Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2019

Nakano, Masanao; Fujii, Tomoko; Nemoto, Masashi; Tobita, Keiji; Seya, Natsumi; Nishimura, Shusaku; Hosomi, Kenji; Nagaoka, Mika; Yokoyama, Hiroya; Matsubara, Natsumi; et al.

JAEA-Review 2020-069, 163 Pages, 2021/02

JAEA-Review-2020-069.pdf:4.78MB

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 2019 to March 2020. 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.

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2017

Nakano, Masanao; Fujita, Hiroki; Mizutani, Tomoko; Nemoto, Masashi; Tobita, Keiji; Kono, Takahiko; Hosomi, Kenji; Hokama, Tomonori; Nishimura, Tomohiro; Matsubara, Natsumi; et al.

JAEA-Review 2018-025, 171 Pages, 2019/02

JAEA-Review-2018-025.pdf:3.81MB

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 2016 to March 2017. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Electric Power Company Holdings, Inc. 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 were exceeded the normal range of fluctuation in the monitoring, were evaluated.

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2015

Nakano, Masanao; Fujita, Hiroki; Mizutani, Tomoko; Hosomi, Kenji; Nagaoka, Mika; Hokama, Tomonori; Yokoyama, Hiroya; Nishimura, Tomohiro; Matsubara, Natsumi; Maehara, Yushi; et al.

JAEA-Review 2016-035, 179 Pages, 2017/03

JAEA-Review-2016-035.pdf:4.2MB

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 2015 to March 2016. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Electric Power Company Holdings, Inc. 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 were exceeded the normal range of fluctuation in the monitoring, were evaluated.

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2013

Watanabe, Hitoshi; Nakano, Masanao; Fujita, Hiroki; Takeyasu, Masanori; Mizutani, Tomoko; Isozaki, Tokuju; Morisawa, Masato; Nagaoka, Mika; Hokama, Tomonori; Yokoyama, Hiroya; et al.

JAEA-Review 2014-042, 175 Pages, 2015/01

JAEA-Review-2014-042.pdf:10.89MB

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 2013 to March 2014. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Plant of Tokyo Electric Power Co. in March 2011.

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2011

Sumiya, Shuichi; Watanabe, Hitoshi; Nakano, Masanao; Takeyasu, Masanori; Nakada, Akira; Fujita, Hiroki; Isozaki, Tokuju; Morisawa, Masato; Mizutani, Tomoko; Nagaoka, Mika; et al.

JAEA-Review 2013-009, 195 Pages, 2013/06

JAEA-Review-2013-009.pdf:3.35MB

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 2011 to March 2012. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Plant on Tokyo Electric Power Co. in March 2011.

Results of the environmental radiation monitoring following the accident at the Fukushima Daiichi Nuclear Power Plant; Interim report (Ambient radiation dose rate, radioactivity concentration in the air and radioactivity concentration in the fallout)

Furuta, Sadaaki; Sumiya, Shuichi; Watanabe, Hitoshi; Nakano, Masanao; Imaizumi, Kenji; Takeyasu, Masanori; Nakada, Akira; Fujita, Hiroki; Mizutani, Tomoko; Morisawa, Masato; et al.

JAEA-Review 2011-035, 89 Pages, 2011/08

JAEA-Review-2011-035.pdf:2.97MB

As a correspondence to the accident at the Fukushima Daiichi Nuclear Power Plant, the environmental radiation monitoring was performed at the Nuclear Fuel Cycle Engineering Laboratories, JAEA. This report presented the measurement results of ambient radiation dose rate, radioactivity concentration in the air and radioactivity concentration in fallout and meteorological observation result until May 31, 2011. The ambient radiation dose rate increased, with the peak dose rate of several thousand nGy/h at 7 o'clock in March 15, at 5 o'clock in March 16, and at 4 o'clock in March 21. The variation on the radioactivity concentration in the air and in fallout showed the almost same tendency as that of the dose rate. The concentration ratio of I-131/Cs-137 in the air increased to about 100. The dose was estimated resulting from internal exposure due to inhalation.

Development of calculation code for estimating radiation dose for hypothetical accident of nuclear facility considering radioactive decay chain during atmospheric dispersion of released radionuclides

Takeyasu, Masanori; Nakano, Masanao; Sumiya, Shuichi; Nemoto, Hiromi*; Kanno, Mitsuhiro*; Kurosawa, Naohiro*

Proceedings of 3rd Asian and Oceanic Congress on Radiation Protection (AOCRP-3) (CD-ROM), 4 Pages, 2010/05

The dose to the public at hypothetical accident of nuclear facility is estimated on the basis of the method described in the Japanese meteorological guideline. However, the radioactive decay during atmospheric dispersion of released radionuclide is not considered in the calculation formula in the guideline. Therefore, when the radionuclide of the half life such as a few min is released, the dose may be excessively over-estimated. In this study, the calculation code was developed which could consider the radioactive decay of the released radionuclide and the generation of the product. The dose calculated on the basis of the developed code was compared with that on the basis of the guideline.

Wind effect on currents in a thin surface layer of coastal waters faced open-sea

Nakano, Masanao; Isozaki, Hisaaki; Isozaki, Tokuju; Nemoto, Masashi*; Hasunuma, Keiichi*; Kitamura, Takashi*

Umi No Kenkyu, 18(1), p.37 - 55, 2009/01

https://ci.nii.ac.jp/naid/110007028667

To investigate the relationship between the wind and the current along the coast, the continuous observation of wind and current carried out for two years. The observed area was off shore Tokai-mura in Ibaraki prefecture, where faces open ocean. Considering the existence of strong pycnocline, the observation was carried out at the shallow depth over the pycnocline. The period of wind and current variation for 1 day and over several days was significant. Although the long period variation is caused from the variation of weather and season, the south current is formed by the permanent north wind component. The high correlation factor (0.64) between wind and surface current at 0.5 m was obtained throughout two years. As the result of harmonic analysis, both wind and current variations of 1 day period were appeared as S1 component tide, and it was confirmed to be land and sea breeze, and wind driven current, respectively. The land and sea breeze, which contains solar component except S1, adds the wind driven current except S1 to the corresponding component tide. From these results, it is considered that the land and sea breeze makes the pseudo S1 tidal current to the sea surface in the open coastal sea.

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2006

Takeishi, Minoru; Miyagawa, Naoto; Nakano, Masanao; Takeyasu, Masanori; Isozaki, Hisaaki; Isozaki, Tokuju; Morisawa, Masato; Fujita, Hiroki; Kokubun, Yuji; Kato, Chiaki; et al.

JAEA-Review 2007-044, 155 Pages, 2008/02

JAEA-Review-2007-044.pdf:2.58MB
JAEA-Review-2007-044(errata).pdf:0.13MB

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 JAEA, Chapter 4; 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 to the atmosphere and the sea during April 2006 to March 2007. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and its trends, meteorological data and discharged radioactive wastes.

The Relationship between the Surface Current Offshore Tokai and the Wind Field

Nakano, Masanao; Isozaki, Hisaaki; Isozaki, Tokuju; Ao, Hidetoshi*; Nemoto, Masashi*

JNC TN8400 2005-030, 189 Pages, 2005/09

JNC-TN8400-2005-030.pdf:136.62MB

The marine observation has been performed along the coast of JNC Tokai Reprocessing Plant (TRP) that discharges low level radioactive effluent. Recently the underslung electromagnetic flow-meter measured the current field at the very surface layer (depth: 0.5m, 1.0m, 3.0m). Then, the characteristic of the surface current field was analysed with correlation to the wind field that observed at 20m above sea level in Tokai Works. The tidal component is apparently detected by the harmonic analysis since the diel contents (land and sea breeze) is included in the wind that drives the surface seawater. However it is not the tidal current but the wind current. As the result, it made sure that the surface current is induced by the wind. Especially the wind current develops at the thin surface (skin) layer with pycnocline. The effluent from TRP has no salt and relatively high temperature, and it induces pycnocline near the discharge port. Assessing the marine diffusion of the radioactive materials from TRP, it is important to consider wind current especially.