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Yamano, Hidemasa; Okamura, Shigeki*
Transactions of the 26th International Conference on Structural Mechanics in Reactor Technology (SMiRT-26) (Internet), 9 Pages, 2022/07
Seismic response analyses were conducted for the pipe with and without the seismic isolation system based on the response waveforms. This study performed a fragility analysis by setting uncertainty parameters on the basis of existing studies. The comparison results showed that the seismic isolation technology is effective for the pipe to prevent cliff-edge effects. In other words, the seismic margin for the seismically isolated plant is 1.2 times larger than that of the non-isolated plant. To evaluate the response reduction effect, this study focused on response coefficients of components as uncertainty parameters, which were specified within a physically possible range. Even if the uncertainty is considered, the HCLPF for the isolated plant is nearly twice as high as the non-isolated plant, namely the response reduction effect is still significant for the isolated plant. Therefore, the isolation technology is effective to avoid cliff-edge effects.
Igarashi, Hiroshi
JAEA-Review 2020-006, 261 Pages, 2020/09
JAEA-Review-2020-006.pdf:4.42MB
A literature review was conducted on the increase in surface area of vitrified products of HLW due to the fracturing caused by cooling during glass pouring process and by mechanical impact, from the perspective of a parameter of the radionuclide release model in the performance assessment of geological disposal system studied overseas. The review was focused on the value of surface area increase factor set as a parameter in the model, the experimental work to evaluate an increase in surface area, and how the parameters on surface area were determined based on the experimental results. The surface area obtained from the experiments executed in Japan was also discussed in comparison with the overseas studies. On the basis of the investigation, the effects of various conditions on the surface area were studied, such as a diameter of vitrified product, cooling condition during and after the glass pouring, impact on vitrified products during their handling, environment after the closure of disposal facility, and others. The causes of fracturing are associated with the phenomena or events in the waste management process such as production, transport, storage, and disposal. The surface area increase factors set in the nuclide release model of the glass and their bases were reviewed. In addition, the measured values and the experimental methods for surface increase factors published so far were compared. Accordingly, the methods for measuring surface area as the bases were identified for these factors set in the models. The causes of fracturing and features of these factors were studied with respect to the relation with the waste management process. The results from the review and assessment can contribute to the expanding the knowledge for the conservative and realistic application of these factors to performance assessment, and to the developing and upgrading of safety case as a consequence.
Ohashi, Hirofumi; Nishihara, Tetsuo; Takeda, Tetsuaki; Inagaki, Yoshiyuki
Proceedings of 13th International Conference on Nuclear Engineering (ICONE-13) (CD-ROM), 8 Pages, 2005/05
A hydrogen production system connected to the High-Temperature Engineering Test Reactor (HTTR) is being designed to be able to produce hydrogen using a nuclear heat of 10 MW supplied by the HTTR. The HTTR hydrogen production system is first connected to a nuclear reactor in the world, hence an mock-up model test is planned to carry out prior to the demonstration test of the HTTR hydrogen production system. In parallel to the mock-up model test, the following tests as an essential problem, a corrosion test of a reforming tube, a permeation test of hydrogen isotopes through a heat exchanger tube, an integrity test of a high-temperature isolation valve, and a performance test of a hydrogen permselective membrane are carried out to obtain detailed data for a safety review and development of analytical codes. This paper describes the present status of the component tests on the R&D of the HTTR hydrogen production system.
Takeda, Nobukazu; Nakahira, Masataka; Kakudate, Satoshi; Takahashi, Hiroyuki*; Shibanuma, Kiyoshi; Yabana, Shuichi*; Matsuda, Akihiro*
Proceedings of 9th World Seminar on Seismic Isolation, Energy Dissipation and Active Vibration Control of Structures (CD-ROM), p.299 - 306, 2005/00
For the ITER, a fusion experimental reactor, it is planned to use rubber bearings in order to enhance the reliability of integrity with a sufficient margin even for the earthquakes beyond the design basis earthquake. In application for nuclear plants, the vertical compression of the isolator is 2
5 MPa and there is no experience for such a high compression as 10 MPa to be used for the ITER. Therefore, there is not enough design data of the rubber bearings with high compression, and thus a detailed estimation of performance is necessary. As a result of the endurance test after aging, it was validated that the bearing can be applied safely until 400th cycle even after 40 years of aging. On the other hand, the residual deformation was found at the 246th cycle. This means that the residual deformation can be observed enough earlier than the change of the macroscopic mechanical parameter such as stiffness. Therefore, it is possible to prevent break of the bearing during operation by sensing a sign of break with a periodical visual inspection.
Takeda, Nobukazu; Nakahira, Masataka; Tada, Eisuke; Fujita, Satoshi*; Fujita, Takafumi*
Nihon Jishin Kogakkai Rombunshu (Internet), 4(3), p.298 - 304, 2004/04
ITER is a Tokamak-type international fusion experimental device composed of superconducting magnets, a vacuum vessel, and so on. These are operated at a quie wide temperature ranging from 4K to 200 degree C. For this, multiple plates have been chosen as the machine support so as to peovide flexibility in the radial direction while keeping high rigidity vertically. This results in a low natural frequency of around 4Hz in the horizontal direction. Since those structures are designed in accordance with the IAEA seismic acceleration of 0.2g as a reference, a seismic isolation is required if earthquake-proof larger than 0.2g is necessary. Considering these conditions, analytical and experimental studies have been conducted to characterize the ITER dynamic response in Japan. This paper outlines the latest status on seismic design for ITER in Japan and evaluation on tokamak dynamic response and verification tests using scaled tokamak model.
Nishihara, Tetsuo; Shimizu, Akira; Inagaki, Yoshiyuki; Tanihira, Masanori*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(4), p.517 - 524, 2003/12
no abstracts in English
Yoshida, Hiroshi; Glugla, M.*; Hayashi, Takumi; L
sser, R.*; Murdoch, D.*; Nishi, Masataka; Haange, R.*
Fusion Engineering and Design, 61-62, p.513 - 523, 2002/11
Times Cited Count：28 Percentile：84.04(Nuclear Science & Technology)ITER tritium plant is composed of tokamak fuel cycle systems, tritium confinement and detritation systems. The tokamak fuel cycle systems, composed of various tritium sumsystems such as vacuum vessel cleaning gas processing, tokamak exhaust processing, hydrogen isotope separation, fuel storage, mixing and delivery, and external tritium receiving and long-term storage, has been designed to meet not only ITER operation scenarios but safety requirements (minimization of equipment tritium inventory and reduction of environmental tritium release at different off-normal events and accident scenarios). Multiple confinement design was employed because tritium easily permeates through metals (at 
150 
C) and plastics (at ambient temperature) and mixed with moisture in room air. That is, tritium process equipment and piping are designed to be the primary confinement barrier, and the process equipments (tritium inventory 1 g) are surrounded by the secondary confinement barrier such as a glovebox. Tritium process rooms, which contains these facilities, form the tertiary confinement barrier, and equipped with emergency isolation valves in the heating ventillation and air conditioning ducts as well as atmosphere detritiation systems. This confinement approach has been applied to tokamak building, tritium building, and hotcell and radwaste building.
Tada, Eisuke; Hada, Kazuhiko; Maruo, Takeshi; Safety Design/Evaluation Group
Purazuma, Kaku Yugo Gakkai-Shi, 78(11), p.1145 - 1156, 2002/11
no abstracts in English
Yabana, Shuichi*; Matsuda, Akihiro*; Nakahira, Masataka; Osaki, Toshio*
Nihon Kenchiku Gakkai 2002-Nendo Taikai Koen Kogaishu, P. 495, 2002/08
no abstracts in English
Tsutsumi, Hideaki*; Yamada, Hiroyuki; Teragaki, Toshio*; Ebisawa, Katsumi; Shibata, Katsuyuki
Seismic Engineering 2000 (PVP-Vol.402-1), p.141 - 146, 2000/00
no abstracts in English
Nakahira, Masataka; Takeda, Nobukazu; Takahashi, Hiroyuki*; Yagenchi, Akira*; Akutsu, Yoichi; Tada, Eisuke; Yabana, Shuichi*
Proceedings of 7th International Conference on Nuclear Engineering (ICONE-7) (CD-ROM), 10 Pages, 1999/00
no abstracts in English
Tsunematsu, Toshihide; Namba, Haruyuki*; Akutsu, Yoichi; Okawa, Yoshinao; Yagenji, Akira; Takeda, Masatoshi*; Yajima, Kensaku*; Nitta, Yoshio*; Kobayashi, Kenichi*; Maeda, Ikuo*; et al.
Fusion Engineering and Design, 41(1-4), p.415 - 420, 1998/09
Times Cited Count：3 Percentile：31.82(Nuclear Science & Technology)no abstracts in English
Shibata, Katsuyuki; ;
Proc. of 7th German-Japan Joint Seminar on Research in Structural Strength and NDE-Problems, 12 Pages, 1997/00
no abstracts in English
Sobajima, Makoto; ; Kondo, Masaaki; ; Muramatsu, Ken;
10th Pacific Basin Nuclear Conf. (10-PBNC), 1, p.629 - 636, 1996/00
no abstracts in English
Sakai, T.*; Naito, Yoshitaka
Proc.Int.Seminar on Nuclear Criticality Safety, p.156 - 160, 1987/00
no abstracts in English
Nuclear Instruments and Methods in Physics Research A, 249, p.137 - 140, 1986/00
Times Cited Count：1 Percentile：41.11(Instruments & Instrumentation)no abstracts in English
Journal of Inorganic and Nuclear Chemistry, 29, p.1374 - 1376, 1967/00
Times Cited Count：10no abstracts in English
Suzuki, Shinichi; Kobayashi, Toru; Shiwaku, Hideaki; Yaita, Tsuyoshi
no journal, ,
Yamamoto, Tomohiko; Watakabe, Tomoyoshi; Miyagawa, Takayuki*; Okamura, Shigeki*; Fukasawa, Tsuyoshi*; Fujita, Satoshi*
no journal, ,
This report describes that the concepts and specifications of "3-dimensional seismic isolation device" adopting in a Sodium-cooled fast reactor, summary of various tests and analyzes, and shows feasibility of 3-dimensional seismic isolation device for earthquake response reduction effect.
Tamazawa, Satoshi*; Ueno, Akio*; Tamaki, Hideyuki*; Tamamura, Shuji*; Murakami, Takuma*; Kiyama, Tamotsu*; Inomata, Hidenori*; Miyakawa, Kazuya; Naganuma, Takeshi*; Kaneko, Katsuhiko*
no journal, ,
no abstracts in English
