Objective Hotspot Software Gaussian Dispersion Equation Meteorology Effects: Wind and Air...
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Transcript of Objective Hotspot Software Gaussian Dispersion Equation Meteorology Effects: Wind and Air...
Air Dispersion Modeling:Planning for Airborne Terrorism
Release
Tiffany LeBlanc Gerald GruberREU Program
University of Texas at Arlington
Outline
Objective Hotspot Software Gaussian Dispersion Equation Meteorology Effects: Wind and Air
Stability Scenarios Modeling Results Conclusion
REU Objective
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.
Hotspot
The HotSpot program provides approximation of the radiation effects associated with the atmospheric release of radioactive materials.
Short term accidents or releases
Gaussian Dispersion Equation
C = Downwind concentration, µg/m3
Q = Pollution source emission rate, µg/su = Average wind speed, m/sσy = y direction plume standard deviation, mσz = z direction plume standard deviation, m
x = Position in the x direction or downwind direction, m
y = Position in the y direction, mz = Position in the z direction, mH = Effective stack height, m
Gaussian Dispersion Equation
Air Stability
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
Air Stability How do you determine air stability?
Wind
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.
Scenario
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.)
http://www.stadiumsofprofootball.com/afc/LucasOilStadium.htm, 2006
Plutonium-238 Why Plutonium- 238? Health effects of Plutonium-238 What is MAR? (Materials at Risk)
http://www.clarku.edu/departments/marsh/projects/community/plutonium.pdf, 2002http://news.discovery.com/space/as-nasas-plutonium-supply-dwindles-esa-eyes-nuclear-energy-program.htm, 2010
Scenario
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
Methods using HotSpotStep 1: Models
Methods using HotSpotStep 2: Source Term
Methods using HotSpotStep 3: Meteorology
Methods using HotSpotStep 4: Output
Using Google Earth: Plotting our source
Modeling- Backpack Category F 2 m/s
Modeling- Backpack Category F 2 m/s
Table Output
Results
Modeling-Car Category F 12 m/s
Table 1: Total Results
Scenario Stabilit
y ClassWind Speed(m/s)
Lbs of explosive
MAR(Curies)
Area of 1000 rem isopleths(km2)
Backpack A 2 20 2,000 0.076
Backpack A 12 20 2,000 0.019
Backpack F 2 20 2,000 0.14
Backpack F 12 20 2,000 0.017
Car A 2 200 2,000 0.037
Car A 12 200 2,000 0.015
Car F 2 200 2,000 0.046
Car F 12 200 2,000 0.008
Conclusion
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.
Sources
Cooper, C. David., and F. C. Alley. "Chapter 20 Atmospheric Dispersion Modeling." Air Pollution Control: a Design Approach. Third ed. Prospect Heights, IL: Waveland, 2002. 607-48. Print.
Burns, Casey. Overview of Plutonium and Its Health Effects (2002): 6-9. Web. 07 July 2011. <http://www.clarku.edu/departments/marsh/projects/community/plutonium.pdf>.
Homann, Steven G. HotSpot. Computer software. National Atmospheric Release Advisory Center (NARAC). Vers. 2.07.1. 2 Mar. 2010. Web. <https://narac.llnl.gov/HotSpot/HotSpot.html>.
Lucas Oil Stadium. Photograph. Indianapolis. Stadiums of Pro Football. Web. 13 July 2011. <http://www.stadiumsofprofootball.com/afc/LucasOilStadium.htm>.
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 2010. Web. 07 July 2011. <http://news.discovery.com/space/as-nasas-plutonium-supply-dwindles-esa-eyes-nuclear-energy-program.html>.
"Radiation Risk and Realities." United States Environmental Protection Agency. May 2007. Web. 4 July 2011. <http://www.epa.gov/rpdweb00/docs/402-k-07-006.pdf>.