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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.
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.
Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.
Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07
This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.
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.
Yuguchi, Takashi*; Shobuzawa, Kaho*; Ogita, Yasuhiro*; Yagi, Koshi*; Ishibashi, Masayuki; Sasao, Eiji; Nishiyama, Tadao*
American Mineralogist, 104(4), p.536 - 556, 2019/04
Times Cited Count：23 Percentile：74.41(Geochemistry & Geophysics)This study describes the plagioclase alteration process with a focus on the role of micropores, mass transfer and reaction rate in the Toki granitic pluton, central Japan. The plagioclase alteration process involves albitization, K-feldspathization, and the formation of illite, calcite, fluorite and epidote. Such secondary minerals of hydrothermal origin in plagioclase within granitic rocks record the chemical characteristics of the hydrothermal fluid. Our results highlight (1) the nature of micropores such as distribution and volume in plagioclase, (2) the reaction nature of plagioclase alteration inferred by petrography and chemistry, (3) the physical conditions including alteration age and temperature, (4) the sequential variations of the fluid chemistry and (5) the mass transfer rate and reaction rate in the plagioclase alteration.
Yuguchi, Takashi*; Sueoka, Shigeru; Iwano, Hideki*; Izumino, Yuya*; Ishibashi, Masayuki; Danhara, Toru*; Sasao, Eiji; Hirata, Takafumi*; Nishiyama, Tadao*
Journal of Asian Earth Sciences, 169, p.47 - 66, 2019/01
Times Cited Count：18 Percentile：62.95(Geosciences, Multidisciplinary)This study presents position-by-position 
paths within a granitic pluton based on thermochronological data, and describes their constraints and their relationship with fracture frequency, as an example from the Toki granite, central Japan. The cooling paths have position-specific characteristics; a single path does not represent the cooling behavior of the entire pluton. Such position-specific paths enable us to evaluate three-dimensional thermal evolution within the granitic pluton, and thus can clarify the detailed formation history of the entire pluton after the incipient intrusion of the granitic magma into the shallow crust. This study reveals the relationship between position-specific paths and fracture frequency, and thus provides a criterion for evaluating the fracture population in terms of thermal stress.
Yuguchi, Takashi*; Sueoka, Shigeru; Iwano, Hideki*; Danhara, Toru*; Ishibashi, Masayuki; Sasao, Eiji; Nishiyama, Tadao*
Island Arc, 26(6), p.e12219_1 - e12219_15, 2017/11
Times Cited Count：12 Percentile：34.98(Geosciences, Multidisciplinary)The spatial distribution of AFT age in the granitic body is a favorable key to reveal a cooling behavior of the whole pluton. The cooling behavior is attributable to the regional exhumation of the Toki granite related to the regional denudation of the Tono district. Combination of the AERs and AFT inverse model applying to the granite is a powerful procedure for evaluating the cooling and exhumation history of the granitic pluton and thus denudation history of the tectonic region that surrounded the rock body.
Theis, C.*; Carbonez, P.*; Feldbaumer, E.*; Forkel-Wirth, D.*; Jaegerhofer, L.*; Pangallo, M.*; Perrin, D.*; Urscheler, C.*; Roesler, S.*; Vincke, H.*; et al.
EPJ Web of Conferences, 153, p.08018_1 - 08018_5, 2017/09
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)At CERN, gas-filled ionization chambers PTW-34031 (PMI) are commonly used in radiation fields including neutrons, protons and 
-rays. A response function for each particle is calculated by the radiation transport code FLUKA. To validate a response function to high energy neutrons, benchmark experiments with quasi mono-energetic neutrons have been carried out at RCNP, Osaka University. For neutron irradiation with energies below 200 MeV, very good agreement was found comparing the FLUKA simulations and the measurements. In addition it was found that at proton energies of 250 and 392 MeV, results calculated with neutron sources underestimate the experimental data due to a non-negligible gamma component originating from the target 
Li(p,n)Be reaction.
Matsumoto, Tetsuro*; Masuda, Akihiko*; Nishiyama, Jun*; Iwase, Hiroshi*; Iwamoto, Yosuke; Satoh, Daiki; Hagiwara, Masayuki*; Yashima, Hiroshi*; Yashima, Hiroshi*; Shima, Tatsushi*; et al.
EPJ Web of Conferences, 153, p.08016_1 - 08016_3, 2017/09
Times Cited Count：1 Percentile：58.71(Nuclear Science & Technology)Neutron energy spectra behind concrete and iron shields were measured for quasi-monoenergetic neutrons above 200 MeV using a Bonner sphere spectrometer (BSS). Quasi-monoenergetic neutrons were produced by the Li(p,xn) reaction with 246-MeV and 389-MeV protons. The response function of BSS was also measured at neutron energies from 100 MeV to 387 MeV. In data analysis, the measured response function was used and the multiple neutron scattering effect between the BSS and the shielding material was considered. The neutron energy spectra behind the concrete and iron shields were obtained by the unfolding method using the MAXED code. Ambient dose equivalents were obtained as a function of a shield thickness successfully. For the case of the 244 MeV neutron incidence, the multiple neutron scattering effect on the effective dose is large under 50 cm thickness of the concrete shield.
Masuda, Akihiko*; Matsumoto, Tetsuro*; Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Sato, Tatsuhiko; Iwase, Hiroshi*; Yashima, Hiroshi*; Nakane, Yoshihiro; Nishiyama, Jun*; et al.
Nuclear Instruments and Methods in Physics Research A, 849, p.94 - 101, 2017/03
Times Cited Count：1 Percentile：9.61(Instruments & Instrumentation)Quasi-monoenergetic high-energy neutron fields induced by Li(p,n) reactions are used for the response evaluation of neutron-sensitive devices. The quasi-monoenergetic high-energy field consists of high-energy monoenergetic peak neutrons and unwanted continuum neutrons down to the low-energy region. A two-angle differential method has been developed to compensate for the effect of the continuum neutrons in the response measurements. In this study, the two-angle differential method was demonstrated for Bonner sphere detectors, which are typical examples of moderator-based neutron-sensitive detectors, to investigate the method's applicability and its dependence on detector characteristics. Through this study, the adequacy of the two-angle differential method was experimentally verified, and practical suggestions were made pertaining to this method.
Yuguchi, Takashi*; Iwano, Hideki*; Kato, Takenori*; Sakata, Shuhei*; Hattori, Kentaro*; Hirata, Takafumi*; Sueoka, Shigeru; Danhara, Toru*; Ishibashi, Masayuki; Sasao, Eiji; et al.
Journal of Mineralogical and Petrological Sciences, 111(1), p.9 - 34, 2016/02
Times Cited Count：19 Percentile：54.18(Mineralogy)Zircon growth collected from a granitic pluton shows four (1st - 4th) events with specific mechanisms, crystallization temperatures and U-Pb ages, revealing the sequential formation process from intrusion through emplacement to crystallization / solidification. The events are recognized by: (1) internal structure of zircon based on the cathodoluminescence observation, (2) crystallization temperatures by the Ti-in-zircon thermometer in the internal structure and (3) U-Pb ages in the internal structure.
Yuguchi, Takashi; Sasao, Eiji; Ishibashi, Masayuki; Nishiyama, Tadao*
American Mineralogist, 100(5-6), p.1134 - 1152, 2015/05
Times Cited Count：39 Percentile：76.10(Geochemistry & Geophysics)This paper describes the biotite chloritization process with a focus on mass transfer in the Toki granitic pluton, Central Japan, and also depicts the temporal variations in chemical characteristics of hydrothermal fluid associated with chloritization during the sub-solidus cooling of the pluton. Singular value decomposition (SVD) analysis results in chloritization reaction equations for eight mineral assemblages, leading to the quantitative assessment of mass transfer between the reactant and product minerals, and inflow and outflow of components through the hydrothermal fluid. The matrices for SVD analysis consist of arbitrary combinations of molar volume and closure component in the reactant and product minerals. The eight reactions represent the temporal variations of chemical characteristics of the hydrothermal fluid associated with chloritization: the progress of chloritization results in gradual increase of silicon, potassium and chlorine and gradual decrease of calcium and sodium in the hydrothermal fluid with temperature decrease. The biotite chloritization involves two essential formation processes: Formation Process 1, small volume decrease from biotite to chlorite and large inflow of metallic ions from the hydrothermal fluid, and Formation Process 2, large volume decrease and large outflow of metallic ions into hydrothermal fluid. Chlorite produced during Formation Process 1 dominates over that of Formation Process 2, resulting in the gradual decrease of metallic components in the hydrothermal fluid with chloritization progress. The combination of continuous reactions based on compositional variations in chlorite together with corresponding continuous Al
variations gives an indication of the temporal variations in rates of decreasing and increasing concentration of chemical components in the hydrothermal fluid associated with chloritization.
Watanabe, Hitoshi; Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Inoue, Kazumi; Yoshii, Hideki*; Otani, Kazunori*; Hiyama, Yoshinori*; Goto, Ichiro*; Kibe, Satoshi*; et al.
JAEA-Review 2014-040, 115 Pages, 2015/01
JAEA-Review-2014-040.pdf:4.26MB
Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2013. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.
Terada, Kentaro*; Ninomiya, Kazuhiko*; Osawa, Takahito; Tachibana, Shogo*; Miyake, Yasuhiro*; Kubo, Kenya*; Kawamura, Naritoshi*; Higemoto, Wataru; Tsuchiyama, Akira*; Ebihara, Mitsuru*; et al.
Scientific Reports (Internet), 4, p.5072_1 - 5072_6, 2014/05
Times Cited Count：49 Percentile：83.14(Multidisciplinary Sciences)After the discovery of X-ray by Rontgen, mankind got a new eye to see through things. This fluoroscopy, so-called X-ray radiography that gives the density distribution of the inside of an object, has been applied to the vast research field such as natural/material/medical sciences, industry and technology. The recent development on the intense pulsed muon source at J-PARC MUSE (rate of 106 cps for 60 MeV/c) enabled us to pioneer a new frontier of analytical sciences. Here we report on a non-destructive elemental analysis by using muon capture. Controlling muon's momentum from 32.5 to 57.5 MeV/c. we successfully demonstrated a depth-profile analysis of light elements from several mm-thick layered materials, and non-destructive bulk analyses of meteorites containing organics. Now it is a beginning to utilize a new eye, muon radiography.
Matsumoto, Tetsuro*; Masuda, Akihiko*; Nishiyama, Jun*; Harano, Hideki*; Iwase, Hiroshi*; Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Yashima, Hiroshi*; Nakane, Yoshihiro; et al.
Progress in Nuclear Science and Technology (Internet), 4, p.332 - 336, 2014/04
Recently, many high-energy accelerators are used for various fields. Shielding data for high-energy neutrons are therefore very important from the point of view of radiation protection in high energy accelerator facilities. However, the shielding experimental data for high energy neutrons above 100 MeV are very poor both in quality and in quantity. In this study, neutron penetration spectral fluence and ambient dose through iron and concrete shields were measured with a Bonner sphere spectrometer (BSS). Quasi-monoenergetic neutrons were produced by the Li(p,xn) reaction by bombarding a 1-cm thick Li target with 246-MeV and 389-MeV protons in the Research Center for Nuclear Physics (RCNP) of the Osaka University. Shielding materials are iron blocks with a thickness from 10 cm to 100 cm and concrete blocks with a thickness from 25 cm to 300 cm.
Hikima, Ryoichi*; Hirano, Toru*; Yamashita, Masayuki*; Ishiyama, Koji*; Tanno, Takeo*; Sanada, Hiroyuki; Sato, Toshinori
JAEA-Research 2013-040, 51 Pages, 2014/03
JAEA-Research-2013-040.pdf:6.86MB
For the research and development about high-level radioactive waste disposal, it is important to evaluate the mechanical stability of the excavation and the long-term behavior of in situ rock. However, from the limited information such as the bowling core before the excavation, it is difficult to evaluate the mechanical properties of in situ rock containing cracks. For this reason, evaluation of rock properties based on Specific Energy using mechanical data from an excavation machine is carried out. This report describes the results of the joint research carried out in FY 2010 to FY 2012.
Sumiya, Shuichi; Watanabe, Hitoshi; Miyagawa, Naoto; Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Inoue, Kazumi; Yoshii, Hideki; Otani, Kazunori*; Hiyama, Yoshinori*; et al.
JAEA-Review 2013-041, 115 Pages, 2014/01
JAEA-Review-2013-041.pdf:19.01MB
Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, and the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), this report describes the effluent control results of liquid waste discharged from the JAEA's Nuclear Fuel Cycle Engineering Laboratories in the fiscal year 2012, from 1st April 2012 to 31st March 2013. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other facilities were much lower than the authorized limits of the above regulations.
Hikima, Ryoichi*; Hirano, Toru*; Yamashita, Masayuki*; Ishiyama, Koji*; Sato, Toshinori; Sanada, Hiroyuki; Tanno, Takeo
Heisei-25 Nendo (2013 Nen) Shigen, Sozai Gakkai Shuki Taikai Koenshu, p.247 - 248, 2013/08
no abstracts in English
