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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:10 Percentile:18.74(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.

Journal Articles

Estimation of dry deposition velocities of radionuclides released by the accident at the Fukushima Dai-ichi Nuclear Power Plant

Takeyasu, Masanori; Sumiya, Shuichi

Progress in Nuclear Science and Technology (Internet), 4, p.64 - 67, 2014/04

On the basis of I-131 measured after Fukushima primary nuclear power plant in nuclear fuel cycle engineering laboratory and atmosphere radioactive material concentration of cesium isotope and atmospheric deposition quantity data, the deposition velocity of atmosphere radioactive material to the surface was estimated. As the result, the deposition velocity was the 10$$^{-3}$$m/s order. It was the order equal to I-131 deposition velocity estimated after Chernobyl accident estimated from until now environmental radiation monitoring result around Tokai Nuclear Fuel Reprocessing Plant from the monitoring result in I-129 deposition velocity and this laboratory. It was guessed that it included the gaseous component for I-131 and cesium isotope discharged by Fukushima accident in atomic powered generation and that the deposition velocity varied by the ratio of the component.

JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY 2012

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.

JAEA Reports

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2012

Sumiya, Shuichi; Watanabe, Hitoshi; Miyagawa, Naoto; Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Inoue, Kazumi; Yoshii, Hideki; Otani, Kazunori*; Hiyama, Yoshinori*; et al.

JAEA-Review 2013-041, 115 Pages, 2014/01

JAEA-Review-2013-041.pdf:19.01MB

Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, and the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), this report describes the effluent control results of liquid waste discharged from the JAEA's Nuclear Fuel Cycle Engineering Laboratories in the fiscal year 2012, from 1st April 2012 to 31st March 2013. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other facilities were much lower than the authorized limits of the above regulations.

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.

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

Examination on the long-term practicability of a Doppler Lidar; Data missing rate and comparison of wind direction and speed with the propeller type

Nakano, Masanao; Watanabe, Hitoshi; Sumiya, Shuichi

JAEA-Testing 2013-003, 29 Pages, 2013/11

JAEA-Testing-2013-003.pdf:11.89MB

Since the remote sensing technique for the meteorological observation has been developing these years, the Doppler Lidar is available in the commercial market. Although some investigation organization carried out the examination on the method and application of Doppler Lidars and had generally good results, the duration of the examination was limited in a short period. So it is unknown that the Doppler Lidar can be applicable to the long-term meteorological observation in the nuclear facilities to assess the public dose around nuclear facilities. In order to examine the long-term performance requested by the Japanese guideline for meteorological observation (i.e., the annual and the sequential 30-days missing rate should be less than 10% and 30%, respectively.) and the consistency with the data measured by conventional type, the wind direction and speed was measured by the Doppler Lidar (Windcube WLS7 made by Leosphere Co Ltd.) for one year, then compared with those by the propeller type installed at the top of the meteorological observation tower. As the result, the missing rate of the Doppler Lidar was satisfied with the guideline at the height less than 180 m, and the data at 68 m above the ground level (100 m above sea level) had a good relationship with the propeller data. From this fact, the Doppler Lidar used in this examination is considered to have a practicability for the dose assessment of the public.

Journal Articles

Estimation of dose from the measurement results of airborne radionuclide concentrations following the Fukushima Dai-ichi Nuclear Power Plant accident; For the public around Tokai-mura, Ibaraki

Takeyasu, Masanori; Sumiya, Shuichi; Furuta, Sadaaki

Hoken Butsuri, 48(3), p.141 - 149, 2013/11

On the basis of airborne concentrations of radionuclides in the Nuclear Fuel Cycle Engineering Laboratories, JAEA, the committed effective dose to adult and committed equivalent dose to thyroid of infant by inhalation were estimated by setting the realistic parameters for indoor-outdoor air concentration ratio, inhalation rate and dose coefficient, and the margin of safety in projected dose was examined. As the results, the estimated doses were about 1/7 for the projected committed effective dose to adult and about 1/10 for the projected committed equivalent dose to thyroid of infant, respectively. These facts indicated that the projected dose had the degrees of safety margin of the factor of 7 for committed effective dose to adult and the factor of 10 for committed equivalent dose to thyroid of infant, respectively. It was the most important parameter for estimating the committed dose that the indoor-outdoor air concentration ratio.

JAEA Reports

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

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.

JAEA Reports

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2011

Sumiya, Shuichi; Watanabe, Hitoshi; Miyagawa, Naoto; Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Hiyama, Yoshinori; Yoshii, Hideki*; Otani, Kazunori*; Goto, Ichiro*; et al.

JAEA-Review 2013-005, 116 Pages, 2013/05

JAEA-Review-2013-005.pdf:9.69MB

Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, and the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and byelaw of Ibaraki prefecture), this report describes the effluent control results of liquid waste discharged from the JAEA's Nuclear Fuel Cycle Engineering Laboratories in the fiscal year 2011, from 1st April 2011 to 31st March 2012. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other facilities were much lower than the authorized limits of the above regulations.

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

ORION-WIN; A Computer code to estimate environmental concentration and radiation dose due to airborne discharge of radioactive materials from nuclear facilities

Takeyasu, Masanori; Onuma, Toshimitsu; Sumiya, Shuichi

JAEA-Data/Code 2012-021, 29 Pages, 2012/09

JAEA-Data-Code-2012-021.pdf:1.42MB

A computer code, ORION-WIN, has been developed to estimate environmental concentration and radiation dose to public due to airborne discharge of radioactive materials from multiple sources of nuclear fuel cycle facilities. The modified Gaussian plume model is applied to calculate atmospheric dispersion of the discharged radioactive material. The plume depletion processes such as gravitational settling, dry deposition, precipitation scavenging and radioactive decay are considered. Inhalation and oral intake are considered as internal pathways, and submersion in the radioactive cloud and external exposure to contaminated ground surface are considered as external pathways, respectively. Radiation dose to an individual is calculated. ORION-WIN is an updated version of ORION-II and runs on PC mounting Windows OS, and has a graphical user interface for inputting the parameters and referring output files.

JAEA Reports

ORION-WIN; A Computer code to estimate environmental concentration and radiation dose due to airborne discharge of radioactive materials from nuclear facilities

Takeyasu, Masanori; Onuma, Toshimitsu; Sumiya, Shuichi

JAEA-Data/Code 2012-011, 28 Pages, 2012/07

JAEA-Data-Code-2012-011.pdf:1.22MB

A computer code, ORION-WIN, has been developed to estimate environmental concentration and radiation dose to the public due to the airborne release of radioactive materials from multiple sources of nuclear fuel cycle facilities. The modified Gaussian plume model is applied to calculate atmospheric dispersion of the released radioactive material. The plume depletion processes such as gravitational settling, dry deposition, precipitation scavenging and radioactive decay are considered, and re-suspension from the ground and the produce of progeny from the parent radionuclides are also considered. Inhalation and oral intake are considered as internal pathways, and submersion in the radioactive cloud and external exposure to contaminated ground surface are considered as external pathways, respectively. Radiation dose to an individual is calculated.

JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY 2010

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.

Journal Articles

Special environmental monitoring around Tokai-mura after the accident of the Fukushima Dai-ichi Nuclear Power Station

Fujita, Hiroki; Nagaoka, Mika; Kono, Takahiko; Takeyasu, Masanori; Kawasaki, Masatsugu; Okura, Takehisa; Tsujimura, Norio; Sumiya, Shuichi; Momose, Takumaro; Furuta, Sadaaki

Proceedings of 13th International Congress of the International Radiation Protection Association (IRPA-13) (Internet), 7 Pages, 2012/05

The nuclear accident at Fukushima Dai-ichi Nuclear Power Station of Tokyo Electric Power Co. (TEPCO) was caused by the Tohoku District-off the Pacific Ocean Earthquake. Various kinds of radionuclides were released from the power station right after the accident occurred and then reached our laboratories. Therefore, environmental monitoring was reinforced by observation of air absorbed dose rate, periodic collection of airborne dust, precipitation. The collected samples were used to determine radioactivity of $$gamma$$ ray emitters by High pure Germanium semiconductor detector. Moreover, rainwater and humidity were collected to do the usual routine monitoring. In some samples, $$^{90}$$Sr, $$^{131}$$I, $$^{134}$$Cs and $$^{137}$$Cs were detected with radioactivity released from the Fukushima station. In other samples such as seawater, seabed soil and etc., similar radionuclides were detected including the influence of the accident.

JAEA Reports

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2010

Sumiya, Shuichi; Watanabe, Hitoshi; Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Hiyama, Yoshinori; Yoshii, Hideki*; Kikuchi, Masaaki*; Otani, Kazunori*; Goto, Ichiro*

JAEA-Review 2012-006, 114 Pages, 2012/03

JAEA-Review-2012-006.pdf:3.36MB

Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, and the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and byelaw of Ibaraki prefecture), this report describes the effluent control results of liquid waste discharged from the JAEA's Nuclear Fuel Cycle Engineering Laboratories in the fiscal year 2010, from 1st April 2010 to 31st March 2011. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other facilities were much lower than the authorized limits of the above regulations.

Journal Articles

Results of environmental radiation monitoring at the Nuclear Fuel Cycle Engineering Laboratories, JAEA, following the Fukushima Daiichi Nuclear Power Plant accident

Takeyasu, Masanori; Nakano, Masanao; Fujita, Hiroki; Nakada, Akira; Watanabe, Hitoshi; Sumiya, Shuichi; Furuta, Sadaaki

Journal of Nuclear Science and Technology, 49(3), p.281 - 286, 2012/03

 Times Cited Count:18 Percentile:16.54(Nuclear Science & Technology)

As a response to the Fukushima Daiichi Nuclear Power Plant accident, emergency environmental radiation monitoring was performed at the Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency (JAEA). This paper provisionally describes the results of the monitoring including ambient radiation dose rate and radioactivity concentrations in airborne and fallout. The ambient radiation dose rate began to increase since about 1:00 on March 15 2011, and varied with three peak dose rate of several thousand $$mu$$Gy/h at 8:00 on March 15, at 5:00 on March 16, and at 4:00 on March 21. The variation over time in radioactivity concentrations in airborne and fallout almost showed the same tendency as that of the dose rate. The fallout of $$^{137}$$Cs for 1 month from March 15 to April 15 was about 120 times higher than that in May 1986 after the Chernobyl accident. The internal dose by inhalation was estimated from the airborne concentration observed.

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 FY 2009

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.

69 (Records 1-20 displayed on this page)