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Yonezawa, Chushiro*; Yamamoto, Yoichi
Bunseki, (440), p.451 - 458, 2011/08
A worldwide radionuclide monitoring network for nuclear tests has detected the anthropogenic radioactive materials released in the atmosphere due to the accident of the Fukushima Daiichi Nuclear Power Plant impacted by the Great East Japan Earthquake on March 11, 2011. After four months have passed since the accident occurred, most overseas stations do not detect the radionuclides of Fukushima origin any more. The Takasaki station in Japan, however, is still detecting them every day. This paper describes radionuclide monitoring stations and the network of them as part of the International Monitoring System (IMS) in the Comprehensive Nuclear Test Ban Treaty (CTBT), as well as the measurement results of radionuclide particulates and radioactive isotopes of xenon released from the Fukushima Daiichi Nuclear Power Plant with the monitoring network.
Usuda, Shigekazu; Shinohara, Nobuo; Sakurai, Satoshi; Magara, Masaaki; Miyamoto, Yutaka; Esaka, Fumitaka; Yasuda, Kenichiro; Kokubu, Yoko; Hirayama, Fumio; Lee, C. G.; et al.
KEK Proceedings 2007-16, p.13 - 22, 2008/02
For the purpose of controlling and monitoring radiations and radioactive materials emitted from nuclear facilities to the environment and also evaluating their effects, various R&D on environmental radioactivity has been carried out at Japan Atomic Energy Agency (JAEA). Especially, for the abolition of nuclear weapons and for peaceful uses nuclear energy, ultra-trace analysis of environmental samples for safeguards and ultra-high sensitive monitoring of radionuclides for the CTBT verification, which have been scheduled in the middle of 1990s, have been promotted under the auspices of the Japanese Government at JAERI, the former of JAEA. In this presentation, the outline of R&D on environmental radioactivity for nuclear non-proliferation is introduced. In addition, applications of the developed techniques and future perspectives will be discussed.
Yamamoto, Yoichi; Kijima, Yuichi; Oda, Tetsuzo
no journal, ,
The Japanese NDC-2 estimated the movement of virtual radioactive plume by the Atmospheric Transport Modelling (ATM) simulations with regard to the DPRK 2016 event. The simulations were done in two hypothetical cases of coincident and delayed emission of radionuclides. The NDC-2 decided which IMS radionuclide stations should be monitored based on the simulation results. As the result, no radionuclides generated from the nuclear explosion were found in any IMS data obtained from the selected radionuclide stations in January. However, xenon-133 with high activity concentration above the normal background levels was detected 5 times at the Takasaki station in the middle of February. The NDC-2 estimated the location of emission source of the Xe-133 by ATM backward tracking simulations. Some ATM simulations and the analysis results by the NDC-2 are shown in the presentation.
-ray emitters including 
Cs, 1; Collaborative experiment by the committee on preparation of reference materials for radioactivity analysis of JSACYonezawa, Chushiro*; Kakita, Kazutoshi*; Takahashi, Takanori*; Aono, Tatsuo*; Maeda, Satoshi; Abe, Takaaki*; Arakawa, Fumihiro*; Kiho, Nobuharu*; Akiyama, Masakazu*; Muramatsu, Isamu*; et al.
no journal, ,
no abstracts in English
Yamamoto, Yoichi; Kijima, Yuichi; Tomita, Yutaka
no journal, ,
As a member of the CTBT National Operation System of Japan (NOSJ), JAEA monitors and evaluates radionuclides derived from nuclear tests. For this purpose, Takasaki and Okinawa radionuclide stations, Tokai radionuclide laboratory, and a national data center already were put in place and have been operated. This presentation introduces outline of NOSJ and each facility, the response to a nuclear test event, JAEA's recent activities etc.
