Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
)Kutsukake, Kenichi; Matsuda, Makoto; Hanashima, Susumu; Obara, Kenjiro*
JAEA-Technology 2007-068, 52 Pages, 2008/01
JAEA-Technology-2007-068.pdf:3.02MB
Many measurement and control equipment is installed inside of a high voltage terminal of the JAEA-Tokai tandem accelerator and operated under pressurized sulfur hexafluoride (SF) of 0.5 MPa. This screening test has been carried out to select a relay, which is usable under the SF for turn on and off a power supply of the devices, from commercial relays used in the atmospheric condition. Four kinds of relay were tested: electromechanical relay (EMR), magnet contactor (MAG), solid-state relay (SSR) and hybrid relay (HYB). Temperature of the relay, change of appearance of the relay including contact surface using the SEM and EDS were measured and observed. The EMR and the MAG showed irregular contact because of the sulfide or fluoride, and these compounds which are formed by chemical reaction between metals and sulfur or hydrogen fluoride due to dissociation of SF in electric arcs. Solid-state relay and hybrid relay are available in the pressurized SF of 0.5 MPa.
Obara, Kenjiro; Kakudate, Satoshi; Shibanuma, Kiyoshi; Sago, Hiromi*; Ue, Koichi*; Shimizu, Katsusuke*; Onozuka, Masanori*
JAEA-Technology 2006-034, 85 Pages, 2006/06
JAEA-Technology-2006-034.pdf:9.18MB
The International Thermonuclear Experimental Reactor (ITER) tokamak is composed of many kinds of components. The dimensions and weight of the respective components are around a few ten-meters and several hundred-tons. In addition, the whole tokamak assembly, which are composed of these components, are roughly estimated, 26 m in diameter, 18 m in height and over 16,500 tons in total weight. On the other hand, as for positioning and assembly tolerances of these components are required to be a high accuracy of 
3mm in spite of large size and heavy weight. The assembly procedures and techniques of the ITER tokamak are therefore studied, taking account of the tolerance requirements. Based on the above background, the assembly procedures and techniques, which are able to assemble the tokamak with high accuracy, are described in the present report. The following newly developed tokamak assembly procedures and techniques, jigs and tools for assembly and metrology concept based on the available knowledge and experiences of the installation of the large components, in order to improve the IT (International Team) design toward the more realistic one. As a result, we show the realistic tokamak assembly procedures and techniques to be able to assemble the large and heavy ITER tokamak with high accuracy. (1)Assembly and alignment of the toroidal field coil with high accuracy. (2)Simplification of the assembly procedures, and the jigs/tools and procedures to reduce the misalignment. (3)Assembly procedures and techniques for the vacuum vessel to reduce the weld distortion. (4)Supporting procedures and techniques of the vacuum vessel sector to prevent the toridal field coil from the deformation due to the dead weight of the vacuum vessel sector. (5)Datum points and lines for the required positions and assembly tolerances during tokamak assembly.
Obara, Kenjiro; Kakudate, Satoshi; Yagi, Toshiaki; Morishita, Norio; Shibanuma, Kiyoshi
JAEA-Technology 2006-023, 38 Pages, 2006/03
JAEA-Technology-2006-023.pdf:5.21MB
The components in the vacuum vessel of ITER (International Thermonuclear Experimental Reactor), e.g. blanket and divertor, are replaced using the dedicated remote handling systems. The environment conditions inside the vacuum vessel during the operation are temperature of 50
C, gamma ray radiation and air or inert gas atmosphere at 1 atm. ; therefore multiple elements are required as durability of the remote handling systems. In addition, the remote handling system it is desired to be able to operate over a long time. The radiation resistance motor driving equipment, which comprises parts with different radiation resistance levels, was designed simulating mechanisms of the ITER remote handling systems. The equipment being the servomotor, turns the weight (dummy load) of 8 kgf and controls, and continuous running test under high gamma ray irradiation was started from March, 2000. Irradiation conditions on the test were the dose rate of 3.6 kGy/h, the target accumulation dose of 30 MGy at the minimum. The irradiation test was performed two stages which was divided by overhaul of the equipment. The achieved accumulation dose and running time in these stages were approximately 47.6 MGy/13,200 hours and 23.9 MGy/6,640 hours, respectively. As a result, it has been confirmed that sufficient radiation resistance of the equipment, which is required from the latest dose rate of 0.5 kGy/h inside the vacuum vessel was achieved. In this report, we describe design conditions of the equipment and the results of the 1st and 2nd irradiation tests and the overhaul after the 1st irradiation test.
Obara, Kenjiro; Yagi, Toshiaki; Yokoo, Noriko*; Shibanuma, Kiyoshi
JAERI-Tech 2003-035, 107 Pages, 2003/03
JAERI-Tech-2003-035.pdf:9.45MB
no abstracts in English
Higashijima, Takeshi*; Obara, Kenjiro; Shibanuma, Kiyoshi; Koizumi, Koichi; Kobayashi, Kazuhiro; Oya, Yasuhisa; Shu, Wataru; Hayashi, Takumi; Nishi, Masataka
Fusion Science and Technology, 41(3), p.731 - 735, 2002/05
no abstracts in English
Nakahira, Masataka; Shibanuma, Kiyoshi; Kajiura, Soji*; Shibui, Masanao*; Koizumi, Koichi; Takeda, Nobukazu; Kakudate, Satoshi; Taguchi, Ko*; Oka, Kiyoshi; Obara, Kenjiro; et al.
JAERI-Tech 2002-029, 27 Pages, 2002/03
JAERI-Tech-2002-029.pdf:2.04MB
The ITER vacuum vessel (VV) R&D has progressed with the international collaborative efforts by the Japan, Russia and US Parties during the Engineering Design Activities (EDA). Fabrication and testing of a full-scale VV sector model and a port extension have yielded critical information on the fabrication and assembly technologies of the vacuum vessel, magnitude of welding distortions, dimensional accuracy and achievable tolerances during sector fabrication and field assembly. In particular, the dimensional tolerances of 3 mm for VV sector fabrication and 10 mm for VV sector field assembly have been achieved and satisfied the requirements of 5 mm and 20 mm, respectively. Also, the basic feasibility of the remote welding robot has been demonstrated. This report presents detailed fabrication and assembly technologies such as welding technology applicable to the thick wall without large distortion, field joint welding technology between sectors and remote welding technology through the VV R&D project.
Obara, Kenjiro
Genshiryoku eye, 48(2), p.46 - 48, 2002/02
no abstracts in English
Obara, Kenjiro
Hoshasen To Sangyo, (92), p.56 - 60, 2001/12
no abstracts in English
Oya, Yasuhisa; Kobayashi, Kazuhiro; Shu, Wataru; Hayashi, Takumi; Ohira, Shigeru; Nakamura, Hirofumi; Iwai, Yasunori; Nishi, Masataka; Higashijima, Takeshi*; Obara, Kenjiro; et al.
Fusion Technology, 39(2-Part2), p.1023 - 1027, 2001/03
no abstracts in English
Kakudate, Satoshi; Oka, Kiyoshi; Yoshimi, Takashi*; Taguchi, Ko*; Nakahira, Masataka; Takeda, Nobukazu; Shibanuma, Kiyoshi; Obara, Kenjiro; Tada, Eisuke; Matsumoto, Yasuhiro*; et al.
Fusion Engineering and Design, 51-52(1-4), p.993 - 999, 2000/11
Times Cited Count：9 Percentile：53.61(Nuclear Science & Technology)no abstracts in English
Obara, Kenjiro; Tada, Eisuke; Koizumi, Koichi; Yagi, Toshiaki; Morita, Yosuke
Proceedings of Radiation Effects on Components and Systems (RADECS 2000), p.214 - 218, 2000/09
no abstracts in English
; Obara, Kenjiro; Tada, Eisuke; Morita, Yosuke; Yagi, Toshiaki;
JAERI-Tech 99-029, 36 Pages, 1999/03
no abstracts in English
Obara, Kenjiro; Kakudate, Satoshi; ; Shibanuma, Kiyoshi; Tada, Eisuke
JAERI-Tech 99-009, 83 Pages, 1999/02
no abstracts in English
-rays irradiation tests of critical components for ITER (International Thermonulear Experimental Reactor) in-vessel remote handling systemObara, Kenjiro; Kakudate, Satoshi; Oka, Kiyoshi; ; ; Koizumi, Koichi; Shibanuma, Kiyoshi; Yagi, Toshiaki; Morita, Yosuke; ; et al.
JAERI-Tech 99-003, 312 Pages, 1999/02
[This article is unavailable to download the full text due to various reasons.]
Morita, Yosuke; Obara, Kenjiro
Denki Gakkai Yuden, Zetsuen Zairyo Kenkyukai Shiryo; DEI-99-18, p.55 - 58, 1999/02
no abstracts in English
Obara, Kenjiro; ; Kakudate, Satoshi; Oka, Kiyoshi; Nakahira, Masataka; Morita, Yosuke; ; ; Takeda, Nobukazu; Takahashi, Hiroyuki*; et al.
Fusion Engineering and Design, 42, p.501 - 509, 1998/00
Times Cited Count：3 Percentile：31.58(Nuclear Science & Technology)no abstracts in English
Obara, Kenjiro; Kakudate, Satoshi; Nakahira, Masataka;
J. Robot. Mechatron., 10(2), p.96 - 103, 1998/00
no abstracts in English
Obara, Kenjiro; Kakudate, Satoshi; Oka, Kiyoshi; ; Yagi, Toshiaki; Morita, Yosuke
J. Robot. Mechatron., 10(2), p.121 - 132, 1998/00
no abstracts in English
; Oka, Kiyoshi; Kakudate, Satoshi; Obara, Kenjiro; ; Tada, Eisuke; A.Tesini*; Shibanuma, Kiyoshi; R.Haange*
Proceedings of 17th IEEE/NPSS Symposium Fusion Engineering (SOFE'97), 2, p.921 - 924, 1998/00
no abstracts in English
; Obara, Kenjiro; Tada, Eisuke; Morita, Yosuke; Yagi, Toshiaki; ;
JAERI-Tech 97-065, 62 Pages, 1997/12
no abstracts in English
