الفهرس | Only 14 pages are availabe for public view |
Abstract Review studies for all parameters affect on moving atomic cloud in atmosphere such as wind speed, temperature, stability conditions, mixing height, dispersion parameters, decay isotopes distance, deposition velocity, emission rate, eddy diffusivities, effective height and plume rise are discussed in the first chapter. Theoretical aspects of air pollution transport and theoretical discussion of planetary boundary layer near from the surface earth were shown with short notes about Gaussian distribution model and FLEXPART model are introduced in second chapter. Gaussian plume model is a common model to study advection diffusion equation which is solved in three dimensions by using Laplace transformation considering constant eddy diffusivity and wind speed power law. Different schemes such as Irwin, Power Law, Briggs and Standard methods are used to obtain crosswind integrated concentration. Statistical measures are used in to know which is the best scheme which agrees with the observed concentration data obtained from Copenhagen, Denmark. The results of model are compared with observed data after this the advection diffusion equation (ADE) is solved in two directions to obtain the crosswind integrated concentration. The solution is solved using Laplace transformation technique and separation of variables method and considering the wind speed depends on the vertical height and eddy diffusivity depends on downwind and vertical distances. We compared between the two predicted concentrations and observed concentration data are taken on the Copenhagen in Denmark The study of mixing height (MH) of the proposed region of reactor in Dabaa is very important for several reasons, including: i. It is the height of the layer adjacent to the ground over which pollutants become vertically dispersed by convection or mechanical turbulence, and atmospheric stability determines turbulence intensity. ii. Measuring mixing height experimentally is very expensive. iii. To manage and control air pollution dispersion. Theoretical equation was deduced. It relates mixing height with temperature, wind speed and relative humidity. It gives values of MH with average percentage error equals 3%. Mixing height has minimum value in the early morning while it reaches its maximum value at the afternoon. The minimum value of MH is 1243.8 m at January and maximum value is 2182.53 m at July. The ventilation index behaves as MH where it increases as MH increases in both spring and summer and it decreases in winter and autumn. According to (VTG) method, stability classes were studied in Dabaa in the period 1/9/2007 to 1/5/2008 all six hours beginning at 12 AM where the temperature by Kelvin scale at two altitudes 10 m and 100 m were taken in account. from the study it was deduced that: Total data of study subject is 972 distributed on four hours all day. Number of D class is 711 with percentage 73% distributed on all studied period. Number of E class is 249 with percentage 26% most values at early morning 12 AM and 6 AM and small number of values is at 6 PM. Number of F class is 12 with percentage 1% distributed as two values in November, one value in both December and January,5 values in March and remained three values in April and all values at 12 AM. It is important to study inversion layer using the comparison of temperature at different altitudes in Dabaa. from the study it was deduced that: There is remarkable inversion layer at 12 AM. There is not inversion layer at 12 PM. While at other time steps there are weak stable (inversion layer). The study of planetary boundary layer PBL of Dabaa in the period 1/9/2007 to 1/5/2008 leads to some important conclusions as following: a. The mixing height in Dabaa is higher than MH in Cairo. Then Dabaa will suffer less pollution problems. b. Dabaa has high ventilation index compared with Cairo. c. There is inversion layer at 12 AM and this has significant impact effect on environmental in the layer (10-100) m. The study of planetary boundary layer PBL of Dabaa in the period 1/9/2007 to 1/5/2008 leads to some important conclusions as following: a. The mixing height in Dabaa is higher than MH in Cairo. Then Dabaa will suffer less pollution problems. b. Dabaa has high ventilation index compared with Cairo. c. There is inversion layer at 12 AM and this has significant impact effect on environmental in the layer (10-100) m. In the end of the thesis a hypothetical nuclear accident in El Dabaa which is the proposed location for construction the new nuclear power plant was simulated. Although we have the simulated atmospheric parameters for the whole year of 2010 we choose only four months for hypothetical accident simulation. These four months are January, April, July, and October which gives a good seasonal representative for winter, spring, summer, and autumn respectively. The hypothetical accident has been simulated for three days started from 13th to 18th for each month. Distribution of surface air concentration of Cs137 (KBq/m3) calculated by FLEXPART model from 13th to 18th for each month 2010 00 UTC with increment 12- hours. Inhalation Pathway and external Exposure Pathway are calculated at different distances from Dabaa represent Alexandria, Cairo, Delta region and Upper Egypt. It was deduced that the dose acquired by inhalation and external Exposure Pathway are smaller than threshold limit of dose per day. |