铀矿通风井尾气核素氡大气迁移数值模拟

发布时间：2018-02-24 05:51

本文关键词： 铀矿通风井核素氡迁移扩散数值模拟　出处：《南华大学》2015年硕士论文　论文类型：学位论文

【摘要】：铀矿通风向周边环境排放大量含有铀矿尘、氡气及其子体的尾气,排出来的放射性有害物随大气向下游区域迁移稀释,具有影响范围广、半衰期长、会产生累积效应等特点,对公众的集体剂量贡献大,危害周边生态环境和居民健康。核素氡随尾气在大气中迁移扩散主要受矿井位置、大气风场、污染源特性、矿山下垫面条件和季节气候等因素影响,对其输运机理和扩散规律的研究是合理预测与评价辐射安全防护距离的基础,也是防治大气污染与核辐射防护领域的重点课题。本文在国家自然科学资金项目(铀矿井通风尾气多组分放射性核素气固耦合大气扩散模拟,项目号:11105068)资助下,采用数值模拟方法研究了不同下垫面粗糙度、污染源排放高度和季节气候条件(大气稳定度、风向等)下核素氡迁移扩散规律,论文主要研究内容包括:(1)分析了目前国内外相关研究内容与方法,概述了影响铀矿井尾气放射性核素氡在大气中迁移的各种因素,确定以下垫面粗糙度、污染源排放高度和季节气候条件(大气稳定度、风向等)为主要研究因素。(2)以某实际铀矿地形为对象建立三维大气风场物理模型,应用数值模拟方法求解核素氡大气迁移扩散的数学模型,获得了铀矿山大气风场状况及核素氡迁移扩散规律,为评价铀矿区辐射安全距离提供有用数据以促进我国核工业可持续发展。(3)综合研究粗糙度、排放源高度和大气稳定度因素对铀矿井尾气核素氡迁移扩散影响,分析了各因素对核素氡迁移扩散影响的主导地位,并研究了排放源高度因素对距矿井不同距离处的控制效果,以指导铀矿井的优化设计及选址。(4)针对地表粗糙度与大气稳定度的季节性变化,分别对冬季、夏季和过渡季节的核素氡气扩散情况展开了研究,并对铀矿周边区域公众个人有效剂量进行了评价分析,揭示了铀矿区域氡气大气迁移的季节性特征。
[Abstract]:Uranium mine ventilation releases a large amount of uranium dust, radon gas and tail gas from its offspring to the surrounding environment. The radioactive harmful substances emitted from uranium mine migrate and dilute with the atmosphere to the downstream area, which has the characteristics of wide range of influence, long half-life and cumulative effect. The radionuclide radon migration and diffusion with tail gas in the atmosphere is mainly affected by mine location, atmospheric wind field, pollution source characteristics, mine underlying surface conditions and seasonal climate, etc. The study of its transport mechanism and diffusion law is the basis of reasonably predicting and evaluating the distance of radiation safety protection. It is also a key topic in the field of prevention and control of air pollution and nuclear radiation protection. This paper is supported by the National Natural Science Fund (project No.: 11105068), supported by the National Natural Science Fund Project (Multi-component radionuclide gas-solid coupling atmospheric diffusion simulation in uranium mine ventilation tail gas). The radionuclide radon transport and diffusion under different underlying surface roughness, emission height of pollution source and seasonal climatic conditions (atmospheric stability, wind direction, etc.) were studied by numerical simulation method. The main research contents in this paper include: (1) analyzing the relevant research contents and methods at home and abroad, summarizing the factors that affect the radionuclide radon migration in the atmosphere from the tail gas of uranium mines, and determining the roughness of the following surface. The emission height of pollution source and seasonal climatic conditions (atmospheric stability, wind direction, etc.) are the main research factors. Taking the actual uranium ore terrain as the object, a three-dimensional physical model of atmospheric wind field is established. The mathematical model of radionuclide radon migration and diffusion is solved by using numerical simulation method, and the atmospheric wind field and the radionuclide radon migration and diffusion law are obtained. In order to provide useful data to evaluate the radiation safety distance in uranium mine area in order to promote the sustainable development of nuclear industry in China, the effects of roughness, emission source height and atmospheric stability on radionuclide migration and diffusion in uranium mine tail gas are studied. The dominant position of various factors on the radionuclide radon migration and diffusion is analyzed, and the control effect of the emission source height factor on the different distance from the mine is studied. According to the seasonal variation of surface roughness and atmospheric stability, the radionuclide radon diffusion in winter, summer and transitional seasons are studied respectively. The evaluation and analysis of the effective dose to the public in the area around the uranium mine reveal the seasonal characteristics of radon atmospheric migration in the uranium mine area.
【学位授予单位】：南华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X753;X51

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