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Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.
Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09
Times Cited Count：6 Percentile：84.97(Nuclear Science & Technology)In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.
Ishitsuka, Etsuo; Mitsui, Wataru*; Yamamoto, Yudai*; Nakagawa, Kyoichi*; Ho, H. Q.; Ishii, Toshiaki; Hamamoto, Shimpei; Nagasumi, Satoru; Takamatsu, Kuniyoshi; Kenzhina, I.*; et al.
JAEA-Technology 2021-016, 16 Pages, 2021/09
JAEA-Technology-2021-016.pdf:1.8MB
As a summer holiday practical training 2020, the feasibility study for nuclear design of a nuclear battery using HTTR core was carried out, and the downsizing of reactor core were studied by the MVP-BURN. As a result, it is clear that a 1.6 m radius reactor core, containing 54 (18
3 layers) fuel blocks with 20% enrichment of 
U, and BeO neutron reflector, could operate continuously for 30 years with thermal power of 5 MW. Number of fuel blocks of this compact core is 36% of the HTTR core. As a next step, the further downsizing of core by changing materials of the fuel block will be studied.
Yamamoto, Kazami; Kawase, Masato; Iwama, Yuhei; Fukuta, Shimpei; Kato, Yuko; Ouchi, Nobuo; Meigo, Shinichiro; Oi, Motoki; Kamikubota, Norihiko*
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.771 - 774, 2014/10
The radiation leak accident happened in the hadron experimental hall of J-PARC on May 23, 2013. The accident was caused by a target sublimation due to an unanticipated beam from the 50 GeV main ring (MR). To detect and prevent the radiation leakage in all facilities of J-PARC, we improve the machine protection system (MPS). In the J-PARC 3GeV synchrotron (Rapid Cycling Synchrotron, RCS), a monitoring system of an abnormal state of the extraction beam to the mercury target of material life science experiment facility (MLF) were prepared. The radiation level of the gas in the tunnel were able to always observed by connecting radiation safety system and accelerator control system. The dump temperature was included in the MPS. We also developed new interlock system that can stop the beam immediately when the beam current exceed the limit.
-coated FePt nanoparticles studied by X-ray magnetic circular dichroismTakahashi, Yukio*; Kadono, Toshiharu*; Yamamoto, Shimpei*; Singh, V. R.*; Verma, V.*; Ishigami, Keisuke*; Shibata, Goro*; Harano, Takayuki*; Takeda, Yukiharu; Okane, Tetsuo; et al.
Physical Review B, 90(2), p.024423_1 - 024423_5, 2014/07
Times Cited Count：11 Percentile：44.58(Materials Science, Multidisciplinary)Yoshikawa, Hiroshi; Sakaki, Hironao; Sako, Hiroyuki; Takahashi, Hiroki; Shen, G.; Kato, Yuko; Ito, Yuichi; Ikeda, Hiroshi*; Ishiyama, Tatsuya*; Tsuchiya, Hitoshi*; et al.
Proceedings of International Conference on Accelerator and Large Experimental Physics Control Systems (ICALEPCS '07) (CD-ROM), p.62 - 64, 2007/10
J-PARC is a large scale facility of the proton accelerators for the multi-purpose of scientific researches in Japan. This facility consists of three accelerators and three experimental stations. Now, J-PARC is under construction, and LINAC is operated for one year, 3GeV synchrotron has just started the commissioning in this October the 1st. The completion of this facility will be next summer. The control system of accelerators established fundamental performance for the initial commissioning. The most important requirement to the control system of this facility is to minimize the activation of accelerator devices. In this paper, we show that the performances of each layer of this control system have been achieved in the initial stage.
Oyama, Sunao*; Hamamoto, Shimpei; Kaneshiro, Noriyuki*; Nemoto, Takahiro; Sekita, Kenji; Isozaki, Minoru; Emori, Koichi; Ito, Yoshiteru*; Yamamoto, Hideo*; Ota, Yukimaru; et al.
JAEA-Technology 2007-047, 40 Pages, 2007/08
JAEA-Technology-2007-047.pdf:18.83MB
High-Temperature engineering Test Reactor (HTTR) built by Japan Atomic Energy Agency (JAEA) has commonly used reciprocating compressor to extract helium gas and discharge helium gas into primary/secondary coolant helium loop from helium purification system. Rod-seal structure of the compressor is complicated from a prevention coolant leak standpoint. Because of frequently leakage of seal oil in operation, Rod seal structure isn't as reliable as it should be sustainable in the stable condition during long term operation. As a result of investigations, leakage's root is found in that seal were used in a range beyond limit sliding properties of seal material. Therefore a lip of the seal was worn and transformed itself and was not able to sustain a seal function. Endurance test using materials testing facility and verification test using a actual equipment on candidate materials suggest that a seal of fluorine contained resin mixed graphite is potentially feasible material of seal.
Furuichi, Takuya*; Fujimaki, Shu; Kawachi, Naoki; Suzui, Nobuo; Ishii, Satomi; Ishioka, Noriko; Matsuhashi, Shimpei; Yamamoto, Yoko*; Sokabe, Masahiro*
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 130, 2007/02
no abstracts in English
Gunji, Minoru; Yamamoto, Shimpei; Onojima, Takamitsu
PNC TN9450 98-009, 150 Pages, 1998/06
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