Application Of Footprint Analysis Of Turbulent Diffusion On Environmental Impact Accessment Programs Of Nuclear Power Stations

Turbulent diffusion plays a great important role in the pollution, especially in people's life and environment. Atmospheric diffusion parameters are keys to know the character of turbulent diffusion. There are uncertainties about the atmospheric diffusion parameters in different atmospheric situations and under different underlying surfaces. Using recommended diffusion scales and times when calculating the atmospheric diffusion parameters in in environmental impact assessment programs. Although the recommended diffusion scales and times are based on many experiments, they can't describe the characters of diffusion on different places correctly. It is intended to improve the way of calculating the atmospheric diffusion parameters based on footprint analysis.It involves calculating turbulent flux and atmospheric diffusion parameters using wind data being measured by three-dimensional sonic anemometers in Guangxi where a nuclear power station will be located. Three different coordinate rotation methods including the double rotation, the triple rotation method and the planar fit method will be used to correct the eddy covariance and fluxes obtained from the flux profile method which will be compared to those derived from the eddy covariance method. Because of the uncertainty of diffusion parameters footprint analysis is applied to confirm the horizontal diffuse scale and time to calculate the horizontal diffusion parameters. The research also involves calculating the atmospheric diffusion parameters in different atmospheric situations including land and sea breezes.Results show that (1) diffuse scale and time have obvious influences on determine of diffusion parameters. (2)The diffusion parameters not based on footprint analysis underestimate the pollution concentration near the source and underestimate the diffusion at the area far from the source. (3)The diffusion parameters are very different in winter and summer, and are also different on different heights. (4) The diffusion parameters of land breeze are larger than sea breeze, which implies that land breeze is in favor of pollution diffuse. (5) The diffusion parameters are conservative and depend on local topography and regions. Footprint analysis may be helpful in obtaining diffusion parameters.