| The uranium mines produced a large amount of waste rocks and tailings in themining and smelting process, which was piled up in the tailings impoundment. A largenumber of radioactive materials were contained in uranium tailings impoundment,and30%of radioactive half-life is more than1000years, especially the radiumcontent accounted for98%of the uranium ore. Radon is decayed by the radium wouldcontinue to decay into radon daughter that can release into the atmosphere and moveseveral kilometers in the air, which may pose a long-term potential radiation hazard tothe environment and publics.Measurement results show that the radon exhalation rate of uranium tailingsimpoundment beach surface in China is between1.65-26.5Bq/m2s, and it is greaterthan the national standard limit value0.74Bq/m2s. In order to meet the standard,some soils are needed to cover the uranium tailings impoundment. The radonmigration, radon decay process and the method of controlling the radon in the coversoils must be studied in a variety of terrain uranium tailings impoundment. It isimpact on residents’ health and it is urgent to the surrounding ecological environment.Using CFD method, the model of optimization analysis technology of uraniumtailings impoundment radon migration of soil-atmospheric coupled model is needed todevelopment, the characteristics of different soils and the impact of environmentalparameters on radon migration process is needed to study. To inquire into the methodof control the radon exhalation rate of uranium tailings impoundment beach surfacediffusing into the surrounding environment, effective method and scientific basis fordesign and analysis is needed. In this paper, the main work is embodied in the following aspects:(1) The present research situation and the main research on treatment of uraniumtailings impoundment and the influence factors and migration regularity of radon inthe cover soils of uranium tailings impoundment beach surface is introduced; Andalso the porous media model and the research methods of heavy gas in the complexunderlying surface is analyzed in this paper.(2)Based on the porous medium model and CFD technology, the mathematicalmodel of radon migration in the cover soil of the uranium tailings impoundmentbeach surface is established, and the numerical method of the model were determined.The radon migration in the cover soils and the radon concentration distributioncharacteristics is studied.(3) The equation of radon migration in atmospheric in the valley type uraniumtailings impoundment and its physical model were determined. And it will be studiedabout the characteristics of the atmospheric wind field under complicated boundaryconditions and distribution characteristics of heavy gas radon.(4)To the ground type uranium tailings as the research object, the equation andphysical model of radon migration of the soil-atmosphere coupled mode weredetermined. The different wind speed, radon exhalation rate, radon diffusioncoefficient of cover soils were considered in these modes. |
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