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Yamamoto, Keisuke; Nakagawa, Takuya; Shimojo, Hiroto; Kijima, Jun; Miura, Daiya; Onose, Yoshihiko*; Namba, Koji*; Uchida, Hiroaki*; Sakamoto, Kazuhiko*; Ono, Chika*; et al.
JAEA-Technology 2024-019, 211 Pages, 2025/02
JAEA-Technology-2024-019.pdf:35.35MB
The uranium enrichment facilities at the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency (JAEA) were constructed sequentially to develop uranium enrichment technology with centrifugal separation method. The developed technologies were transferred to Japan Nuclear Fuel Limited until 2001. And the original purpose has been achieved. Wastewater Treatment Facility, one of the uranium enrichment facilities, was constructed in 1976 to treat radioactive liquid waste generated at the facilities, and it finished the role in 2008. In accordance with the Medium/Long-Term Management Plan of JAEA Facilities, interior equipment installed in this facility had been dismantled and removed since November 2021 to August 2023. This report summarizes the findings obtained through the work related to the contamination inspection methods cancellation the controlled area of Wastewater Treatment Facility from September 2023 to March 2024.
Yoshitomi, Hiroshi; Futagawa, Kazuo
JAEA-Research 2024-016, 26 Pages, 2025/02
JAEA-Research-2024-016.pdf:2.0MB
In environmental radiation monitoring around nuclear facilities, dose measurements have been implemented by passive dosimetry systems using thermoluminescence dosimeters or radiophotoluminescence dosimeters. Optically stimulated luminescence (OSL) dosimeter, hereinafter called OSLD, is one of the commonly used passive dosimeter for personal dose monitoring and provides highly reliable measurements. However, it has not been utilized for environmental dose monitoring purposes. The OSLD will be a promising dosimeter, which make it possible to conduct cost-effective and reliable environmental dose measurements by utilizing existing resources, such as readers and dosimeters. When considering the application of the OSLD using aluminum oxide (
-Al
O
:C) for environmental dose monitoring, the following problems should be solved: (1) the lack of a dose calculation algorithm to evaluate air-absorbed dose from OSL signals, and (2) the conformity with JIS Z 4346:2017, which specifies the required performance of passive dosimeters for environmental monitoring, has not been evaluated. Therefore, in this study, a dose calculation algorithm was developed using Monte Carlo simulations, and tests based on JIS Z 4346:2017 were conducted. As a result, it was confirmed that the OSLD meets the performance criteria mentioned in JIS Z 4346:2017. The effective measurement range is from 0.1 mGy to 1 Gy, the range of energy and angle of incidence are from 30 keV to 1.25 MeV and from 0
to 
60, the temperature and humidity range are from -20C to 40C and from 10% to 90%, which are adequate for environmental dose monitoring.
Nakada, Akira; Kanai, Katsuta; Seya, Natsumi; Nishimura, Shusaku; Futagawa, Kazuo; Nemoto, Masashi; Tobita, Keiji; Yamada, Ryohei*; Uchiyama, Rei; Yamashita, Daichi; et al.
JAEA-Review 2022-078, 164 Pages, 2023/03
JAEA-Review-2022-078.pdf:2.64MB
Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2021 to March 2022. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Co., Inc. (the trade name was changed to Tokyo Electric Power Company Holdings, Inc. on April 1, 2016) in March 2011. Appendices present comprehensive information, such as monitoring programs, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data which were influenced by the accidental release and exceeded the normal range of fluctuation in the monitoring, were evaluated.
Futagawa, Kazuo; Kashimura, Keita; Sato, Daiki*; Kawasaki, Masatsugu
JAEA-Data/Code 2022-011, 75 Pages, 2023/03
JAEA-Data-Code-2022-011.pdf:1.49MB
These statistical results are based on the meteorological data observed at the Nuclear Science Research Institute in Japan Atomic Energy Agency and statistically processed according to "The guideline of meteorological statistics for the safety analysis of nuclear power reactor" (Nuclear Safety Commission on January 28, 1982; revised on March 29, 2001). The statistics are based on 5 years of meteorological data, from January 2017 to December 2021. These are statistical results of wind direction, wind speed, atmospheric stability, etc., which are used for dose assessment of the general public due to radioactive materials discharged into the atmosphere from nuclear reactor facilities.
Kashimura, Keita; Shoro, Takuya*; Futagawa, Kazuo; Kawasaki, Masatsugu
JAEA-Data/Code 2021-020, 218 Pages, 2022/03
JAEA-Data-Code-2021-020.pdf:2.51MB
These statistical results are based on the meteorological data observed at the Nuclear Science Research Institute in Japan Atomic Energy Agency and statistically processed according to "The guideline of meteorological statistics for the safety analysis of nuclear power reactor" (Nuclear Safety Commission on January 28, 1982; revised on March 29, 2001). The statistics are based on 15 years of meteorological data, from January 2006 to December 2020, processed into five-year periods. These are statistical results of wind direction, wind speed, atmospheric stability, etc., which are used for dose assessment of the general public due to radioactive materials discharged into the atmosphere from nuclear reactor facilities.
Nakada, Akira; Nakano, Masanao; Kanai, Katsuta; Seya, Natsumi; Nishimura, Shusaku; Nemoto, Masashi; Tobita, Keiji; Futagawa, Kazuo; Yamada, Ryohei; Uchiyama, Rei; et al.
JAEA-Review 2021-062, 163 Pages, 2022/02
JAEA-Review-2021-062.pdf:2.87MB
Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2020 to March 2021. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Co., Inc. (the trade name was changed to Tokyo Electric Power Company Holdings, Inc. on April 1, 2016) in March 2011. Appendices present comprehensive information, such as monitoring programs, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data which were influenced by the accidental release and exceeded the normal range of fluctuation in the monitoring, were evaluated.
Nidaira, Atsushi; Murayama, Takashi; Taguchi, Kazuaki; Futagawa, Kazuo; Suzuki, Takashi; Oi, Yoshihiro
no journal, ,
no abstracts in English
Kato, Takuya; Torii, Yosuke; Futagawa, Kazuo; Yamasoto, Kotaro
no journal, ,
no abstracts in English
Takahashi, Teruhiko; Niinuma, Shinichi; Futagawa, Kazuo; Otsuka, Yoshikazu; Muto, Yasushi; Sakai, Toshiya; Umehara, Takashi; Shimizu, Isamu; Umino, Takaaki; Yamada, Satoshi; et al.
no journal, ,
no abstracts in English