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Journal Articles

Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex, 2; Neutron scattering instruments

Nakajima, Kenji; Kawakita, Yukinobu; Ito, Shinichi*; Abe, Jun*; Aizawa, Kazuya; Aoki, Hiroyuki; Endo, Hitoshi*; Fujita, Masaki*; Funakoshi, Kenichi*; Gong, W.*; et al.

Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12

The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.

Journal Articles

JT-60SA superconducting magnet system

Koide, Yoshihiko; Yoshida, Kiyoshi; Wanner, M.*; Barabaschi, P.*; Cucchiaro, A.*; Davis, S.*; Decool, P.*; Di Pietro, E.*; Disset, G.*; Genini, L.*; et al.

Nuclear Fusion, 55(8), p.086001_1 - 086001_7, 2015/08

 Times Cited Count:30 Percentile:83.62(Physics, Fluids & Plasmas)

The most distinctive feature of the superconducting magnet system for JT-60SA is the optimized coil structure in terms of the space utilization as well as the highly accurate coil manufacturing, thus meeting the requirements for the steady-state tokamak research: A conceptually new outer inter-coil structure separated from the casing is introduced to the toroidal field coils to realize their slender shape, allowing large-bore diagnostic ports for detailed plasma measurements. A method to minimize the manufacturing error of the equilibrium-field coils has been established, aiming at the precise plasma shape/position control. A compact butt-joint has been successfully developed for the Central Solenoid, which allows an optimized utilization of the limited space for the Central Solenoid to extend the duration of the plasma pulse.

Journal Articles

Feeder components and instrumentation for the JT-60SA magnet system

Yoshida, Kiyoshi; Kizu, Kaname; Murakami, Haruyuki; Kamiya, Koji; Honda, Atsushi; Onishi, Yoshihiro; Furukawa, Masato; Asakawa, Shuji; Kuramochi, Masaya; Kurihara, Kenichi

Fusion Engineering and Design, 88(9-10), p.1499 - 1504, 2013/10

 Times Cited Count:6 Percentile:44.21(Nuclear Science & Technology)

The modifying of the JT-60U magnet system to the superconducting coils (JT-60SA) is progressing as a satellite facility for ITER by both parties of Japanese government and European commission (EU) in the Broader Approach agreement. The magnet system for JT-60SA consists of 18 Toroidal Field (TF) coils, a Central Solenoid (CS) with 4 modules, and 6 Equilibrium Field (EF) coils. The manufacturing of the JT-60SA magnet system is in progress in EU and Japan. The JT-60SA superconducting magnet system generates an average heat load of 3.2 kW at 4 K to the cryoplant, from nuclear and thermal radiation, conduction and electromagnetic heating, and requires current supplies 20 kA for 4 CS modules and 6 EF coils, 25.7 kA to 18 TF coils. The helium flow to remove this heat, consisting of supercritical helium at pressures up to 0.5 MPa and temperature between 4.4-4.8 K, is distributed to the coils and structures through the valve box (VB) from the cryoline connecting to the auxiliary cold box located outside the torus hall. The feeders also contain the electrical supplies from the current lead transitions to room temperature to the coil. The feeder components consist of the in-cryostat feeders with flexible parts to allow coil operational displacements from the connection pipes out of the cryostat, including S-bend conductor to allow differential thermal contraction and the coil terminal boxes (CTBs) with HIS current leads. A measurement and control system is required to monitor and control these coils and feeders for safety and optimal operational availability. For each coil, both current and supercritical helium are supplied from external systems and are controlled from a central system as part of the regular operation with plasma pulses. Quench detection instruments for superconducting coils, feeders and HTS current leads are provided as a separate, stand alone system.

Journal Articles

Design and trial manufacturing of the thermal shield for JT-60SA

Kamiya, Koji; Ichige, Toshikatsu; Honda, Atsushi; Yoshida, Kiyoshi

Proceedings of International Cryogenic Engineering Conference 23 (ICEC-23) and International Cryogenic Materials Conference 2010 (ICMC 2010), p.797 - 802, 2011/07

The JT-60 is planned to be upgraded to a full-superconducting tokamak referred as the JT-60 Super Advance (JT-60SA) as one of the JA-EU Broader Approach projects. In the JT-60SA, the superconducting magnets are to be surrounded with the thermal shield to reduce the radiation heat from the plasma vacuum vessel and from the ambient temperature. This study describes the design concept and current status of the JT-60SA thermal shield followed by thermal analysis focusing on the vacuum vessel side thermal shield (VVTS). Subsequently, the structural analysis in the plasma operation mode and at assembly was conducted. Finally, the trial model of the 10 degree VVTS and its manufacturing tolerance are presented.

JAEA Reports

Modification of the drift ducts reionization loss estimation for JT-60U NBI

Kawai, Mikito; Akino, Noboru; Ikeda, Yoshitaka; Ebisawa, Noboru; Honda, Atsushi; Kazawa, Minoru; Kikuchi, Katsumi; Mogaki, Kazuhiko; Noto, Katsuya; Oshima, Katsumi; et al.

JAEA-Technology 2008-069, 32 Pages, 2008/10

JAEA-Technology-2008-069.pdf:6.75MB

The neutral beam injection system for JT-60U consists of positive-ion based type(P-NBI) and negative-ion based type(N-NBI). The reionization losses of neutral beams in the drift ducts of both P-NBI and N-NBI are estimated using the data of ambient pressure and gas flow rate into the beamlines. This system was not enough to obtain detail injection power for a long pulse operation. Modifications of the system to obtain reionization loss for a long pulse operation have been conducted. The new system has a capability to measure the pressures of drift duct during operation. The system can calculate the reionization loss automatically during the pulse from the measured pressure. More acurate injection power can be obtained by this new system.

Journal Articles

Recent R&D activities of negative-ion-based ion source for JT-60SA

Ikeda, Yoshitaka; Hanada, Masaya; Kamada, Masaki; Kobayashi, Kaoru; Umeda, Naotaka; Akino, Noboru; Ebisawa, Noboru; Inoue, Takashi; Honda, Atsushi; Kawai, Mikito; et al.

IEEE Transactions on Plasma Science, 36(4), p.1519 - 1529, 2008/08

 Times Cited Count:11 Percentile:41.29(Physics, Fluids & Plasmas)

The JT-60SA N-NBI system is required to inject 10 MW for 100 s at 500 keV. Three key issues should be solved for the JT-60SA N-NBI ion source. One is to improve the voltage holding capability. Recent R&D tests suggested that the accelerator with a large area of grids may need a high margin in the design of electric field and a long time for conditioning. The second issue is to reduce the grid power loading. It was found that some beamlets were strongly deflected due to beamlet-beamlet interaction and strike on the grounded grid. The grids are to be designed by taking account of beamlet-beamlet interaction in three-dimensional simulation. Third is to maintain the D- production for 100 s. A simple cooling structure is proposed for the active cooled plasma grid, where a key is the temperature gradient on the plasma grid for uniform D- production. The modified N-NBI ion source will start on JT-60SA in 2015.

JAEA Reports

Prototype development of P-NBI data acquisition system for the JT-60SA

Shinozaki, Shinichi; Honda, Atsushi; Oshima, Katsumi; Shimizu, Tatsuo; Numazawa, Susumu*; Ikeda, Yoshitaka

JAEA-Technology 2008-048, 23 Pages, 2008/07

JAEA-Technology-2008-048.pdf:8.1MB

The modification of the JT-60U to a fully superconducting coil tokamak, JT-60SA, has been programmed as the satellite devise for the ITER and as the national centralized tokamak. The present positive-ion-based NBI system, which has employed the expensive CAMAC and has been operated for 20 years, is required to extend its pulse duration from 30 s to 100 s for JT-60SA. Recently, the frequency of troubles on the data acquisition system has increased due to its age-induced deterioration. To realize the long pulse operation and to maintain the high reliability on JT-60SA, we set to develop a new acquisition system. As a first step, we have designed and constructed a prototype acquisition system, which is combined with instruments highly available on the market, to confirm the basic performance. The result indicates that the new system allows us to construct a highly flexible and user-friendly acquisition system at low cost without highly technical software developing.

Journal Articles

Tokamak machine monitoring and control system for JT-60

Miyo, Yasuhiko; Yagyu, Junichi; Nishiyama, Tomokazu; Honda, Masao; Ichige, Hisashi; Kaminaga, Atsushi; Sasajima, Tadayuki; Arai, Takashi; Sakasai, Akira

Fusion Engineering and Design, 83(2-3), p.337 - 340, 2008/04

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Design of a new P-NBI control system for 100-s injection in JT-60SA

Okano, Fuminori; Shinozaki, Shinichi; Honda, Atsushi; Oshima, Katsumi; Numazawa, Susumu*; Ikeda, Yoshitaka

Fusion Engineering and Design, 83(2-3), p.280 - 282, 2008/04

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Application of PLC to dynamic control system for liquid He cryogenic pumping facility on JT-60U NBI system

Honda, Atsushi; Okano, Fuminori; Oshima, Katsumi; Akino, Noboru; Kikuchi, Katsumi; Tanai, Yutaka; Takenouchi, Tadashi; Numazawa, Susumu*; Ikeda, Yoshitaka

Fusion Engineering and Design, 83(2-3), p.276 - 279, 2008/04

 Times Cited Count:11 Percentile:59.25(Nuclear Science & Technology)

The control system of the cryogenic facility in the JT-60 NBI system has been renewed by employing the PLC (Programmable Logic Controller) and SCADA (Supervisory Control And Data Acquisition) system. The original control system was constructed about 20 years ago by specifying the DCS (Distributed Control System) computer to deal with 400 feedback loops. Recently, troubles on this control system have increased due to its aged deterioration. To maintain a high reliability of the cryogenic facility, a new control system has been intended with PLC and SCADA system. By optimizing the function blocks and connecting them in the FBD language, the feedback loops in the new control system have been successfully replaced from DCS to PLC without software developer. At present, the new control system has worked well. This is the first application of the marketable PLC to the actual system with feedback loops of $$>$$ 400 produced by the user itself.

Journal Articles

Long pulse production of high current D$$^{-}$$ ion beams in the JT-60 negative ion source

Hanada, Masaya; Kamada, Masaki; Akino, Noboru; Ebisawa, Noboru; Honda, Atsushi; Kawai, Mikito; Kazawa, Minoru; Kikuchi, Katsumi; Komata, Masao; Mogaki, Kazuhiko; et al.

Review of Scientific Instruments, 79(2), p.02A519_1 - 02A519_4, 2008/02

 Times Cited Count:6 Percentile:32.39(Instruments & Instrumentation)

A long pulse production of high-current, high-energy D$$^{-}$$ ion beams was studied in the JT-60U negative ion source that was designed to produce 22 A, 500 keV D$$^{-}$$ ion beams. Prior to the long pulse production, the short pulse beams were produced to examine operational ranges for a stable voltage holding capability and an allowable grid power loading. From a correlation between the voltage holding capability and a light intensity of cathodoluminescence from the insulator made of Fiber Reinforced Plastic insulator, the voltage holding was found to be stable at $$<$$ 340 kV where the light was sufficiently suppressed. The grid power loading for the long pulse operation was also decreased to the allowable level of $$<$$ 1 MW without a significant reduction of the beam power by tuning the extraction voltage (Vext) and the arc power (Parc). These allow the production of 30 A D$$^{-}$$ ion beams at 340 keV from two ion sources at Vacc = 340 kV. The pulse length was extended step by step, and finally reached up to 21 s, where the beam pulse length was limited by the surface temperature of the beam scraper without water cooling. The D$$^{-}$$ ion beams were neutralized to via a gas cell, resulting in a long pulse injection of 3.2 MW D$$^{0}$$ beams for 21 s. This is the first long injection of $$>$$ 20 s in a power range of $$>$$ 3 MW.

JAEA Reports

Development and management of the knowledge base for the geological disposal technology; Annual report 2006

Umeda, Koji; Oi, Takao; Osawa, Hideaki; Oyama, Takuya; Oda, Chie; Kamei, Gento; Kuji, Masayoshi*; Kurosawa, Hideki; Kobayashi, Yasushi; Sasaki, Yasuo; et al.

JAEA-Review 2007-050, 82 Pages, 2007/12

JAEA-Review-2007-050.pdf:28.56MB

This report shows the annual report which shows the summarized results and topic outline of each project on geological disposal technology in the fiscal year of 2006.

Journal Articles

Technical design of NBI system for JT-60SA

Ikeda, Yoshitaka; Akino, Noboru; Ebisawa, Noboru; Hanada, Masaya; Inoue, Takashi; Honda, Atsushi; Kamada, Masaki; Kawai, Mikito; Kazawa, Minoru; Kikuchi, Katsumi; et al.

Fusion Engineering and Design, 82(5-14), p.791 - 797, 2007/10

 Times Cited Count:20 Percentile:79.69(Nuclear Science & Technology)

Modification of JT-60U to a superconducting device (so called JT-60SA) has been planned to contribute to ITER and DEMO. The NBI system is required to inject 34 MW for 100 s. The upgraded NBI system consists of twelve positive ion based NBI (P-NBI) units and one negative ion based NBI (N-NBI) unit. The injection power of the P-NBI units are 2 MW each at 85 keV, and the N-NBI unit will be 10 MW at 500 keV, respectively. On JT-60U, the long pulse operation of 30 s at 2 MW (85 keV) and 20 s at 3.2 MW (320 keV) have been achieved on P-NBI and N-NBI units, respectively. Since the temperature increase of the cooling water in both ion sources is saturated within 20 s, further pulse extension up to 100 s is expected to mainly modify the power supply systems in addition to modification of the N-NBI ion source for high acceleration voltage. The detailed technical design of the NBI system for JT-60SA is presented.

JAEA Reports

Development of protection system for power supply facilities in JT-60U P-NBI for long pulse operation

Oshima, Katsumi; Okano, Fuminori; Honda, Atsushi; Shinozaki, Shinichi; Usui, Katsutomi; Noto, Katsuya; Kawai, Mikito; Ikeda, Yoshitaka

JAEA-Technology 2007-044, 27 Pages, 2007/06

JAEA-Technology-2007-044.pdf:26.9MB

In the positive ion based NBI (P-NBI) system, we have developed a protection system to protect the power supply facilities from over load during long pulse operation. The protection system monitors the voltage (V) and current (I) in the power supply facilities, and calculates the parameters of V2t and I2t in real-time, where T is the pulse duration. It turns off the power supply facilities when V2t and I2t are beyond the critical values. After two development stages, we have completed the protection system using a package typed PLC (Programmable Logic Controller) which has a high expandability of multi-unit operation. Moreover, we have constructed a user-friendly system by using a SCADA (Supervisory Control and Data Acquisition) system.

JAEA Reports

Design study of a new P-NBI control system for 100-s injection in JT-60SA

Honda, Atsushi; Okano, Fuminori; Shinozaki, Shinichi; Oshima, Katsumi; Numazawa, Susumu*; Ikeda, Yoshitaka

JAEA-Technology 2007-026, 19 Pages, 2007/03

JAEA-Technology-2007-026.pdf:3.36MB

The modification of the JT-60U to a fully superconducting coil tokamak, JT-60SA (Super Advanced), has been programmed as the satellite devise for the ITER (International Thermonuclear Experimental Reactor) and as the national centralized tokamak. The present positive-ion-based NBI system (P-NBI), which has been operated for 20 years and will be the main heating system on JT-60SA, is required to manage the long pulse injection extended from 30 s to 100 s at the power of 24 MW with 12 units. To realize such a requirement, the original control system handling more than 4000 digital data is to be fully remodeled. Design study of the new control system has been conducted from viewpoint of market availability, system extensibility, cost-effectiveness and independent development in programming. It has been concluded that a distributed control system using PLC (Programmable Logic Controller) could be applied to the large-scale control system for 100-s operations with satisfaction of the evaluation viewpoints.

Journal Articles

Present status of the negative ion based NBI system for long pulse operation on JT-60U

Ikeda, Yoshitaka; Umeda, Naotaka; Akino, Noboru; Ebisawa, Noboru; Grisham, L. R.*; Hanada, Masaya; Honda, Atsushi; Inoue, Takashi; Kawai, Mikito; Kazawa, Minoru; et al.

Nuclear Fusion, 46(6), p.S211 - S219, 2006/06

 Times Cited Count:58 Percentile:87.29(Physics, Fluids & Plasmas)

Recently, the extension of the pulse duration up to 30 sec has been intended to study quasi-steady state plasma on JT-60U N-NBI system. The most serious issue is to reduce the heat load on the grids for long pulse operation. Two modifications have been proposed to reduce the heat load. One is to suppress the beam spread which may be caused by beamlet-beamlet interaction in the multi-aperture grid due to the space charge force. Thin plates were attached on the extraction grid to modify the local electric field. The plate thickness was optimized to steer the beamlet deflection. The other is to reduce the stripping loss, where the electron of the negative ion beam is stripped and accelerated in the ion source and then collides with the grids. The ion source was modified to reduce the pressure in the accelerator column to suppress the beam-ion stripping loss. Up to now, long pulse injection of 17 sec for 1.6 MW and 25 sec for $$sim$$1 MW has been obtained by one ion source with these modifications.

JAEA Reports

PLC control of NBI cryogenic facility on JT-60U

Honda, Atsushi; Okano, Fuminori; Oshima, Katsumi; Akino, Noboru; Kikuchi, Katsumi; Tanai, Yutaka; Takenouchi, Tadashi; Numazawa, Susumu*

JAEA-Technology 2006-020, 20 Pages, 2006/03

JAEA-Technology-2006-020.pdf:2.96MB

no abstracts in English

Journal Articles

Application of PLC to dynamic feedback control of a large liquid-He refrigerator system on nuclear fusion facility

Okano, Fuminori; Honda, Atsushi; Oshima, Katsumi; Akino, Noboru; Kikuchi, Katsumi; Numazawa, Susumu*

Keiso, 49(3), p.22 - 26, 2006/03

no abstracts in English

Journal Articles

Relation between the oxygen contents in the neutral beam and in the core plasma in JT-60U

Nakano, Tomohide; Koide, Yoshihiko; Honda, Atsushi; Umeda, Naotaka; Akino, Noboru; Higashijima, Satoru; Takenaga, Hidenobu; Kubo, Hirotaka

Purazuma, Kaku Yugo Gakkai-Shi, 81(9), p.708 - 716, 2005/09

no abstracts in English

Journal Articles

Control of thermal load on the JT-60 NBI power supply system for 30 second operation

Oshima, Katsumi*; Honda, Atsushi; Okano, Fuminori; Usui, Katsutomi; Noto, Katsuya*; Muto, Hideki*; Kawai, Mikito; Oga, Tokumichi; Ikeda, Yoshitaka

Heisei-16-Nendo Osaka Daigaku Sogo Gijutsu Kenkyukai Hokokushu (CD-ROM), 4 Pages, 2005/03

no abstracts in English

60 (Records 1-20 displayed on this page)