Presentation on theme: "Modeling the Effects of a Radiological Dispersion Device Detonation"— Presentation transcript:
1 Modeling the Effects of a Radiological Dispersion Device Detonation Tragan Knight and Nathaniel TidwellDr. Melanie Sattler, P.E.Dr. Yvette Weatherton, P.E.Roja Haritha Gangupomu
2 Nathaniel Tidwell Completed first year at North Central Texas College Attending University of Texas Arlington as a sophomoreMajoring in Mechanical Engineering
3 Tragan Knight Eastfield College University of Texas at Arlington Major: Civil Engineering (Environmental Engineer)Goals: Master (Material in Science) Ph.D.: (Theology)Aspirations: Reevaluate and innovate the recycling process.
4 ObjectivesModel the effects of a dirty bomb detonation at Cotton Bowl Stadium in Dallas, TexasUse the HotSpot air dispersion model to run simulationsCompare different radionuclides, as well as various atmospheric conditions
5 Radiological Dispersion Devices Also known as RDDs, or “dirty bombs”Use conventional explosives to spread radioactive material over an areaAlthough there is concern that terrorist groups may use dirty bombs, so far none have actually been detonated.
6 Radionuclides Isotopes that undergo radioactive decay Several types of radionuclides are used in medicine and industryWe used three different radionuclides in our simulations: 241Am, 137Cs, and 60CoThis backscatter gauge, used in industry, contains 137Cs.11 Nitus Gamma Backscatter Gauge. Digital image. ThermoScientific.com. Thermo Fisher Scientific Inc., n.d. Web. 23 July 2012.
7 Radiation Three types of radioactive decay Alpha Beta Gamma Helium nucleus (alpha particle) is emitted from an atomMost harmful, but least penetratingBetaElectron or positron (beta particle) is emittedModerate harm, and moderate penetrationGammaGamma rays are emittedLeast harmful, but highly penetrating
8 Total Effective Dose Equivalent Sum of external and internal effective dose equivalentsUnit of measure is the Sievert (Sv) or roentgen equivalent in man (rem) for biological tissue1 Sv = 100 rems
9 Biological Effects of Radiation 1EffectDoseBlood count changes50 remVomiting (threshold)100 remMortality (threshold)150 remLD50/60* (with minimal supportive care)320 – 360 remLD50/60 (with supportive medical treatment)480 – 540 rem100% mortality (with best available treatment)800 rem * The LD50/60 is that dose at which 50%of the exposed population will die within 60 days.1"Biological Effects of Ionizing Radiation." Princeton.edu. Trustees of Princeton University, 30 Apr Web. 26 July 2012.
10 Air Dispersion Modeling Often used to predict downwind concentrations of pollutants, especially from smokestacksWe used HotSpot to model an RDD detonation, which uses the Gaussian Plume Model.𝐶= 𝑄 2𝜋𝑢 𝜎 𝑦 𝜎 𝑧 exp −𝑦 𝜎 𝑦 exp − 𝑧−𝐻 𝜎 𝑧 exp − 𝑧+𝐻 𝜎 𝑧 2
12 HotSpotCreated by National Atmospheric Release Advisory Center (NARAC)A computer program designed to calculate radiation dosesUses the Gaussian EquationProvides numerous amounts of potential radiological dispersal devices scenariosUsed for short-term, short-range (up to 10 km) simulations
13 HotSpot 2.07.2 Relatively simple surroundings data Built-in standard terrain informationOne meteorological condition per runLess sophisticated than other air dispersion models
19 ResultsComparing differences in stability classes with 241AmBDF
20 ResultsThe figures below compare rainout and dry conditions using 60Co and stability class B.No Rain Rain
21 ResultsComparing each isotope in dry conditions with stability class B(a) 241Am(b) 137Cs(c) 60Co(d) MixtureABCD
22 Conclusions 60 Co generally had the highest TEDE 137 Cs generally had the lowest TEDERadiation doses are higher in scenarios with rainStability Class F had the largest isopleth area of sickness in all scenariosWorst-case scenario is 60Co, stability class F, in rainy conditions