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Journal Articles

Concentrations of $$^{129}$$I and $$^{127}$$I in soil samples within 10km radius from the Tokai Reprocessing Plant measured by Accelerator Mass Spectrometry method

Kokubun, Yuji; Yokoyama, Hiroya; Fujita, Hiroki; Nakano, Masanao; Sumiya, Shuichi

Hoken Butsuri, 48(4), p.193 - 199, 2013/12

Since the reprocessing contracts with electric power companies were completed in March 2006, the horizontal distribution of $$^{129}$$I in soil within 10 km radius from Tokai Reprocessing Plant (TRP) as well as the vertical distribution at 2 km southwest from TRP were measured using the Accelerator Mass Spectrometry (AMS) method. As a result, the small amounts of $$^{129}$$I were observed due to the atmospheric discharge from TRP. It was good agreement with the predicted concentrations in safety assessment. The validity of the diffusion calculation was confirmed in the 10 km radius. Moreover, the results of vertical distribution of $$^{129}$$I show that the $$^{129}$$I remaining there for several decades that it will be hard to move soil is adsorbed.

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.

JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2009

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

JAEA-Review 2011-004, 161 Pages, 2011/03

JAEA-Review-2011-004.pdf:4.09MB

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 2009 to March 2010. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes.

Journal Articles

An Application of accelerator mass spectrometry to determine $$^{129}$$I concentration in soil sample

Kokubun, Yuji; Fujita, Hiroki; Nakano, Masanao; Sumiya, Shuichi

Radioisotopes, 60(3), p.109 - 116, 2011/03

The pretreatment procedure to measure the atom ratio of $$^{129}$$I/$$^{127}$$I(10$$^{-8}$$$$sim$$10$$^{-7}$$ and $$^{129}$$I concentration in the soil around the Tokai reprocessing plant by accelerator mass spectrometry (AMS) has been investigated and applied. The measured data by AMS method were compared with those by neutron activation analysis (NAA) method, and then the relatively good agreement was confirmed. Also from the view of the relatively easy and quick pretreatment, AMS method is considered to be very efficient and practical for environmental radioactivity research especially for measurement of many samples.

Journal Articles

Tritium concentration and diffusion in seawater discharged from Tokai Reprocessing Plant

Kokubun, Yuji; Fujita, Hiroki; Nakano, Masanao; Sumiya, Shuichi

Progress in Nuclear Science and Technology (Internet), 1, p.384 - 387, 2011/02

The Tokai Reprocessing Plant has reprocessed the total amount of 1,140 tons of spent fuels since 1977 to the end of fiscal year 2008. During the operation, radioactive liquid effluent has been discharged into the sea from the outlet of the pipeline stretching about 3.7 km from shoreline, after the discharge approval and discharged total amounts of 4.5 PBq of $$^{3}$$H to the sea. Therefore, since 1978, JAEA has sampled seawater around the outlet every month. Tritium concentrations in seawater were analyzed and measured using a liquid scintillation counter. All data were used to calculate the dilution factor which means the ratio of the $$^{3}$$H concentration in seawater to that in liquid effluent. The number of $$^{3}$$H concentrations below the detection limit was 9,079 (82.0%) and the number of those from the limit to 40 Bq/L (as quantification limit) was 1,964 (17.7%). The maximum concentration was 1,700 Bq/L at the point just above the outlet in 1979. Moreover, the dilution factors were ranged between 240 and 6,500,000. All the concentrations were confirmed to be those below 60,000 Bq/L of $$^{3}$$H concentration limit included in water decided by the law and that it were not concern of environmental safety.

Journal Articles

Journal Articles

Development on pretreatment of analysis method of $$^{129}$$I in soil using accelerator mass spectrometry

Kokubun, Yuji; Nakano, Masanao; Sumiya, Shuichi

JAEA-Conf 2010-001, p.26 - 29, 2010/03

no abstracts in English

JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2008

Takeishi, Minoru; Sumiya, Shuichi; Matsuura, Kenichi; Watanabe, Hitoshi; Nakano, Masanao; Takeyasu, Masanori; Isozaki, Hisaaki*; Isozaki, Tokuju; Morisawa, Masato; Fujita, Hiroki; et al.

JAEA-Review 2009-048, 177 Pages, 2009/12

JAEA-Review-2009-048.pdf:19.3MB
JAEA-Review-2009-048(errata).pdf:0.12MB

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 2008 to March 2009. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes.

Journal Articles

Tritium concentration and diffusion in seawater discharged from Tokai reprocessing plant

Nakano, Masanao; Kokubun, Yuji; Takeishi, Minoru

Hoken Butsuri, 44(1), p.60 - 65, 2009/03

The tritium concentrations in seawater collected around the Tokai Reprocessing Plant (TRP) were measured for 10,800 samples in 30 years from 1978. The tritium concentration, dillution factor and diffusion situation were investigated. As a result, the tritium was occationaly detected due to the discharge from TRP. But it was considered to be the result of normal diffusion assumed in the safety assessment. It was confirmed that the tritium concentration was much lower than the concentration limit defined in the law and that it was not concern of environmental safety.

Journal Articles

Analytical method of $$gamma$$ emitters in seawater using coprecipitation with nickel hexacyanoferrate(II) and iron(III) hydroxide

Nakano, Masanao; Kokubun, Yuji; Sasaki, Takeshi*; Takeishi, Minoru

Radioisotopes, 58(2), p.61 - 69, 2009/02

The analytical yield of $$gamma$$ emitters in seawater by coprecipitation method with nickel hexacyanoferrate(II) and iron(III) hydroxide was confirmed using spiked radioisotope ($$^{137}$$Cs) and stable elements. Ninety-nine % of spiked $$^{137}$$Cs was adsorbed on nickel hexacyanoferrate(II), and 88 $$sim$$ 94% of spiked Ce, Co, Mn, Ru, Zn, Zr was adsorbed on iron(III) hydroxide. This analytical method is considered tobe very efficient and practical for environmental radiation monitoring from the view of quick and simple operation, especially easy analysis of plural samples.

Journal Articles

Tritium concentration in seawater and its diffusion around Tokai reprocessing plant

Nakano, Masanao; Kokubun, Yuji; Kono, Takahiko; Takeishi, Minoru

Dai-50-Kai Kankyo Hoshano Chosa Kenkyu Seika Rombun Shorokushu (Heisei-19-Nendo), p.53 - 54, 2008/12

The tritium concentrations in seawater collected around the Tokai Reprocessing Plant (TRP) were measured for 10,800 samples in 30 years from 1978. The tritium concentration, dillution factor and diffusion situation were investigated. As a result, the tritium was occationaly detected due to the discharge from TRP. But it was considered to be the result of normal diffusion assumed in the safety assessment. It was confirmed that the tritium concentration was much lower than the concentration limit defined in the law and that it was not concern of environmental safety.

JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2007

Takeishi, Minoru; Matsuura, Kenichi; Watanabe, Hitoshi; Nakano, Masanao; Takeyasu, Masanori; Isozaki, Hisaaki; Isozaki, Tokuju; Morisawa, Masato; Fujita, Hiroki; Kokubun, Yuji; et al.

JAEA-Review 2008-057, 155 Pages, 2008/11

JAEA-Review-2008-057.pdf:2.15MB

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 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 to the atmosphere and the sea during April 2007 to March 2008. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and its trends, meteorological data and discharged radioactive wastes.

JAEA Reports

Environmental monitoring for discharge of low level liquid waste from the Tokai Reprocessing Plant to the marine environment; Evaluation for influence of released radionuclides in the marine environment from the hot-test to the end of contract based reprocessing

Takeishi, Minoru; Nakano, Masanao; Kokubun, Yuji; Kono, Takahiko; Maejima, Kyoko*

JAEA-Review 2008-044, 93 Pages, 2008/10

JAEA-Review-2008-044.pdf:9.23MB

The Tokai Reprocessing Plant (TRP) was designed for commercial Light Water Reactor (LWR) power station as the first reprocessing plant in Japan. The TRP had been processed over 1000 tons of spent fuels up to 2006 through the hot test operation since 1977 and the routine operations since 1981. Almost of radioactive materials in the liquid waste were removed out by the process using multiple evaporators. However, low level liquid effluents were discharged to the sea through a long pipeline after confirmation of concentration of radionuclides beneath the limits by the Safety regulation of the TRP. The environmental monitoring had confirmed whether an unexpected release caused an influence to the environment. The environmental monitoring for seawater, sea sediments and marine products such as fishes, shellfish and seaweeds had been carried out offshore the Tokai-mura since 1977. This report reviewed comprehensively the all data obtained marine environmental monitoring since 1977.

Journal Articles

A Study on analysis of $$^{129}$$I concentration in soil by AMS

Kokubun, Yuji; Nakano, Masanao; Takeishi, Minoru

JAEA-Conf 2008-003, p.32 - 35, 2008/04

no abstracts in English

JAEA Reports

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.

Journal Articles

Environmental tritium in the vicinity of Tokai Reprocessing Plant

Fujita, Hiroki; Kokubun, Yuji; Koarashi, Jun

Journal of Nuclear Science and Technology, 44(11), p.1474 - 1480, 2007/11

 Times Cited Count:12 Percentile:63.76(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Annual report on the environmental radiation monitoring around Tokai Reprocessing Plant FY2005

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

JAEA-Review 2006-031, 155 Pages, 2006/10

JAEA-Review-2006-031.pdf:7.76MB
JAEA-Review-2006-031(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 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 to the atmosphere and the sea during April 2005 to March 2006. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and its trends, meteorological data and discharged radioactive wastes.

Oral presentation

Tritium concentration in sea water around the reprocessing plant

Kokubun, Yuji; Fujita, Hiroki; Nakano, Masanao; Koarashi, Jun; Takeyasu, Masanori

no journal, , 

no abstracts in English

Oral presentation

A Study on concentration of radionuclides in marine environment; From the monitoring results around the Tokai reprocessing plant

Nakano, Masanao; Fujita, Hiroki; Kokubun, Yuji; Takeishi, Minoru

no journal, , 

no abstracts in English

28 (Records 1-20 displayed on this page)