercise was performed based on conservative calculation methods used in assessments for unsealed contamination exercises performed at other sites. The assessment was broken into four parts: activation, distribution, exercise participation, and post-exercise monitoring. The computer code, MicroShield, was used to determine external exposure from the source during and after distribution. Internal exposure via inhalation and ingestion was estimated by assuming fractional intakes of activity and converting to dose using allowable limits on intake and dose conversion factors. The selection process identified seven radionuclides that could be used in an unsealed contamination exercise at Disaster City. Pharmaceuticals ^99mTc and ^18F are suitable and available for purchase from nearby vendors. In addition, the Texas A&M Nuclear Science Center TRIGA reactor could be used to produce ^24Na, ^56Mn, ^64Cu, ^82Br, and ^140La via thermal neutron activation. It was determined from the dose assessment that a radionuclide-dependent range of 1-40 mCi can be used to achieve detectable dose rates during the exercise without exceeding assumed administrative dose limits. Tc-99m results in the lowest dose and is recommended from a radiological safety standpoint. However, the choice of which radionuclide and what activity to use for an exercise should be made based on budget and the logistics of the actual exercise.
Cochran, Lainy Dromgoole (2016). Preliminary Dose Assessment for Emergency Response Exercise at Disaster City Using Unsealed Radioactive Contamination. Master's thesis, Texas A & M University. Available electronically from