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Hayakawa, Kosetsu; Muraguchi, Masakazu*; Masebo, Yumeno*; Kojima, Yoichiro*; Oda, Masato*; Yabuta, Rina*; Ishii, Hiroyuki*; Honda, Mitsunori
AIP Advances (Internet), 16(2), p.025337_1 - 025337_8, 2026/02
Times Cited Count：0 Percentile：0.00Weathered biotite (WB), a clay-based layered mineral, becomes thermoelectrically active after molten-salt treatment above 700
C. In this study, we investigate how Cs and Sr intercalation influences its local structure and electrical conductivity. WB was treated with molten salts containing CsCl and/or SrCl
, and the resulting materials were analyzed using X-ray fluorescence (XRF), X-ray diffraction (XRD), X-ray absorption fine structure (XAFS), and four-probe conductivity measurements. XRF verified Cs/Sr incorporation, while XRD confirmed retention of the layered structure. XAFS revealed that, in the Cs/Sr-intercalated sample, the Sr-Si distance shortens by 
,
at elevated temperatures, indicating a closer interaction with the Si-O layer. Electrical conductivity measured from 630
860C showed that Cs/Sr-WB exhibits higher conductivity than Sr-WB in the 630780C region. These results suggest that interlayer ion rearrangement enhances conduction pathways, demonstrating the potential of interlayer structural control for designing clay-based thermoelectric materials.
Hayakawa, Kosetsu*; Muraguchi, Masakazu*; Masebo, Yumeno*; Kojima, Yoichiro*; Oda, Masato*; Yabuta, Rina*; Ishii, Hiroyuki*; Honda, Mitsunori
e-Journal of Surface Science and Nanotechnology (Internet), 23(3), p.290 - 295, 2025/07
We are developing materials using clay minerals for thermoelectric materials that can be used at high temperatures in environmental friendly applications. We have succeeded in obtaining thermoelectric properties at high temperatures, but we do not know why these properties are exhibited. In order to elucidate the structural changes of weathered biotite under high temperature conditions, we will develop an XAFS analysis method and clarify the local structure of Fe at high temperatures. The local structure analysis of Fe in samples sintered in atmospheric and vacuum environments reveals changes in the chemical bonding state of Fe.
Kusumoto, Toshiyuki*; Saruta, Koichi; Naoe, Takashi; Teshigawara, Makoto; Futakawa, Masatoshi; Hasegawa, Kazuo*; Tsuboi, Akihiko
Jikken Rikigaku, 23(4), p.310 - 315, 2023/12
Reducing spatter, i.e., melt droplets flown out of the melt pool, is one of the critical issues when laser cutting is employed as a machining tool for radioactive wastes because the ejected droplets can lead to radioactive contamination with potential human exposure. The spattering phenomena are complicated processes that involve multiple physical phenomena, causing difficulty in the determination of laser parameters to minimize the amount of spatter. Here we observe the spatter ejected from 316L stainless steel plates using a high-speed camera and apply a machine learning technique to these captured images on the basis of three distinctive behaviors appeared at specific time intervals of the process of spattering phenomena: (I) a vapor, (II) a liquid film and breakup into droplets, and (III) a liquid capillary. The numerical model established through the machine learning technique predicts the spattering phenomena with an accuracy of 89% and can be used to determine the laser power and beam diameter that reduce the spatter eruption during laser irradiation.
Ariyoshi, Gen; Saruta, Koichi; Kogawa, Hiroyuki; Futakawa, Masatoshi; Maeno, Koki*; Li, Y.*; Tsutsui, Kihei*
Proceedings of 20th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-20) (Internet), p.1407 - 1420, 2023/08
Cavitation damage on a target vessel due to proton beam-induced pressure waves is one of the crucial issues for the pulsed neutron source using a mercury spallation target. As a mitigation technique for the damage, the helium microbubble injection into the mercury has been carried out by using a swirl bubbler in order to utilize compressibility of bubbles. Moreover, double-walled structure, which consists of an outer wall and an inner wall, has been applied as the target head structure. In this study, we aim to develop an abnormality diagnostic technology to detect the inner wall cracking, which is caused by such cavitation damage, from the outside of the target vessel. The mercury flow fields in the case with the cracking are evaluated by computational fluid dynamics analysis based on finite element method. And then, effect of the cracking on the flow field is discussed from the point of view of the flow-induced vibration and the acoustic vibration.
Nomoto, Yasunobu; Mizuta, Naoki; Morita, Keisuke; Aoki, Takeshi; Okita, Shoichiro; Ishii, Katsunori; Kurahayashi, Kaoru; Yasuda, Takanori; Tanaka, Masato; Isaka, Kazuyoshi; et al.
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 7 Pages, 2023/05
Mizuta, Naoki; Morita, Keisuke; Aoki, Takeshi; Okita, Shoichiro; Ishii, Katsunori; Kurahayashi, Kaoru; Yasuda, Takanori; Tanaka, Masato; Isaka, Kazuyoshi; Noguchi, Hiroki; et al.
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 6 Pages, 2023/05
Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.
Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09
Times Cited Count：10 Percentile：75.71(Nuclear Science & Technology)In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.
Takeda, Tetsuaki*; Inagaki, Yoshiyuki; Aihara, Jun; Aoki, Takeshi; Fujiwara, Yusuke; Fukaya, Yuji; Goto, Minoru; Ho, H. Q.; Iigaki, Kazuhiko; Imai, Yoshiyuki; et al.
High Temperature Gas-Cooled Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.5, 464 Pages, 2021/02
As a general overview of the research and development of a High Temperature Gas-cooled Reactor (HTGR) in JAEA, this book describes the achievements by the High Temperature Engineering Test Reactor (HTTR) on the designs, key component technologies such as fuel, reactor internals, high temperature components, etc., and operational experience such as rise-to-power tests, high temperature operation at 950C, safety demonstration tests, etc. In addition, based on the knowledge of the HTTR, the development of designs and component technologies such as high performance fuel, helium gas turbine and hydrogen production by IS process for commercial HTGRs are described. These results are very useful for the future development of HTGRs. This book is published as one of a series of technical books on fossil fuel and nuclear energy systems by the Power Energy Systems Division of the Japan Society of Mechanical Engineers.
Naito, Fujio*; Anami, Shozo*; Ikegami, Kiyoshi*; Uota, Masahiko*; Ouchi, Toshikatsu*; Onishi, Takahiro*; Oba, Toshiyuki*; Obina, Takashi*; Kawamura, Masato*; Kumada, Hiroaki*; et al.
Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1244 - 1246, 2016/11
The proton linac installed in the Ibaraki Neutron Medical Research Center is used for production of the intense neutron flux for the Boron Neutron Capture Therapy (BNCT). The linac consists of the 3-MeV RFQ and the 8-MeV DTL. Design average beam current is 10mA. Target is made of Beryllium. First neutron production from the Beryllium target was observed at the end of 2015 with the low intensity beam as a demonstration. After the observation of neutron production, a lot of improvement s was carried out in order to increase the proton beam intensity for the real beam commissioning. The beam commissioning has been started on May 2016. The status of the commissioning is summarized in this report.
Terunuma, Akihiro; Mimura, Ryuji; Nagashima, Hisao; Aoyagi, Yoshitaka; Hirokawa, Katsunori*; Uta, Masato; Ishimori, Yuu; Kuwabara, Jun; Okamoto, Hisato; Kimura, Yasuhisa; et al.
JAEA-Review 2016-008, 98 Pages, 2016/07
JAEA-Review-2016-008.pdf:11.73MB
Japan Atomic Energy Agency formulated the plan to achieve the medium-term target in the period of April 2010 to March 2015(hereinafter referred to as "the second medium-term plan"). JAEA determined the plan for the business operations of each year (hereinafter referred to as "the year plan"). This report is that the Sector of Decommissioning and Radioactive Waste Management has summarized the results of the decommissioning technology development and decommissioning of nuclear facilities which were carried out in the second medium-term plan.
TiO
pebbleTsuchiya, Akihito*; Yamauchi, Yuji*; Nobuta, Yuji*; Hino, Tomoaki*; Akiba, Masato; Enoeda, Mikio
Fusion Engineering and Design, 89(7-8), p.1280 - 1283, 2014/10
Times Cited Count：3 Percentile：20.85(Nuclear Science & Technology)Lithium titanate (LiTiO) pebbles were irradiated with D3+ ions with energy of 5.0 keV, and the amounts of retained deuterium in the pebbles were measured by thermal desorption spectroscopy. Cycles of irradiation and heating were carried out repeatedly in order to investigate the influence of surface condition on deuterium release from LiTiO. The composition of Li decreased with the increase in the number of the irradiation and heating cycle. The desorption peaks of the gases contained deuterium atoms were shifted to higher temperature region. Total amount of desorbed deuterium showed the tendancy to increase. These results suggest that the tritium recovery efficiency would deteriorate with the increase in the damages and the defects especially at the lower temperature region during the use of blanket.
Yamamoto, Kazami; Kawase, Masato; Iwama, Yuhei; Fukuta, Shimpei; Kato, Yuko; Ouchi, Nobuo; Meigo, Shinichiro; Oi, Motoki; Kamikubota, Norihiko*
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.771 - 774, 2014/10
The radiation leak accident happened in the hadron experimental hall of J-PARC on May 23, 2013. The accident was caused by a target sublimation due to an unanticipated beam from the 50 GeV main ring (MR). To detect and prevent the radiation leakage in all facilities of J-PARC, we improve the machine protection system (MPS). In the J-PARC 3GeV synchrotron (Rapid Cycling Synchrotron, RCS), a monitoring system of an abnormal state of the extraction beam to the mercury target of material life science experiment facility (MLF) were prepared. The radiation level of the gas in the tunnel were able to always observed by connecting radiation safety system and accelerator control system. The dump temperature was included in the MPS. We also developed new interlock system that can stop the beam immediately when the beam current exceed the limit.
Oguri, Hidetomo; Hasegawa, Kazuo; Ito, Takashi; Chishiro, Etsuji; Hirano, Koichiro; Morishita, Takatoshi; Shinozaki, Shinichi; Ao, Hiroyuki; Okoshi, Kiyonori; Kondo, Yasuhiro; et al.
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.389 - 393, 2014/10
no abstracts in English
Sawabe, Yuki; Ito, Yuichi; Kawase, Masato; Fukuta, Shimpei; Suzuki, Takahiro*; Kikuzawa, Nobuhiro; Ouchi, Nobuo
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.748 - 751, 2014/10
no abstracts in English
Fukuta, Shimpei; Sawabe, Yuki; Suzuki, Takahiro*; Ishiyama, Tatsuya*; Kawase, Masato*; Ito, Yuichi; Kato, Yuko; Yoshii, Akinobu; Kikuzawa, Nobuhiro; Ouchi, Nobuo
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1122 - 1125, 2014/06
The installation of Cs-seeded RF-driven H
ion source (RF ion source) to J-PARC LINAC is scheduled in 2014. Similarly the replacement of RFQ III from RFQ is scheduled in 2014. The test stand of the cooperation of RF ion source & RFQ III is being made in the J-PARC LINAC building for the beam acceleration examination now. The J-PARC control group designed test stand control system by thinking that test stand control system had to be equal to J-PARC accelerator control system. Specifically, Introduction of MPS for protect an apparatus. Implementation of EPICS environment for remotely controlling the equipment. It is construction of the timing system for sending a timing signal to each accelerator component device. This report describes construction of the control system in a test stand.
Tsuchiya, Akihito*; Hino, Tomoaki*; Yamauchi, Yuji*; Nobuta, Yuji*; Akiba, Masato; Enoeda, Mikio
Fusion Engineering and Design, 88(9-10), p.2298 - 2301, 2013/10
Times Cited Count：2 Percentile：16.73(Nuclear Science & Technology)Lithium titanate (LiTiO) pebbles were irradiated with deuterium ions with energy of 1.7 keV and then exposed to helium or helium and hydrogen mixed gas at various temperatures, in order to evaluate the effects of gas exposure on deuterium removal from the pebbles. The amounts of residual deuterium in the pebbles were measured by thermal desorption spectroscopy. The mixing of hydrogen gas into helium gas enhanced the removal amount of deuterium. In addition, we also evaluated the pebbles exposed to the helium gas with different hydrogen mixture ratio from 0% to 1%, at 573 K. Although the amount of residual deuteriumin the pebbles after the exposure decreased with increasing the hydrogen mixture ratio, the implanted deuterium partly remained after the exposure. These results suggest that the tritium inventory may occur at low temperature region in the blanket during the operation.
Nobuta, Yuji*; Yamauchi, Yuji*; Hino, Tomoaki*; Akamaru, Satoshi*; Hatano, Yuji*; Matsuyama, Masao*; Suzuki, Satoshi; Akiba, Masato
Fusion Engineering and Design, 87(7-8), p.1070 - 1073, 2012/08
Times Cited Count：2 Percentile：16.24(Nuclear Science & Technology)Ito, Tatsuya*; Yamauchi, Yuji*; Hino, Tomoaki*; Shibayama, Tamaki*; Nobuta, Yuji*; Ezato, Koichiro; Suzuki, Satoshi; Akiba, Masato
Journal of Nuclear Materials, 417(1-3), p.1147 - 1149, 2011/10
Times Cited Count：14 Percentile：68.45(Materials Science, Multidisciplinary)Nobuta, Yuji*; Yokoyama, Kenji; Kanazawa, Jun*; Yamauchi, Yuji*; Hino, Tomoaki*; Suzuki, Satoshi; Ezato, Koichiro; Enoeda, Mikio; Akiba, Masato
Journal of Nuclear Materials, 417(1-3), p.607 - 611, 2011/10
Times Cited Count：2 Percentile：17.04(Materials Science, Multidisciplinary)Hino, Tomoaki*; Shibata, Hironobu*; Yamauchi, Yuji*; Nobuta, Yuji*; Suzuki, Satoshi; Akiba, Masato
Journal of Nuclear Materials, 417(1-3), p.713 - 717, 2011/10
Times Cited Count：9 Percentile：53.65(Materials Science, Multidisciplinary)