用于计算较大尺度面源气载放射性释放的环境辐射剂量的一种套网格模型

A NESTED GRID MODEL FOR CALCULATING ENVIRON MENTAL RADIATION DOSES FROM AIRBORNE RADIO ACTIVITY RELEASED FROM LARGER AREA SOURCE

本文介绍一种用于较大尺度面源气载放射性释放环境影响评价的套网格模型。该模型采用扇形网格和正方形网格相结合，以扇形网格为基本框架，而将面源区和近源区划分成正方形网格。在进行大气扩散估算时，为合理模拟空气浓度分布，在面源区和近源区，采用大气湍流扩散实验室（ＡＴＤＬ）模式；在其它区域，将面源视作若干个虚拟点源，采用高斯烟羽模式。在进行环境辐射剂量估算时，先将正方形网格点的空气浓度值内插到扇形网格，然后按扇形网格下的剂量估算模式进行计算。

A nested numeric grid model is presented in this paper. It can be used in environmental impact assessment of airborne radioactivity released from larger area source. In the model, the basic grids are sectorial ones, but the source area and near source area is regularly shaped to rectangular grids. To reasonably simulate air concentration distribution the ATDL model is used for source area and near source field, and Gaussian plume model with multiple virtual point sources replacing the area source is used for the far field. To estimate the dose distribution of environmental radiation, the air concentration at rectangular grids is interpolated to sectorial grids first, then the model of environmental radiation doses is used in the sectorial grids. The determination of the size of rectangular area depends on the size of the area source. (