地浸采铀钻孔场区氡致周边辐射环境影响研究

摘要/Abstract

摘要： 氡是铀矿采冶过程中释放的主要气载放射性流出物,地浸钻孔场区的氡释放主要来源于抽液孔,传统高斯模型对此类源项的适用性有限。用CFD方法建立大气扩散数学模型耦合求解,探究了实际地形、氡源项和2019年的气象数据下某典型地浸铀矿山钻孔场区及周边近地面核素氡的浓度分布特征,并由个人剂量年均分布数学模型计算得到其所致的公众年有效剂量。结果表明:地形和大气风速对钻孔场区氡的迁移扩散具有重要的影响,风速占主导作用,风速越大,氡浓度越小,低地势凹洼处易造成排放源附近氡的积聚,局部污染较重;近地面氡的分布范围主要受风速和风向频率的协同作用影响,且随风速和风频的增大而变大;氡浓度衰减速度与扩散距离呈正相关性,但钻孔场区各抽液孔排放氡浓度水平较低,对环境氡浓度贡献值较小,对周边环境和公众辐射影响较小,其所致的个人剂量均不大于0.001 1 mSv·a^-1。研究结果可为地浸铀矿山钻孔场区布置和辐射安全距离的确定提供理论支持。

关键词: 地浸采铀, 钻孔场区, 氡扩散, CFD, 辐射安全距离

Abstract: Radon is the main gaseous radioactive effluents released in the process of uranium mining and metallurgy, and radon release in in-situ leaching uranium mine borehole area mainly comes from the liquid extraction hole. The applicability of the traditional Gaussian model to such source terms is limited. Concentration distribution characteristics of radionuclide radon near ground surface in borehole area and its surroundings of a typical in-situ uranium leaching mine was studied by establishing CFD atmospheric diffusion mathematical model to couple solution under the actual terrain, radon source term and 2019 meteorological data, and the annual effective dose of the public was calculated by the annual average distribution mathematical model of individual dose. The results showed that terrain and wind speed had an important impact on radon diffusion in the drilling site, and wind speed played a dominant role. The higher the wind speed, the lower the radon concentration. Low and concave areas were easy to cause radon accumulation near emission sources, and local pollution was heavier. The distribution range of radon near the ground was mainly affected by the synergistic effect of wind speed and wind direction frequency, which grew as the latter increases. There was a positive correlation between radon concentration decay rate and diffusion distance. However, the radon emission concentration was at low level from liquid extraction hole, which had small contribution to the environmental radon concentration, impact on the surrounding environment and the public radiation, and the individual dose was not more than 0.001 1 mSv·a^-1. This study provides the theoretical supports for the layout of borehole area and the determination of the radiation safety distance.

Key words: in-situ uranium leaching, borehole area, radon diffusion, CFD, radiation safety distance

中图分类号:

TL75

武旭阳, 孙娟, 连国玺, 宋旺旺, 安毅夫, 高扬. 地浸采铀钻孔场区氡致周边辐射环境影响研究[J]. 辐射防护, 2023, 43(6): 611-619.

WU Xuyang, SUN Juan, LIAN Guoxi, SONG Wangwang, AN Yifu, GAO Yang. Study on the influence of radon on the surrounding radiation environment of in-situ leaching uranium mine borehole area[J]. RADIATION PROTECTION, 2023, 43(6): 611-619.

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