• Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads

Views

Total Views
583
On Slideshare
0
From Embeds
0
Number of Embeds
0

Actions

Shares
Downloads
18
Comments
0
Likes
0

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Mathematical modeling for atmospheric dispersion of radioactive cloud passing over Jeddah Presented By Dr. Najlaa D. Alharbi Physics department - Sciences Faculty for Girls King Abdulaziz University December 2011
  • 2. On March 11, 2011, at around 08:15 CET an earthquake of magnitude 8.9 near the east coast of Honsu, Japan occurred, followed by a tsunami. After that the nuclear power plants at Onagawa with three BWR reactors, at Fukushima Daichi with six BWR reactors, at Fukushima Daini with four BWR reactors, and at Tokai With two BWR reactors were shut down automatically and no radiation release had been detected there. *According to the IAEA Report on Japan Earthquake(IAEA, 2011).
  • 3. On March 26, 2011, the highest values of fission product radionuclides were observed in the prefecture of Yamagata, Japan as high as 7500 Bq.m-2 for 131I & 1200 Bq.m-2 for 137Cs *(IAEA, 2011).
  • 4. On March 28, 2011, the highest values of the above radionuclides were observed in the prefecture of Fukushima with 23000 Bq.m-2 for 131I & 790 Bq.m-2 for 137Cs *(IAEA, 2011).
  • 5. According to the Reinish Institute for Environmental Research at the University of Cologne, Germany. Acloud containing radioactivity formed in air over the Fukushima nuclear power plant and moved over the Pacific Ocean, north from Japan in the direction to the Arctic Ocean and entered to the Atlantic Ocean over Iceland and then diffused over the European continent. *(Jakobs, 2011).
  • 6. The prediction of dispersion of radionuclides to the atmosphere is a important element of the emergency response procedures.  Numerical models are used in several countries around the world .  The dispersion models are used to estimate or to predict the downwind concentration of air pollutants emitted from sources such as industrial plants.
  • 7. Atmospheric Dispersion Modeling  A dispersion model is the mathematical simulation of how air pollutants disperse in the ambient atmosphere. Routinely used in:  Environmental impact assessments  Risk analysis  Emergency planning It’s parallel terms with  Air pollution dispersion models  Air quality models
  • 8. Classes of Air Quality Models  The air quality modeling procedures can be categorized into four generic classes: Gaussian, numerical, statistical or empirical and physical  The emphasis is on Gaussian-plume type models for continuous releases, which are at the core of most U.S. Environmental Protection Agency (EPA) regulatory models  Gaussian models are the most widely used techniques for estimating the impact of nonreactive pollutants
  • 9. Model Parameters The model is based on our knowledge of the following parameters:  Meteorological conditions (wind speed & direction, stability class, the ambient air temperature)  Emissions parameters (source location &height, stack diameter, pollutants exit velocity, exit temperature, plume rise )  Terrain (surface roughness, local topography, nearby buildings)
  • 10. CASE STUDY Mathematical modeling for atmospheric dispersion of radioactive cloud passing over Jeddah
  • 11. Meteorological Data The study area chosen is Jeddah city which is located on the east coast of Kingdom of Saudi Arabia at 21.7 N and 39.2 E. Month Temperature Mean wind speed (deg.c) at elevation: 10 m Pre. Direction. Sky cover oktes mean January 23 2.8 NNE 3.3 February 24.4 3.2 N 1.1 March 26.8 2.4 SW 0.95 April 29.2 2.8 N 2.4 May 30 2.8 N 2.45 June 31.7 2.4 W 1.15 July 33.4 2.4 N 1.25 August 32.9 2.8 NNW 1.25 September 32.3 2.4 NNW 2.35 October 29.9 2.4 N 0.65 November 27.6 2.4 N 1.7 December 25.8 2.8 ENE 1.2 The average meteorological and climatological data for Jeddah city per month
  • 12. Atmospheric stability Pasquill's stability classification method is used to determine atmospheric stability classes. This method defines six stability classes ranging from A (extremely unstable) to F(moderately stable) on the basis of wind speed at 10 m level, Stability class A B C D E F sum Repetition Percentage 29 67 38 15 15 12 176 16.47 38.07 21.6 8.52 8.52 6.82 100
  • 13. Wind Speed  The predominant wind direction is North (N)  The mean wind speed at 10m is 2.4 m/s.
  • 14. Dispersion Model GAUSSIAN PLUME MODEL (GPM)
  • 15. The concentration distribution of a pollutant released from a continuous single point source having emission rates Q, is expressed in the following formula :   y2 Q exp −  χ ( x, y , z ) =  2σ 2 2πU σ y σ z  y     − ( z − H ) 2   − ( z + H ) 2     exp   + exp   2 2    2σ z   2σ z     Effective Stack Height H =hs +∆ h
  • 16. Plume Dispersion by Gaussian Distribution and Coordinate System
  • 17. The ground level concentration (glc) below the centerline of the plume is obtained by setting y=z=0 then we have: − H 2  Q χ ( x, 0, 0) = exp  2  π uσ y σ z  2σ z 
  • 18. Radioactive decay factor  −H  Q −λ x χ ( x, 0, 0) = exp  2 2 d  exp   b+d π uac x  u   2c x  2
  • 19. ACCIDENT SCENARIO
  • 20. It was assumed that:  The radioactive plume passing over Jeddah city has been emitted in an accidental conditions from a nuclear power plant.  The reactor was assumed to operate full with its power of 10 MW. The release scenario was assumed to occur at a stack height of 61m.  The radionuclide activity released to the atmosphere is picked up by the wind and transported to the receptor site (Jeddah city).  The wind was blowing with a mean speed of 4.95 m/s at 61m height and corrected to 2.4m/s at 10m height. The wind direction was(N) dir.  The dominant stability class was the class B (moderately unstable).
  • 21. Half - life for different radionuclides released to the environment. Radionuclide Half-life Rb-88 I-134 Kr-85m Xe-135 Te-131 Xe-133 Ba-140 Sr-89 Ce-144 Cs-134 Kr-85 Sr- 90 18 min 52.5 min 4.5 h 9.1 h 30 h 5.2 d 12.8 d 50 d 285 d 754 d 10.7 yr 29 yr
  • 22. NCD NCD (Rb-88) Distance (18 min) (km) (before decay) NCD (I -134) (52.5 min) NCD (Kr-85m) (4.5h) NCD (Sr-89) (50 d) NCD (Kr-85) (10.7y) 1 3.41145 ×10-6 2.99594 ×10-6 3.2622 ×10-6 3.38204 ×10-6 3.41134 ×10-6 3.41145 ×10-6 2 9.27778 ×10-7 7.15538 ×10-7 8.48371 ×10-7 9.11851 ×10-7 9.27717 ×10-7 9.27777 ×10-7 3 4.24299 ×10-7 2.87379 ×10-7 3.7101 ×10-7 4.1342 ×10-7 4.24258 ×10-7 4.24298 ×10-7 4 2.42588 ×10-7 1.44294 ×10-7 2.0284 ×10-7 2.34331 ×10-7 2.42556 ×10-7 2.42588 ×10-7 5 1.57022 ×10-7 8.20223 ×10-8 1.25549 ×10-7 1.50369 ×10-7 1.56996 ×10-7 1.57021 ×10-7 6 1.09992 ×10-7 5.04576 ×10-8 8.4098 ×10-8 1.04424 ×10-7 1.0997 ×10-7 1.09991 ×10-7 7 8.13804 ×10-8 3.27855 ×10-8 5.95 ×10-8 7.65948 ×10-8 8.13619 ×10-8 8.13802 ×10-8 8 6.26773 ×10-8 2.21751 ×10-8 4.38206 ×10-8 5.8483 ×10-8 6.2661 ×10-8 6.26771 ×10-8 9 4.97773 ×10-8 1.54661 ×10-8 3.32791 ×10-8 4.60459 ×10-8 4.97628 ×10-8 4.97772 ×10-8 10 4.05024 ×10-8 1.10516 ×10-8 2.58935 ×10-8 3.71432 ×10-8 4.04892 ×10-8 4.05022 ×10-8 Concentration Calculations before and after inserting Decay Factor for different Radionuclides.
  • 23. Conclusion  we conclude that: radioactive decay effect is clear in cases of short lived isotopes.  The concentration was reduce by 75% in Rb-88 radionuclide, 50% in I-134 and by 25% in Kr-85m.  while it was reduce by 0.01% in Sr-89 and 0.00001 in Kr-85.
  • 24. Future Vision & Considerations
  • 25. Acknowledgements The author sincerely thanks King Abdul-Aziz University Deanship of scientific research - for its support this research of project no.(21- 007/429‫.)ح‬ Also thanks Dr. Sadah Alkhateeb for help in designing Mathematica program. I am grateful for Vice President for Development- Center for teaching & learning development for give me this chance.
  • 26. References • • • • • • • • • • • IAEA, Information to be submitted in support of licensing application for nuclear power plants, A safety guide, technical report series No. 50-SG-G2, Vienna, (1979). Nuclear Regulatory Commission (NRC), Reactor safety study: An assessment of accident risk in US commercial nuclear power plants, WASH-1400, NUREG-75/014, (1975). IAEA, Research reactor core conversion guide book, IAEA-TECDOC-643,Vienna, (1992). Davidson M. Moreira, Tiziano Tirabassi, Marco T.Vilhena, Jonas C.Carvalho. A semi- analytical model for the tritium dispersion simulation in the PBL from the Angra I nuclear power plant, Ecological Modeling 189(2005). Denis Quelo, Bruno Sportisse, Olivier Isnard. Data assimilation for short range atmospheric dispersion: a case study of second-order sensitivity. Journal of Environmental Radioactivity 84(2005). D.Q.Zheng, J.K.C.leung, B.Y.Lee and .H.Y.Lam, Data assimilation in the atmospheric dispersion model for nuclear accident assessment, Atmospheric Environment, 41(2007) 2438. Surface monthly climatological report, National Meteorology and Environment Center, Presidency of meteorology and environment protection, (2008). Pasquill, F., Atmospheric Diffusion, Van Nostrand, New York, London (1962). Apismon, H.M, and Goddard, A.J.H., Atmospheric transport of radioisotopes and the assessment of population doses on European scale, CEC Luxembourg EUR-9128 (1984). C.V.Srinivas, R.Venkatesan, A simulation study of dispersion of air borne radionuclides from a nuclear power plant under a hypothetical accidental scenario at a tropical coastal site, Atmospheric Environment, 39 (2005) 1497. S.Shoaib Raza, M.Iqbal, Atmospheric dispersion modeling for an accidental release from the Pakistan research reactor-1(PARR-1), Annals of nuclear energy, 32 (2005)1157.
  • 27. THANK YOU THANK YOU