东部区域核事故核素大气扩散特征研究

Atmospheric Diffusion Characteristics of Radionuclide Released from Nuclear Accident in the Eastern Region

针对核事故核素大气环境影响,建立一种基于区域尺度天气预报模式WRF(weather research forecasting model)的核素不同尺度大气扩散特征分析方法。以东部多个核电厂为研究对象,基于再分析气象数据(final reanalysis data,FNL)驱动WRF,并结合高斯大气扩散模式研究了东部区域尺度以及核电厂周边尺度的核事故核素大气扩散分布特征。结果表明:区域尺度大气弥散因子最大值主要分布在计算区域的西部地区,并且其随距离增加呈现下降趋势,距离500 m和5000 m处二者相差约一个量级。核电厂周边尺度大气弥散因子最大值比区域尺度大气弥散因子最大值偏低一个量级;除秦山核电厂外,其他核电厂距离500 m和5000 m处的大气弥散因子最大值相差约一个量级。不同核电厂大气弥散因子最大值出现的方位受厂址气象条件影响存在显著差异;东部沿海地区比内陆大气扩散能力较强,有利于放射性核素的大气传输。

In order to address the impact of nuclear accident on the atmospheric environment,an analysis method for the atmospheric diffusion characteristics of radionuclides at different scales was established,which was based on the regional scale weather prediction model weather research forecasting model(WRF).Taking multiple nuclear power plants in the eastern region as the research object,the atmospheric diffusion distribution characteristics of radionuclides released from nuclear accident in the eastern region and in the nuclear power plant surrounding region were studied.The WRF model was used,which was driven by final reanalysis data(FNL)reanalysis meteorological data,combined with the Gaussian atmospheric diffusion model.The results show that the maximum atmospheric diffusion factor at the regional scale mainly distributes in the western region of the calculation area,and it shows a decreasing trend with increasing distance.The difference of the maximum atmospheric diffusion factor at distances of 500 m and 5000 m is about one order of magnitude.The maximum atmospheric diffusion factor of nuclear power plant surrounding region scale is one order of magnitude lower than that of the regional scale.The difference of the maximum atmospheric diffusion factor at distances of 500 m and 5000 m is about one order of magnitude for other nuclear power plants,except Qinshan Nuclear Power Plant.There are significant differences of the direction of the maximum atmospheric diffusion factor among different nuclear power plants due to the influence of meteorological conditions of the plant site.The atmospheric diffusion capacity in eastern coastal region is stronger than that in inland region,which is conducive to the atmospheric transport of radioactive radionuclides.