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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
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.
Sumi, Tatsuya*; Nagai, Kazuki*; Bao, J.*; Terasawa, Tomoo; Norimatsu, Wataru*; Kusunoki, Michiko*; Wakabayashi, Yusuke*
Applied Physics Letters, 117(14), p.143102_1 - 143102_5, 2020/10
Times Cited Count：4 Percentile：25.35(Physics, Applied)A systematic structural study of epitaxial graphene samples on the SiC (0001) surface has been performed by the surface X-ray diffraction method, which is a non-contact technique. For samples with only a buffer layer, one layer graphene, and multilayer graphene, the distances between the buffer layer and the surface Si atoms were found to be 0.23 nm. This value is the same as reported values. For quasi-free-standing graphene samples prepared by the rapid cooling method, there was no buffer layer and the distance between the quasi-free-standing graphene and the surface Si atoms was 0.35 nm, which is significantly shorter than the value in hydrogen-intercalated graphene and slightly longer than the interplane distance in graphite. The Si occupancy deviated from unity within 1 nm of the SiC surface. The depth profile of the Si occupancy showed little sample dependence, and it was reproduced by a simple atomistic model based on random hopping of Si atoms.
AsIida, Kazuki*; Nagai, Yuki; Ishida, Shigeyuki*; Ishikado, Motoyuki*; Murai, Naoki; Christianson, A. D.*; Yoshida, Hiroyuki*; Inamura, Yasuhiro; Nakamura, Hiroki; Nakao, Akiko*; et al.
Physical Review B, 100(1), p.014506_1 - 014506_8, 2019/07
Times Cited Count：34 Percentile：84.65(Materials Science, Multidisciplinary)Magnetic excitations and magnetic structure of EuRbFeAs were investigated by neutron scattering measurements.
-AlOOH under mantle conditions using neutron diffractionSano, Asami; Hattori, Takanori; Komatsu, Kazuki*; Kagi, Hiroyuki*; Nagai, Takaya*; Molaison, J. J.*; Dos Santos, A. M.*; Tulk, C. A.*
Scientific Reports (Internet), 8(1), p.15520_1 - 15520_9, 2018/10
Times Cited Count：44 Percentile：92.58(Multidisciplinary Sciences)The pressure response of hydrogen bond in aluminous hydroxide -AlOOH, which is an important candidate for water carrier to the deep Earth in a subducting slab, was investigated using neutron diffraction under high pressure. The symmetrization of hydrogen bond in which hydrogen locates at the center between two oxygen atoms was observed directly for the first time. The present result indicates that the changes of mineral properties such as increase in bulk modulus and sound velocities, which were previously found, were induced by the symmetrization and disorder state that was also found at just below the symmetrization pressure. Even the symmetrization is a small change in the hydrogen location but it is playing an important role in determining the physical properties of minerals.
AsIida, Kazuki*; Ishikado, Motoyuki*; Nagai, Yuki; Yoshida, Hiroyuki*; Christianson, A. D.*; Murai, Naoki; Kawashima, Kenji*; Yoshida, Yoshiyuki*; Eisaki, Hiroshi*; Iyo, Akira*
Journal of the Physical Society of Japan, 86(9), p.093703_1 - 093703_4, 2017/09
Times Cited Count：23 Percentile：78.66(Physics, Multidisciplinary)Hattori, Takanori; Sano, Asami; Arima, Hiroshi*; Komatsu, Kazuki*; Yamada, Akihiro*; Inamura, Yasuhiro; Nakatani, Takeshi; Seto, Yusuke*; Nagai, Takaya*; Utsumi, Wataru; et al.
Nuclear Instruments and Methods in Physics Research A, 780, p.55 - 67, 2015/04
Times Cited Count：75 Percentile：98.97(Instruments & Instrumentation)PLANET is a time-of-flight (ToF) neutron beamline dedicated to high-pressure and high-temperature experiments. The large six-axis multi-anvil high-pressure press designed for ToF neutron diffraction experiments enables routine data collection at high pressures and high temperatures up to 10 GPa and 2000 K, respectively. To obtain clean data, the beamline is equipped with the incident slits and receiving collimators to eliminate parasitic scattering from the high-pressure cell assembly. The high performance of the diffractometer for the resolution (
/ 
0.6%) and the accessible -spacing range (0.2-8.4 
) together with low-parasitic scattering characteristics enables precise structure determination of crystals and liquids under high pressure and temperature conditions.
Iizuka, Riko*; Komatsu, Kazuki*; Kagi, Hiroyuki*; Nagai, Takaya*; Sano, Asami; Hattori, Takanori; Goto, Hirotada*; Yagi, Takehiko*
Journal of Solid State Chemistry, 218, p.95 - 102, 2014/10
Times Cited Count：7 Percentile：33.52(Chemistry, Inorganic & Nuclear)In situ neutron diffraction measurements combined with the pulsed neutron source at the Japan Proton Accelerator Research Complex (J-PARC) were conducted on high-pressure polymorphs of deuterated portlandite (Ca(OD)
) using a Paris-Edinburgh cell and a multi-anvil press. The atomic positions including hydrogen for the unquenchable high-pressure phase at room temperature (phase II') were first clarified. The bent hydrogen bonds under high pressure were consistent with results from Raman spectroscopy. The structure of the high-pressure and high-temperature phase (Phase II) was concordant with that observed previously by another group for a recovered sample. The observations elucidate the phase transition mechanism among the polymorphs, which involves the sliding of CaO polyhedral layers, position modulations of Ca atoms, and recombination of Ca-O bonds accompanied by the reorientation of hydrogen to form more stable hydrogen bonds.
Iizuka, Riko*; Kagi, Hiroyuki*; Komatsu, Kazuki*; Ushijima, Daichi*; Nakano, Satoshi*; Sano, Asami; Nagai, Takaya*; Yagi, Takehiko*
Physics and Chemistry of Minerals, 38(10), p.777 - 785, 2011/12
Times Cited Count：10 Percentile：33.16(Materials Science, Multidisciplinary)The pressure responses of portlandite and the isotope effect on the phase transition were investigated at room temperature from single-crystal Raman and IR spectra and from powder X-ray diffraction using diamond anvil cells under quasi-hydrostatic conditions in a helium pressure-transmitting medium. Phase transformation and subsequent peak broadening observed from the Raman and IR spectra of Ca(OH) occurred at lower pressures than those of Ca(OD). In contrast, no isotope effect was found on the volume and axial compressions observed from powder X-ray diffraction patterns. X-ray diffraction lines attributable to the high-pressure phase remained up to 28.5 GPa, suggesting no total amorphization in a helium pressure medium within the examined pressure region. These results suggest that the H-D isotope effect is engendered in the local environment surrounding H(D) atoms.
Utsumi, Wataru; Kagi, Hiroyuki*; Komatsu, Kazuki*; Arima, Hiroshi*; Nagai, Takaya*; Okuchi, Takuo*; Kamiyama, Takashi*; Uwatoko, Yoshiya*; Matsubayashi, Kazuyuki*; Yagi, Takehiko*
Nuclear Instruments and Methods in Physics Research A, 600(1), p.50 - 52, 2009/02
Times Cited Count：13 Percentile：64.57(Instruments & Instrumentation)The application of high pressure can induce dramatic changes in the physical properties of condensed matter. Diffraction experiments under high pressure provide precise structural information, which is fundamental to understand their origin. When in situ high pressure neutron diffraction becomes possible at J-PARC, further outstanding researches are expected such as crystal structure of hydrogen-bearing materials including hydrous minerals, order-disorder transitions of minerals, structure of light element liquid at high pressure, etc.. Conceptual designs of neutron optics and high pressure devices for J-PARC are introduced.
Hara, Tomohiro*; Oba, Ryoji*; Okabayashi, Kazuki*; Yoneda, Jiro*; Nagai, Haruyasu; Hayashi, Takashi*
Proceedings of International Workshop on Physical Modelling of Flow and Dispersion Phenomena (PHYSMOD 2007), p.167 - 174, 2007/08
We simulated a meandering effect of wind direction fluctuation on horizontal gas diffusion over Mt. Tsukuba, using a rotating turntable in the wind tunnel experiment. Experimental results were validated with field data observed by Japan Atomic Energy Research Institute (JAERI), 1989 and 1990. We also simulated actual unsteady phenomena of airflow and gas diffusion over Mt. Tsukuba, and compared the calculated results with field data. Both data agreed well under neutral, stable and unstable atmospheric stabilities.
Hayashi, Takashi; Chino, Masamichi; Yamazawa, Hiromi; Nagai, Haruyasu; Moriuchi, Shigeru*; Ishikawa, Hirohiko*; Adachi, Takashi*; Kojima, Hiromi*; Okano, Hiroshi*; Odagawa, Fumiaki*; et al.
JAERI-Tech 2001-034, 137 Pages, 2001/06
no abstracts in English
Hattori, Takanori; Sano, Asami; Arima, Hiroshi*; Komatsu, Kazuki*; Yamada, Akihiro*; Nagai, Takaya*; Katayama, Yoshinori; Inoue, Toru*; Utsumi, Wataru; Kagi, Hiroyuki*; et al.
no journal, ,
The PLANET is the world's first neutron beamline specialized for high-pressure and high-temperature experiments. The most characteristic feature is the capability to investigate the state of the matter at high-pressure and high-temperatures up to 20 GPa and 2000 K with the multi-anvil high-pressure apparatus. The construction was started in 2008. The beamline was commissioned in the first half year of JFY 2012 and the new data is being taken by project members. This year, the beamline is reborn to a public beamline of J-PARC. In this talk, the performance of the PLANET and the typical results are introduced. The resolution of the diffraction pattern (d/d=c.a 0.6%) was found to be almost equal to the designed value (0.5%). The elimination of the background from the sample surrounding materials, which is the most important feature of the high-pressure experiments, was found to be accomplished with the use of the severe incident collimator and radial receiving collimator system. The beamline is opened for general users since the last half year of JFY2013 (from Feb.).
Hattori, Takanori; Sano, Asami; Shioya, Masahiro; Yamada, Akihiro*; Arima, Hiroshi*; Inoue, Toru*; Inamura, Yasuhiro; Ito, Takayoshi*; Komatsu, Kazuki*; Kagi, Hiroyuki*; et al.
no journal, ,
The PLANET is the world's first neutron beamline specialized for high-pressure and high-temperature experiments. The most characteristic feature is the capability to investigate the state of the matter at high-pressure and high-temperatures up to 20 GPa and 2000 K with the multi-anvil high-pressure apparatus. The construction was started in 2008, and the beamline was commissioned in the last spring. The performance revealed by the commissioning will be introduced. The resolution of the diffraction pattern (d/d = 0.6%) was found to be almost equal to the designed value (0.5%). The elimination of the background from the sample surrounding materials, which is the most important feature of the high-pressure experiments, was found to be accomplished with the use of the severe incident collimator and radial receiving collimator system. The beamline is used by project members since this autumn and will be opened for general users in the next April.
Hattori, Takanori; Sano, Asami; Arima, Hiroshi*; Inamura, Yasuhiro; Yamada, Akihiro*; Komatsu, Kazuki*; Nagai, Takaya*; Katayama, Yoshinori; Inoue, Toru*; Kagi, Hiroyuki*; et al.
no journal, ,
The PLANET is the high-pressure neutron beamline newly constructed at Japanese pulsed neutron source J-PARC. The most characteristic feature of this beamline is to possess the huge 6-axis multi-anvil press with the maximum load of 500 ton per axis. By combining with time-of-flight neutron diffraction and neutron radiography techniques, we can observe high-pressure and high-temperature state of the matter at 10 GPa and 2000 K. To eliminate scattering from sample surrounding materials, we designed and installed the severe incident and receiving collimators. This can confine the diffraction gauge volume into less than 3 mm cube, which results in no contamination of sample diffraction pattern. This character has a big advantage in solving unidentified structures of high-pressure phases as well as the precise structure refinement.
Hattori, Takanori; Sano, Asami; Arima, Hiroshi*; Inamura, Yasuhiro; Yamada, Akihiro*; Komatsu, Kazuki*; Nagai, Takaya*; Katayama, Yoshinori; Inoue, Toru*; Kagi, Hiroyuki*; et al.
no journal, ,
The PLANET is the high-pressure beamline newly constructed at J-PARC. The beamline aims at revealing the effect of water on the Earth's interior. The most characteristic feature is to possess the huge 6-axis press with the maximum load of 500ton/axis, which can generate high-PT condition of 10 GPa and 2000 K, simultaneously. By using the state-of-the-art neutron diffraction and radiography techniques, the beamline offers microscopic and macroscopic information of materials at high-PT conditions. The beamline is designed so as to analyze structures of both crystalline and amorphous materials. The beamline is now being used by project members and will be opened for general users in the next February.
Sano, Asami; Komatsu, Kazuki*; Kagi, Hiroyuki*; Nagai, Takaya*; Hattori, Takanori
no journal, ,
-AlOOH, distorted rutile type oxyhydroxide is an important hydrous mineral in the deep earth because it is stable at the lower mantle condition. X-ray diffraction study found the change in the compressibility at high pressure which would be attributed to the symmetrization of hydrogen bond, but there is a difference in the pressure where the compression behaviors change. To investigate the D/H isotope effect on the symmetrization, high pressure neutron diffraction experiments were conducted at SNAP, SNS. The intensity of 120 reflection continues to decrease at high pressure and become almost zero intensity at 6.7 GPa, suggesting the transition from P2
nm to Pnnm as a precursor of the symmetrization. Strong D/H isotope effect was found in the hydrogen bond geometry; O-H distances are longer than O-D whereas H...O distances are shorter than D...O.
-AlOOH at high pressureSano, Asami; Komatsu, Kazuki*; Hattori, Takanori; Nagai, Takaya*; Kagi, Hiroyuki*; Molaison, J.*; Moreira Dos Santos, A.*; Tulk, C.*
no journal, ,
-AlOOH is a high pressure polymorph of diaspore. Previous theoretical studies predict that hydrogen bond become symmetric at high pressure. Neutron diffraction experiment at high pressure found that O-D bond is elongated at high pressure, in support these predictions. Powder X-ray diffraction studies also found that the change in compressibility occurs at high pressure. To investigate the sequence to the symmetrization and its relation with the change in compressibility, we conducted neutron diffraction experiments on -AlOOH was conducted at SNAP, SNS. The results suggest the transition from hydrogen ordered structure to disordered structure at 6.7 GPa. Strong DH isotope effect was also found in the hydrogen bond geometry at high pressure.
Sano, Asami; Komatsu, Kazuki*; Hattori, Takanori; Kagi, Hiroyuki*; Nagai, Takaya*
no journal, ,
no abstracts in English
Sano, Asami; Hattori, Takanori; Komatsu, Kazuki*; Kagi, Hiroyuki*; Nagai, Takaya*
no journal, ,
Hydrogen exists not only on the Earth's surface as liquid water but also incorporated into minerals in the deep mantle as hydroxyl ion. At ambient pressure on the surface of the Earth, hydrogen in minerals generally takes an asymmetric position between two oxygen atoms, which forms a short covalent bond on the one side and a long and relatively weak hydrogen bond on the other side. However, it was theoretically predicted in 1970' that the hydrogen in ice locates at the center between two oxygen atoms under high pressure, which is so-called symmetrization of hydrogen bond. To investigate how the symmetrization affects on the physical properties of minerals, we conducted neutron diffraction experiments on -AlOOH at high pressure. We observed that hydrogen reaches at the center between two oxygen atoms at 18.1 GPa. The present study revealed that even small change of hydrogen atomic position but the symmetrization can change the physical property of mineral.
Utsumi, Wataru; Abe, Jun; Hattori, Takanori; Fukazawa, Hiroshi; Yamauchi, Hiroki; Igawa, Naoki; Kagi, Hiroyuki; Arima, Hiroshi*; Arakawa, Masashi; Komatsu, Kazuki*; et al.
no journal, ,
no abstracts in English
