Release Rate Estimation of Radioactive Noble Gases in the Criticality Accident at Tokai-Mura from Off-Site Monitoring Data
Release Rate Estimation of Radioactive Noble Gases in the Criticality Accident at Tokai-Mura from Off-Site Monitoring Data
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根据场外监测数据估算东海村临界事故中放射性惰性气体的释放率
DOI：
10.1080/18811248.2010.9711924
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发表时间：
2010
影响因子：
1.2
通讯作者：
H. Yamazawa
中科院分区：
文献类型：
--
作者：
S. Hirao;H. Yamazawa
提出了一种估算事故核设施放射性惰性气体释放速率的方法。该方法被应用于东海村的临界事故案例，以评估结果的不确定度。释放率是通过将场外监测站测得的伽马剂量率与使用大气扩散模型计算的伽马剂量率相结合来估算的。为了分析估计释放率的不确定性对风场的依赖性，使用了两个风场数据;一个来自气象模型MM 5，另一个来自实测风数据的分析。分析风场与实测风场的比较结果表明，分析风场与实测风场的一致性优于MM 5风场，从而导致分析风场的不确定性小于MM 5风场。在分析的风的情况下，释放率随时间的逐渐减少清楚地表明，而它是由一个大的分散在MM 5风的情况下掩盖。对于惰性气体保留时间（即惰性气体释放到大气中之前所经过的时间）为5和10 min的情况，用本方法估算的释放的放射性惰性气体的总活度分别为3：0 × 102和2：1 × 102 TBq。将10 min的保留时间与假设保留时间相同的裂变反应总数评价的保留时间进行了合理比较。
A method of release rate estimation of radioactive noble gases from an accidental nuclear facility was proposed. This method was applied to the criticality accident case at Tokai-mura to evaluate an uncertainty of results. The release rate is estimated by combining the gamma dose rates measured at off-site monitoring posts and those calculated using an atmospheric dispersion model. To analyze the dependence of uncertainty of estimated release rate on that of the wind field, two wind field data were used; one from the meteorological model MM5 and the other from the analysis of measured wind data. The results of comparison that the analyzed wind field was in better agreement with the measured wind data than the MM5 wind field led to the smaller uncertainty in the analyzed wind case than that in the MM5 wind case. A gradual decrease in release rate with time was clearly shown in the analyzed wind case, while it was obscured by a large scatter in the MM5 wind case. The total activities of the released radioactive noble gases evaluated by the present method were 3:0 × 102 and 2:1 × 102 TBq for the cases with the retention times of noble gases, that is, the time elapsed before the noble gases are released into the atmosphere, of 5 and 10 min, respectively. The retention time of 10 min was reasonably compared with that evaluated from the total number of the fission reactions with the assumption of the same retention time.