工作场所放射性气溶胶粒径分布研究

Study on Particle Size Distribution of Radioactive Aerosols in Workplace

为了更科学地评价不同粒径范围放射性气溶胶造成的内照射危害,首先选择某场所天然放射性气溶胶作为研究对象,利用计算流体力学(CFD)模拟技术开展流场分布研究,得到代表性采样点位。接着使用8级撞击式采样器捕集场所气溶胶并对各级滤膜中铀和210Po浓度进行分析。结果表明气溶胶中铀浓度没有明显的粒径分布规律;由于210Po更容易吸附在比表面积更大的小粒径颗粒物上,空气动力学直径为0.43μm的气溶胶中测得的210Po活度浓度最大,活度浓度范围为(90.3~105.7)μBq/m^(3),占比为(37.0~43.9)%。该工作将为下一步开展乏燃料后处理场所内照射剂量估算参数的修正奠定基础。

The natural radioactive aerosols in a certain workplace was selected and analyzed as the research object in order to evaluate the internal radiation hazards caused by radioactive aerosols with different particle sizes.The computational fluid dynamics(CFD)simulation technology was used to study the flow field distribution,obtaining representative sampling points.Subsequently,an eight-stage impact collector was used to capture the workplace aerosols and the concentrations of uranium and 210 Po in the filter membranes of all stages were analyzed.The results indicate that there were no obvious particle size distribution pattern of uranium concentration in aerosols.Due to the fact that 210 Po was more easily adsorbed on small size particles with larger specific surface area,the maximum activity concentration of 210 Po was found in the aerosols with an aerodynamic diameter of 0.43μm,and the activity concentration range of which was(90.3~105.7)μBq/m^(3),accounting for(37.0~43.9)%of total activity concentration.This work will contribute to the revision of internal irradiation dose estimation parameters in the spent fuel reprocessing workshop in the future.