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Itoi, Hiroyuki*; Ninomiya, Takeru*; Hasegawa, Hideyuki*; Maki, Shintaro*; Sakakibara, Akihiro*; Suzuki, Ryutaro*; Kasai, Yuto*; Iwata, Hiroyuki*; Matsumura, Daiju; Owada, Mao*; et al.
Journal of Physical Chemistry C, 124(28), p.15205 - 15215, 2020/07
Times Cited Count：8 Percentile：40.15(Chemistry, Physical)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：64.63(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.
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.
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.
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
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：40.4(Nuclear Science & Technology)no abstracts in English
Takamatsu, Kuniyoshi; Takegami, Hiroaki; Ito, Chikara; Hino, Ryutaro; Suzuki, Keiichi*; Akiyama, Mitsuru*
no journal, ,
no abstracts in English
Takamatsu, Kuniyoshi; Takegami, Hiroaki; Ito, Chikara; Hino, Ryutaro; Suzuki, Keiichi*; Akiyama, Mitsuru*
no journal, ,
Cosmic ray muons can pass through large structures such as industrial plants and buildings including foundation. Engineering Advancement Association of Japan (ENAA) and Kawasaki Geological Engineering (KGE) have developed an exploration system using cosmic ray muons for detecting underground cavities which have a potential to bring about disasters. Japan Atomic Energy Agency (JAEA) has started an applicability test of this technology to the Fukushima Dai-ichi Nuclear Power Plants together with ENAA and KGE in October, 2012. In the test, core internal structures of the High Temperature Engineering Test Reactor (HTTR) will be visualized to obtain practical data on resolution and measuring time necessary for improving the system.
Ozeki, Ryutaro*; Sekino, Kodai*; Suzuki, Tsuyoshi*; Sawai, Kei*; Takemura, Fumiaki*; Kawabata, Kuniaki; Yamashiro, Hideyuki*
no journal, ,
This paper proposed the browsing system and functions for underwater environmental data gathered by wireless sensor network. The discussions were done for the design approaches and implementation examples with gathered data.
Ozeki, Ryutaro*; Suzuki, Tsuyoshi*; Sawai, Kei*; Takemura, Fumiaki*; Kawabata, Kuniaki; Yamashiro, Hideyuki*; Ogasawara, Kei*
no journal, ,
This article describes our latest stationary underwater sensor node configuration that is used to construct an underwater monitoring sensor network (UMSN) to support the coral ecological system survey activities, and also describes about study of the required functions of a data browsing system to monitor information of underwater environmental conditions gathered by UMSN.
Suzuki, Tsuyoshi*; Ozeki, Ryutaro*; Sawai, Kei*; Yamashiro, Hideyuki*; Takemura, Fumiaki*; Kawabata, Kuniaki; Takahashi, Satoru*; Sagara, Shinichi*; Ogasawara, Kei*
no journal, ,
In the current study, we developed an underwater monitoring sensor network system to support the observational activities to maintain the coral reef environment. This paper describes the measurement method to detect the growth area of the coral for a quantitative evaluation of the coral condition change using fluorescence coral image by capturing the underwater monitoring sensor network.
Takeno, Ryutaro*; Matsuura, Haruaki*; Sato, Isamu*; Suzuki, Eriko
no journal, ,
In order to investigate the influence of neutralization of concrete on the penetration behavior of Cs into concrete, the penetration tests of CsI and CsCl solution into neutralized concrete were performed. It was revealed that the acceleration through voids generated by the neutralization was dominant in the case of CsI solution, and the suppression due to the decrease of pH difference between concrete and solution was dominant in the case of CsCl solution.
