Research On Atmospheric Migration Of Tailing Sands And Pollution Control In Uranium Tailings Impoundment

Tailing sands had the double influence of small particles and radiation hazard as one of themain pollutants in uranium tailings impoundment, the migration process caused soil pollution,water pollution and surrounding environmental pollution and the pollution radii was fargreater than uranium tailings area. Residents’ health was closely related to urban areaatmospheric environment quality which the dust in industrial sites made an importantcontribution, therefore the serious dust pollution problem in such large bare industrial sites asuranium tailings impoundment urgently need to be solved. considering the difficulty of largescale space control experimental study at the same time, based on the numerical method,Thesis was supported by the national natural science fund project (11075072), which wasnamed “the study on uranium tailings soil-vegetation-coupled atmospheric diffusion modelof atmospheric nuclide and numerical simulation”, the content were as follow:(1) Establish a numerical prediction model of tailing sans atmospheric migration in auranium tailings impoundment. According to the typical geography environment andmeteorological characteristics of uranium tailings impoundment, the inlet boundaryconditions were set and the atmospheric boundary layer wind field mathematical model wasestablished. Then analysis dust source and the radioactive pollutants composition, determinedust causes and particle size distribution.(2) Based on the discrete stochastic tracking model, study the radioactive contaminantsatmospheric diffusion process in the condition of two phase flow. Numerical simulate theinfluence degree of the tailing sands atmospheric migration of different boundary conditionsand initial conditions. Simulate the migration regulation and settlement characteristics ofdifferent particle sizes of radioactive tailing sands under different wind speeds in two type’suranium tailings impoundment. (3) Numerical simulate and analysis the dust-controlling effect of beach surface coveredvegetations. Establish simplified porous medium model by vegetation types and coveragecondition of the typical uranium tailings area; simulate the migration and sedimentationcondition under different vegetation distributions based on the model to seek a optimalvegetation dust-controlling model.(4) Numerical simulation and analysis the dust-controlling effect of modification beachsurface structures. Theory analyzed the beach surface dusting mechanism and put forward themethod of beach face structure transformation, then assumed a variety of beach surfacestructure and established the corresponding numerical prediction models, analyze the flowfield and of tailing sands radioactive concentration distribution to guide the engineeringapplication.