Study On The Atmospheric Diffusion Characteristics And Diffusion Parameters Of BaiSha Nuclear Power Plant

The data of the SF6 tracer tests on the atmospheric diffusion of the BaiSha nuclear power plant located at north shore of the XunJiang River in GuangXi are studied and analyzed in this thesis. Ten experiments were carried out,of which 7 sets were carried out on the height of 70m by the Weather type: the class A has 5 times and the class B has 2 times;and 3 sets were carried out on the height of 30m,all the weather types of which are class A.Based on the analyses of the collected data about the diffusion characteristics of the site, the results show that the distribution of the diffusion factor under the class A of weather type is (1.67×10-9～4.16×10-4s?m-3),and that under no differentiating the Weather type is (1.67×10-9～4.16×10-4s?m-3) on the height of 70m in the experimental range.The diffusion parameters are calculated by the computer fitting using the least squares. The agreement degree of the predicted concentration by the agreement degree between the calculated results and the measured results is determined with the value of accordant factor (? =3.5). In all the 10 sets,the match ratio is 69.67% when the value of accordant factor ? is 3.5 with no differentiating the weather type on the height of 70m.In this thesis, the diffusion parameters between the calculate concentration and the actual concentration are compared. The results show that the fitting results are very different from the P-G curves. The spread curve have not enough representation under such limited conditions as the slower wind speed, the fewer weather types and the fewer SF6 tracer tests than the author expects. Therefore, other tests or research are needed for further analysis.In this thesis, the representative SF6 tracer tests with the different types of weather conditions were carried out, and the diffusion parameters were fitted by using the least squares,thus the puff models were achieved in research and application on the calculating of the average diffusion factor of the nuclear power plant. As a result, the influences of local terrains on the radioactive gas diffusion during the opening of the nuclear power plant can be further disclosed and the atmospheric environment assessment of the nuclear power plant site can provide the theory and data support for the built-up of the future nuclear power plant.