School of Energy Science and Engineering, Central South University, Changsha 410083, China; School of Urban Construction, University of South China, Hengyang 421001, China.
School of Civil Engineering, University of Hunan Technology, Zhuzhou 412007, China.
J Environ Radioact. 2014 Mar;129:57-62. doi: 10.1016/j.jenvrad.2013.12.003. Epub 2013 Dec 28.
In the present study, the roles of atmospheric wind profiles in the neutral atmosphere and surface roughness parameters in a complex terrain were examined to determine their impacts on radon ((222)Rn) dispersion from an actual uranium mine ventilation shaft. Simulations were completed on (222)Rn dispersion extending from the shaft to a vulnerable distance, near the location of an occupied farmhouse. The eight dispersion scenarios for the ventilation shaft source included four downwind velocities (0.5, 1.0, 2.0 and 4.0 m s(-1)) and two underlying surface roughness characteristics (0.1 m and 1.0 m). (222)Rn distributions and elevated pollution regions were identified. Effective dose estimation methods involving a historical weighting of wind speeds in the direction of interest coupled to the complex dispersion model were proposed. Using this approach, the radiation effects on the residents assumed to be outside at the location of the farm house 250 m downwind from the ventilation shaft outlet were computed. The maximum effective dose rate calculated for the residents at the outside of the farm house was 2.2 mSv y(-1), which is less than the low limit action level of 3-10 mSv y(-1) recommended by the International Commission on Radiological Protection (ICRP) occupational exposure action level for radon.
在本研究中，考察了中性大气中的大气风廓线和复杂地形下的地表粗糙度参数的作用，以确定它们对从实际铀矿通风井排放的氡（^(222)Rn）扩散的影响。完成了从井到易受影响的距离（位于有人居住的农舍附近）的^(222)Rn 扩散的模拟。通风井源的八个扩散情景包括四个下风速度（0.5、1.0、2.0 和 4.0 m s^(-1)) 和两个基础表面粗糙度特征（0.1 m 和 1.0 m）。确定了^(222)Rn 分布和升高的污染区域。提出了涉及感兴趣方向风速历史加权与复杂扩散模型相结合的有效剂量估算方法。使用这种方法，计算了假定在通风井出口下风 250 米处农舍位置外的居民的辐射影响。在农舍外，居民的最大有效剂量率计算值为 2.2 mSv y^(-1)，低于国际放射防护委员会 (ICRP) 推荐的氡职业暴露行动水平的 3-10 mSv y^(-1)的低限行动水平。
