ABSTRACT After direct discharges of highly contaminated water of the Fukushima Daiichi Nuclear Power Plant (1 F) from April to May 2011, Kanda suggested that relatively small amounts of run-off of radionuclides from the 1 F port into the Fukushima coastal region subsequently continued by his estimation method. However, the estimation period was limited to up to September 2012. Therefore, this paper estimatesthe discharge inventory up to June 2018. In the missing period, the Japanese government and Tokyo Electric Power Company Holdings have continued efforts to stop the discharge, and consequently, the radionuclide concentration in seawater inside the 1 F port has gradually diminished. We show the monthly discharge inventory of 137Cs up to June 2018 by two methods, i.e., Kanda method partially improved by the authors and a more sophisticated method using Voronoi tessellation reflecting the increase in the number of monitoring points inside the 1 F port. The results show that the former always yields overestimated results compared with the latter, but the ratio of the former to the latter is less than one order of magnitude. Using these results, we evaluate the impact of the discharge inventory from the 1 F port into the coastal area and radiation dose upon fish ingestion.

中文翻译：

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福岛第一核电站港口Caesium-137排放存量7年时间变化：2011年4月至2018年6月Caesium-137排放量连续月估算

摘要 2011 年 4 月至 5 月福岛第一核电站 (1 F) 高污染水直接排放后，神田提出，相对少量的放射性核素径流从 1 F 港口流入福岛沿海地区他的估计方法。然而，估算期仅限于 2012 年 9 月。因此，本文估算了截至 2018 年 6 月的排放存量。在缺失期，日本政府和东京电力公司控股公司继续努力停止排放，因此， 1F口内海水中放射性核素浓度逐渐降低。我们通过两种方法展示了截至 2018 年 6 月的 137Cs 的月排放量，即，作者部分改进了 Kanda 方法，以及使用 Voronoi 镶嵌的更复杂的方法，反映了 1 F 端口内监测点数量的增加。结果表明，与后者相比，前者总是产生高估的结果，但前者与后者的比值不到一个数量级。使用这些结果，我们评估了从 1 F 港口到沿海地区的排放量和辐射剂量对鱼类摄入的影响。