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Otokawa, Yoshinori; Matsuda, Makoto; Abe, Shinichi
JAEA-Technology 2022-037, 23 Pages, 2023/03
JAEA-Technology-2022-037.pdf:5.38MB
Bearing units of rotating shaft system for power generation in the JAEA-Tokai Tandem accelerator had a short operating life from the beginning of the accelerator installation, and even after replacing the bearing unit, early failures often occurred. Therefore, the quantity and frequency of replacement are large, and a lot of time is spent in regular maintenance performed by opening the accelerator pressure vessel, and solving this problem has been a long-standing concern. As a result of considering the cause of this early failure, it was considered that the load caused by parallel, angular, and axial misalignment of the upper and lower bearing units was the cause. In order to solve this problem, we have developed a bearing unit having metal disc-spring couplings in the upper and lower flanges to allow for parallel, angular, and axial misalignment of bearing units. As a result, it is now possible to allow variations in the distance between castings and parallel, angular, and axial misalignment of the upper and lower bearing units. By installing the developed new bearing unit on the rotating shaft system and making improvements while continuing to use it in actual operation, we succeeded in reducing the early failure and extending the operating life by more than double. With this development, the maintenance time has been reduced to one week by reducing the number of replacing the bearing unit. In addition, we have realized one regular maintenance that was carried out about three times a year, and as a benefit, we were able to reduce the amount of sulfur hexafluoride (SF
) gas, which is a greenhouse gas, to about 33
50% per year. We describe about development of new bearing units and these maintenance status from 2006 to 2020.
Kabumoto, Hiroshi; Matsuda, Makoto; Nakamura, Masahiko; Ishizaki, Nobuhiro; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; Nakagawa, Sohei; Abe, Shinichi
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1109 - 1113, 2023/01
no abstracts in English
-Mn and 
-MnOnuki, Yoshichika*; Aoki, Dai*; Nakamura, Ai*; Matsuda, Tatsuma*; Nakashima, Miho*; Haga, Yoshinori; Takeuchi, Tetsuya*
Journal of the Physical Society of Japan, 91(6), p.065001_1 - 065001_2, 2022/06
Times Cited Count：0 Percentile：0(Physics, Multidisciplinary)
IrSiOnuki, Yoshichika*; Kaneko, Yoshio*; Aoki, Dai*; Nakamura, Ai*; Matsuda, Tatsuma*; Nakashima, Miho*; Haga, Yoshinori; Takeuchi, Tetsuya*
Journal of the Physical Society of Japan, 91(6), p.065002_1 - 065002_2, 2022/06
Times Cited Count：0 Percentile：0(Physics, Multidisciplinary)
P, NiP, and PdSiOnuki, Yoshichika*; Nakamura, Ai*; Aoki, Dai*; Matsuda, Tatsuma*; Haga, Yoshinori; Harima, Hisatomo*; Takeuchi, Tetsuya*; Kaneko, Yoshio*
Journal of the Physical Society of Japan, 91(6), p.064712_1 - 064712_10, 2022/06
Times Cited Count：0 Percentile：0(Physics, Multidisciplinary)Matsuda, Makoto; Tayama, Hidekazu; Ishizaki, Nobuhiro; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; Abe, Shinichi
Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.394 - 398, 2021/10
no abstracts in English
Nishimura, Shoichiro*; Torii, Hiroyuki*; Fukao, Yoshinori*; Ito, Takashi; Iwasaki, Masahiko*; Kanda, Sotaro*; Kawagoe, Kiyotomo*; Kawall, D.*; Kawamura, Naritoshi*; Kurosawa, Noriyuki*; et al.
Physical Review A, 104(2), p.L020801_1 - L020801_6, 2021/08
Times Cited Count：12 Percentile：86.61(Optics)Matsuda, Makoto; Ishizaki, Nobuhiro; Tayama, Hidekazu; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; Abe, Shinichi; et al.
Proceedings of 17th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.948 - 952, 2020/09
no abstracts in English
and EuAu with the characteristic hexagonal structureMatsuda, Shinya*; Ota, Joji*; Nakaima, Kenri*; Iha, Wataru*; Gochi, Jun*; Uwatoko, Yoshiya*; Nakashima, Miho*; Amako, Yasushi*; Honda, Fuminori*; Aoki, Dai*; et al.
Philosophical Magazine, 100(10), p.1244 - 1257, 2020/04
Times Cited Count：3 Percentile：21.67(Materials Science, Multidisciplinary)
-electron state of the heavy fermion superconductor NpPdAl and the isostructural familyMetoki, Naoto; Aczel, A. A.*; Aoki, Dai*; Chi, S.*; Fernandez-Baca, J. A.*; Griveau, J.-C.*; Hagihara, Masato*; Hong, T.*; Haga, Yoshinori; Ikeuchi, Kazuhiko*; et al.
JPS Conference Proceedings (Internet), 30, p.011123_1 - 011123_6, 2020/03
Rare earths (4) and actinides (5) provide variety of interesting states realized with competing interactions between the increasing number of electrons. Since crystal field splitting of many-body electron system is smaller than the bandwidth, (1) high resolution experiments are needed, (2) essentially no clear spectrum with well defined peaks is expected in itinerant Ce and U compounds, and (3) Np and Pu is strictly regulated. Therefore, systematic research on magnetic excitations by neutron scattering experiments of localized compounds and rare earth iso-structural reference is useful. We describe the electron states of heavy electron compounds NpPdAl and actinide and rare earth based iso-structural family.
Si; Our current understandingKambe, Shinsaku; Tokunaga, Yo; Sakai, Hironori; Matsuda, Tatsuma*; Haga, Yoshinori; Walstedt, R. E.*; Harima, Hisatomo*
JPS Conference Proceedings (Internet), 30, p.011035_1 - 011035_5, 2020/03
Owing to recent investigations, understanding of the symmetry of hidden order and superconductivity in URuSi is fairly progressed. It seems that we are not far from the answer. Following issues and perspectives will be discussed.
Matsuda, Makoto; Osa, Akihiko; Ishizaki, Nobuhiro; Tayama, Hidekazu; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; et al.
Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1270 - 1273, 2019/07
The JAEA-Tokai tandem accelerator was operated over a total of 138 days, and delivered 16 different ions to the experiments in the research fields of nuclear physics, nuclear chemistry, atomic physics, solid state physics and radiation effects in material in FY2018. Maximum acceleration voltage was 16.6 MV. A new beam attenuator was installed at the entrance beam line of the tandem accelerator to facilitate control of the beam current and minimize stripper foil consumption. The main maintenance items included replacing the pellet chain used for about 68,000 hours and the drive motor for the high voltage terminal generator used for about 9 years. A fault has occurred in the building's oxygen deficiency monitor. This paper describes the operational status of the accelerators and the major technical developments of our facility.
Iha, Wataru*; Kakihana, Masashi*; Matsuda, Shinya*; Honda, Fuminori*; Haga, Yoshinori; Takeuchi, Tetsuya*; Nakashima, Miho*; Amako, Yasushi*; Gochi, Jun*; Uwatoko, Yoshiya*; et al.
Journal of Alloys and Compounds, 788, p.361 - 366, 2019/06
Times Cited Count：4 Percentile：36.18(Chemistry, Physical)Matsuda, Makoto; Osa, Akihiko; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro
JAEA-Conf 2018-003, p.126 - 131, 2019/02
no abstracts in English
Strasser, P.*; Abe, Mitsushi*; Aoki, Masaharu*; Choi, S.*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; et al.
EPJ Web of Conferences, 198, p.00003_1 - 00003_8, 2019/01
Times Cited Count：13 Percentile：99.33Kaneko, Koji; Frontzek, M. D.*; Matsuda, Masaaki*; Nakao, Akiko*; Munakata, Koji*; Ohara, Takashi; Kakihana, Masashi*; Haga, Yoshinori; Hedo, Masato*; Nakama, Takao*; et al.
Journal of the Physical Society of Japan, 88, p.013702_1 - 013702_5, 2019/01
Times Cited Count：56 Percentile：95.09(Physics, Multidisciplinary)
states in UPdAl and valence crossover in the Vicinity of Heavy-Fermion superconductivityMetoki, Naoto; Haga, Yoshinori; Yamamoto, Etsuji; Matsuda, Masaaki*
Journal of the Physical Society of Japan, 87(11), p.114712_1 - 114712_9, 2018/11
Times Cited Count：3 Percentile：30.28(Physics, Multidisciplinary)The localized 5 states with 5 (
) configuration of U
ion have been revealed in UPdAl. We found that the low-lying states are the same as PrPdAl flat orbitals with large 
are stabilized by a two-dimensional CEF potential in the unique crystal structure. The present study involves the valence crossover from tetravalent to trivalent in a series of AnPdAl, demonstrated by lattice and/or transport anomaly as well as many body effects in the vicinity of the boundary. The valence instability plays important role for the unusual heavy fermion superconductivity in NpPdAl.
electrons in actinide ferromagnets with spin fluctuation theoryTateiwa, Naoyuki; Posp
il, J.*; Haga, Yoshinori; Sakai, Hironori; Matsuda, Tatsuma*; Yamamoto, Etsuji
Progress in Nuclear Science and Technology (Internet), 5, p.104 - 107, 2018/11
Uranium ferromagnetic superconductors UGe, URhGe and UCoGe have attracted much attention from both theoretical and experimental sides since the same 5 electrons underlie carry both the ferromagnetism and superconductivity. Recently, we have analysed 69 uranium, 7 neptunium, and 4 plutonium ferromagnets with spin fluctuation theory originally developed for researches on itinerant ferromagnets in the 3
transition metals and their intermetallics. The applicability of the spin fluctuation theory to the actinide 5 system has been confirmed and the itinerant character of the 5f electrons is suggested in the actinide ferromagnets. In this conference, two results will be shown. One is the results of the analyses on 80 actinide ferromagnets and the other is the pressure dependence of the spin fluctuation parameters in UGe.
Matsuda, Makoto; Kabumoto, Hiroshi; Tayama, Hidekazu; Nakanoya, Takamitsu; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; Ishizaki, Nobuhiro; et al.
Proceedings of 15th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1271 - 1275, 2018/08
The JAEA-Tokai tandem accelerator was operated over a total of 64 days, and delivered 13 different ions to the experiments in the research fields of nuclear physics, nuclear chemistry, atomic physics, solid state physics and radiation effects in material in FY2017. After the vacuum accident occurred in December 2016 the accelerating voltage dropped to 12 MV. In order to remove dust and broken carbon foil in the accelerating tube, all 80 accelerator tubes were removed and rewashed. It took 4 months for cleaning and 2 months for reassembly. Therefore about 10 months were a maintenance period of an accelerator from February 2017. Along with the reconstruction of the accelerating tube, re-alignment of the accelerating tube was carried out. The operation resumed in December 2017 and it was possible to recover the maximum voltage to 17.4 MV without beam and 16.6 MV with beam with periodic conditioning work.
precipitate in Al-Mg-Zn alloysTsuru, Tomohito; Yamaguchi, Masatake; Ebihara, Kenichi; Itakura, Mitsuhiro; Shiihara, Yoshinori*; Matsuda, Kenji*; Toda, Hiroyuki*
Computational Materials Science, 148, p.301 - 306, 2018/06
Times Cited Count：37 Percentile：81.07(Materials Science, Multidisciplinary)Hydrogen embrittlement susceptibility of high strength 7xxx series Al alloys has been recognized as the critical issues in the practical use of Al alloys. Focusing on the interface between MgZn precipitates and an Al matrix, which is considered as one of the important segregation sites in these alloys, we investigated the stable 
-MgZn-Al interface, and the possible hydrogen trap sites in MgZn and at the -MgZn-Al interface via first-principles calculation. Most of the interstitial sites inside the MgZn crystal were not possible trap sites because their energy is relatively higher than that of other trap sites. The trap energy of the most favorable site at the -MgZn-Al is approximately -0.3 eV/H, which is more stable that of the interstitial site at the grain boundary. The interface between MgZn and Al is likely to be a possible trap site in Al alloys.
