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Journal Articles

Vacuum insulation and achievement of 980 keV, 185 A/m$$^{2}$$ H$$^{-}$$ ion beam acceleration at JAEA for the ITER neutral beam injector

Tobari, Hiroyuki; Taniguchi, Masaki; Kashiwagi, Mieko; Dairaku, Masayuki; Umeda, Naotaka; Yamanaka, Haruhiko; Tsuchida, Kazuki; Takemoto, Jumpei; Watanabe, Kazuhiro; Inoue, Takashi; et al.

Plasma Science and Technology, 15(2), p.179 - 183, 2013/02

 Times Cited Count:1 Percentile:4.42(Physics, Fluids & Plasmas)

Vacuum insulation is a common issue for the accelerator and the HV bushing for the ITER NBI. The HV bushing has five-stage structure and each stage consists of double-layered insulators. Hence, several triple points exist around the insulators. To reduce electric field at those points simultaneously, three types of stress ring were developed. In voltage holding test of a full-scale mockup equipped with those stress rings, 120% of rated voltage was sustained and the voltage holding capability required in ITER was verified. In the MeV accelerator, voltage holding capability was not sufficient due to breakdown triggered by electric field concentration at edge and corner on grid components. By extending gap length, 1 MV was sustained in vacuum. Furthermore, with new accelerator grids which compensates beam deflection due to magnetic field and space charge repulsion between beamlets, 980 keV, 185 A/m$$^{2}$$ H$$^{-}$$ ion beam acceleration was demonstrated, which was close to ITER requirement.

Journal Articles

Voltage holding study of 1 MeV accelerator for ITER neutral beam injector

Taniguchi, Masaki; Kashiwagi, Mieko; Umeda, Naotaka; Dairaku, Masayuki; Takemoto, Jumpei; Tobari, Hiroyuki; Tsuchida, Kazuki; Yamanaka, Haruhiko; Watanabe, Kazuhiro; Kojima, Atsushi; et al.

Review of Scientific Instruments, 83(2), p.02B121_1 - 02B121_3, 2012/02

 Times Cited Count:11 Percentile:47.28(Instruments & Instrumentation)

JAEA has developed the MeV accelerator to demonstrate 1 MeV, 200 A/m$$^{2}$$ H$$^{-}$$ ion beam acceleration required for ITER NBI. A key to realize such a high power accelerator is improvement of voltage holding capability. Based on detailed investigation of the voltage holding characteristics, MeV accelerator was modified to reduce electric field concentration by extending gaps between the grid supports and increasing curvature radiuses at the support corners. After the modifications, accelerator succeeded in sustaining -1 MV in vacuum without beam acceleration. Moreover, beam deflection due to the magnetic field for electron suppression and space charge repulsion was compensated by aperture displacement technique. As the result, beam deflection was compensated and voltage holding during the beam acceleration was improved. Beam parameter of the MeV accelerator was increased to 980 keV, 185 A/m$$^{2}$$, which is close to the requirement of ITER accelerator.

Journal Articles

Study of beamlet deflection and its compensations in a MeV accelerator

Kashiwagi, Mieko; Inoue, Takashi; Taniguchi, Masaki; Umeda, Naotaka; Grisham, L. R.*; Dairaku, Masayuki; Takemoto, Jumpei; Tobari, Hiroyuki; Tsuchida, Kazuki; Watanabe, Kazuhiro; et al.

AIP Conference Proceedings 1390, p.457 - 465, 2011/09

 Times Cited Count:9 Percentile:89.2

In a five stage multi-aperture and multi-grid (MAMuG) accelerator in JAEA, beam acceleration tests are in progress toward 1 MeV, 200 A/m$$^{2}$$ H$$^{-}$$ ion beams for ITER. The 1 MV voltage holding has been successfully demonstrated for 4000 s with the accelerator of expanded gap length that lowered local electric field concentrations. The led to increase of the beam energy up to 900 keV-level. However, it was found that beamlets were deflected more in long gaps and direct interceptions of the deflected beamlet caused breakdowns. The beamlet deflection and its compensation methods were studied utilizing a three-dimensional multi beamlet analysis. The analysis showed that the 1 MeV beam can be compensated by a combination of the aperture offset of 0.8 mm applied in the electron suppression (ESG) and the metal bar called a field shaping plate with a thickness of 1 mm attached beneath the ESG. The paper reports analytical predictions and experimental results of the MAMuG accelerator.

Journal Articles

Development of full-size mockup bushing for 1 MeV ITER NB system

Tobari, Hiroyuki; Inoue, Takashi; Hanada, Masaya; Dairaku, Masayuki; Watanabe, Kazuhiro; Umeda, Naotaka; Taniguchi, Masaki; Kashiwagi, Mieko; Yamanaka, Haruhiko; Takemoto, Jumpei; et al.

Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2011/03

High voltage (HV) bushing in the ITER NBI is one of critical components, which acts as a feedthrough for electric power and cooling water from the -1 MV power supply in SF$$_{6}$$ gas to beam source inside vacuum. JAEA has overcome a longstanding issue on manufacturing of a large bore ceramic ring with 1.56 m in diameter as the insulator of the five-stage HV bushing. Joining method of the ceramic and metal flange with thick Kovar plate to form vacuum boundary was also developed. By assembling components, a full-size mockup bushing simulating one stage of the HV bushing was successfully manufactured. In the voltage holding test, the high voltage of 240 kV including the margin of 20 % of a rated voltage was sustained for 3600 s without breakdown, and the voltage holding capability required in ITER was successfully verified.

Journal Articles

1 MV holding and beam optics in a multi-aperture multi-grid accelerator for ITER NBI

Kashiwagi, Mieko; Taniguchi, Masaki; Kojima, Atsushi; Dairaku, Masayuki; Hanada, Masaya; Hemsworth, R. S.*; Mizuno, Takatoshi*; Takemoto, Jumpei; Tanaka, Masanobu*; Tanaka, Yutaka*; et al.

Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2011/03

At JAEA, a multi-aperture multi-grid accelerator has been developed for the ITER neutral beam system. A target is H$$^{-}$$ ion beam acceleration of 0.5 A (200 A/m$$^{2}$$) at 1 MeV. In real accelerators, it was found that the voltage holding was about a half of that obtained in an ideal small electrode. After applying necessary gap length and radii of edges of grid supports to lower local electric field concentrations, the accelerator succeeded in sustaining 1 MV for 4000 s. As a result, beam parameters were increased to 879 keV, 0.36 A (157 A/m$$^{2}$$) at perveance matched condition from 796 kV, 0.32 A (140 A/m$$^{2}$$) reported in FEC2008. In the beam acceleration, the beamlet deflections due to magnetic field and space charge repulsion caused direct interceptions, that resulted in limitations in the beam energy and current. Compensation of these beamlet deflections has been tested applying aperture offset and field shaping plate, which were examined in a three-dimensional beam analysis.

JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2008

Takeishi, Minoru; Sumiya, Shuichi; Matsuura, Kenichi; Watanabe, Hitoshi; Nakano, Masanao; Takeyasu, Masanori; Isozaki, Hisaaki*; Isozaki, Tokuju; Morisawa, Masato; Fujita, Hiroki; et al.

JAEA-Review 2009-048, 177 Pages, 2009/12

JAEA-Review-2009-048.pdf:19.3MB
JAEA-Review-2009-048(errata).pdf:0.12MB

Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV; Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2008 to March 2009. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes.

Journal Articles

Design of a -1 MV dc UHV power supply for ITER NBI

Watanabe, Kazuhiro; Yamamoto, Masanori; Takemoto, Jumpei; Yamashita, Yasuo*; Dairaku, Masayuki; Kashiwagi, Mieko; Taniguchi, Masaki; Tobari, Hiroyuki; Umeda, Naotaka; Sakamoto, Keishi; et al.

Nuclear Fusion, 49(5), p.055022_1 - 055022_5, 2009/05

 Times Cited Count:27 Percentile:71.24(Physics, Fluids & Plasmas)

Japan Atomic Energy Agency as the Japan Domestic Agency (JADA) for ITER contributes procurement of dc -1 MV ultra-high voltage (UHV) components such as a dc -1 MV generator, a transmission line and a -1 MV insulating transformer for the ITER NBI power supply. Inverter frequency of 150 Hz in the -1 MV power supply and major circuit parameters have been proposed and adopted in the ITER NBI. The dc UHV insulation at the multi-layer insulation structure of the transformer for a long pulse up to 3600 s has been designed with electric field simulation. Based on the simulation overall dimensions of the dc UHV components have been finalized. The JADA contributes to provide an effective surge suppression system composed of core snubbers and resistors. Input energy into the accelerator from the power supply can be reduced to about 20 J which satisfies the design criteria of the total 50 J at -1 MV breakdown.

JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2007

Takeishi, Minoru; Matsuura, Kenichi; Watanabe, Hitoshi; Nakano, Masanao; Takeyasu, Masanori; Isozaki, Hisaaki; Isozaki, Tokuju; Morisawa, Masato; Fujita, Hiroki; Kokubun, Yuji; et al.

JAEA-Review 2008-057, 155 Pages, 2008/11

JAEA-Review-2008-057.pdf:2.15MB

Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of JAEA, Chapter IV; Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged to the atmosphere and the sea during April 2007 to March 2008. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and its trends, meteorological data and discharged radioactive wastes.

Journal Articles

Mutation breeding of a new chrysanthemum variety by irradiation of ion beams to "Jinba"

Watanabe, Hideki*; Toyoda, Tomomi*; Emoto, Keishi*; Yoshimatsu, Shuji*; Hase, Yoshihiro; Kamisoyama, Shigeru*

JAEA-Review 2008-055, JAEA Takasaki Annual Report 2007, P. 81, 2008/11

no abstracts in English

Journal Articles

-1 MV DC UHV power supply for ITER NBI

Watanabe, Kazuhiro; Yamamoto, Masanori; Takemoto, Jumpei; Yamashita, Yasuo*; Dairaku, Masayuki; Kashiwagi, Mieko; Taniguchi, Masaki; Tobari, Hiroyuki; Umeda, Naotaka; Sakamoto, Keishi; et al.

Proceedings of 22nd IAEA Fusion Energy Conference (FEC 2008) (CD-ROM), 7 Pages, 2008/10

The JADA contributes procurement of DC -1 MV ultra-high voltage (UHV) components such as a -1 MV DC generator, a transmission line and a -1 MV insulating transformer. The DC UHV insulation has been carefully analyzed since DC long pulse insulation is quite different from conventional AC insulation. The insulation structure has been designed and the overall dimensions of the DC UHV components have been finalized. The JADA contributes to provide an effective surge suppression system composed of core snubbers and resistors. Input energy into the accelerator from the power supply can be reduced to about 20 J which satisfies the design criteria of the total 50 J at -1 MV breakdown. From these studies, major technical issues were considered and the functional technical specifications of the UHV components have been developed for the procurement by the JADA.

Journal Articles

Induction of new color variation by irradiation of ion beams to light yellow "Jinba"

Toyoda, Tomomi*; Watanabe, Hideki*; Emoto, Keishi*; Yoshimatsu, Shuji*; Hase, Yoshihiro; Kamisoyama, Shigeru*

JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 81, 2008/03

no abstracts in English

JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2006

Takeishi, Minoru; Miyagawa, Naoto; Nakano, Masanao; Takeyasu, Masanori; Isozaki, Hisaaki; Isozaki, Tokuju; Morisawa, Masato; Fujita, Hiroki; Kokubun, Yuji; Kato, Chiaki; et al.

JAEA-Review 2007-044, 155 Pages, 2008/02

JAEA-Review-2007-044.pdf:2.58MB
JAEA-Review-2007-044(errata).pdf:0.13MB

Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of JAEA, Chapter 4; Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged to the atmosphere and the sea during April 2006 to March 2007. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and its trends, meteorological data and discharged radioactive wastes.

JAEA Reports

Annual report on the environmental radiation monitoring around Tokai Reprocessing Plant FY2005

Takeishi, Minoru; Miyagawa, Naoto; Nakano, Masanao; Takeyasu, Masanori; Isozaki, Hisaaki; Isozaki, Tokuju; Morisawa, Masato; Fujita, Hiroki; Kokubun, Yuji; Kato, Chiaki; et al.

JAEA-Review 2006-031, 155 Pages, 2006/10

JAEA-Review-2006-031.pdf:7.76MB
JAEA-Review-2006-031(errata).pdf:0.13MB

Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of JAEA, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged to the atmosphere and the sea during April 2005 to March 2006. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and its trends, meteorological data and discharged radioactive wastes.

JAEA Reports

Data Book on the Current of Tokai Reprocessing Plant; From January to December in 2001

Takeishi, Minoru; Naoto, Miyagawa,; Nakano, Masanao; Isozaki, Hisaaki; Isozaki, Tokuju; Ao, Hidetoshi*; Nemoto, Masashi*

JNC TN8450 2004-006, 117 Pages, 2004/06

JNC-TN8450-2004-006.pdf:10.31MB

Current direction, velocity, water temperature, salinity and etc. were observed by the current meters which were set near the outlet (36 26' 51" N, 140 39' 02"E)of the discharge pipe of the reprocessing plant in JNC Tokai Works. Besides, the horizontal (26 points) and vertical (14 points) observation of water temperature and salinity were executed using the monitoring ship (Seikai). The observation region ranged from 36 22' N to 36 30' N and from 140 37' E to 140 42'E. The data, which were observed in 2001, were described in this report.

JAEA Reports

Data Book on the Current of Tokai Reprocessing Plant; From January to December in 2000

Takeishi, Minoru; Naoto, Miyagawa,; Nakano, Masanao; Isozaki, Hisaaki; Isozaki, Tokuju; Ao, Hidetoshi*; Nemoto, Masashi*

JNC TN8450 2004-005, 139 Pages, 2004/06

JNC-TN8450-2004-005.pdf:12.13MB

Current direction, velocity, water temperature, salinity and etc. were observed by the current meters which were set near the outlet (36 26' 51" N, 140 39' 02"E)of the discharge pipe of the reprocessing plant in JNC Tokai Works. Besides, the horizontal (26 points) and vertical (14 points) observation of water temperature and salinity were executed using the monitoring ship (Seikai). The observation region ranged from 36 22' N to 36 30' N and from 140 37' E to 140 42'E. The data, which were observed in 2000, were described in this report.

Journal Articles

Recent RF activities on JT-60U

Ikeda, Yoshitaka; Fujita, Takaaki; Hamamatsu, Kiyotaka; Ide, Shunsuke; Imai, Tsuyoshi; Isayama, Akihiko; Iwase, Makoto; Kasugai, Atsushi; Kondoh, Takashi; Kusama, Yoshinori; et al.

AIP Conference Proceedings 485, p.279 - 287, 1999/09

no abstracts in English

Journal Articles

Simultaneous heating by high power lower hybrid waves and neutral beams in the JT-60 tokamak

Ushigusa, Kenkichi; Imai, Tsuyoshi; Ikeda, Yoshitaka; Sakamoto, Keishi; F.X.Soeldner*; *; Tsuji, Shunji; Shimizu, Katsuhiro; Naito, Osamu; Uehara, Kazuya; et al.

Nuclear Fusion, 29(2), p.265 - 276, 1989/02

 Times Cited Count:17 Percentile:58.82(Physics, Fluids & Plasmas)

no abstracts in English

JAEA Reports

Lower hybrid wave heating into neutral beam heated plasma in the JT-60 tokamak

Ushigusa, Kenkichi; Imai, Tsuyoshi; Ikeda, Yoshitaka; Sakamoto, Keishi; F.X.Soldner*; *; Tsuji, Shunji; Shimizu, Katsuhiro; Naito, Osamu; Uehara, Kazuya; et al.

JAERI-M 88-115, 28 Pages, 1988/06

JAERI-M-88-115.pdf:0.87MB

no abstracts in English

Oral presentation

Flower color mutation induction in light yellow lineage of chrysanthemum "Jinba" using ion beam irradiation

Toyoda, Tomomi*; Kamisoyama, Shigeru*; Emoto, Keishi*; Watanabe, Hideki*; Yoshimatsu, Shuji*; Hase, Yoshihiro

no journal, , 

no abstracts in English

Oral presentation

Design of -1 MV UHV power supply for the ITER NBI

Takemoto, Jumpei; Watanabe, Kazuhiro; Yamamoto, Masanori; Inoue, Takashi; Sakamoto, Keishi; Yamashita, Yasuo*

no journal, , 

no abstracts in English

26 (Records 1-20 displayed on this page)