Diffusion Law Of Radon In Uranium Tailings Reservoir Based On CFD And Protection Measures

At present,it is necessary to unswervingly promote the development of nuclear power industry to ensure the energy security and promote the optimization and upgrading of energy layout.However,in the context of rapid economic growth to high-quality development,how to develop nuclear power more safely and efficiently has become an important issue.In order to keep up with the rapid development of nuclear power,China’s demand for uranium is increasing.At the same time,the price of uranium in the world continues to rise.The contradiction between domestic and foreign demand and price promotes the exploitation of uranium in China.In the process of uranium mining and smelting,tailing and crushed stone are usually covered and piled up on site by damming or enclosure,so as to form uranium tailing pond.A large number of radionuclides are usually produced in tailings pond,of which radon is the most harmful to the surrounding environment.As a long-lived nuclide,radon in uranium tailing pond precipitates from the covering soil of uranium tailing pond and enters the atmosphere.Under the action of horizontal wind speed,it diffuses to the area with lowconcentration through turbulence mechanism.During the diffusion process,nuclide particles are deposited on the ground and vegetation,and radiation harm is caused to residents and workers through inhalation,external irradiation and ingestion,which results in significant area of uranium tailing pond Potential safety problems.With the purpose of solving the potential safety hazard of uranium tailings pond to the surrounding environment and people in the nuclear industry system,studies the diffusion law of radionuclide radon in the soil and atmosphere,which is of great significance to the decommissioning treatment and environmental protection of uranium tailings pond.In view of this,The research results have been achieved as followed.(1)On the basis of systematically expounding the theoretical knowledge of radon exhalation,radon atmospheric diffusion and CFD related theoretical knowledge,combined with the technical characteristics of CFD method,the main influencing factors of radionuclide migration of uranium tailings in different media of soil and atmosphere are determined,which lays a theoretical foundation for numerical simulation.(2)Based on the CFD coupled DEM technology,the relatively accurate viscosity resistance coefficient and inertia resistance coefficient in the small-scale range are obtained,and the parameters are applied to the large-scale fluent porous media model.The basic control equation is modified according to the porous media model,the turbulence model andmulti-component transport model are established,and the radon transport rule in the overburden is explored by using the research method of multi-scale combined application Law.(3)A numerical simulation method based on CFD is proposed.Based on the steady-state flow field parameters obtained by wind field simulation,the turbulent diffusion model of radionuclide radon and the random orbit model of radionuclide particles are established.The numerical simulation method is used in this paper.The distribution of concentration field and track field of radionuclide radon and radionuclide particle diffusion is obtained by analyzing the comprehensive influencing factors such as wind speed level,roughness of underlying surface,radionuclide decay and gravity settlement and the law of radionuclide diffusion is explored.(4)Combined with the comprehensive factors of radioactive source intensity,meteorological conditions,population distribution,topography,decommissioning treatment methods,the environmental effect and protection distance of uranium tailings pond area are evaluated,and the safety protection and treatment measures of uranium tailings pond are put forward.The above research methods and work have far-reaching significance for determining pollution area and degree,getting correct evaluation,taking corresponding protective measures and reducing theadverse factors in the process of nuclear energy utilization,and provide systematic reference for the decommissioning treatment of uranium tailings pond in theory and engineering application.