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Okita, Shoichiro; Mizuta, Naoki; Takamatsu, Kuniyoshi; Goto, Minoru; Yoshida, Katsumi*; Nishimura, Yosuke*; Okamoto, Koji*
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 10 Pages, 2023/05
Sakurai, Yosuke*; Sato, Hirotaka*; Adachi, Nozomu*; Morooka, Satoshi; Todaka, Yoshikazu*; Kamiyama, Takashi*
Applied Sciences (Internet), 11(11), p.5219_1 - 5219_17, 2021/06
Times Cited Count:3 Percentile:41.12(Chemistry, Multidisciplinary)Sakai, Kenji; Oi, Motoki; Takada, Hiroshi; Kai, Tetsuya; Nakatani, Takeshi; Kobayashi, Yasuo*; Watanabe, Akihiko*
JAEA-Technology 2018-011, 57 Pages, 2019/01
For safely and efficiently operating a spallation neutron source and a muon target, a general control system (GCS) operates within Materials and Life Science Experimental Facility (MLF). GCS administers operation processes and interlocks of many instruments. It consists of several subsystems such as an integral control system (ICS), interlock systems (ILS), shared servers, network system, and timing distribution system (TDS). Although GCS is an independent system that controls the target stations, it works closely with the control systems of the accelerators and other facilities in J-PARC. Since the first beam injection, GCS has operated stably without any serious troubles after modification based on commissioning for operation and control. Then, significant improvements in GCS such as upgrade of ICS by changing its framework software and function enhancement of ILS were proceeded until 2015. In this way, many modifications have been proceeded in the entire GCS during a period of approximately ten years after start of beam operation. Under these situation, it is important to comprehend upgrade history and present status of GCS in order to decide its upgrade plan. This report summarizes outline, structure, roles and functions of GCS in 2017.
Nakayama, Masashi; Matsuzaki, Tatsuji*; Niunoya, Sumio*
JAEA-Research 2016-010, 57 Pages, 2016/08
The Horonobe URL Project has being pursued by JAEA to enhance the reliability of relevant disposal technologies through investigations of the deep geological environment within the host sedimentary formation at Horonobe, northern Hokkaido. The in-situ experiment for performance confirmation of engineered barrier system (EBS experiment) had been prepared from 2013 to 2014 fiscal year at G.L.-350m gallery, and heating by electric heater in simulated overpack had started in January, 2015. One of objectives of the experiment is acquiring data concerned with Thermal -Hydrological - Mechanical - Chemical coupled behavior. These data will be used in order to confirm the performance of engineered barrier system. In this report, It is summarized the production of casing drilling machine for large diameter, simulated overpack, buffer material blocks and backfilling material for EBS experiment.
Sakai, Kenji; Oi, Motoki; Watanabe, Akihiko; Kai, Tetsuya; Kato, Yuko; Meigo, Shinichiro; Takada, Hiroshi
JAEA-Conf 2015-002, p.593 - 598, 2016/02
For safe and stable beam operation, a MLF general control system (GCS) consists of several subsystems such as an integral control, interlock, server, network, and timing distribution systems. Since the first beam injection in 2008, the GCS has operated stably without any serious troubles in comparison with upgrade of target devices for ramping up beam power and increment of user apparatuses year by year. In recent years, however, it has been improved significantly in view of sustainable long-term operation and maintenance. The monitor and operation system of the GCS has been upgraded by changing its framework software to improve potential flexibility in its maintenance. Its interlock system was also modified in accordance with the re-examination of the risk management system of J-PARC. This paper reports recent progress of the MLF-GCS.
Miyabe, Masabumi; Oba, Masaki; Kato, Masaaki; Wakaida, Ikuo; Watanabe, Kazuo
JAERI-Tech 2005-043, 27 Pages, 2005/08
Multi-step resonance ionization spectrometry for long-lived nuclei in nuclear waste materials requires laser sources having high frequency stability and tunability. In this study we have developed a novel frequency control system consisting of digital circuitry and computer to improve the frequency tunability of the developed laser stabilization system using dichroic atomic vapor laser lock (DAVLL) and fringe offset lock (FOL) techniques. Based on the heterodyne experiment and multi-step laser induced fluorescence spectroscopy of atomic Ca, the frequency stability and tunability of the developed system were evaluated.
Yoshida, Katsuhiko*; Maekawa, Fujio; Takada, Hiroshi
JAERI-Tech 2003-019, 52 Pages, 2003/03
Under the JAERI-KEK High-Intensity Proton Accelerator Project (J-PARC), a spallation neutron source driven by a 3 GeV-1MW proton beam is planed to be constructed as a main part of the Materials and Life Science Facility. Overall dimensions of a biological shield of the neutron source had been determined by evaluation of shielding performance by Monte Carlo calculations. This report describes results of design studies on an optimum dividing scheme in terms of cost and treatment and mechanical strength of shield blocks for the biological shield. As for mechanical strength, it was studied whether the shield blocks would be stable, fall down or move to a horizontal direction in case of an earthquake of seismic intensity of 5.5 (250 Gal) as an abnormal load. For ceiling shielding blocks being supported by both ends of the long blocks, maximum bending moment and an amount of maximum deflection of their center were evaluated.
Sumita, Junya; Sawa, Kazuhiro; Tsuchie, Yasuo*; Urakami, Masao*; Kunitomi, Kazuhiko
JAERI-Tech 2002-104, 23 Pages, 2003/02
This report describes the result of study on disposal method of graphite blocks in future block-type reactor. Present study was carried out within a framework of joint research, "Research of Modular High Temperature Gas-cooled Reactors (No. 3)", between Japan Atomic Energy Research Institute (JAERI) and the Japan Atomic Power Company (JAPCO), in 2000. In this study, activities in fuel and reflector graphite blocks were evaluated and were compared with the disposal limits defined as low-level of radioactive waste. As a result, it was found that the activity for only C-14 was higher than disposal limits for the low-level of radioactive waste and that the amount of air in the graphite is important to evaluate precisely of C-14 activity. In addition, spent fuels can be stored in air-cooled condition at least after two years cooling in the storage pool.
Takada, Eiji*; Fujimoto, Nozomu; Nojiri, Naoki; Umeta, Masayuki; Kokusen, Shigeru; Ashikagaya, Yoshinobu
JAERI-Data/Code 2002-009, 83 Pages, 2002/05
Dose equivalent rate around the fuel handling machine, the control rod handling machine, stand pipe compartment, maintenance pit were measured during gamma ray measurements from HTTR fuel, which was called as “power distribution measurements". The power distribution measurement was the first time to handle the fuel blocks irradiated in the core. Dose equivalent rate measurement aiming the check of shielding performance of components, the check of unexpected streaming path. The radiation monitoring during operation was carried out. As the results, there was no problem on shielding. The measured data at operation condition were also obtained. The data will be useful to expect operation circumstance in the future.
Yamamoto, Kazuyoshi; Watanabe, Shukichi; Nagatomi, Hideki; Kaminaga, Masanori; Funayama, Yoshiro
JAERI-Tech 2002-034, 40 Pages, 2002/03
JRR-4, a swimming-pool type research reactor with a thermal power of 3.5MW, attained criticality in July 1998, after replacing its 90% enrichment fuel with a 20% enrichment fuel under the Reduced Enrichment Program. As a part of the program, safety analysis on thermo-hydraulics of the reactor core was conducted on cases including single channel blockage accident. With the conclusion that a certain margin on thermo-hydraulics was necessary, investigation and experiments were carried out with an aim to increase the core flow rate. To increase the core flow, it was carried out to reduce the bypass flow in the core and to increase the primary coolant flow rate from 7m/min to 8m/min. After flow measurements using a mock-up fuel element, flow velocity of the fuel channel was determined as 1.45m/s as opposed to the designed value of 1.44m/s, and the ratio of core flow to total flow was 0.88, exceeding the value 0.86 used for the safety analysis.This report describes the JRR-4 core flow increase plan as well as the results of the channel flow rate measurement
Hanawa, Satoshi; Iyoku, Tatsuo
JAERI-Data/Code 2001-021, 150 Pages, 2001/08
no abstracts in English
Ezato, Koichiro; Taniguchi, Masaki; Sato, Kazuyoshi; Araki, Masanori; Akiba, Masato
Physica Scripta, T91, p.110 - 112, 2001/07
Times Cited Count:2 Percentile:20.72(Physics, Multidisciplinary)no abstracts in English
Imamura, Toshiyuki
Journal of Supercomputing, 15(1), p.95 - 110, 2000/00
Times Cited Count:2 Percentile:30.01(Computer Science, Hardware & Architecture)no abstracts in English
Kaminaga, Masanori
JAERI-Tech 97-015, 74 Pages, 1997/03
no abstracts in English
Kaminaga, Masanori; Yamamoto, Kazuyoshi; Watanabe, Shukichi
JAERI-Tech 96-039, 72 Pages, 1996/09
no abstracts in English
Shibamoto, Yasuteru; Yonomoto, Taisuke; Kukita, Yutaka; Tsuji, Yoshiyuki*; *
Journal of Nuclear Science and Technology, 33(9), p.703 - 711, 1996/09
Times Cited Count:2 Percentile:24.71(Nuclear Science & Technology)no abstracts in English
Haga, Katsuhiro; *; Kukita, Yutaka
Journal of Nuclear Science and Technology, 32(9), p.846 - 854, 1995/09
Times Cited Count:4 Percentile:43.23(Nuclear Science & Technology)no abstracts in English
; Araki, Masanori; Nakamura, Kazuyuki; Sato, Kazuyoshi; ; Dairaku, Masayuki; Akiba, Masato
JAERI-Tech 95-033, 63 Pages, 1995/06
no abstracts in English
; Mori, Masahiro; Kikuchi, Mitsuru; Ninomiya, Hiromasa; Jitsukawa, Shiro; Ito, Takao; Kuriyama, Masaaki;
16th IEEE/NPSS Symp. on Fusion Engineering (SOFE '95), p.1214 - 1217, 1995/06
no abstracts in English
Yoshino, Ryuji; Neyatani, Yuzuru; Isei, Nobuaki; Koide, Yoshihiko; Kawano, Yasunori; A.Tanga*; Campbell, D. J.*; M.F.Johnson*; L.Rossi*
IAEA-CN-60/A5-8, 0, p.685 - 695, 1995/00
no abstracts in English