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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.
Kokubun, Yuji; Nakada, Akira; Seya, Natsumi; Koike, Yuko; Nemoto, Masashi; Tobita, Keiji; Yamada, Ryohei*; Uchiyama, Rei; Yamashita, Daichi; Nagai, Shinji; et al.
JAEA-Review 2023-046, 164 Pages, 2024/03
JAEA-Review-2023-046.pdf:4.2MB
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 2022 to March 2023 and the results of dose calculations for the surrounding public due to the release of radioactive materials into the atmosphere and ocean. In the results of the above environmental radiation monitoring, many items were affected by radioactive materials emitted from the accident at the Fukushima Daiichi Nuclear Power Plant of Tokyo Electric Power Company, Incorporated (changed to Tokyo Electric Power Company Holdings, Inc. on April 1, 2016), which occurred in March 2011. Also included as appendices are an overview of the environmental monitoring plan, an overview of measurement methods, measurement results and their changes over time, meteorological statistics results, radioactive waste release status, and an evaluation of the data which deviated of the normal range.
Ohashi, Yusuke; Shimaike, Masamitsu; Matsumoto, Takashi; Takahashi, Nobuo; Yokoyama, Kaoru; Morimoto, Yasuyuki
Nuclear Technology, 209(5), p.777 - 786, 2023/05
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)At the Ningyo-Toge Center, technical development related to uranium refining conversion and enrichment has been completed, and decommissioning of these facilities has begun. The error between the quantity of dismantled materials estimated from the facility design drawings and the actual quantity of dismantled materials was minimal when averaging over the entire Uranium Refining and Conversion Plant and Uranium Enrichment Engineering Facility, which results indicated that the preliminary estimate of the quantity of dismantled materials for decommissioning was reasonable. Most of the dismantled materials, which have no contamination history and are properly managed were able to be carried out to recyclers as non-radioactive waste (NR). In addition, the possibility of evaluating the uranium concentration of clearance level in dismantled objects was confirmed through gamma-ray measurement tests using mock-up waste.
Rodriguez, D. C.; Abbas, K.*; Bertolotti, D.*; Bonaldi, C.*; Fontana, C.*; Fujimoto, Masami*; Geerts, W.*; Koizumi, Mitsuo; Macias, M.*; Nonneman, S.*; et al.
Proceedings of INMM & ESARDA Joint Annual Meeting 2023 (Internet), 8 Pages, 2023/05
Nakada, Akira; Kanai, Katsuta; Seya, Natsumi; Nishimura, Shusaku; Futagawa, Kazuo; Nemoto, Masashi; Tobita, Keiji; Yamada, Ryohei*; Uchiyama, Rei; Yamashita, Daichi; et al.
JAEA-Review 2022-078, 164 Pages, 2023/03
JAEA-Review-2022-078.pdf:2.64MB
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 2021 to March 2022. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Co., Inc. (the trade name was changed to Tokyo Electric Power Company Holdings, Inc. on April 1, 2016) in March 2011. Appendices present comprehensive information, such as monitoring programs, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data which were influenced by the accidental release and exceeded the normal range of fluctuation in the monitoring, were evaluated.
Nakada, Akira; Nakano, Masanao; Kanai, Katsuta; Seya, Natsumi; Nishimura, Shusaku; Nemoto, Masashi; Tobita, Keiji; Futagawa, Kazuo; Yamada, Ryohei; Uchiyama, Rei; et al.
JAEA-Review 2021-062, 163 Pages, 2022/02
JAEA-Review-2021-062.pdf:2.87MB
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 2020 to March 2021. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Co., Inc. (the trade name was changed to Tokyo Electric Power Company Holdings, Inc. on April 1, 2016) in March 2011. Appendices present comprehensive information, such as monitoring programs, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data which were influenced by the accidental release and exceeded the normal range of fluctuation in the monitoring, were evaluated.
Nakano, Masanao; Fujii, Tomoko; Nemoto, Masashi; Tobita, Keiji; Seya, Natsumi; Nishimura, Shusaku; Hosomi, Kenji; Nagaoka, Mika; Yokoyama, Hiroya; Matsubara, Natsumi; et al.
JAEA-Review 2020-069, 163 Pages, 2021/02
JAEA-Review-2020-069.pdf:4.78MB
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 2019 to March 2020. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Co., Inc. (the trade name was changed to Tokyo Electric Power Company Holdings, Inc. on April 1, 2016) in March 2011. Appendices present comprehensive information, such as monitoring programs, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data which were influenced by the accidental release and exceeded the normal range of fluctuation in the monitoring, were evaluated.
Toyomori, Yuka*; Tsuji, Satoru*; Mitsuda, Shinobu*; Okayama, Yoichi*; Ashida, Shiomi*; Mori, Atsunori*; Kobayashi, Toru; Miyazaki, Yuji; Yaita, Tsuyoshi; Arae, Sachie*; et al.
Bulletin of the Chemical Society of Japan, 89(12), p.1480 - 1486, 2016/09
Times Cited Count：9 Percentile：29.06(Chemistry, Multidisciplinary)Koike, Masato; Imazono, Takashi; Nagano, Tetsuya*; Sasai, Hiroyuki*; Oue, Yuki*; Yonezawa, Zeno*; Kuramoto, Satoshi*; Terauchi, Masami*; Takahashi, Hideyuki*; Notoya, Satoshi*; et al.
AIP Conference Proceedings 1741, p.040045_1 - 040045_4, 2016/07
Born is a trace element to improve quenching characteristics in steel. In order to detect the B-K emission band at around 6.76 nm more efficiently, we performed a feasibility study to enhance the diffraction efficiency of laminar-type diffraction grating based on a newly discovered physical phenomenon in the region of total reflection. The phenomenon is embodied as a transparent high-density material layer overcoated on a metal layer on grating grooves. The material should have intermediate diffractive index of vacuum and the metal layer. We found that high density diamond-like-carbon (DLC) is a one of the best material and simulated the diffraction efficiency in a spectral region of 3.5
8.5 nm. The optimum thickness and density of DLC are 24 nm and 3.1 g/cm
, respectively, for an incidence angle of 87
. Then the first order diffraction efficiency is expected to achieve up to 29.7 %, which is improved from 15.6 % for Ni or 14.1 % for Au, at 6.76 nm.
Imazono, Takashi; Koike, Masato; Nagano, Tetsuya*; Sasai, Hiroyuki*; Oue, Yuki*; Kuramoto, Satoshi*; Terauchi, Masami*; Takahashi, Hideyuki*; Notoya, Satoshi*; Murano, Takanori*; et al.
AIP Conference Proceedings 1741, p.040043_1 - 040043_4, 2016/07
We have experimentally found that the diffraction efficiency of a Ni-coated grating can be improved by merely overcoating a high-density carbon film, i.e., diamond-like carbon (DLC), on the grating. The thickness of Ni and DLC layers were 30 nm and 23 nm, respectively. The diffraction efficiencies of the Ni grating with DLC overcoating was measured to be 26.9% at 6.76 nm at an incident angle of 87.07
, which is about 90% of a simulation value of 29.7% and exceeds the measured efficiencies of the reference gratings, i.e., 16.9% for the Ni grating and 12.5% for the Au grating. This is the first experimental results of the enhancement of the diffraction efficiency by overcoating with a DLC on a conventional grating.
Takahashi, Masamitsu; Kozu, Miwa*; Sasaki, Takuo
Japanese Journal of Applied Physics, 55(4S), p.04EJ04_1 - 04EJ04_4, 2016/04
Times Cited Count：5 Percentile：21.98(Physics, Applied)Suzuki, Hidetoshi*; Nakata, Yuka*; Takahashi, Masamitsu; Ikeda, Kazuma*; Oshita, Yoshio*; Morohara, Osamu*; Geka, Hirotaka*; Moriyasu, Yoshitaka*
AIP Advances (Internet), 6(3), p.035303_1 - 035303_6, 2016/03
Times Cited Count：4 Percentile：17.55(Nanoscience & Nanotechnology)
synchrotron X-ray diffractionSasaki, Takuo; Ishikawa, Fumitaro*; Takahashi, Masamitsu
Applied Physics Letters, 108(1), p.012102_1 - 012102_5, 2016/01
Times Cited Count：5 Percentile：21.98(Physics, Applied) X-ray diffractionShimomura, Kenichi*; Suzuki, Hidetoshi*; Sasaki, Takuo; Takahashi, Masamitsu; Oshita, Yoshio*; Kamiya, Itaru*
Journal of Applied Physics, 118(18), p.185303_1 - 185303_7, 2015/11
Times Cited Count：9 Percentile：34.77(Physics, Applied)Takahashi, Masamitsu; Kozu, Miwa*; Sasaki, Takuo; Hu, W.*
Crystal Growth & Design, 15(10), p.4979 - 4985, 2015/10
Times Cited Count：16 Percentile：72.06(Chemistry, Multidisciplinary)Takahashi, Koji; Abe, Ganji; Kajiwara, Ken; Oda, Yasuhisa; Isozaki, Masami; Ikeda, Ryosuke; Sakamoto, Keishi; 2 of others*
Fusion Engineering and Design, 96-97, p.602 - 606, 2015/10
The recent physics analysis reveals that there is the potential to more than double the drive current at the range of 
= 0.4
0.6 if a beam steering direction can be modified from toroidal to poloidal. However, the change of steering direction has a significant impact on the design of the Equatorial EC Launcher (EL), especially, mm-wave propagation and blanket shield modules (BSMs) and a knock-on effect impacting the internal shield structure. The EL has three sets of mm-wave beam row and each is composed of eight waveguide lines and a quasi-optical transmission region that is formed a steering and fixed mirror, locating in front of the waveguide outlet. It has been successfully performed that the outstanding configuration of the mirrors is developed, the mirror actuator is changed from the push-pull to pneumatic concept and the modification of the internal shield structure is minimized as much as possible. This creative modification ensures that both mm-wave beams from the middle and bottom row pass through the same BSM opening and then, the feasible and reliable design of BSMs can be carried out. The nuclear analysis of this design modification shows that the residual dose rate at the launcher back end is reduced by 20%. This paper summarizes that the possible solution of the mm-wave design modification enhancing the off axis current drive functionality is developed and ensures the effective mm-wave propagation, feasible design of the EL BSMs and nuclear shield structure.
synchrotron X-ray diffractionSasaki, Takuo; Takahashi, Masamitsu
Nihon Kessho Seicho Gakkai-Shi, 42(3), p.210 - 217, 2015/10
Takahashi, Masamitsu
Nihon Kessho Seicho Gakkai-Shi, 42(3), p.201 - 209, 2015/10
three-dimensional X-ray reciprocal-space mapping of InGaAs multilayer structures grown on GaAs(001) by MBESasaki, Takuo; Takahashi, Masamitsu; Suzuki, Hidetoshi*; Oshita, Yoshio*; Yamaguchi, Masafumi*
Journal of Crystal Growth, 425, p.13 - 15, 2015/09
Times Cited Count：4 Percentile：34.19(Crystallography)
Co
O
filmHu, W.*; Hayashi, Koichi*; Fukumura, Tomoteru*; Akagi, Kazuto*; Tsukada, Masaru*; Happo, Naohisa*; Hosokawa, Shinya*; Owada, Kenji; Takahashi, Masamitsu; Suzuki, Motohiro*; et al.
Applied Physics Letters, 106(22), p.222403_1 - 222403_5, 2015/06
Times Cited Count：42 Percentile：80.35(Physics, Applied)