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The 42nd Annual Midyear Meeting
of the Health Physics Society |
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The 42nd Annual Midyear Meeting
of the Health Physics Society |
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MAM-A
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| Chair(s): Dan Strom, |
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MAM-A.1 8:30 Emergency Intakes of Fission Product Mixtures and Single Radionuclides for Triage. Brodsky A.*, Georgetown University; Reeves, M.D. G., Northrop Grumman IT ALBRODSKY@AOL.COM
Abstract: Members of the public will need to know quickly whether they have inhaled or ingested amounts of radioactive material that would be likely to harm them following a radiological or nuclear attack. Data on symptoms and effects of exposures to humans, as well as animals, to fission products in plumes from underground Soviet tests have been declassified by the Khazakhstan government and recently published. These human data tend to confirm the estimates of one of the authors that an inhalation of about 11 MBq (300 microcuries) of gross fission products decayed less than 30 days after a nuclear detonation could be chosen as an “acceptable” emergency intake, comparable in acute and chronic effects to the original standard of 25 R of external gamma irradiation. These observations indicate that, for fission product mixtures as well as most other nuclides potentially useful to terrorists for dispersion among the public, emergency intake quantities can be derived that would allow rapid detection of gamma emission outside the body for initial triage with simple portable instruments. |
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MAM-A.2 8:45 Assessing Internal Contamination Using the Canberra Inspector 1000 Following an RDD Event. Burgett E.*, Georgia Institute of Technology; Hertel N., Georgia Institute of Technology eric.burgett@nnrc.gatech.edu
Abstract: The Canberra Inspector 1000 has been investigated as a triage tool following a radiological dispersal device. This widely available handheld spectrometer offers an easy to use interface and allows for isotope identification. Dual settings allow the user to record a spectrum for analysis as well as read dose rates. The detector utilizes a gain stabilized 3 inch by 3 inch NaI(Tl) detector. The detector’s response has been measured using a slab phantom. These measurements were used to validate an MCNP model of the detector. The detector’s response to internal contamination after inhalation as a function of time after the RDD event has been investigated. Monte Carlo simulations using six phantoms based on the stylized Medical Internal Radiation Dose (MIRD) phantoms were used in the study to determine the count rates for the detectors placed on four different locations, the front and rear right lungs, left thigh, and neck (thyroid). Isotopes that were chosen for investigation were those most likely to be used in an RDD event. The time dependent distribution of the radioactive material in the body organs was calculated using DCAL. Results for both photopeak integration as well as dose rate response for the Canberra Inspector 1000 will be presented. This work was performed under funding provided by the Radiation Studies Branch of the Centers for Disease Control and Prevention |
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MAM-A.4 9:15 The Relative Importance of Internal Dose: An Analysis of the Detonation of a Low Yield Improvised Nuclear Device in an Urban Setting. Raine D*, Applied Research Associates, Inc.; McClellan G, Applied Research Associates, Inc.; Millage K, Applied Research Associates; Nelson E, Defense Threat Reduction Agency dudley.raine@ara.com
Abstract: One scenario envisioned by those concerned with a potential terrorist attack involves the detonation of a low yield (<10 kiloton (kT)) improvised nuclear device (IND) in an urban location in the United States. The fatalities and casualties from prompt weapon effects must obviously be considered in such a scenario, as should potential external radiation exposure due to fallout. The question of the relative importance of potential internal doses to the external dose in the fallout area is invariably raised; this consideration is of particular interest when evaluating evacuation vice shelter-in-place options. Calculations were performed using the Defense Threat Reduction Agency’s Hazard Prediction and Assessment Capability (HPAC) tool, the Fallout Inhalation and Ingestion Dose to Organs (FIIDOS) code, and other post-processing algorithms. The analysis provides estimates of the internal doses expected to be accrued during the aftermath of the detonation of an IND and compares them to the expected external doses. The internal dose pathways considered include inhalation and incidental ingestion of both descending and resuspended fallout. The relative impact of each exposure pathway for shelter and evacuation scenarios is assessed at various locations downwind from ground zero. The HPAC calculations of expected casualties from prompt effects (radiation, thermal pulse, and blast overpressure) and external exposure to fallout are also presented to provide an additional context for the analysis. |
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MAM-A.5 9:30 Update on Plans to Eliminate Cesium Choloride. Rushton R.*, Hopewell Designs, Inc. rorushton@hopewelldesigns.com
Abstract: The elimination of cesium choloride is under review by the Nuclear Regulatory Commission. Cesium-137 is used in hundreds of irradiators for instrument calibration, blood irradiators, research, and other uses. A report by the National Academy of Sciences in spring of 2008 recommended that cesium chloride be eliminated because of the potential risk and large impact that would result from a dirty bomb made of cesium chloride. This presentation will review the current status of rulings, hearings, and possible schedule for the elimination of cesium chloride. This program has the potential to cause major disruption to the nuclear and medical communities if it is implemented too quickly. The potential impact and costs will be reviewed. Alternative technologies to cesium chloride will be covered. |
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MAM-A.6 9:45 Radiological Dispersion Events: When There’s No Device and No Bomb. Strom DJ*, Pacific Northwest National Laboratory strom@pnl.gov
Abstract: This presentation is a plea to “think out of the box” in planning and preparation for radiological attack. Politicians and the popular press talk about “dirty bombs.” More technical people talk about “radiological dispersion (or dispersal) devices” or RDDs. The use of these terms excludes radiological dispersion events (RDEs) in which there is no bomb and no device. Historically, not all chemical and biological attacks have involved the use of a bomb or device, and such attacks may have relied on their victims being unaware of the attack until it was too late to invoke protective actions or countermeasures. It is evident that no announcement of an RDE, through an explosion or otherwise, is needed from the standpoint of producing dose. From the standpoint of producing terror or mass disruption, once the event is discovered, these will most likely occur with no help form those responsible for the RDE. As a basis for planning and preparedness, it may be prudent to assume that all radioactive sources are dispersible, regardless of their original form. Furthermore, consideration of means of dispersion other than emplacement or airborne release should be considered. Finally, large sources in IAEA Categories 1 and 2 are likely to become more dispersible over time due to the fact that they are above room temperature due to decay heat, they may have significant degradation of source form due to self-irradiation, and they may have significant transmutation of material. Considering transmutation, in the absence of oxygen, 137CsCl becomes BaCl2 and Ba metal over time, and 90SrTiO4 becomes Zr(TiO4)2 and Zr metal over time; these mixtures may be expected to have different chemical properties from the original compounds. Considering self-irradiation, large sources over a decade old may experience doses in excess of 10 billion grays, levels that may change their material properties. RDEs encompass RDD events and dirty bomb events, but may include other means of dispersion. |
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MAM-A.7 10:00 Lessons Learned from the First Nuclear Test at Trinity. Shonka J*; Widner T jjshonka@shonka.com
Abstract: Trinity was the first test of a nuclear weapon. It was conducted on July 16, 1945 near Alamogordo, New Mexico. Trinity was a test of an implosion-type plutonium bomb with a nominal yield of 20 kilotons. Aside from the external exposure rate, the impact on a downwind population with no protective actions taken has not previously been considered. Current day lessons can be gleaned for consideration of modern radiation emergencies, including considerations of capabilities in tools such as the HOTSPOT code. For the last decade, the authors have been part of a team conducting the Los Alamos Historical Document Retrieval and Assessment Project (LAHDRA) for the Centers for Disease Control and Prevention. As an element of our activity, we have retrieved all of the available information on the Trinity test, and have attempted to understand the significance of the radiological impact, including internal exposures, to off-site populations from Trinity. It was surprising to us that this study had not previously been performed. Trinity is unique among nuclear tests in that a population was present as close as 25 kilometers downwind from a low altitude (30 m) detonation, with no protective measures taken before or afterwards. Numerous pathways for exposure to man were available. Our studies to date will be summarized. As an example of the complexities that can be considered, exposure to radioactive iodine was possible through milk (both from grass consumption by the cows or goats as well as by ingestion of contaminated water from dammed impoundments (ponds) used for watering livestock that served as large-scale fallout collectors), consumption of cistern water derived from rooftop collectors, inhalation with significant fallout and resuspension reported by downwinders for days post-event. Any of these pathways can provide significant thyroid exposures when no protective action is taken. Other nuclides that have been considered include fission products, strontium and plutonium. |