Radiocarbon Concentrations in Environmental Samples Collected Near the Spent Nuclear Fuel Reprocessing Plant at Rokkasho, Aomori, Japan, During Test Operation Using Spent Nuclear Fuel
Radiocarbon Concentrations in Environmental Samples Collected Near the Spent Nuclear Fuel Reprocessing Plant at Rokkasho, Aomori, Japan, During Test Operation Using Spent Nuclear Fuel
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DOI：
10.1097/hp.0b013e318292b9fc
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发表时间：
2013-09
期刊：
影响因子：
2.2
通讯作者：
N. Akata;K. Abe;H. Kakiuchi;T. Iyogi;Nagayoshi Shima;S. Hisamatsu
中科院分区：
文献类型：
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作者：
N. Akata;K. Abe;H. Kakiuchi;T. Iyogi;Nagayoshi Shima;S. Hisamatsu
摘要 通过对日本青森县六所村乏核燃料后处理厂周围采集的环境样本中的¹⁴C进行分析，研究了大气排放的¹⁴C对当地¹⁴C浓度的贡献。2006年6月至2011年10月，在距该厂2.6公里处采集的大气二氧化碳月平均比活度范围为0.226 - 0.279贝克勒尔每克碳；在若干采样时间，观测到的浓度高于本底值。利用大气扩散模型与中尺度天气模型耦合模拟的大气¹⁴C比活度较好地重现了测量值，支持了测量到的较高比活度是由于后处理厂排放的¹⁴C所致这一观点。为了研究该设施周围的¹⁴C分布情况，从9个地点采集了有芒碎米莎草（一种野生一年生莎草）样本。2008年在该设施东西两侧采集的植物样本比在其他地点采集的样本比活度略高，这反映了盛行风向。在该设施周围采集的蔬菜、精米、牧草和牛奶样本中测量到的¹⁴C比活度与本底值没有显著差异（除了一个精米样本，其值略高于本底值）。因食用精米而导致的人类年约定有效辐射剂量估计为3.6×10⁻⁴毫希沃特，与1毫希沃特（公众剂量限值的一个指标）相比，可忽略不计。
Abstract The contribution of atmospheric discharged 14C to local 14C concentrations was investigated by analysis of 14C in environmental samples collected around the spent nuclear fuel reprocessing plant in Rokkasho, Aomori, Japan. From June 2006 to October 2011, the range of monthly averaged specific activities in atmospheric CO2 collected 2.6 km from the plant was 0.226–0.279 Bq g C−1; at several sampling times, the observed concentrations were higher than the background value. Specific activities of atmospheric 14C simulated with an atmospheric dispersion model coupled with a mesoscale weather model reproduced the measured values fairly well, supporting the idea that the higher measured specific activities were due to 14C discharged from the reprocessing plant. For investigation of the 14C distribution around the facility, samples of Cyperus microiria, wild annual sedge, were collected from nine locations. Plant samples collected east and west of the facility in 2008 showed slightly higher specific activities than samples collected at the other locations, reflecting the prevailing wind direction. The measured 14C specific activities in vegetable, polished rice, pasture, and milk samples collected around the facility did not differ significantly from the background value (except for one polished rice sample, which had a value slightly higher than background). The annual committed effective radiation dose to humans resulting from consumption of the polished rice was estimated as 3.6 × 10−4 mSv, which is negligibly small compared with 1 mSv, an index of the dose limit for the general public.