Numerical reconstruction of high dose rate zones due to the Fukushima Dai-ichi Nuclear Power Plant accident
Numerical reconstruction of high dose rate zones due to the Fukushima Dai-ichi Nuclear Power Plant accident
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DOI：
10.1016/j.jenvrad.2011.09.011
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发表时间：
2012-09-01
影响因子：
2.3
通讯作者：
Chino, Masamichi
中科院分区：
文献类型：
--
作者：
Katata, Genki;Terada, Hiroaki;Chino, Masamichi
为了解2011年3月福岛第一核电站事故期间高剂量率区的形成过程，利用基于计算机的核应急响应系统WSPEEDI-II再现了3月15日至17日期间放射性核素的大气弥散。利用有限的环境监测数据，提高了该系统对气象和辐射场的预测精度，以获得对释放率、辐射剂量图和烟羽运动的最佳估计。福岛目前高剂量率区的很大一部分是由于3月15日大量释放放射性核素而模拟的放射性核素表面沉积造成的。在模拟中，FNPP 1西北部的最高剂量率区是由FNPP 1在下午排放的放射性核素的大量沉积造成的。结果表明，两个环境因素，即，降雨量和地形对放射性核素表面沉积的空间格局有很大影响。降雨引起的湿沉降在形成宽而不均匀分布的高剂量率区中起着重要作用。模拟结果还表明，放射性羽流沿着山谷流向背风面，在复杂地形条件下，会扩大大量地表沉积的区域。(C)2011爱思唯尔有限公司版权所有。
To understand how the high dose rate zones were created during the Fukushima Dai-ichi Nuclear Power Plant (FNPP1) accident on March 2011, the atmospheric dispersion of radionuclides during the period from 15 to 17 March was reproduced by using a computer-based nuclear emergency response system, WSPEEDI-II. With use of limited environmental monitoring data, prediction accuracy of meteorological and radiological fields by the system was improved to obtain best estimates of release rates, radiation dose maps, and plume movements. A large part of current high dose rate zones in Fukushima was explained by simulated surface deposition of radionuclides due to major releases of radionuclides on 15 March. In the simulation, the highest dose rate zones to the northwest of FNPP1 were created by a significant deposition of radionuclides discharged from FNPP1 during the afternoon. The results indicate that two environmental factors, i.e., rainfall and topography, strongly affected the spatial patterns of surface deposition of radionuclides. The wet deposition due to rainfall particularly played an important role in the formation of wide and heterogeneous distributions of high dose rate zones. The simulation also demonstrated that the radioactive plume flowed along the valleys to its leeward, which can expand the areas of a large amount of surface deposition in complex topography. (C) 2011 Elsevier Ltd. All rights reserved.