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Journal Articles

Basic analysis of weldability and machinability of structural materials for ITER toroidal field coils

Onozuka, Masanori*; Shimizu, Katsusuke*; Urata, Kazuhiro*; Kimura, Masahiro*; Kadowaki, Hirokazu*; Okamoto, Mamoru*; Nakajima, Hideo; Hamada, Kazuya; Okuno, Kiyoshi

Fusion Engineering and Design, 82(5-14), p.1431 - 1436, 2007/10

 Times Cited Count:2 Percentile:79.49(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Demonstration tests for manufacturing the ITER vacuum vessel

Shimizu, Katsusuke*; Onozuka, Masanori*; Usui, Yukinori*; Urata, Kazuhiro*; Tsujita, Yoshihiro*; Nakahira, Masataka; Takeda, Nobukazu; Kakudate, Satoshi; Omori, Junji; Shibanuma, Kiyoshi

Fusion Engineering and Design, 82(15-24), p.2081 - 2088, 2007/10

 Times Cited Count:4 Percentile:65.57(Nuclear Science & Technology)

To confirm the manufacturing and assembly process of the ITER vacuum vessel (VV), a series of related tests has been conducted. (1) Using a full-scale partial mock-up, fabrication methods are to be examined to determine feasibility. (2) To simulate a series of field-joint assembly operations, a test stand was built. (3) To provide an appropriate shield gas supply on the back side of the outer shell during field-joint welding, three types of back-seal structures have been tested. (4) The applicability of UT methods for volumetric inspection has been investigated. (5) Applicability of Liquid Penetrant Testing as a surface examination for the VV interior surface (i.e. ultra-vacuum side) has been investigated.

Journal Articles

Ripple reduction with ferritic insert in JFT-2M

Shinohara, Koji; Sato, Masayasu; Kawashima, Hisato; Tsuzuki, Kazuhiro; Suzuki, Sadaaki; Urata, Kazuhiro*; Isei, Nobuaki; Tani, Takashi; Kikuchi, Kazuo; Shibata, Takatoshi; et al.

Fusion Science and Technology, 49(2), p.187 - 196, 2006/02

 Times Cited Count:7 Percentile:50.67(Nuclear Science & Technology)

In JFT-2M, the toroidal field ripple was reduced by ferritic insert. Two kinds of ripple reduction were carried out. In the first case, ferritic steel was installed between toroidal field coil and vacuum vessel, just under toroidal field coil, outside vacuum vessel. In the second one, ferritic steel was installed inside vacuum vessel covering almost whole inside wall. The ripple was successfully reduced in the both cases. The temperature increment on the first wall measured by infrared TV was also reduced. A new version of OFMC code was also developed to analyze fast ion behavior in the complex structure of the toroidal field. The TF ripple reduction with ferritic insert in JFT-2M is summarized in this article.

Journal Articles

Engineering design, installation, and conditioning of ferritic steel plates/wall for AMTEX in JFT-2M

Yamamoto, Masahiro*; Shibata, Takatoshi; Tsuzuki, Kazuhiro; Sato, Masayasu; Kimura, Haruyuki; Okano, Fuminori; Kawashima, Hisato; Suzuki, Sadaaki; Shinohara, Koji; JFT-2M Group; et al.

Fusion Science and Technology, 49(2), p.241 - 248, 2006/02

 Times Cited Count:2 Percentile:81.05(Nuclear Science & Technology)

JFT-2M has been modified three times in the Advanced Material Tokamak Experiment (AMTEX) program to investigate compatibility of the low activation ferritic steel F82H with tokamak plasmas as a structural material for future reactors. The ferritic steel plate/wall was installed inside and/or outside of the vacuum vessel to reduce the ripple of toroidal magnetic field step by step through three modifications. This paper focuses on engineering aspects in these modifications; electromagnetic analysis to find a suitable way for fixing these plates, installation procedure to keep small tolerance, a three-dimensional magnetic field measurement device used to obtain information of the actual shape of the vacuum vessel used as a installation standard surface. To keep a good surface condition of the ferritic steel plate/wall that rusts easily, careful treatment was executed before the installation. To reduce oxygen impurities further, a boronization system with tri-methyl boron, which is safe and easy to operate, was developed.

JAEA Reports

None

Takamiya, Kazuhiro; Murata, Masato

JNC-TY6440 2004-002, 47 Pages, 2005/03

JNC-TY6440-2004-002.pdf:0.7MB

None

JAEA Reports

None

Takamiya, Kazuhiro; Murata, Masato

JNC-TY6440 2004-001, 37 Pages, 2005/03

JNC-TY6440-2004-001.pdf:0.62MB

None

JAEA Reports

Parameter study on dynamic behavior of ITER tokamak scaled model

Nakahira, Masataka; Takeda, Nobukazu; Urata, Kazuhiro*

JAERI-Tech 2004-069, 55 Pages, 2004/12

JAERI-Tech-2004-069.pdf:11.46MB

This report summarizes the study on dynamic behavior of ITER tokamak scaled model according to the parametric analysis of base plate thickness, in order to find a solution to give the sufficient rigidity without affecting the dynamic behavior. For this, modal analyses were performed changing the base plate thickness from the present design of 55mm to 100, 150 and 190 mm. It was found that the thickness of 150mm gives well fitting of 1st natural frequency about 90% of ideal rigid case. Thus, the modification study was performed to find out the adequate plate thickness. Considering the material availability, transportation and weldability, it was found that the 300mm thickness would be a limitation. The analysis result of 300mm thickness case showed 97% fitting of 1st natural frequency to the ideal rigid case. It was however found that the bolt length was too long and it gave additional twisting mode. As a result, it was concluded that the base plate thickness of 150mm or 190mm gives sufficient rigidity for the dynamic behavior of the scaled model.

Journal Articles

Energetic particle physics in JT-60U and JFT-2M

Shinohara, Koji; Takechi, Manabu; Ishikawa, Masao; Kusama, Yoshinori; Tsuzuki, Kazuhiro; Urata, Kazuhiro*; Kawashima, Hisato; Tobita, Kenji; Fukuyama, Atsushi*; Cheng, C. Z.*; et al.

Plasma Physics and Controlled Fusion, 46(7), p.S31 - S45, 2004/07

 Times Cited Count:39 Percentile:20.4(Physics, Fluids & Plasmas)

Recent energetic particle physics research has been devoted to Alfven eigenmodes (AEs) in reversed-shear (RS) plasmas, energetic ion transport in the appearance of modes in the frequency range of TAE, energetic ion behavior in the plasma with a current hole, and ripple loss in the complex toroidal field ripple due to ferritic steel plates. We will report these recent progresses for energetic particle physics in JT-60U and JFT-2M.

Journal Articles

Advanced control scenario of high-performance steady-state operation for JT-60 superconducting tokamak

Tamai, Hiroshi; Kurita, Genichi; Matsukawa, Makoto; Urata, Kazuhiro*; Sakurai, Shinji; Tsuchiya, Katsuhiko; Morioka, Atsuhiko; Miura, Yushi; Kizu, Kaname; Kamada, Yutaka; et al.

Plasma Science and Technology, 6(3), p.2281 - 2285, 2004/06

 Times Cited Count:0 Percentile:100(Physics, Fluids & Plasmas)

High performance steady-state operation for JT-60SC are evaluated by the TOPICS analysis. $$beta$$$$_N$$$$sim$$5 and bootstrap current fraction $$sim$$86% is kept steady at I$$_p$$=1.5 MA, B$$_t$$=2 T by neutral beam power of 11 MW. The ERATO-J analysis shows that the external-kink mode with multiple toroidal mode numbers of n=1 and n=2 is stable at $$beta$$$$_N$$ $$leq$$5.5 at the average ratio of conducting wall radius to plasma minor radius of about 1.2 with the wall stabilisation effect. Resistive wall modes, induced by a close location of the wall to plasma, is expected to be suppressed by the active feedback stabilisation with a set of non-axisymmetric field coils behind the stabilising plates. Further optimisation for the high-$$beta$$$$_N$$ accessibility by the plasma shaping is performed with the TOSCA analysis. The plasma shaping factor defined as S=(I$$_p$$/aB$$_t$$)q$$_9$$$$_5$$ and strongly correlated to the plasma elongation and triangularity, is scanned from $$sim$$4 to $$sim$$6, which extends the availability of current and pressure profile control for the high performance plasma operation.

JAEA Reports

Fast ion loss calculation in the ripple compensation magnetic field by ferritic steel insertion using the FEMAG/OFMC code

Urata, Kazuhiro*; Shinohara, Koji; Suzuki, Masanobu*; Kamata, Isao*

JAERI-Data/Code 2004-007, 45 Pages, 2004/03

JAERI-Data-Code-2004-007.pdf:5.63MB

As the toroidal magnetic field generated by discrete TF coils involves magnetic field ripple, the fast ion loss is induced to damage vacuum vessel in tokamaks. An idea of ripple compensation using ferromagnetic is proposed. Since low activation ferritic steel have low activation and thermal conduction properties, the ferritic steel is planned to install in tokamak reactors. Installation of ferritic steel plates with toroidal symmetry is effective to compensate ripple, however in the actual devices it is difficult for interference with other components. Besides the first wall shapes are often asymmetric. So it is better to treat toroidal asymmetry to evaluate the ripple induced loss in the actual devices. For the purpose, magnetic field calculation code considering ferritic steel; FEMAG(FErrite generating MAGnetic field)has been speeded up. On the basis of this magnetic field data, OFMC (Orbit Following Monte Carlo) has been upgraded to treat toroidal asymmetry. The use of FEMAG/OFMC, applications to the JFT-2M experiments, and the national centralized tokamak facility are reported.

Journal Articles

Advanced fusion technologies developed for JT-60 superconducting Tokamak

Sakasai, Akira; Ishida, Shinichi; Matsukawa, Makoto; Akino, Noboru; Ando, Toshinari*; Arai, Takashi; Ezato, Koichiro; Hamada, Kazuya; Ichige, Hisashi; Isono, Takaaki; et al.

Nuclear Fusion, 44(2), p.329 - 334, 2004/02

no abstracts in English

Journal Articles

Advanced fusion technologies developed for JT-60 superconducting Tokamak

Sakasai, Akira; Ishida, Shinichi; Matsukawa, Makoto; Akino, Noboru; Ando, Toshinari*; Arai, Takashi; Ezato, Koichiro; Hamada, Kazuya; Ichige, Hisashi; Isono, Takaaki; et al.

Nuclear Fusion, 44(2), p.329 - 334, 2004/02

 Times Cited Count:7 Percentile:74.52(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Progress in physics and technology developments for the modification of JT-60

Tamai, Hiroshi; Matsukawa, Makoto; Kurita, Genichi; Hayashi, Nobuhiko; Urata, Kazuhiro*; Miura, Yushi; Kizu, Kaname; Tsuchiya, Katsuhiko; Morioka, Atsuhiko; Kudo, Yusuke; et al.

Plasma Science and Technology, 6(1), p.2141 - 2150, 2004/02

 Times Cited Count:2 Percentile:92.83(Physics, Fluids & Plasmas)

The dominant issue for the the modification program of JT-60 (JT-60SC) is to demonstrate the steady state reactor relevant plasma operation. Physics design on plasma parameters, operation scenarios, and the plasma control method are investigated for the achievement of high-$$beta$$. Engineering design and the R&D on the superconducting magnet coils, radiation shield, and vacuum vessel are performed. Recent progress in such physics and technology developments is presented.

Journal Articles

Design and analysis of plasma position and shape control in superconducting tokamak JT-60SC

Matsukawa, Makoto; Ishida, Shinichi; Sakasai, Akira; Urata, Kazuhiro*; Senda, Ikuo*; Kurita, Genichi; Tamai, Hiroshi; Sakurai, Shinji; Miura, Yushi; Masaki, Kei; et al.

Fusion Engineering and Design, 66-68(1-4), p.703 - 708, 2003/09

 Times Cited Count:2 Percentile:79.94(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Design and structural analysis for the vacuum vessel of superconducting Tokamak JT-60SC

Kudo, Yusuke; Sakurai, Shinji; Masaki, Kei; Urata, Kazuhiro*; Sasajima, Tadayuki; Matsukawa, Makoto; Sakasai, Akira; Ishida, Shinichi

Fusion Science and Technology, 44(2), p.333 - 337, 2003/09

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

A modification of the JT-60U is planned to a superconducting coil tokamak (JT-60SC) to establish steady-state operation of high beta plasma during a long duration of 100 s, and to ensure the plasma applicability of ferritic steel as reduced activation materials at reactor relevant break-even class plasma. This paper describes the detailed design of vacuum vessel, which has a unique structure for the cost effective manufacturing, and also the structural analysis results for the feasibility study. Eddy current and electromagnetic load analyses in case of stationary plasma disruption is performed and the result is used as the input for the static and dynamic analyses. As a result, the dynamic analysis is necessary to avoid unpredictable inertial force.

Journal Articles

Effects of complex magnetic ripple on fast ions in JFT-2M ferritic insert experiments

Shinohara, Koji; Kawashima, Hisato; Tsuzuki, Kazuhiro; Urata, Kazuhiro*; Sato, Masayasu; Ogawa, Hiroaki; Kamiya, Kensaku; Sasao, Hajime; Kimura, Haruyuki; Kasai, Satoshi; et al.

Nuclear Fusion, 43(7), p.586 - 593, 2003/07

 Times Cited Count:45 Percentile:18.71(Physics, Fluids & Plasmas)

In JFT-2M, the ferritic steel was installed inside the vacuum vessel as the third step of tne Advanced Material Tokamak Experiment (AMTEX) programme. The magnetic field structure has become the complex ripple strucuture such as non-periodic ripple structure in the toroidal direction and high Fourier-number ripple because of the existence of the port and the limitation of the periodic installation. Under such a complex ripple structure, we have performed the experiment to understand its effect on fast ions. To actively change the ripple structure, we have installed the additional ferritic steel plates (FPs). We also have compared the experiment result with the newly updated OFMC code which does not need the toroidal 16-folded symmetry. The experiment results were almost consistent with the OFMC calcution with the complex magnetic field and the complex first wall.

JAEA Reports

Development of FEMAG; Calculation code of magnetic field generated by ferritic plates in the tokamak devices

Urata, Kazuhiro*

JAERI-Data/Code 2003-005, 36 Pages, 2003/03

JAERI-Data-Code-2003-005.pdf:2.96MB

In design of the fusion devises in which ferritic steel is planned to use as the plasma facing material and/or the inserts for ripple reduction, the appreciation of the error field effect and the optimization of ferritic plate arrangement to reduce the toroidal field ripple require calculation of ferritic magnetic field. However iterative calculations by the non-linearity in B-H curve disturbs high-speed calculation. In the strong toroidal magnetic field in the tokamak, fully magnetic saturation of ferritic steel occurs. Hence a distribution of magnetic charges as magnetic field source is determined straightforward. Additionally objective ferritic steel geometry is limited to the thin plate and they are installed along the toroidal magnetic field. Taking them into account, high-speed calculation code FEMAG has been developed. In this report, the formalization of FEMAG, how to use FEMAG, and the validity check in comparison with a 3D FEM code, with the measurements of the magnetic field in JFT-2M are described. The presented examples are design studies for JT-60 modification.

Journal Articles

Engineering design study of JT-60 superconducting modification

Sakasai, Akira; Ishida, Shinichi; Matsukawa, Makoto; Kurita, Genichi; Akino, Noboru; Ando, Toshinari*; Arai, Takashi; Ichige, Hisashi; Kaminaga, Atsushi; Kato, Takashi; et al.

Proceedings of 19th IEEE/NPSS Symposium on Fusion Engineering (SOFE), p.221 - 225, 2002/00

no abstracts in English

Journal Articles

Dynamic analyses of electromagnetic force on ferritic board for AMTEX on JFT-2M

Urata, Kazuhiro*; Suzuki, Yutaka*; Kudo, F.*; Kimura, Haruyuki; Miura, Yukitoshi; Yamamoto, Masahiro

Fusion Engineering and Design, 56-57, p.849 - 853, 2001/10

 Times Cited Count:4 Percentile:64.62

no abstracts in English

Journal Articles

Analyses of divertor high heat-flux components on thermal and electromagnetic loads

Araki, Masanori; Kitamura, Kazunori*; Urata, Kazuhiro*; Suzuki, Satoshi

Fusion Engineering and Design, 42(1-4), p.381 - 387, 1998/09

 Times Cited Count:1 Percentile:84.18(Nuclear Science & Technology)

no abstracts in English

30 (Records 1-20 displayed on this page)