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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
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.
Kitazawa, Takafumi; Ikeda, Yoichi*; Sakakibara, Toshiro*; Matsuo, Akira*; Shimizu, Yusei*; Tokunaga, Yo; Haga, Yoshinori; Kindo, Koichi*; Nambu, Yusuke*; Ikeuchi, Kazuhiko*; et al.
Physical Review B, 108(8), p.085105_1 - 085105_7, 2023/08
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
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
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
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.
Kobayashi, Daima*; Yoshikawa, Tomohide*; Matsuo, Mamoru*; Iguchi, Ryo*; Maekawa, Sadamichi; Saito, Eiji; Nozaki, Yukio*
Physical Review Letters, 119(7), p.077202_1 - 077202_5, 2017/08
Times Cited Count:119 Percentile:97.53(Physics, Multidisciplinary)Matsuo, Yoichi*; Hase, Yoshihiro; Nozawa, Shigeki; Yoshihara, Ryohei; Narumi, Issei
JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 66, 2011/01
no abstracts in English
Li, T.*; Garg, U.*; Liu, Y.*; Marks, R.*; Nayak, B. K.*; Madhusudhana Rao, P. V.*; Fujiwara, Mamoru*; Hashimoto, Hisanobu*; Nakanishi, Kosuke*; Okumura, Shun*; et al.
Physical Review C, 81(3), p.034309_1 - 034309_11, 2010/03
Times Cited Count:107 Percentile:97.48(Physics, Nuclear)Matsuo, Yoichi*; Hase, Yoshihiro; Nozawa, Shigeki; Yoshihara, Ryohei; Narumi, Issei
JAEA-Review 2009-041, JAEA Takasaki Annual Report 2008, P. 76, 2009/12
no abstracts in English
Michiuchi, Takamasa*; Yokota, Yusuke*; Komatsu, Takuma*; Hayakawa, Hironori*; Kuroda, Tomoko*; Maeda, Daisuke*; Matsuo, Yoji*; Mori, Shigeo*; Yoshii, Kenji; Hanasaki, Noriaki*; et al.
Ferroelectrics, 378(1), p.175 - 180, 2009/00
Times Cited Count:18 Percentile:59.66(Materials Science, Multidisciplinary)We have synthesized the samples of LuFeO, which shows the ferroelectricity due to charge ordering of Fe ions, under several different reducing conditions using a CO-CO flow. The reducing condition was changed by changing a flow ratio of CO and CO. It was found that the flow ratio of CO/CO of about 5 provided the sample with the highest magnetic transition temperature of 240-250 K. This sample showed the dielectric constant of 10000 at room temperature. The imaginary part of the dielectric response offered the activation energy of 0.4-0.5 eV, which is slightly larger than that reported previously (about 0.3 eV). We will perform further investigation of the physical properties of this sample to clarify full details and their origin of LuFeO.
Matsuo, Yoichi*; Hase, Yoshihiro; Yoshihara, Ryohei; Narumi, Issei
JAEA-Review 2008-055, JAEA Takasaki Annual Report 2007, P. 74, 2008/11
no abstracts in English
Matsuo, Yoichi*; Hase, Yoshihiro; Yoshihara, Ryohei; Narumi, Issei
no journal, ,
no abstracts in English
Matsuo, Yoichi*; Hase, Yoshihiro; Nozawa, Shigeki; Yoshihara, Ryohei; Yokota, Yuichiro; Narumi, Issei; Oyabu, Eiko*
no journal, ,
no abstracts in English
Ikeda, Naoshi*; Kambe, Takashi*; Komatsu, Takuma*; Michiuchi, Takamasa*; Hayakawa, Hironori*; Hanasaki, Noriaki*; Yoshii, Kenji; Matsuo, Yoji*; Mori, Shigeo*
no journal, ,
A review will be given on the new type of ferroelectric material LuFeO. This oxide becomes ferroelectric below about 330 K, owing to the charge-ordered arrangement of Fe ions on a triangular lattice: This is a novel mechanism of ferroelectricity. We discuss the experimental results obtained from resonant X-ray diffraction, dielectric response, polarization and magnetization to show some interesting properties of this new ferroelectric oxide.
Matsumoto, Keisuke*; Matsuo, Yoji*; Oishi, Daisuke*; Akahama, Yuji*; Yoshii, Kenji; Hanasaki, Noriaki*; Kambe, Takashi*; Ikeda, Naoshi*; Kimizuka, Noboru*; Mori, Shigeo*
no journal, ,
We have investigated the charge-ordered structure and physical properties of YbFeMnO. Electron diffraction measurements showed a disappearance of charge-ordered structure of Fe ions by the Mn substitution. The Mn substitution also led to a monotonic decrease in magnetic transition temperature, low-temperature magnetization and dielectric constants. The results are explained in connection with several factors such as short-range ionic order.
Matsuo, Yoichi*; Nozawa, Shigeki; Hase, Yoshihiro; Yoshihara, Ryohei; Narumi, Issei
no journal, ,
no abstracts in English
Kiyanagi, Ryoji; Matsuo, Yasumitsu*; Ohara, Takashi; Kawasaki, Takuro; Oikawa, Kenichi; Kaneko, Koji; Tamura, Itaru; Hanashima, Takayasu*; Munakata, Koji*; Nakao, Akiko*; et al.
no journal, ,
The materials represented as MH(XO) is known to exhibit a super protonic conductivity at rather low temperature. The protonic conductivity emerges upon a structural phase transition, and the phase transition temperature varies depending on the elements at M and X. In addition, the protonic conductivity also varies depending on the elements, but the origin has not been uncovered. In order to clarify the relation between the structure and the protonic conductivity including the phase transition mechanism, Solid solutions of super protonic conductors, RbKH(SeO) (x=0, 1, 2, 3), were structurally investigated by single crystal neutron diffraction. The structure analyses showed evident linear relation between the lattice parameters and x. Meanwhile, K was found to preferably reside at one of the two M sites. A apparent relation between the occupancy of K at one site and the transition temperature and the hydrogen-bond length were demonstrated.
Kiyanagi, Ryoji; Matsuo, Yasumitsu*; Ohara, Takashi; Kawasaki, Takuro; Oikawa, Kenichi; Kaneko, Koji; Tamura, Itaru; Nakao, Akiko*; Hanashima, Takayasu*; Munakata, Koji*; et al.
no journal, ,
The materials represented as MH(XO) are known to exhibit super protonic conductivity at rather low temperature, but the mechanism of the super protonic phase transition and the protonic conduction have not been clarified. In this study, a mixed material, RbKH(SeO), was investigated by means of conductivity measurements and neutron diffraction. The neutron diffraction experiments were conducted on BL18 at J-PARC/MLF. The conductivity measurements revealed that the phase transition temperature significantly changes below x=2. Meanwhile, the neutron structure analyses revealed that K atoms exclusively occupy one of two non-equivalent sites for M atoms below x=2. These observations are indicative of the close relationship between the phase transition and the internal atomic arrangement.
Kiyanagi, Ryoji; Matsuo, Yasumitsu*; Ohara, Takashi; Kawasaki, Takuro; Oikawa, Kenichi; Kaneko, Koji; Tamura, Itaru; Hanashima, Takayasu*; Munakata, Koji*; Nakao, Akiko*; et al.
no journal, ,
MH(SeO) forms a material group that exhibits superprotonic conductivity at rather low temperature. The superprotonic conductivity manifests itself upon a structural phase transition. The phase transition temperature varies depending on the elements of M and X. In order to clarify the relation between the crystal structure and the phase transition, RbKH(SeO) was investigated by means of a conductivity measurement and single crystal neutron structure analyses. The phase transition temperature was found to be non-linear to the variation of x by the conductivity measurement. The structure analyses revealed that the site occupancy of K at one of two M sites non-linearly varied with respect to x. This suggest that a close relation between the M site and the superprotonic phase transition.
Kiyanagi, Ryoji; Matsuo, Yasumitsu*; Ohara, Takashi; Kawasaki, Takuro; Oikawa, Kenichi; Kaneko, Koji; Tamura, Itaru; Hanashima, Takayasu*; Munakata, Koji*; Nakao, Akiko*; et al.
no journal, ,
The materials, MH(XO) (M=alkaline metal, X=Se, S), exhibit high protonic conductivities in a relatively low temperature region. The high protonic conductivities emerge upon a structural phase transition and the phase transition temperature (Tc) varies depending on the elements of M and X. In this study, mixed materials, RbKH(SeO), were studied by means of conductivity measurements and single crystal neutron structure analyses in order to clarify how the elements at the M site affect the Tc from the structural aspect. The conductivity measurements revealed that the Tc decreased as the K content increased. The variation of the Tc was found to be non-linear with respect to the K content. The structure analyses showed that the K ions preferred to occupy one of two M sites and the occupancy of the K ion at this site non-linearly varied. In addition, the SeO tetrahedron became more distorted as the K content increased, suggesting the close relationship between the distortion and the Tc.