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Suzuki, Masaaki*; Ito, Mari*; Hashidate, Ryuta; Takahashi, Keita; Yada, Hiroki; Takaya, Shigeru
2020 9th International Congress on Advanced Applied Informatics (IIAI-AAI 2020), p.797 - 801, 2021/07
Yamauchi, Hiroki; Metoki, Naoto; Watanuki, Ryuta*; Suzuki, Kazuya*; Fukazawa, Hiroshi; Chi, S.*; Fernandez-Baca, J. A.*
Journal of the Physical Society of Japan, 86(4), p.044705_1 - 044705_9, 2017/04
Times Cited Count：14 Percentile：67.59(Physics, Multidisciplinary)Neutron diffraction experiments have been carried out to characterize the magnetic structures and order parameters in an intermediate phase of NdB showing the successive phase transitions at 
K, 
K, and 
K. The observed patterns in phase II (
) are successfully explained by postulating a planar structure with static magnetic moments in the tetragonal 
-plane. We have found that the magnetic structure in phase II can be uniquely determined to be a linear combination of noncolinear "all-in/all-out"-type and "vortex"-type antiferromagnetic structures. We propose that the quadrupolar interaction holds the key to stabilizing the noncollinear magnetic structure and quadrupolar order. Here, the frustration in the Shastry - Sutherland lattice would play an essential role in suppressing the dominance of the magnetic interaction.
Takamatsu, Kuniyoshi; Takegami, Hiroaki; Ito, Chikara; Suzuki, Keiichi*; Onuma, Hiroshi*; Hino, Ryutaro; Okumura, Tadahiko*
Annals of Nuclear Energy, 78, p.166 - 175, 2015/04
Times Cited Count：10 Percentile：64(Nuclear Science & Technology)In our study, we focused on a nondestructive inspection method by which cosmic-ray muons could be used to observe the internal reactor from outside the RPV and the CV. We conducted an observation test on the HTTR to evaluate the applicability of the method to the internal visualization of a reactor. We also analytically evaluated the resolution of existing muon telescopes to assess their suitability for the HTTR observation, and were able to detect the major structures of the HTTR based on the distribution of the surface densities calculated from the coincidences measured by the telescopes. Our findings suggested that existing muon telescopes could be used for muon observation of the internal reactor from outside the RPV and CV.
Mitamura, Hiroyuki*; Watanuki, Ryuta*; Kaneko, Koji; Onozaki, Norimichi*; Amo, Yuta*; Kittaka, Shunichiro*; Kobayashi, Riki*; Shimura, Yasuyuki*; Yamamoto, Isao*; Suzuki, Kazuya*; et al.
Physical Review Letters, 113(14), p.147202_1 - 147202_5, 2014/10
Times Cited Count：23 Percentile：75.83(Physics, Multidisciplinary)Takegami, Hiroaki; Takamatsu, Kuniyoshi; Ito, Chikara; Hino, Ryutaro; Suzuki, Keiichi*; Onuma, Hiroshi*; Okumura, Tadahiko*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 13(1), p.7 - 16, 2014/03
One of the important problems for controlling of the Fukushima Daiichi Nuclear Power Plant is removing of fuel debris. As this preparation, the nondestructive inspection method for grasping the position of fuel debris is required. Therefore, we focused on a nondestructive inspection method using cosmic-ray muons. In this study, the applicability of this method for internal visualization of reactor was confirmed by preliminary test of internal visualization of High Temperature Engineering Test Reactor (HTTR). By using cosmic-ray muons, major components in the HTTR, such as concrete wall and reactor core, can be observed from the outside of a containment vessel. From the results, it appears that the inspection method with muons is a candidate method for searching the fuel debris in a reactor. Based on the results, we also proposed some improvements of this system for inspection at the Fukushima Daiichi Nuclear Power Station.
Takegami, Hiroaki; Terada, Atsuhiko; Noguchi, Hiroki; Kamiji, Yu; Ono, Masato; Takamatsu, Kuniyoshi; Ito, Chikara; Hino, Ryutaro; Suzuki, Keiichi*; Onuma, Hiroshi*; et al.
JAEA-Research 2013-032, 25 Pages, 2013/12
JAEA-Research-2013-032.pdf:3.56MB
We focused on a non-destructive inspection method using cosmic-ray muons as a candidate method for observation of internal the reactor from the outside of a reactor building. In this study, the applicability of this method for the reactor investigation was confirmed by a preliminary examination with High Temperature Engineering Test Reactor (HTTR). From the results of this examination, it appears that high density structures, such as the core and concrete walls, were able to observe by using muon telescope with coincidence method from the outside of the pressure vessel. Furthermore, we proposed some improvements of this muon inspection system for on-site investigation at the Fukushima Daiichi NPS.
Tokunaga, Tomonori*; Watanabe, Hideo*; Yoshida, Naoaki*; Nagasaka, Takuya*; Kasada, Ryuta*; Lee, Y.-J.*; Kimura, Akihiko*; Tokitani, Masayuki*; Mitsuhara, Masatoshi*; Hinoki, Tatsuya*; et al.
Journal of Nuclear Materials, 442(1-3), p.S287 - S291, 2013/11
Times Cited Count：11 Percentile：63.81(Materials Science, Multidisciplinary)Suzuki, Keiichi*; Onuma, Hiroshi*; Takegami, Hiroaki; Takamatsu, Kuniyoshi; Hino, Ryutaro; Okumura, Tadahiko*
Shadan Hojin Butsuri Tansa Gakkai Dai-129-Kai (Heisei-25-Nendo Shuki) Gakujutsu Koenkai Koen Rombunshu, p.131 - 134, 2013/10
In the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, the nuclear fuel had melted down due to loss of coolant and had already become debris. The debris would fall to the bottom of the CV. To remove the debris for future decommission is necessary; however the area and the size are unclear. On the other hand, cosmic ray muons are absorbed extremely in the debris because of the high density of uranium and plutonium. The inner structure of the nuclear reactor may be visualized with muons penetrating easily throught such the high-density material, as a non-contact or -destructive inspection. In this study, the muons through the HTTR were measured and visualizing the internal structure was attempted. As a result, high density areas were recognized at the same position as that of the reactor pressure vessel (RPV); therefore, the technical possibility with muons could be demonstrated. In the near future, new R&Ds will be promoted toward the practical use.
Kobayashi, Riki; Kaneko, Koji; Wakimoto, Shuichi; Chi, S.*; Sanada, Naoyuki*; Watanuki, Ryuta*; Suzuki, Kazuya*
Journal of the Korean Physical Society, 63(3), p.337 - 340, 2013/08
Times Cited Count：4 Percentile：33.49(Physics, Multidisciplinary)
Tokunaga, Yo; Saito, Yo*; Sakai, Hironori; Kambe, Shinsaku; Sanada, Naoyuki*; Watanuki, Ryuta*; Suzuki, Kazuya*; Kawasaki, Yu*; Kishimoto, Yutaka*
Physical Review B, 84(21), p.214403_1 - 214403_7, 2011/12
Times Cited Count：8 Percentile：36.01(Materials Science, Multidisciplinary)We report NMR studies of TbCoGa, which has the tetragonal HoCoGa structure and exhibits two antiferromagnetic (AF) transitions at 
=36.2 K and 
=5.4 K. From a symmetry analysis of internal magnetic fields at orthorhombic Ga sites, we have successfully determined the magnetic structures in the AF-I (
) and AF-II (
) phases. The AF-I phase is a collinear AF order with a propagation vector ![$$q=[1/2, 0, 1/2]$$](/search/images/ERYT0WZRF2ZCYIBQFQQDCLZSLUSA.gif)
and ordered moments parallel to the [001] direction. In the AF-II phase, on the other hand, we found a non-collinear AF structure described by double propagation vectors ![$$q_1=[1/2, 0, 1/2]$$](/search/images/ERYV4MJ3LMYS4MRMEAYCYIBRF2ZF0JA.gif)
and ![$$q_{2}=[0, 1/2, 1/2]$$](/search/images/ERYV44ZSPU4VWMBMEAYS4MRMEAYS4MS3EQ.gif)
, where the moments tilt away from the [001] direction toward [100], keeping a constant value along the [001] direction. In the context of these results we discuss the possible presence of magnetic frustration in this system.
Hino, Ryutaro; Yokomizo, Hideaki; Yamazaki, Yoshishige; Hasegawa, Kazuo; Suzuki, Hiromitsu; Soyama, Kazuhiko; Hayashi, Makoto*; Haga, Katsuhiro; Kaminaga, Masanori; Sudo, Yukio*; et al.
Nihon Kikai Gakkai-Shi, 107(1032), p.851 - 882, 2004/11
no abstracts in English
Oyama, Yukio; Mizumoto, Motoharu; Hino, Ryutaro; Takizuka, Takakazu; *; Yasuda, Hideshi; Watanabe, Noboru*; Mukaiyama, Takehiko
Proc. of 2nd Int. Topical Meeting on Nuclear Applications of Accelerator Technology (AccApp'98), p.337 - 344, 1998/00
no abstracts in English
Hino, Ryutaro; Fujisaki, Katsuo; ; ; Ota, Yukimaru; ; ; Haga, Katsuhiro; ; Mogi, Haruyoshi; et al.
JAERI-Tech 96-037, 45 Pages, 1996/09
no abstracts in English
Hino, Ryutaro; Suzuki, Kunihiro; Haga, Katsuhiro; Nekoya, Shinichi; Fukaya, Kiyoshi; Shimizu, Saburo; Onuki, Kaoru; Takada, Shoji; Mogi, Haruyoshi; Sudo, Yukio
JAERI-Review 95-016, 115 Pages, 1995/10
no abstracts in English
; Hino, Ryutaro; Inagaki, Yoshiyuki; Takase, Kazuyuki; Ioka, Ikuo; Takada, Shoji; Suzuki, Kunihiro; Kunitomi, Kazuhiko; Maruyama, So;
JAERI 1333, 196 Pages, 1995/03
no abstracts in English
; Suzuki, Kunihiro; Hino, Ryutaro; Takase, Kazuyuki; Inagaki, Yoshiyuki; Ioka, Ikuo
Nucl. Eng. Des., 120, p.435 - 445, 1990/00
Times Cited Count：3 Percentile：40.34(Nuclear Science & Technology)no abstracts in English
Suzuki, Kazuyuki; Nakamura, Yoshinobu; Miyoshi, Ryuta; Sugai, Eiji; Hayashi, Shinichiro; Uchida, Toshitsugu*
no journal, ,
The pulse filter used by the dissolution and clarification process of the Tokai Reprocessing Plant uses the sintering metal powder filter. As for the sintering metal powder filter, being jammed is easy to occur by sludge. The basic examination of the sintering laminating wire mesh filter for the sintering metal powder filter was carried out.
Hata, Katsuro; Suzuki, Kazuyuki; Miyoshi, Ryuta; Sugai, Eiji; Hikita, Keiichi; Nakamura, Yoshinobu; Hayashi, Shinichiro
no journal, ,
The pulse filter of the clarification process used the sintered metal powder filter at Tokai reprocessing plant. It is known that the sintered metal powder filter is easy to be clogged up by sludge. Therefore, we examined the filtration performance of the sintered laminated wire mesh filter which might substitute for the sintered metal powder filter.
Michimura, Shinji; Inami, Toshiya; Sanada, Naoyuki*; Watanuki, Ryuta*; Suzuki, Kazuya*
no journal, ,
no abstracts in English
Kaneko, Koji; Sanada, Naoyuki*; Watanuki, Ryuta*; Suzuki, Kazuya*; Osakabe, Toyotaka
no journal, ,
no abstracts in English
