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Journal Articles

$$^{90}$$Sr contamination monitor of drainage water using a fiber type detector

Sanada, Yukihisa

Isotope News, (772), p.21 - 25, 2020/12

no abstracts in English

Journal Articles

Evaluation of a surface collection efficiency and a stability of flow rate for the commercially available filters used for ambient radioactive aerosols

Tamakuma, Yuki*; Yamada, Ryohei; Iwaoka, Kazuki*; Hosoda, Masahiro*; Tokonami, Shinji*

Hoken Butsuri (Internet), 54(1), p.5 - 12, 2019/03

Airborne radioactivity measurements are necessary to know the contamination level and internal doses for residents after a nuclear accident. In addition, measurements of radon progenies in air, which are the risk factor of lung cancer, are also important to evaluate lung dose. In these measurements, a filter sampling is used to collect radioactive aerosols. However, it is well known that results of the measurement using a filter are strongly dependent on characteristics of the used filter. Selection of a suitable filter is important to achieve the high-resolution and long-term measurement. "Surface collection efficiency (SCE)" and "stability of air flow rate" were examined for six types of filter that are commercially available in Japan. In Japan, cellulose-glass fiber filter paper (HE-40T) is used for an environmental monitoring in Japan. In this study, it was found that the SCE of HE-40T was lower than that of mixed cellulose ester type membrane filter by Merck Millipore (DAWP02500). Attenuation ratio of flow rate for DAWP02500 was evaluated to be 2.9% which was lowest in six filters. The results suggest that the DAWP02500 is the most suitable for collecting radioactive aerosols for a long term.

JAEA Reports

Comprehensive evaluation system for environmental remediation of Fukushima; Toward integration of three components as a whole system

Saito, Hiroshi; Nozawa, Takashi; Takemiya, Hiroshi; Seki, Akiyuki; Matsubara, Takeshi; Saito, Kimiaki; Kitamura, Akihiro

JAEA-Review 2017-040, 34 Pages, 2018/03

JAEA-Review-2017-040.pdf:9.52MB

The accidents at Fukushima Daiichi Nuclear Power Station on March 11th 2011, released significant amount of radionuclide to the environment. It has migrated to the human habitation and raised concerns of possible effect on human health, and for that a lot of researches have been performed. JAEA created and opened "Database for Radioactive Substance Monitoring Data" for usage of obtained data. For accurate modelling and future forecast using numerical code and the data, "Supporting Environment for Processing Simulation Codes" has been operated. In addition, research results have been opened as Q&A style "Knowledge Base for Environmental Remediation" in JAEA's website. The "Comprehensive Evaluation System" composed of these components, should act more interrelated and integrated as one system. Besides, information dissemination is not enough to the outside. The report summarizes the current status, remaining issues and expected improvement of each component and the system.

JAEA Reports

Analysis of meteorological observation data for the atmospheric diffusion calculation; FY2005-2015

Nishimura, Tomohiro; Onuma, Toshimitsu*; Mizutani, Tomoko; Nakano, Masanao

JAEA-Technology 2017-019, 60 Pages, 2017/09

JAEA-Technology-2017-019.pdf:3.2MB

The meteorological observation has been performed since 1969's in the Nuclear Fuel Cycle Engineering Laboratories, JAEA after 1974. The meteorological observation data has been applied for the calculation of the atmospheric diffusion of radioactive wastes since the hot run was started 1977. This report presents statistical results of meteorological observation based on the decadal data from fiscal year 2005 to 2015. The characteristics of atmospheric diffusion related to the meteorological parameter are also discussed in this report.

Journal Articles

Investigation to evaluate the influence of the TEPCO's Fukushima Daiichi NPS accident for environmental monitoring about marine organisms

Nagaoka, Mika; Matsubara, Natsumi; Fujita, Hiroki; Nakano, Masanao

KEK Proceedings 2016-8, p.134 - 138, 2016/10

no abstracts in English

Journal Articles

Level of detail control for environmental monitoring datasets

Miyamura, Hiroko; Takemiya, Hiroshi; Wu, H.-Y.*; Takahashi, Shigeo*

Kashika Joho Gakkai-Shi, 36(143), p.152 - 156, 2016/10

Broad survey on the distribution of the air dose rate has been performed after the accident at the Fukushima Daiichi Nuclear Power Plant continuously. The surveyed monitoring datasets are stored in a database and are made available to the public. Recently, the size of the datasets have been significantly increased as more detailed measurements in space and time are available, and effective reduction of the size of the datasets is necessary for visualizing and exploring such large scale datasets. However, if the datasets are not carefully reduced, we often miss a part of important features of the distribution data. Therefore, we develop an effective Level of Detail control (LoD) method for retaining critical features of the distribution. In the method, the global and local features of the distribution are extracted by means of differential topology analyses. Then, the simplified data is created by edge collapse operation with taking into account these features of the data.

Journal Articles

Experience gained from the Fukushima-Daiichi accident as input for developing a technical knowledge base including remediation technologies

Miyahara, Kaname; Iijima, Kazuki; Saito, Kimiaki

Jiban Kogakkai-Shi, 63(11/12), p.62 - 69, 2015/11

AA2015-0380.pdf:1.64MB

This review provides a concise overview of knowledge and experience gained from the activities for environmental remediation after the Fukushima Dai-ichi accident as input for developing a technical knowledge base including remediation technologies which is translated into actions that enable the rapid return of evacuees. It is reflecting JAEA's key role in the research associated with both remediation of contaminated areas and the natural processes influencing contamination migration in non-remediated areas, working together with a number of Japanese and international organisations and research institutes. This review also provides a perspective on the future actions required to remediate areas outside the Fukushima Dai-ichi site.

Journal Articles

Source term estimation for the Fukushima Daiichi Nuclear Power Station accident by combined analysis of environmental monitoring and plant data through atmospheric dispersion simulation

Nagai, Haruyasu; Terada, Hiroaki; Chino, Masamichi; Katata, Genki; Mikami, Satoshi; Saito, Kimiaki

Proceedings of 16th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-16) (USB Flash Drive), p.4044 - 4052, 2015/08

JAEA has estimated the atmospheric releases of radionuclide during the Fukushima Daiichi Nuclear Power Station (FNPS1) accident by comparing measurements of air concentration of a radionuclide or its dose rate in the environment with the ones calculated by atmospheric transport and deposition model (ATDM). To improve our source term, we are trying to develop more sophisticated estimation method and use new information from severe accident analysis and observation data. As the first step of new trial, we used $$^{134}$$Cs/$$^{137}$$Cs ratios of inventories in FNPS1 reactors Unit 1 to 3 and those in surface deposition. By considering temporal change in $$^{134}$$Cs/$$^{137}$$Cs ratio of released plume and ATDM simulations, spatial distribution of $$^{134}$$Cs/$$^{137}$$Cs ratio in surface deposition was explained. This result can be used to specify from which reactor the dominant release occurred for each time period, and consequently provide useful information to severe accident analysis for the FNPS1 case.

Journal Articles

Outline of the national mapping projects implemented after the Fukushima accident

Saito, Kimiaki; Onda, Yuichi*

Journal of Environmental Radioactivity, 139, p.240 - 249, 2015/01

 Times Cited Count:44 Percentile:4.81(Environmental Sciences)

no abstracts in English

JAEA Reports

Annual report on the environmental radiation monitoring around Tokai reprocessing plant FY 2000

Maruo, Yoshihiro; ; Takeishi, Minoru; ; ; Takeyasu, Masanori;

JNC-TN8440 2001-011, 146 Pages, 2001/06

JNC-TN8440-2001-011.pdf:2.98MB

Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed since 1975, based on "Safety Regulations for the Tokai Reprocessing Plant, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitants due to the radioactivity discharged from the plant during April 2000 to March 2001. Appendices present comprehensive information, such as monitoring program, monitoring results, meteorological data and annual discharges from the plant.

JAEA Reports

The Results of the envilonmental monitoring related to the criticality accident in JCO

Shinohara, Kunihiko; ; ; ; ; Kano, Yutaka;

JNC-TN8440 2001-004, 62 Pages, 2001/02

JNC-TN8440-2001-004.pdf:4.17MB

Concerming about the action for the criticality accident in JCO Co., Ltd. (JCO) occurred at 10:35 on 30$$^{th}$$ Sept. 1999, Japan Nuclear Cycle Development Institute(JNC) established "JNC's task force" at 12:35 on the same date in conjuction with Head Office and Tokai Works. And JNC's task force had supported the government of Japan, the local governments and JCO humanly, physically and technically until the jobs of the task force was transferred to "Support Assembly for Countermeasure and Research of JCO Criticality Accident" and routine line on 12$$^{th}$$ Oct. 1999. This report compiled the results of the environmental monitoring performed by JNC based on the request from the government of Japan and the local governments.

JAEA Reports

Some experiences of radiation protection activities in nuclear emergency

Noda, Kimio; Shinohara, Kunihiko; Kanamori, Masashi

JNC-TN8410 2001-010, 35 Pages, 2000/10

JNC-TN8410-2001-010.pdf:3.85MB

We, the radiation control section of JNC have had two important experiences on the JCO critical accident and the JNC fire-explosion accident. Especially, at the critical accident in JCO, it was essential to take an action on the radiation protection activities for the evacuated neighboring inhabitants to the safety area. During the accident, we carried out the radiation protection activities, at the beginning of the accident, environmental monitoring of the surrounding area. Especially for the JCO accident, we took an action to terminate criticality, radiation shielding and monitoring, environmental monitoring, radiation survey of the residents, radiation monitoring of exhaust air.

JAEA Reports

None

*

JNC-TJ7400 2000-015, 203 Pages, 2000/08

JNC-TJ7400-2000-015.pdf:6.07MB

no abstracts in English

JAEA Reports

Annual report on the environmental radiation monitoring around Tokai reprocessing plant FY 1999

; Shinohara, Kunihiko; ; ; ; Takeyasu, Masanori;

JNC-TN8440 2000-007, 141 Pages, 2000/06

JNC-TN8440-2000-007.pdf:3.02MB

Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed since 1975, based on "Safety Regulations for the Tokai Reprocessing Plant, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitants due to the radioactivity discharged from the plant during April 1999 to March 2000. Appendices present comprehensive information, such as monitoring program, monitoring results, meteorological data and annual discharges from the plant.

JAEA Reports

None

JNC-TN4420 2000-004, 9 Pages, 2000/03

JNC-TN4420-2000-004.pdf:3.04MB

no abstracts in English

JAEA Reports

None

JNC-TN4420 2000-003, 14 Pages, 2000/03

JNC-TN4420-2000-003.pdf:1.85MB

no abstracts in English

JAEA Reports

None

JNC-TN4420 2000-002, 14 Pages, 2000/03

JNC-TN4420-2000-002.pdf:1.97MB

no abstracts in English

JAEA Reports

None

*

JNC-TJ7420 2000-007, 28 Pages, 2000/03

JNC-TJ7420-2000-007.pdf:11.92MB

no abstracts in English

JAEA Reports

None

; ; Shimizu, Kazuhiko; Miyahara, Kaname; ; Hasegawa, Hiroshi; Makino, Hitoshi

JNC-TN1400 99-007, 497 Pages, 1999/04

JNC-TN1400-99-007.pdf:26.32MB

None

79 (Records 1-20 displayed on this page)