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Futemma, Akira; Sanada, Yukihisa; Nakama, Shigeo; Sasaki, Miyuki; Ochi, Kotaro; Sawahata, Yoshiro*; Kawasaki, Yoshiharu*; Iwai, Takeyuki*; Hiraga, Shogo*; Haginoya, Masashi*; et al.
JAEA-Technology 2024-022, 170 Pages, 2025/03
JAEA-Technology-2024-022.pdf:15.09MB
On March 11, 2011, the 2011 off the Pacific coast of Tohoku Earthquake caused a tsunami that led to the Fukushima Daiichi Nuclear Power Station accident, releasing radioactive material into the environment. Since then, Aerial Radiation Monitoring (ARM) using manned helicopters has been employed to measure radiation distribution. As a commissioned project from the Nuclear Regulation Authority, the Japan Atomic Energy Agency (JAEA) utilizes this technology for emergency monitoring during nuclear facility accidents, aiming to provide prompt results by pre-arranging information on background radiation, topography, and control airspaces around nuclear power plants nationwide. In fiscal year 2023, the commissioned project included conducting ARM around the Sendai Nuclear Power Station and preparing related information. To enhance effectiveness during emergencies, ARM and the first domestic training flight of Unmanned Aerial Vehicles (UAVs) were conducted during the FY2023 Nuclear Energy Disaster Prevention Drill. Furthermore, UAVs radiation monitoring technology was advanced by selecting UAVs and investigating their performance. This report summarizes the results and technical issues identified providing insights to improve emergency preparedness.
Kokubun, Yuji; Hosomi, Kenji; Nagaoka, Mika; Seya, Natsumi; Inoue, Kazumi; Koike, Yuko; Uchiyama, Rei; Sasaki, Kazuki; Maehara, Yushi; Matsuo, Kazuki; et al.
JAEA-Review 2024-054, 168 Pages, 2025/03
JAEA-Review-2024-054.pdf:2.73MB
The Nuclear Fuel Cycle Engineering Laboratories conducts environmental radiation monitoring around the reprocessing plant in accordance with the "Safety Regulations for Reprocessing Plant of JAEA, Part IV: Environmental Monitoring". This report summarizes the results of environmental radiation monitoring conducted during the period from April 2023 to March 2024 and the results of dose calculations for the surrounding public due to the release of radioactive materials from the plant into the atmosphere and ocean. In the results of the above environmental radiation monitoring, several items were affected by radioactive materials emitted from the accident at the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company, Incorporated (changed to Tokyo Electric Power Holdings, Inc. on April 1, 2016), which occurred in March 2011. In addition, environmental monitoring plan, analysis and measurement methods, monitoring data and their chronological change, meteorological data after statistical processing, status of radioactive waste release and evaluation results of the data over the normal range are included as appendices.
Futemma, Akira; Sanada, Yukihisa; Sasaki, Miyuki; Kawasaki, Yoshiharu*; Iwai, Takeyuki*; Hiraga, Shogo*; Haginoya, Masashi*; Matsunaga, Yuki*; Akutsu, Yuichiro*; Arai, Yoshinori*; et al.
JAEA-Technology 2023-026, 161 Pages, 2024/03
JAEA-Technology-2023-026.pdf:14.66MB
By the accident at Tokyo Electric Power Company's (TEPCO's) Fukushima Daiichi Nuclear Power Station (FDNPS), caused by tsunami triggered by the 2011 off the Pacific coast of Tohoku Earthquake, a large amount of radioactive material was released into the surrounding environment. After the accident, Airborne Radiation Monitoring (ARM) via manned helicopter has been utilized as a method to quickly and extensively measure radiation distribution surrounding FDNPS. In order to utilize ARM and to promptly provide the results during a nuclear emergency, information on background radiation levels, topographical features, and controlled airspace surrounding nationwide nuclear facilities have been prepared in advance. In the fiscal year 2022, we conducted ARM around the Mihama Nuclear Power Station of Kansai Electric Power Company (KEPCO), the Tsuruga Power Station of Japan Atomic Power Company (JAPC), and the Ikata Power Station of Shikoku Electric Power Company (YONDEN), and prepared information on background radiation doses and controlled airspace. In addition, we have developed an aerial radiation detection system via unmanned airplane, which is expected to be an alternative to ARM, during a nuclear emergency. This report summarizes the results and technical issues identified.
Oba, Yojiro; Sasaki, Hirokazu*
Nihon Genshiryoku Gakkai-Shi ATOMO
, 65(8), p.499 - 502, 2023/08
no abstracts in English
Futemma, Akira; Sanada, Yukihisa; Sasaki, Miyuki; Kawasaki, Yoshiharu*; Iwai, Takeyuki*; Hiraga, Shogo*; Haginoya, Masashi*; Matsunaga, Yuki*; Akutsu, Yuichiro*; Hokama, Tomonori; et al.
JAEA-Technology 2022-028, 127 Pages, 2023/02
JAEA-Technology-2022-028.pdf:15.21MB
A large amount of radioactive material was released by the nuclear disaster of Fukushima Daiichi Nuclear Power Station (FDNPS), Tokyo Electric Power Company, caused by the Great East Japan Earthquake and the following tsunami on March 11, 2011. After the nuclear disaster, airborne radiation monitoring via manned helicopter has been utilized to grasp rapidly and widely the distribution of the radioactive materials surrounding FDNPS. We prepare the data of background radiation dose, geomorphic characteristics and the controlled airspace surrounding nuclear facilities of the whole country in order to make effective use of the monitoring technique as a way of emergency radiation monitoring and supply the results during an accident of a facility. This report has summarized the knowledge noted above achieved by the aerial radiation monitoring around Ohi and Takahama nuclear power stations. In addition, the examination's progress aimed at introducing airborne radiation monitoring via an unmanned plane during a nuclear disaster and the technical issues are summarized in this report.
Sasaki, Hirokazu*; Akiya, Shunta*; Oba, Yojiro; Onuma, Masato*; Giddings, A. D.*; Okubo, Tadakatsu*
Materials Transactions, 63(10), p.1384 - 1389, 2022/10
Times Cited Count：1 Percentile：4.80(Materials Science, Multidisciplinary)Sasaki, Hirokazu*; Akiya, Shunta*; Oba, Yojiro; Onuma, Masato*; Giddings, A. D.*; Okubo, Tadakatsu*
Do To Dogokin, 60(1), p.309 - 314, 2021/08
no abstracts in English
Yamazaki, Satoshi*; Hirose, Kiyoshige*; Sasaki, Hirokazu*; Oba, Yojiro; Miyazawa, Tomotaka*; Onuma, Masato*
Do To Dogokin, 60(1), p.315 - 319, 2021/08
no abstracts in English
Abe, Mitsushi*; Bae, S.*; Beer, G.*; Bunce, G.*; Choi, H.*; Choi, S.*; Chung, M.*; da Silva, W.*; Eidelman, S.*; Finger, M.*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2019(5), p.053C02_1 - 053C02_22, 2019/05
Times Cited Count：161 Percentile：99.30(Physics, Multidisciplinary)This paper introduces a new approach to measure the muon magnetic moment anomaly 
and the muon electric dipole moment (EDM) 
at the J-PARC muon facility. The goal of our experiment is to measure 
and using an independent method with a factor of 10 lower muon momentum, and a factor of 20 smaller diameter storage-ring solenoid compared with previous and ongoing muon g-2 experiments with unprecedented quality of the storage magnetic field. Additional significant differences from the present experimental method include a factor of 1000 smaller transverse emittance of the muon beam (reaccelerated thermal muon beam), its efficient vertical injection into the solenoid, and tracking each decay positron from muon decay to obtain its momentum vector. The precision goal for is a statistical uncertainty of 450 parts per billion (ppb), similar to the present experimental uncertainty, and a systematic uncertainty less than 70 ppb. The goal for EDM is a sensitivity of 
e
cm.
nanocolumns in Zr-added (Gd,Y)Ba
CuOx superconductor tape by anomalous small-angle X-ray scatteringOba, Yojiro; Sasaki, Hirokazu*; Yamazaki, Satoshi*; Nakasaki, Ryusuke*; Onuma, Masato*
Superconductor Science and Technology, 32(5), p.055011_1 - 055011_5, 2019/05
Times Cited Count：1 Percentile：3.89(Physics, Applied)Sasaki, Hirokazu*; Nishikubo, Hideo*; Nishida, Shinsuke*; Yamazaki, Satoshi*; Nakasaki, Ryusuke*; Isomatsu, Takemi*; Minato, Ryuichiro*; Kinugawa, Kohei*; Imamura, Akihiro*; Otomo, Shinya*; et al.
Furukawa Denko Jiho, (138), p.2 - 10, 2019/02
no abstracts in English
Takeda, Seiji; Sasaki, Toshihisa*; Nagasawa, Hirokazu; Kimura, Hideo
JAEA-Data/Code 2010-019, 61 Pages, 2010/11
JAEA-Data-Code-2010-019.pdf:1.47MB
In deep geological disposal or intermediate depth disposal, human intrusion, i.e. accidental excavation or drilling into the disposal site, may make a direct or indirect effect on the disposal system. Assessment of the human intrusion would need the examination of institutional control to reduce the probability of the intrusion occurring, the estimation of its probability, and the development of method to estimate its associated exposure of persons, as well as some foreign countries. Assuming that drilling action into the disposal site especially leads to the human proximity to the radioactive waste or the damage to the barrier system (drilling scenario), we have developed the evaluation code of radiological effect from the human intrusion into radioactive waste disposal system (HUINT). The evaluation code of human intrusion scenario, HUINT, can calculate the radiation exposure dose for the workers of a series of actions accompanied with drilling and for the workers and public people concerned with the reuse of drilling cores, identified with the actual information on drilling action in Japan. This report provides the descriptions of mathematical models on the drilling scenario, input specification and user information for execution of HUINT (user manual), and the result of verification for calculation with the models in HUINT.
Nagasawa, Hirokazu; Takeda, Seiji; Kimura, Hideo; Sasaki, Toshihisa*
JAEA-Data/Code 2010-018, 85 Pages, 2010/11
JAEA-Data-Code-2010-018.pdf:1.94MB
In deep geological disposal or intermediate depth disposal, human intrusion, i.e. accidental excavation or drilling into the disposal site, may make a direct or indirect effect on the disposal system. Assessment of the human intrusion would need the examination of institutional control to reduce the probability of the intrusion occurring, the estimation of its probability, and the development of method to estimate its associated exposure of persons, as well as some foreign countries. Assuming that drilling action into the disposal site especially leads to the human proximity to the radioactive waste or the damage to the barrier system (drilling scenario), we have collected both the data on borehole drilling implemented in Japan and information on actual situation of drilling activities. We have developed an assembly of the information mentioned above as database, including the model parameters used in the code to assess radiation dose for drilling scenario.
Takeda, Seiji; Yamaguchi, Tetsuji; Nagasawa, Hirokazu; Watanabe, Masatoshi; Sekioka, Yasushi; Kanzaki, Yutaka; Sasaki, Toshihisa; Ochiai, Toru; Munakata, Masahiro; Tanaka, Tadao; et al.
JAEA-Research 2009-034, 239 Pages, 2009/11
JAEA-Research-2009-034.pdf:33.52MB
In safety assessment for geological disposal of high level radioactive waste, it is of consequence to estimate the uncertainties due to the long-term frame associated with long-lived radionuclides and the expanded geological environment. The uncertainties result from heterogeneity intrinsic to engineered and natural barrier materials, insufficient understanding of phenomena occurring in the disposal system, erroneous method of measurement, and incomplete construction. It is possible to quantify or to reduce the uncertainties according to scientific and technological progress. We applied a deterministic and a Monte Carlo-based probabilistic method simulation techniques to the uncertainty analysis for performance of hypothetical geological disposal system for high level radioactive waste. This study provides the method to evaluate the effects of the uncertainties with respect to scenarios, models and parameters in engineering barrier system on radiological consequence. The results also help us to specify prioritized models and parameters to be further studied for long-term safety assessment.
Kuroda, Toshimasa*; Sato, Kazuyoshi; Akiba, Masato; Ezato, Koichiro; Enoeda, Mikio; Osaki, Toshio*; Kosaku, Yasuo; Sato, Satoshi; Sato, Shinichi*; Suzuki, Satoshi*; et al.
JAERI-Tech 2002-044, 25 Pages, 2002/03
JAERI-Tech-2002-044.pdf:2.68MB
no abstracts in English
Sasaki, Hirokazu*; Isomatsu, Takemi*; Higuchi, Masaru*; Oba, Yojiro; Onuma, Masato*
no journal, ,
no abstracts in English
Oba, Yojiro; Sasaki, Hirokazu*; Yamazaki, Satoshi*; Nakasaki, Ryusuke*; Onuma, Masato*
no journal, ,
no abstracts in English
Sasaki, Hirokazu*; Akiya, Shunta*; Oba, Yojiro; Onuma, Masato*; Okubo, Tadakatsu*; Uzuhashi, Jun*
no journal, ,
no abstracts in English
Nagasawa, Hirokazu; Takeda, Seiji; Kimura, Hideo; Sasaki, Toshihisa
no journal, ,
no abstracts in English
Yamashita, Shinichiro; Mohamad, A. B.; Ioka, Ikuo; Nemoto, Yoshiyuki; Kawanishi, Tomohiro; Kaji, Yoshiyuki; Osaka, Masahiko; Murakami, Nozomu*; Owaki, Masao*; Sasaki, Masana*; et al.
no journal, ,
Japan's Accident Tolerant Fuel (ATF) research and development (R&D) program has been conducted since 2015 in cooperation with power plant providers, fuel venders and universities for making the most use of the experiences in R&D, practical design, and evaluations of fuels and cores of commercial Light Water Reactors (LWRs). An overview of the present R&D progress is given, in relation to the role of Japan Atomic Energy Agency (JAEA) in the program. The ATF candidate materials currently under consideration are the following three claddings: the silicon carbide (SiC) composite which is potentially applicable for Pressurized Water Reactor (PWR) and Boiling Water Reactor (BWR), the FeCrAl steel strengthened by dispersion of fine oxide particles (FeCrAl-ODS) for BWR, and Cr-coated zircalloy claddings for PWR. In addition to the cladding materials, R&D on the SiC-made BWR channel box and accident tolerant control rods are also underway.
