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Eto, Masao*; Kamishima, Yoshio*; Okamura, Shigeki*; Watanabe, Osamu*; Oyama, Kazuhiro*; Negishi, Kazuo; Kotake, Shoji*; Sakamoto, Yoshihiko; Kamide, Hideki
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles (FR 2009) (CD-ROM), 10 Pages, 2012/00
In the JSFR design, the diameter of the Reactor Vessel (RV) shall be minimized and the reactor internal structures shall be simplified for reduction in construction cost. The reduction in the RV diameter is achieved by adopting an advanced refueling system and the hot RV with high temperature wall. The flow velocity in the reactor upper plenum increases because the diameter of the RV is decreased. As the result, the coolant flow field in reactor upper plenum is severe. The optimization of the coolant flow field in the reactor upper plenum was carried out for prevention the cover gas entrainment and the vortex cavitations at the hot leg intake. In addition, structural integrities for seismic loadings and thermal loadings were evaluated because the design seismic loading was highly increased and the vessel wall is directly exposed to the thermal transients of the upper plenum. This paper describes the characteristics and the results of the design study of the reactor system.
Okamura, Shigeki*; Eto, Masao*; Kamishima, Yoshio*; Negishi, Kazuo; Sakamoto, Yoshihiko; Kitamura, Seiji; Kotake, Shoji*
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles (FR 2009) (CD-ROM), 10 Pages, 2012/00
This paper describes the seismic design of JSFR, which includes the seismic condition, the seismic isolation system and the seismic evaluation of primary component. JSFR employs a seismic isolation system to mitigate the earthquake force. The design seismic loading is made more severe than ever since Niigata-ken Chuetsu-oki Earthquake in 2007. The earthquake force loaded on the primary components has to be mitigated more than that of the previous seismic isolation system. We examined the advanced seismic isolation system by optimizing the performance of the previous seismic isolation system considering the natural frequency of the primary components. The advanced seismic isolation system for SFR was adopted laminated rubber bearings which are thicker than that of the previous, as well as oil dampers. The seismic evaluation of nuclear reactor components under applying the advanced seismic isolation system was performed; the performance of the system was confirmed.
Kawasaki, Nobuchika; Okamura, Shigeki*; Sawa, Naoki*; Sakamoto, Yoshihiko; Negishi, Kazuo
Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM), 7 Pages, 2011/10
Japan Sodium-Cooled Fast Reactor adopts an compacted hot reactor vessel concept. From the point of structural designs to ensure both seismic design and elevated temperature design is important. In this study, based on a common conservative seismic loading condition considered with the Niigata-ken Chuetsu-oki Earthquake, seismic evaluations were carried out, the thicknesses of reactor vessels of 750 MWe and 500 MWe output plants were determined. For both plants 50 mm was selected as the thickness, and ensured buckling evaluation margins were more than 2.4. From the point of seismic design, the difference of plant output was negligible. With the condition of 50 mm thickness of reactor vessel, thermal integrities were evaluated. For three plant start-up conditions which were 2.2, 3.2, and 4.3 days, thermal ratcheting and creep-fatigue damage were evaluated. As a result plant start-up period needed more than 3.2 days for both 750 MWe and 500 MWe output plants. Caused thermal stress were the nearly same for both plants, therefore from the point of thermal design, the difference of plant output was negligible.
Np for fast neutronsHarada, Hideo; Nakamura, Shoji; Hatsukawa, Yuichi; Toh, Yosuke; Kimura, Atsushi; Ishiwatari, Yuki*; Yasumi, Atsushi*; Mabuchi, Yukio*; Nakagawa, Tsutomu*; Okamura, Kazuo*; et al.
Journal of Nuclear Science and Technology, 46(5), p.460 - 468, 2009/05
Times Cited Count：4 Percentile：30.49(Nuclear Science & Technology)The neutron capture cross section of Np has been measured for fast neutrons supplied at the center of the core in the Yayoi reactor. The activation method was used for the measurement, in which the amount of the product 
Np was determined by 
-ray spectroscopy using a Ge detector. The representative neutron energy and the corresponding capture cross section of Np in the experiment were analytically deduced as 0.80 
0.04 b at 0.214 0.009 MeV from the measured reaction rate by combining the energy dependence of the cross section in the nuclear data library ENDF/VII.0. The deduced cross section of Np at the representative neutron energy agrees with the evaluated data of ENDF/B-VII.0, but shows 15% larger value than that of JENDL-3.3 and 13% larger value than that of JENDL/AC-2008.
Isobe, Mitsutaka*; Toi, Kazuo*; Matsushita, Hiroyuki*; Goto, Kazuyuki*; Suzuki, Chihiro*; Nagaoka, Kenichi*; Nakajima, Noriyoshi*; Yamamoto, Satoshi*; Murakami, Sadayoshi*; Shimizu, Akihiro*; et al.
Nuclear Fusion, 46(10), p.S918 - S925, 2006/10
Times Cited Count：30 Percentile：69.47(Physics, Fluids & Plasmas)no abstracts in English
Kashiwagi, Hirotsugu; Fukuda, Mitsuhiro; Okamura, Masahiro*; Jameson, R. A.*; Hattori, Toshiyuki*; Hayashizaki, Noriyosu*; Sakakibara, Kazuhiko*; Takano, Jumpei*; Yamamoto, Kazuo*; Iwata, Yoshiyuki*; et al.
Review of Scientific Instruments, 77(3), p.03B305_1 - 03B305_4, 2006/03
Times Cited Count：12 Percentile：52.29(Instruments & Instrumentation)Acceleration of a 17mA 100keV/u C
ion beam has been successfully achieved with an RFQ linac by means of "Direct injection scheme". The Direct injection scheme is a new scheme for injecting an ion beam from a laser ion source to the RFQ linac without a low energy beam transport line to avoid a beam loss due to the space charge effect. The high current C beam is required for single turn injection to a synchrotron to reduce the size of synchrotron magnets. The high current C beam produced by an ion source with a Nd-YAG laser was injected to the RFQ linac by the Direct injection scheme. It has been proved experimentally that the fully-stripped carbon ion beam with a current more than 10mA can be accelerated by the RFQ linac.
Okamura, Masahiro*; Kashiwagi, Hirotsugu; Sakakibara, Kazuhiko*; Takano, Jumpei*; Hattori, Toshiyuki*; Hayashizaki, Noriyosu*; Jameson, R. A.*; Yamamoto, Kazuo*
Review of Scientific Instruments, 77(3), p.03B303_1 - 03B303_3, 2006/03
Times Cited Count：10 Percentile：47.11(Instruments & Instrumentation)We have been studying a new heavy-ion production technique called "direct plasma injection scheme", DPIS, since 2000. A new radio frequency quadrupole "RFQ" designed especially for the DPIS was commissioned in 2004 and very intense carbon beam was successfully obtained, reaching more than 60 mA accelerated current from the RFQ. Most of the contents of the accelerated beam was carbon 4+ as verified by beam analysis.
Kashiwagi, Hirotsugu; Okamura, Masahiro*; Hattori, Toshiyuki*; Jameson, R. A.*; Yamamoto, Kazuo*; Fujimoto, Tetsuya*; Kamiya, Tomihiro
Proceedings of 3rd Annual Meeting of Particle Accelerator Society of Japan and 31st Linear Accelerator Meeting in Japan (CD-ROM), p.570 - 572, 2006/00
no abstracts in English
Kashiwagi, Hirotsugu; Okamura, Masahiro*; Jameson, R. A.*; Hattori, Toshiyuki*; Hayashizaki, Noriyosu*; Sakakibara, Kazuhiko*; Takano, Jumpei*; Yamamoto, Kazuo*; Iwata, Yoshiyuki*; Fujimoto, Tetsuya*
Proceedings of 2nd Annual Meeting of Particle Accelerator Society of Japan and 30th Linear Accelerator Meeting in Japan, p.182 - 184, 2005/07
The carbon beam from a Nd-YAG laser ion source was accelerated successfully by an RFQ linac using Direct injection scheme. The "Direct injection scheme" is the way to inject an ion beam to the RFQ linac without a low energy beam transport line to avoid space charge effect due to a high intensity beam from the laser ion source. About 30mA of a carbon beam was detected by a faraday cup just behind the RFQ linac.
Eto, Masao*; Kamishima, Yoshio*; Okamura, Shigeki*; Negishi, Kazuo*; Sakamoto, Yoshihiko; Kawasaki, Nobuchika
no journal, ,
A concept of a compact reactor system for Japan Sodium-cooled Fast Reactor (JSFR) is being studied with aims including streamlining its facilities. A candidate of innovative technology for this purpose is a fuel exchange system which consists of an upper internal structure (UIS) with a radial slit and a single rotating plug, and another candidate is a "ot vessel" concept. The applicability of this structural concept has been studied by considering flow optimization, seismic resistance, thermal evaluation, etc. This paper reports the result of the applicability study.
Okamura, Shigeki*; Kamishima, Yoshio*; Negishi, Kazuo*; Kitamura, Seiji
no journal, ,
A horizontal seismic isolation system is planned to be adopted to Japan Sodium-cooled Fast Reactor (JSFR) as a candidate of innovative technology that suits conditions of fast reactors and reduces the load in the event of an earthquake. The aim of this system and its enhancing effect on seismic resistance in the periodic band specific to reactor structure have been examined. This paper reports the result of applicability study of the innovative technology.
Negishi, Kazuo; Kawasaki, Nobuchika; Sakamoto, Yoshihiko; Kotake, Shoji; Okamura, Shigeki*; Kamishima, Yoshio*
no journal, ,
no abstracts in English
Sakurai, Eiko*; Ishii, Keizo*; Yamanaka, Kentaro*; Okura, Satoru*; Fujiki, Kota*; Yamazaki, Hiromichi*; Matsuyama, Shigeo*; Kamiya, Tomihiro; Sato, Takahiro; Arakawa, Kazuo*; et al.
no journal, ,
Cognitive degradation and behavior disorder occur under the mental disease caused by stimulant drugs. In this study, it was continuously administered to mice. After that, neuropoiesis of dentate gyrus and trace elements in its brain were analyzed by in-air micro-PIXE. As a result, the distribution of trace elements was different from that of normal mice.
