远东地区核风险厂址释放的气载放射性污染物长距离迁移的模拟

SIMULATIONS OF LONG-RANGE TRANSPORT OF AIRBORNE RADIOACTIVE POLLUTANTS RELEASED FROM NUCLEAR RISK SITES IN THE FAR EAST

气载放射性物质在大气中的长距离迁移问题逐渐受到关注。我们开发建立了轨迹模式TraModel和粒子扩散模式ParModel,用以模拟计算气载物质的迁移轨迹和扩散影响,并利用欧洲示踪实验(ETEX)数据对模式进行验证,同时也与国外同类模式进行了比对。结果表明,本研究所开发的模式具有较高的精度。利用美国国家环境预测中心(NCEP)的气象数据进行模拟计算,将其用于模拟我国田湾、秦山核电站以及俄罗斯远东Vladivostok(海参崴)核风险厂址释放的放射性物质的跨国界迁移。模拟结果表明,相对于等熵轨迹,三维轨迹能更真实地反映污染物的实际迁移,对于长距离迁移问题的概率分析,等熵轨迹和三维轨迹的模拟结果基本相同。释放高度对大气迁移途径有显著影响,故由一个释放高度得到的模拟结果用于其它释放高度时应当慎重。此外,由于在中国东部沿海地区气象场的复杂性,特别是受东亚季风的影响,释放点不同地理位置的影响结果也是很不相同的。这些模式、方法今后可用于开展远东核风险厂址大气迁移的概率风险分析以及事故后果评价。

The long-range transport of radioactive pollutants in the atmosphere has received considerable attention in recent years, corresponding with many models to address these issues. In this paper a trajectory model TraModel and a Lagrangian particle dispersion model ParModel were developed and verified using field data and intercomparison. The fitness between the calculated trajectories and concentrations from the models used in this study and those from the data of ETEX (European Tracer Experiment) and other models such as HYSPLIT and RDM-ADPIC was very good. The numerical simulations were performed using NCEP global tropospheric analysis dataset as input for models while these models were applied to simulate transboundary atmospheric transport of radioactive material released from the Tianwan Nuclear Power Plant (NPP) and Qinshan NPP in China and Russian Vladivostok nuclear risk site (NRS) in the Far East. The results indicate that isentropic and 3D trajectories resemble each other closely in probabilistic analysis of long-term transport but might be different for case studies. The results of simulations for different release heights show that there is significant impact of release altitude on atmospheric transport pathways. One should be careful in the application of the results from simulation for certain release altitude to other situations with different of release altitude. In addition, the impact of various geographical locations are very different, since the meteorological patterns are very complex in the eastern coast of China, especially the effect of the East Asia monsoon. These research tools will be applied to carry out analysis of the probabilistic patterns of atmospheric transport from the NRSs in the Far East and to evaluate accident consequences in the further studies.