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Journal Articles

JAEA Reports

Applied research for the establishment of radiation monitoring and evaluation of exposure dose of residence at the zone designated for reconstruction and recovery

Funaki, Hironori; Takahara, Shogo; Sasaki, Miyuki; Yoshimura, Kazuya; Nakama, Shigeo; Sanada, Yukihisa

JAEA-Research 2018-016, 48 Pages, 2019/03

JAEA-Research-2018-016.pdf:29.73MB

Cabinet Office Nuclear Emergency Response Headquarters starts to consider radiation protection in the "specific reconstruction reproduction base area" of which evacuation order will be lifted by 2023. It is essential to grab the present situations of radiation contamination and evaluate exposure dose in the area to realize the plan. Many surveys have evaluated the distributions of air dose rate and exposure dose has been estimated based on the results since the Fukushima Daiichi Nuclear Power Plant accident. Nevertheless, more detailed information on exposure is needed for the areas because its radiation level is relatively high. That is also to help make prudent evaluation plan. This study aimed to evaluate the detailed contamination situation there and estimate exposure dose with considering areal circumstances. Investigations were carried out for (1) airborne survey of air dose rate using an unmanned helicopter (2) evaluation of airborne radiocesium and (3) estimation of external/internal effective doses for typical activity patterns assumed. Additionally, we applied new methods for the airborne survey to evaluate exposure dose. Our study showed a detailed three-dimensional map of air dose rate and clarified the distribution pattern in the areas. Results of effective dose estimation suggested that the internal effective dose due to inhalation accounts for less than 1% of the external effective dose.

Journal Articles

Comparison of the Fukushima radioactive mapping by two different aerial radiation monitoring systems

Kim, B.-J.*; Sasaki, Miyuki; Sanada, Yukihisa

Progress in Nuclear Science and Technology (Internet), 6, p.130 - 133, 2019/01

Journal Articles

Evaluation of ecological half-life of dose rate based on airborne radiation monitoring following the Fukushima Dai-ichi Nuclear Power Plant accident

Sanada, Yukihisa; Urabe, Yoshimi*; Sasaki, Miyuki; Ochi, Kotaro; Torii, Tatsuo

Journal of Environmental Radioactivity, 192, p.417 - 425, 2018/12

 Percentile:100(Environmental Sciences)

Journal Articles

Development of a radiological characterization submersible ROV for use at Fukushima Daiichi

Nancekievill, M.*; Jones, A. R.*; Joyce, M. J.*; Lennox, B.*; Watson, S.*; Katakura, Junichi*; Okumura, Keisuke; Kamada, So*; Kato, Michio*; Nishimura, Kazuya*

IEEE Transactions on Nuclear Science, 65(9), p.2565 - 2572, 2018/09

 Percentile:100(Engineering, Electrical & Electronic)

In order to contribute to the development of technology to search fuel debris submerged in water inside the primary containment vessel of the Fukushima Daiichi Nuclear Power Station, we are developing a remotely operated vehicle (ROV) system equipped with a compact radiation detector and sonar. A cerium bromide (CeBr$$_{3}$$) scintillator detector for dose rate monitoring and $$gamma$$ ray spectroscopy was integrated into ROV and experimentally validated with a $$^{137}$$Cs source, both in the conditions of laboratory and submerged. In addition, the ROV combined with the IMAGENEX 831L sonar could characterize the shape and size of a simulated fuel debris at the bottom of the water pool facility.

Journal Articles

Study for estimation of snow depth by using DSM made by SfM method

Miyasaka, Satoshi*; Unome, Sota*; Tamura, Ayako*; Ito, Yoshiaki*; Ishizaki, Azusa; Sanada, Yukihisa

Nippon Rimoto Senshingu Gakkai Dai-63-Kai (Heisei-29-Nendo Shuki) Gakujutsu Koenkai Rombunshu (CD-ROM), p.81 - 84, 2017/11

Information of snow depth is important to improve the airborne radiation measurement in the winter. The snow depth is enable to estimate by the aerial photograph which is obtained at the same time with the radiation measurement before and after the snowfall. We attempted optimization parameters which used to make a Digital Surface Model (DSM) using Structure from Motion (SfM) method for estimation of the snow depth. As a result, to enable to measure precisely the snow depth was indicated. However, the estimated snow depth in the forest area was relatively not so accurate because fallen leaves and a tree move were prevented to measure DSM precisely.

Journal Articles

Using two detectors concurrently to monitor ambient dose equivalent rates in vehicle surveys of radiocesium contaminated land

Takeishi, Minoru; Shibamichi, Masaru; Malins, A.; Kurikami, Hiroshi; Murakami, Mitsuhiro*; Saegusa, Jun; Yoneya, Masayuki

Journal of Environmental Radioactivity, 177, p.1 - 12, 2017/10

AA2016-0534.pdf:1.79MB

By convention radiation measurements from vehicle-borne surveys are converted to the dose rate at 1 m above the ground in the absence of the vehicle. To improve the accuracy of the converted results from vehicle-borne surveys, we investigated combining measurements from two detectors mounted on the vehicle at different heights above the ground. A dual-detector setup was added to a JAEA monitoring car and compared against hand-held survey meter measurements in Fukushima Prefecture. The dose rates obtained by combining measurements from two detectors were within $$pm$$20% of the hand-held reference measurements. The combined results from the two detectors were more accurate than those from either the roof-mounted detector, or the detector inside the vehicle, taken alone. When radiocesium is deficient on a road compared to the adjacent land, mounting detectors high on vehicles yields dose rates closer to the values adjacent to the road. We also investigated mounting heights for vehicle-borne detectors using Monte Carlo $$gamma$$-ray simulations.

Journal Articles

Release behavior of Cs and its chemical form during late phase of Fukushima Daiichi Nuclear Power Plant accident

Hidaka, Akihide; Yokoyama, Hiroya

Proceedings of Symposium on Water Chemistry and Corrosion in Nuclear Power Plants in Asia 2017 (AWC 2017) (USB Flash Drive), p.29 - 42, 2017/09

no abstracts in English

Journal Articles

Challenges for enhancing Fukushima environmental resilience, 3; Development of measurement and evaluation techniques for the environmental radiation monitoring

Sanada, Yukihisa

Nippon Genshiryoku Gakkai-Shi, 59(7), p.418 - 422, 2017/07

no abstracts in English

Journal Articles

Airborne radiation monitoring using a manned helicopter

Sanada, Yukihisa; Ishizaki, Azusa; Nishizawa, Yukiyasu; Urabe, Yoshimi*

Bunseki Kagaku, 66(3), p.149 - 162, 2017/03

 Times Cited Count:4 Percentile:47.81(Chemistry, Analytical)

The Great East Japan Earthquake that occurred on 11 March 2011 generated a series of large tsunami waves that caused serious damage to the Fukushima Dai-ichi Nuclear Power Station, following which a large amount of radioactive material was discharged from the nuclear power plant into the environment. The airborne radiation measurement using a manned helicopter was applied to measure the radiation distribution immediately after accident of the Fukushima Dai-ichi Nuclear Power Station as technique to quickly measure the radiation distribution in the wide area. In Japan, this technique was researched and developed in the 1980s. However, this technique and system were not applied immediately after the accident because standardization of analysis was not established and the Japanese system became deteriorated. This technique is important for post-accident of nuclear facility. We summarized the methods of the airborne radiation measurement using a manned helicopter. In addition, measurement results of dose rate distribution at the Fukushima Dai-ichi Nuclear Power Station was shown in this paper.

Journal Articles

Survey and countermeasures on radiocesium inflow into a laboratory building for radioactivity analysis

Kurita, Yoshiyuki; Saegusa, Jun; Maeda, Satoshi

Nippon Hoshasen Anzen Kanri Gakkai-Shi, 15(2), p.180 - 185, 2016/11

In 2012, JAEA has established a laboratory in Fukushima-city to implement radioactivity analysis of environmental samples. Key nuclides measured in this laboratory are $$^{134}$$Cs and $$^{137}$$Cs (radiocesium). For the purpose, situation of radiocesium inflow into the laboratory building and its effects were investigated based on high-resolution gamma-spectrometry with germanium detectors. As a result, the surface density of radiocesium in the laboratory was found to be far below the minimum detectable activities of survey instruments routinely used for radiation control purposes.

JAEA Reports

Radiation monitoring using manned helicopter around the Fukushima Daiichi Nuclear Power Station in the fiscal year 2013 (Contract research)

Sanada, Yukihisa; Nishizawa, Yukiyasu; Urabe, Yoshimi; Yamada, Tsutomu; Ishida, Mutsushi; Sato, Yoshiharu; Hirayama, Hirokatsu; Takamura, Yoshihide; Nishihara, Katsuya; Imura, Mitsuo; et al.

JAEA-Research 2014-012, 110 Pages, 2014/08

JAEA-Research-2014-012.pdf:169.17MB
JAEA-Research-2014-012(errata).pdf:0.27MB

By the nuclear disaster of Fukushima Daiichi Nuclear Power Station (NPS), Tokyo Electric Power Company (TEPCO), caused by the East Japan earthquake and the following tsunami occurred on March 11, 2011, a large amount of radioactive materials was released from the NPP. This document was summarized in the results of the aerial radiation monitoring using the manned helicopter in the fiscal 2013.

JAEA Reports

Annual report on the activities of Health Physics in JAERI in 2004; April 1, 2004$$sim$$March 31, 2005

Department of Health Physics; Safety Division, Naka; Safety Division, Takasaki; Radiation Control Division, Oarai; Safety Division, Kansai; Operation Safety Administration Division, Mutsu

JAERI-Review 2005-028, 232 Pages, 2005/08

JAERI-Review-2005-028.pdf:13.23MB

no abstracts in English

Journal Articles

Environmental radiation monitoring system

Matsuura, Kenichi; Tachibana, Haruo

Denki Hyoron, 90(7), p.43 - 46, 2005/07

no abstracts in English

JAEA Reports

Radiation monitoring data of the HTTR rise-to-power test; Results up to 30MW operation on the high-temperature test operation mode

Ashikagaya, Yoshinobu; Kawasaki, Tomokatsu; Yoshino, Toshiaki; Ishida, Keiichi

JAERI-Tech 2005-010, 81 Pages, 2005/03

JAERI-Tech-2005-010.pdf:16.65MB

no abstracts in English

JAEA Reports

Annual report on the activities of Health Physics in JAERI in 2003; April 1, 2003$$sim$$March 31, 2004

Department of Health Physics; Safety Division, Naka; Safety Division, Takasaki; Radiation Control Division, Oarai; Safety Division, Kansai; Operation Safety Administration Division, Mutsu

JAERI-Review 2004-024, 209 Pages, 2004/11

JAERI-Review-2004-024.pdf:26.17MB

no abstracts in English

Journal Articles

Real-time monitoring of oxidation processes on the Si(001) surface using O$$_{2}$$ gas under 1000 K by synchrotron radiation photoemission spectroscopy

Yoshigoe, Akitaka; Moritani, Kosuke; Teraoka, Yuden

Surface Science, 566-568(Part.2), p.1124 - 1129, 2004/09

The Si(001) oxidaion is an important reaction for not only semiconductor technology but also surface science. It is known that the growth mode forming oxide-layers is divided into two regions depending on surface temperature conditions. One is passive oxidation and the other is two dimensional island growth including SiO desorption. Since the oxygen uptake measurements have been measured in many reported studies, Si oxidatuion states related to the growth of oxide-layers have not been clarified yet. In order to measure the time evolution of Si oxidation states depending on the surface temperature, we have performed the real-time photoemission measurements using synchrotron radiation at SUREAC2000 in SPring-8 . We found that the Si$$^{4+}$$ states was formed at the early oxidation stage in the two dimiensional island regions.

JAEA Reports

Standard of radiation monitor based on LAN and PLC technology for J-PARC

Miyamoto, Yukihiro; Sakamaki, Tsuyoshi*; Maekawa, Osamu*; Nakashima, Hiroshi

JAERI-Tech 2004-054, 72 Pages, 2004/08

JAERI-Tech-2004-054.pdf:7.3MB

A standard is provided for the radiation monitor based on LAN (Local Area Network) and PLC (Programmable Logic Controller) technology at the introduction to the Japan Proton Accelerator Research Complex (J-PARC). The monitor consists of radiation measurement equipments and the central monitoring panel. The formers are installed in the radiation field, and the latter is installed in the control room and composed of PLC, which are connected with LAN. Extension of the existing standard and the conformity to the international standard were thought as important in providing the standard. The standard is expected to improve the compatibility, maintenancability and productivity of the components.

JAEA Reports

Annual report of the activities of Health Physics in JAERI in 2002; April 1, 2002$$sim$$March 31, 2003

Department of Health Physics; Safety Division, Naka; Safety Division, Takasaki; Radiation Control Division, Oarai; Safety Division, Kansai; Operation Safety Administration Division, Mutsu

JAERI-Review 2003-034, 208 Pages, 2003/11

JAERI-Review-2003-034.pdf:13.41MB

no abstracts in English

Journal Articles

Radiation control system for J-PARC

Miyamoto, Yukihiro

Hokeikyo Nyusu, (32), p.2 - 3, 2003/10

no abstracts in English

61 (Records 1-20 displayed on this page)