核事故中放射性核素扩散浓度的理论预测

在高斯烟羽模型的基础上,对核事故中放射性云团在大气中的扩散规律进行了研究。利用倾斜烟团模式,考虑实际过程中核素粒子的重力沉降、雨洗作用以及放射性衰变等因素的影响,提出一种迅速估算放射性核素扩散浓度的方法。该方法可计算核事故中连续点源和瞬时点源在不同气象、地形条件下的浓度分布,并可获得地面的干沉积率和湿沉积率。放射性核素浓度的确定是放射性事故抢险救援和辐射防护等工作的基础和前提,是放射性事故应急救援的重要组成部分。该结果在核事故的应急救援过程中,对救援人员划定警戒区和确定周围居民的疏散范围具有重要意义,并可为制定救援方案和应急决策提供科学依据。

Prediction of Diffusion Concentration of Radioactive Nuclides during Nuclear Accident

The diffusion of radio-nuclides in atmosphere was studied on the basis of Gaussian Model. A new method~ of calculating the concentration distribution of radio-nuclides was proposed, in which the effect of gravity settlement, rain washing and the decay of the radioactive species were considered. By this method, the spatiotemporal distribution of radioactive nuclides in atmosphere in different terrain characteristics, different weather situations for instantaneous or continuous leaking source were obtained, and the dry or wet deposition quantifies on the ground were also acquired. The prediction of the concentration of radioactive nuclides is the basis and premise of emergency action and radioprotection. The results could guide to delimit the alerting region and evacuation region, and also could help to determine the emergency-rescue plan and tactics during nuclear accidents.