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JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2020

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.

JAEA Reports

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.

Journal Articles

AMS radiocarbon age of the Kurodake pyroclastic-flow deposit in Kuju volcanic group, SW Japan

Okuno, Mitsuru*; Nagaoka, Shinji*; Kokubu, Yoko; Nakamura, Toshio*; Kobayashi, Tetsuo*

Fukuoka Daigaku Rigaku Shuho, 48(1), p.1 - 5, 2018/03

Kuju volcanic group, located in central Kyushu, Japan, consists of over twenty volcanoes (lava domes as well as small stratovolcanoes). The Kurodake is largest lava dome with a volume of 1.6 km$$^{3}$$, and generated Kurodake pyroclastic-flow (Kj-Kd) and ash-fall (Kj-KdA) deposits. To refine age of the Kurodake eruption, we conducted radiocarbon dating of a charcoal fragment in the Kj-Kd with an AMS system at Tono Geoscience Center, JAEA. The obtained $$^{14}$$C date, 1505$$pm$$40 BP, can correspond to 1310-1423 cal BP (probability= 74.6%), 1430-1442 cal BP (2.4%) and 1456-1521 cal BP (23.0%) in 2$$sigma$$ confidence level. The medium probability date, 1391 cal BP, is consistent with the stratigraphy and gives the reliable age for the Kj-Kd.

JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2016

Nakano, Masanao; Fujita, Hiroki; Mizutani, Tomoko; Nemoto, Masashi; Tobita, Keiji; Hosomi, Kenji; Nagaoka, Mika; Hokama, Tomonori; Nishimura, Tomohiro; Koike, Yuko; et al.

JAEA-Review 2017-028, 177 Pages, 2018/01

JAEA-Review-2017-028.pdf:3.61MB

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.

JAEA Reports

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.

Journal Articles

AMS radiocarbon dates of pyroclastic-flow deposits on the southern slope of the Kuju Volcanic Group, Kyushu, Japan

Okuno, Mitsuru*; Nagaoka, Shinji*; Kokubu, Yoko; Nakamura, Toshio*; Kobayashi, Tetsuo*

Radiocarbon, 59(2), p.483 - 488, 2017/00

 Times Cited Count:3 Percentile:21.86(Geochemistry & Geophysics)

We present here results of AMS $$^{14}$$C dating to refine the history of the middle and western parts of the Kuju Volcanic Group, located in middle Kyushu, Japan, which consists of more than 20 lava domes and cones. $$^{14}$$C dating has conducted by AMS (JAEA-AMS-TONO) under the Common-Use Facility Program of JAEA. The Handa PF deposits, which are products of the largest eruption of the group, were dated to $$sim$$53.5 ka BP. The Shirani and Muro PF deposits, which are block-and-ash flows, were dated to 44 to $$>$$50 cal ka BP and 35$$sim$$39 cal ka BP, respectively. These ages can be correlated with the TL ages for the lava domes. Therefore, both TL and $$^{14}$$C methods can be useful tools in establishing the eruptive sequence of lava domes and pyroclastic flows. This study also demonstrates that these eruptive activities occurred after the Handa pfl, the biggest eruption during the last 150 kyrs without a significant time interval.

JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2014

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

JAEA-Review 2015-034, 175 Pages, 2016/03

JAEA-Review-2015-034.pdf:8.13MB

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 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 2014 to March 2015. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Co. in March 2011.

Journal Articles

Temporal variations of radionuclides in seabed sediments off Ibaraki coast

Nagaoka, Mika; Yokoyama, Hiroya; Matsubara, Natsumi; Fujita, Hiroki; Nakano, Masanao; Watanabe, Hitoshi

KEK Proceedings 2015-4, p.214 - 218, 2015/11

The radiological impact of the radionuclides released from the Fukushima Daiichi Nuclear Power Station to the sea offshore of Ibaraki has been studied in this research. Fifty-one seabed sediments were collected in 2012, 2013 and 2014, respectively. Then, all samples were measured for the activities of $$^{134}$$Cs and $$^{137}$$Cs and some samples were analyzed for the activities of $$^{90}$$Sr. The results indicated that the activities of $$^{134}$$Cs and $$^{137}$$Cs were elevated by the accident and showed a decreasing tendency between 2012 and 2014. The tendency of activity in Kuji Riverestuary area was different from Ibaraki coast area. The difference could be caused by geological feature and grain size of seabed sediment etc. On the other hand, $$^{90}$$Sr activities were ND-0.26 Bq/kg dry. It was no correlation between $$^{90}$$Sr and $$^{137}$$Cs activity. The $$^{90}$$Sr activity released by the accident was small influence on seabed sediment collected around sea offshore of Ibaraki.

Journal Articles

Spatial distribution of radionuclides in seabed sediments off Ibaraki coast after the Fukushima Daiichi Nuclear Power Plant accident

Nagaoka, Mika; Yokoyama, Hiroya; Fujita, Hiroki; Nakano, Masanao; Watanabe, Hitoshi; Sumiya, Shuichi

Journal of Radioanalytical and Nuclear Chemistry, 303(2), p.1305 - 1308, 2015/02

 Times Cited Count:12 Percentile:79.22(Chemistry, Analytical)

Various kinds of radionuclides were released into the atmosphere and the sea from the Fukushima Daiichi Nuclear Power Plant on Tokyo Electric Power Co. (TEPCO) by the accident and then reached around our laboratories. Therefore the accident influence on our environment was investigated to measure the concentrations of cesium-134 ($$^{134}$$Cs), cesium-137 $$^{137}$$Cs, strontium-90 ($$^{90}$$Sr) and plutonium isotopes in seabed sediments. The values for $$^{137}$$Cs ranged from 6.1 to 300 Bq/kg (dry wt) and the ratio of $$^{134}$$Cs /$$^{137}$$Cs ranged from 0.48 to 0.77. The highest point of $$^{137}$$Cs concentration was observed at the northernmost station near Kitaibaraki City and the concentration was similar to report by MEXT.

JAEA Reports

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.

JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2012

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

JAEA-Review 2013-056, 181 Pages, 2014/03

JAEA-Review-2013-056.pdf:6.22MB

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 2012 to March 2013. 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.

Journal Articles

Supplementary explanation to "The result of radionuclide concentrations in fallout around Tokai Reprocessing Plant after Fukushima Daiichi Nuclear Power Plant accident"

Nagaoka, Mika; Fujita, Hiroki; Nakano, Masanao; Watanabe, Hitoshi; Sumiya, Shuichi

Hoken Butsuri, 48(4), p.165 - 166, 2013/12

no abstracts in English

JAEA Reports

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.

Journal Articles

The Result of radionuclide concentrations in fallout around Tokai Reprocessing Plant after Fukushima Daiichi Nuclear Power Plant accident

Nagaoka, Mika; Fujita, Hiroki; Nakano, Masanao; Watanabe, Hitoshi; Sumiya, Shuichi

Hoken Butsuri, 48(2), p.104 - 113, 2013/06

Monthly deposition samples were collected in the NCL which is located at about 115km south of the Fukushima Daiichi NPP, and the radioactive nuclides were analyzed. Although radionuclides such as $$^{131}$$I (T$$_{1/2}$$=8.02 days), $$^{129m}$$Te-$$^{129}$$Te (T$$_{1/2}$$=33.6 days) and $$^{132}$$Te-$$^{132}$$I (T$$_{1/2}$$=3.2 days) with $$^{134}$$Cs and $$^{137}$$Cs were observed by $$gamma$$ spectrometry at the early time of the Fukushima Daiichi NPP accident, only $$^{134}$$Cs and $$^{137}$$Cs were detected as of September 2012. The annual deposition of $$^{134}$$Cs and $$^{137}$$Cs were about 19,000 and 17,000 Bq/m$$^{2}$$, respectively in March 2011 - February 2012 after the accident. Moreover, $$^{90}$$Sr was detected in some samples. Monthly $$^{90}$$Sr deposition in March 2011 was 5.1 Bq/m$$^{2}$$ month and then decreased after that. On the other hand, $$^{239,240}$$Pu concentration was the same level with the concentration before the accident.

Journal Articles

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY 2011

Nagaoka, Mika; Nakano, Masanao; Fujita, Hiroki; Watanabe, Hitoshi; Sumiya, Shuichi

Dai-55-Kai Kankyo Hoshano Chosa Kenkyu Seika Rombun Shorokushu (Heisei-23-Nendo), p.7 - 8, 2013/03

no abstracts in English

JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2010

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

JAEA-Review 2012-015, 166 Pages, 2012/05

JAEA-Review-2012-015.pdf:3.53MB

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 2010 to March 2011. 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 2011 March. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data exceeded the normal range of fluctuation by the accidental release was evaluated in the appendices.

JAEA Reports

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.

Journal Articles

Targeted heavy-ion microbeam irradiation of the embryo but not yolk in the diapause-terminated egg of the silkworm, ${it Bombyx mori}$, induces the somatic mutation

Furusawa, Toshiharu*; Fukamoto, Kana*; Sakashita, Tetsuya; Suzuki, Eiko*; Kakizaki, Takehiko*; Hamada, Nobuyuki*; Funayama, Tomoo; Suzuki, Hiromi*; Ishioka, Noriaki*; Wada, Seiichi*; et al.

Journal of Radiation Research, 50(4), p.371 - 375, 2009/07

 Times Cited Count:8 Percentile:32.37(Biology)

Using heavy-ion microbeam, we report target irradiation of selected compartments within the diapause-terminated egg and its mutational consequences in the silkworm, ${it Bombyx mori}$. On one hand, carbon-ion exposure of embryo to 0.5 - 6 Gy increased the somatic mutation frequency, suggesting targeted radiation effects. On the other, such increases were not observed when yolk was targeted, suggesting a lack of nontargeted bystander effect.

Journal Articles

Study on loss detection algorithms using tank monitoring data

Suzuki, Mitsutoshi; Hori, Masato; Nagaoka, Shinichi; Kimura, Takashi

Journal of Nuclear Science and Technology, 46(2), p.184 - 192, 2009/02

 Times Cited Count:10 Percentile:60.19(Nuclear Science & Technology)

An application of solution monitoring to material balance has been investigated with an actual data of the Solution Monitoring Management System (SMMS) in the Tokai Reprocessing Plant (TRP). Loss detection capabilities of the proposed multivariate statistical methods are examined numerically for a simulated loss corresponding to parameters of a significant quantity in the wait mode. Multi-scale statistical analysis as well as multivariate cumulative sum analysis are successfully used to demonstrate the protracted-loss detection. Since the actual tank data is composed of both records in the wait and the transfer mode, the tank-to-tank transferring data is extracted from the sequence of monitoring data and the effectiveness of error model is evaluated in comparison with calculations. Although the data taken from the SMMS does not describe in the entire solution process, an extended application of solution monitoring to the nuclear material accounting is advanced using the plant data.

Journal Articles

Influence of local irradiation with heavy-ion microbeam on the incidence of somatic mutation arising on the larvae in embryo and yolk in the egg of the silkworm, ${it Bombyx mori}$

Furusawa, Toshiharu*; Suzuki, Eiko*; Nagaoka, Shunji*; Suzuki, Hiromi*; Ishioka, Noriaki*; Hamada, Nobuyuki*; Wada, Seiichi*; Kobayashi, Yasuhiko; Sakashita, Tetsuya; Kakizaki, Takehiko*; et al.

JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 115, 2008/03

Using heavy ion microbeam, we investigated the somatic mutation arising on the larvae in embyro and yolk in the egg of silkworm, ${it Bombyx mori}$. The incidence of the somatic mutation was 12%, and the same level of mutation following the microbeam irradiation at the center of the egg. However, the microbeam irradiation to the abdomen of the silkworm larvae induced the increase of somatic mutation, 63% (3 Gy) and 80% (6 Gy).

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