- 著者
- Yukihiko Satou Keisuke Sueki Kimikazu Sasa Hideki Yoshikawa Shigeo Nakama Haruka Minowa Yoshinari Abe Izumi Nakai Takahiro Ono Kouji Adachi Yasuhito Igarashi
- 出版者
- GEOCHEMICAL SOCIETY OF JAPAN
- 雑誌
- GEOCHEMICAL JOURNAL (ISSN:00167002)
- 巻号頁・発行日
- vol.52, no.2, pp.137-143, 2018-03-30 (Released:2018-04-19)
- 参考文献数
- 14
- 被引用文献数
- 36 77
Two types of radioactive particles were isolated from environmental samples collected at various distances from the Fukushima Dai-ichi Nuclear Power Station. “Type A” particles are 2–10 μm in diameter and display characteristic Cs X-ray emissions when analyzed using energy-dispersive X-ray spectrometry (EDS). “Type B” particles are considerably larger, up to 400 μm in diameter, with Cs concentrations too low to be detectable with EDS. These larger particles were isolated from the region north of the nuclear reactor site, which was contaminated on March 12, 2011. The specific activity of Type B particles is much lower than Type A, and the mean 134Cs/137Cs ratios are ~0.93 and 1.04, respectively. The Type B ratio indicates that power station Unit 1 is the source, implying that these larger radioactive particles were discharged on March 12. This study found that different type of radioactive particles were released not only on March 15 but also on March 12.
- 著者
- Kosuke Morita Kouji Morimoto Daiya Kaji Takahiro Akiyama Sin-ichi Goto Hiromitsu Haba Eiji Ideguchi Rituparna Kanungo Kenji Katori Hiroyuki Koura Hisaaki Kudo Tetsuya Ohnishi Akira Ozawa Toshimi Suda Keisuke Sueki HuShan Xu Takayuki Yamaguchi Akira Yoneda Atsushi Yoshida YuLiang Zhao
- 出版者
- 一般社団法人 日本物理学会
- 雑誌
- Journal of the Physical Society of Japan (ISSN:00319015)
- 巻号頁・発行日
- vol.73, no.10, pp.2593-2596, 2004-10-15 (Released:2007-07-25)
- 参考文献数
- 16
- 被引用文献数
- 461
The convincing candidate event of the isotope of the 113th element, 278113, and its daughter nuclei, 274111 and 270Mt, were observed, for the first time, in the 209Bi+70Zn reaction at a beam energy of 349.0 MeV with a total dose of 1.7×1019. Alpha decay energies and decay times of the candidates, 278113, 274111, and 270Mt, were (11.68±0.04 MeV, 0.344 ms), (11.15±0.07 MeV, 9.26 ms), and (10.03±0.07 MeV, 7.16 ms), respectively. The production cross section of the isotope was deduced to be 55+150−45 fb (10−39 cm2).
- 著者
- Rei YAMASHITA Michio MURAKAMI Yuichi IWASAKI Nao SHIBAYAMA Keisuke SUEKI Mahua SAHA Goro MOURI Soulichan LAMXAY Haechong O Yukio KOIBUCHI Hideshige TAKADA
- 出版者
- 日本水環境学会
- 雑誌
- Journal of Water and Environment Technology (ISSN:13482165)
- 巻号頁・発行日
- vol.13, no.2, pp.179-194, 2015 (Released:2015-04-10)
- 参考文献数
- 49
- 被引用文献数
- 3 15
The release of radiocesium from the Fukushima Dai-ichi Nuclear Power Plant caused environmental contamination. We analyzed sources, behavior, and temporal trends of radiocesium by 1-year monitoring in an urban river, the Ohori River. The concentrations of 137Cs in both particulate and dissolved phases decreased to ~ 16% within 1 year. The partition coefficient in dry weather was estimated to be 3.2 × 104 L/kg. 137Cs concentrations in the particulate phase were higher during wet weather than during dry weather on the basis of both suspended solids (SS) weight and liquid volume. The ratios of 137Cs concentration to deposited 137Cs in the Ohori River (e.g., composite: 0.26 m2/kg-SS in June - July 2012) were higher than those in the Abukuma River, probably because of differences in land use. Source analysis by a chemical mass balance method showed that 22% of 137Cs came from river water in dry weather, 39% from river sediments, and 39% from road dust highlighting urban surface deposits such as road dust as major sources of 137Cs in the river water even 2 years after the accident, and that the wash-off of these deposits increased the 137Cs concentration in the river during wet weather.