核放射性事故应急处置模拟软件

为了提高对核事故的处置能力,利用VC++可视化语言开发了一套模拟软件。软件实现了对放射性物质特性的管理,放射源探测过程的模拟、放射性元素的鉴别模拟、扩散性放射事故浓度分布的模拟,另外实现了核事故处置程序的展示功能以及核典型事故及相关的理论知识、法律法规的学习和查询功能。通过使用该软件,消防官兵对核放射性事故以及事故处置都将有更深入系统的了解。

Radioactive source terms for the Fukushima nuclear accident

A large amount of radioactivity was released into the environment after the Fukushima nuclear accident （FNA） in Japan in 2011. This radioactivity had a significant impact on the global environment, and there was much public concern about its effects. The subsequent assessment of the FNA and the environmental remediation required are proving to be long and complicated tasks. The assessments are based on the radioactive source terms for the FNA, which determine the level of damage caused by the nuclear accident. We investigated the radioactive source terms from three aspects： the amount and composition of the radionuclides; the activity and atomic ratio of the radionuclides; and comparison with other historical events. The total amount of radioactivity, excluding the radioactive noble gases （85Kr and 133Xe）, released by the FNA was about 10% of that released by the Chernobyl nuclear accident in 1986 and 〈1%o of the global fallout from the atmosphere nuclear explosion. However, the FNA was the most serious nuclear accident in terms of radioactive pollution of the marine environment. The recovery actions carried out after the FNA have been evaluated and the environmental impacts of the FNA are discussed.

基于Gauss烟团模型的大气扩散数据同化方法

发生核事故后，可以通过模型迅速预测泄漏的放射性物质的大气扩散情况，但释放源项、气象等参数的不确定性导致大气扩散模型计算的准确性受到影响。通常可以采用数据同化来改善模型预测结果。该文提出一种基于Gauss烟团模型的大气扩散数据同化方法，可以结合观测数据改善模型的预测结果。该方法在迭代搜索中对烟团参数进行线性变换以简化Gauss烟团模型，利用粒子群优化算法对泄漏速率、释放高度、风向、平均风速这4个模型参数进行校正。该方法适用于平坦地形和均匀稳定气象条件下的中尺度扩散。采用稳态条件下双生子实验进行验证，观测点位的模拟值与真实观测值的相关系数达到0．99。在非稳态条件下对源项估计结果进行了测试，结果略优于集合Kalman滤波方法，相关系数达到0．68。该同化方法计算速度快，能有效提升模型的预测，可用于大气扩散数据同化。