Yamada Masatoshi, Zheng Jian
Nakaminato Laboratory for Marine Radioecology, Environmental Radiation Effects Research Group, National Institute of Radiological Sciences, Isozaki 3609, Hitachinaka, Ibaraki 311-1202, Japan.
Appl Radiat Isot. 2008 Jan;66(1):103-7. doi: 10.1016/j.apradiso.2007.08.003. Epub 2007 Aug 15.
Surface seawater samples were collected from a site in the vicinity of the nuclear fuel reprocessing facility at Rokkasho, Japan and sites along the Japan Sea coast. (239+240)Pu activities and (240)Pu/(239)Pu atom ratios were determined by alpha-spectrometry and isotope-dilution sector-field ICP-MS. The (240)Pu/(239)Pu atom ratio with the mean value of 0.227 +/- 0.006 was significantly higher than the mean global fallout ratio of 0.18. The contribution of the Pacific Proving Grounds close-in fallout was estimated to be 33% of the (239+240)Pu.
从日本六所村核燃料后处理设施附近的一个地点以及日本海沿岸的一些地点采集了表层海水样本。通过α光谱法和同位素稀释扇形场电感耦合等离子体质谱法测定了（239 + 240）钚活度和（240）钚/（239）钚原子比。（240）钚/（239）钚原子比的平均值为0.227±0.006，显著高于全球沉降物的平均比值0.18。据估计，太平洋试验场近距离沉降物对（239 + 240）钚的贡献为33%。
