 Objective  Hotspot Software  Gaussian Dispersion Equation  Meteorology Effects: Wind and Air Stability  Scenarios  Modeling  Results  Conclusion

 The objective of this project was to create a scenario portraying a nuclear terrorist attack using the software HotSpot. This software evaluates and models how a pollutant disperses into the atmosphere depending on certain variables.

 The HotSpot program provides approximation of the radiation effects associated with the atmospheric release of radioactive materials.  Short term accidents or releases

C = Downwind concentration, µg/m 3 Q = Pollution source emission rate, µg/s u = Average wind speed, m/s σyσy = y direction plume standard deviation, m σzσz = z direction plume standard deviation, m x = Position in the x direction or downwind direction, m y = Position in the y direction, m z = Position in the z direction, m H = Effective stack height, m

 Turbulent dispersion causes the pollutant concentrations to disperse away from the mean flow.  What are the categories of air stability? › A = Very Unstable › B = Moderately Unstable › C = Slightly Unstable › D = Neutral › E = Slightly Stable › F = Stable

 How do you determine air stability?

 What causes changes in wind flow?  Wind is summarized with direction and velocity.  Urban vs. Rural Environments › Urban environments produce more wind friction than rural environments. › Concentration is inversely proportional to wind speed.

 There is a terrorist attack outside the stadium of the 2012 Super Bowl releasing Plutonium-238.  Variables: › Wind speed (2 m/s, 12m/s) › Air Stability (Category A and F) › Amount of explosive (Backpack 20 lbs., Car 200 lbs.)

 Why Plutonium- 238?  Health effects of Plutonium-238  What is MAR? (Materials at Risk)

 Backpack Scenario › MAR 2,000 Ci of Plutonium-238 › Urban environment › 2 m/s and 12 m/s wind speed from the South › Air Stability Category A and F › 20 lbs. of explosive  Car Scenario › MAR 2,000 Ci of Plutonium-238 › Urban environment › 2 m/s and 12 m/s wind speed from the South › Air Stability Category A and F › 200 lbs. of explosive

ScenarioStability Class Wind Speed (m/s) Lbs of explosive MAR (Curies) Area of 1000 rem isopleths (km 2 ) BackpackA2202, BackpackA12202, BackpackF2202, BackpackF12202, CarA22002, CarA122002, CarF22002, CarF122002,

 By changing the variables, we were able to model the most devastating scenario. The variables that caused the most destruction were wind speed at 2 m/s in a stable environment and a lower amount of explosive. This evidence supports all of the background information we learned about Air Dispersion before we modeled our scenarios.

 Cooper, C. David., and F. C. Alley. "Chapter 20 Atmospheric Dispersion Modeling." Air Pollution Control: a Design Approach. Third ed. Prospect Heights, IL: Waveland, Print.  Burns, Casey. Overview of Plutonium and Its Health Effects (2002): 6-9. Web. 07 July  Homann, Steven G. HotSpot. Computer software. National Atmospheric Release Advisory Center (NARAC). Vers Mar Web..  Lucas Oil Stadium. Photograph. Indianapolis. Stadiums of Pro Football. Web. 13 July  O'Neil, Ian. "As NASA's Plutonium Supply Dwindles, ESA Eyes Nuclear Energy Program : Discovery News." Discovery News: Earth, Space, Tech, Animals, History, Adventure, Human, Autos. Spaceflight Now, 09 July Web. 07 July  "Radiation Risk and Realities." United States Environmental Protection Agency. May Web. 4 July