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Journal Articles

Performance verification tests of JT-60SA CS model coil

Obana, Tetsuhiro*; Murakami, Haruyuki; Takahata, Kazuya*; Hamaguchi, Shinji*; Chikaraishi, Hirotaka*; Mito, Toshiyuki*; Imagawa, Shinsaku*; Kizu, Kaname; Natsume, Kyohei; Yoshida, Kiyoshi

Physica C, 518, p.96 - 100, 2015/11

 Times Cited Count:5 Percentile:67.64(Physics, Applied)

Journal Articles

Development of Terminal Joint and Lead Extension for JT-60SA Central Solenoid

Murakami, Haruyuki; Kizu, Kaname; Ichige, Toshikatsu; Furukawa, Masato; Natsume, Kyohei; Tsuchiya, Katsuhiko; Kamiya, Koji; Koide, Yoshihiko; Yoshida, Kiyoshi; Obana, Tetsuhiro*; et al.

IEEE Transactions on Applied Superconductivity, 25(3), p.4201305_1 - 4201305_5, 2015/06

 Times Cited Count:6 Percentile:55.8(Engineering, Electrical & Electronic)

JT-60U magnet system will be upgraded to the superconducting coils in the JT-60SA programme of the Broader Approach activities. Terminal joint of Central Solenoid (CS) is wrap type Nb$$_{3}$$Sn-NbTi joint used for connecting CS (Nb$$_{3}$$Sn) and current feeder (NbTi). The terminal joints are placed at the top and the bottom of the CS systems. CS modules located at middle position of CS system need the lead extension from the modules to the terminal joint. The joint resistance measurement of terminal joint was performed in the test facility of National Institute for Fusion Science. The joint resistance was evaluated by the operating current and the voltage between both ends of the terminal joint part. Test results met the requirement of JT-60SA magnet system. The structural analysis of the lead extension and its support structure was conducted to confirm the support design. In this paper, the results of resistance test of joint and the structural analysis results of lead extension are reported.

Journal Articles

Magnetic field measurements of JT-60SA CS model coil

Obana, Tetsuhiro*; Takahata, Kazuya*; Hamaguchi, Shinji*; Chikaraishi, Hirotaka*; Mito, Toshiyuki*; Imagawa, Shinsaku*; Kizu, Kaname; Murakami, Haruyuki; Natsume, Kyohei; Yoshida, Kiyoshi

Fusion Engineering and Design, 90, p.55 - 61, 2015/01

 Times Cited Count:2 Percentile:74.03(Nuclear Science & Technology)

In the cold test of the JT-60SA CS model coil made by Nb$$_{3}$$Sn CIC conductor, magnetic fields were measured using Hall sensors. While holding coil current of 20 kA, the magnetic fields were varying slightly with several long time constants. The range of the time constant was from 17 sec to 571 sec, which was much longer than the time constant derived from the measurement using the short straight sample. To validate the measurements, the magnetic fields of the model coil were calculated using the calculation model representing the positions of Nb$$_{3}$$Sn strands inside the CIC conductor. The calculations were in good agreement with the measurements. Consequently, the validity of magnetic field measurements was confirmed.

Journal Articles

Modeling of butt joint composed of Nb$$_{3}$$Sn cable-in-conduit conductors

Obana, Tetsuhiro*; Takahata, Kazuya*; Hamaguchi, Shinji*; Natsume, Kyohei*; Imagawa, Shinsaku*; Mito, Toshiyuki*; Kizu, Kaname; Murakami, Haruyuki; Yoshida, Kiyoshi

Plasma and Fusion Research (Internet), 9(Sp.2), p.3405122_1 - 3405122_4, 2014/07

To evaluate the fabrication technology of the butt joint composed of Nb$$_{3}$$Sn CIC conductors, joint resistance and quench current were measured using a sample developed for the JT-60SA CS coil. The measurements indicate that the butt joint fulfilled the design requirements. To simulate the characteristics of the butt joint, one dimensional numerical model simplifying the butt joint configuration was developed. Using the model, joint resistance and quench current of the butt joint were calculated. The calculations were in good agreement with the measurements. As a result, the model will be valid for the simulation of the butt joint.

Journal Articles

Development and test of JT-60SA central solenoid model coil

Murakami, Haruyuki; Kizu, Kaname; Tsuchiya, Katsuhiko; Koide, Yoshihiko; Yoshida, Kiyoshi; Obana, Tetsuhiro*; Takahata, Kazuya*; Hamaguchi, Shinji*; Chikaraishi, Hirotaka*; Natsume, Kyohei*; et al.

IEEE Transactions on Applied Superconductivity, 24(3), p.4200205_1 - 4200205_5, 2014/06

 Times Cited Count:20 Percentile:23.13(Engineering, Electrical & Electronic)

Central Solenoid (CS) of JT-60SA are designed with the Nb$$_{3}$$Sn cable in conduit conductor. CS model coil (CSMC) was manufactured by using the real manufacturing jigs and procedure to validate the CS manufacturing processes before starting mass production. The dimensions of the CSMC are the same as real quad-pancake. The cold test of the CSMC was performed and the test results satisfied the design requirements. These results indicate that the manufacturing processes of the JT-60SA CS has been established. In this paper, the development and the validation of the CS manufacturing processes are described.

Journal Articles

Thermal stability of butt joint for CS conductor in JT-60SA

Takao, Tomoaki*; Kawahara, Yuzuru*; Nakamura, Kazuya*; Yamamoto, Yusuke*; Yagai, Tsuyoshi*; Murakami, Haruyuki; Yoshida, Kiyoshi; Natsume, Kyohei*; Hamaguchi, Shinji*; Obana, Tetsuhiro*; et al.

IEEE Transactions on Applied Superconductivity, 24(3), p.4800804_1 - 4800804_4, 2014/06

 Times Cited Count:3 Percentile:73.25(Engineering, Electrical & Electronic)

no abstracts in English

Journal Articles

Joint resistance measurements of pancake and terminal joints for JT-60SA EF coils

Obana, Tetsuhiro*; Takahata, Kazuya*; Hamaguchi, Shinji*; Mito, Toshiyuki*; Imagawa, Shinsaku*; Kizu, Kaname; Murakami, Haruyuki; Yoshida, Kiyoshi

Fusion Engineering and Design, 88(11), p.2773 - 2776, 2013/11

 Times Cited Count:3 Percentile:67.8(Nuclear Science & Technology)

To evaluate joint fabrication technology, resistance measurements were conducted using a sample consisting of pancake and terminal joints for the JT-60SA EF coils. Both joints fulfilled the design requirement of 5 $$Omega$$ at the external field of 3 T. The electrical resistance of the pancake joint was slightly lower than that of the terminal joint. Analyses indicated that the characteristics of the conductors used in the joints affect those of the joints. The presence or absence of copper wires in the conductor is one factor that determines the characteristics of the joints.

Journal Articles

Current sharing temperature of central solenoid conductor for JT-60SA under repetition excitation

Murakami, Haruyuki; Kizu, Kaname; Ichige, Toshikatsu; Kamiya, Koji; Tsuchiya, Katsuhiko; Yoshida, Kiyoshi; Obana, Tetsuhiro*; Hamaguchi, Shinji*; Takahata, Kazuya*; Yanagi, Nagato*; et al.

Proceedings of 24th International Cryogenic Engineering Conference (ICEC 24) and International Cryogenic Materials Conference 2012 (ICMC 2012) (CD-ROM), p.575 - 578, 2012/05

The JT-60U magnet system will be upgraded to the superconducting coils (JT-60SA) in the Broader Approach (BA) project. The JT-60SA magnet system has 18 Toroidal Field (TF) coils, a Central Solenoid (CS) with 4 modules and 6 Equilibrium Field (EF) coils. The CS conductors are designed with Nb$$_{3}$$Sn cable in conduit (CIC) conductor because the magnetic field of CS is up to 8.9 T. The short CS conductor was manufactured and processed into the performance verification test sample. The Tcs test results indicate that the initial Tcs of the CS conductor is about 2 K higher than the minimum requirement of the conductor design. In addition the Tcs after the repetition excitation is more important issues for the CS conductor because the CS conductor is made of Nb$$_{3}$$Sn strand. The Tcs changes with the repetition excitation and the influence of the warm up and cool down process on the Tcs were measured. The test results show that there is no degradation while the repetition excitation tests. The AC loss test of the CS conductor was also performed for precise estimation of the conductor heat loads. The Tcs margin analysis of the CS conductor was conducted based on the latest conductor heat loads. The analysis results show that the CS conductor has enough Tcs margin during the JT-60SA operation. These results show that the design and the manufacturing process of the CS conductor satisfy its requirements. Thus CS conductors for the CS1 module have been manufactured on the mass production process. In this paper, the Tcs test, the repetition excitation test, the AC loss test and the Tcs margin analysis of the CS conductor are described.

Journal Articles

Fabrication and tests of EF conductors for JT-60SA

Kizu, Kaname; Kashiwa, Yoshitoshi; Murakami, Haruyuki; Obana, Tetsuhiro*; Takahata, Kazuya*; Tsuchiya, Katsuhiko; Yoshida, Kiyoshi; Hamaguchi, Shinji*; Matsui, Kunihiro; Nakamura, Kazuya*; et al.

Fusion Engineering and Design, 86(6-8), p.1432 - 1435, 2011/10

 Times Cited Count:8 Percentile:39.06(Nuclear Science & Technology)

In JT-60SA, central solenoid (CS) and plasma equilibrium field (EF) coils are procured by Japan. EF coil conductors are NbTi cable-in-conduit (CIC) conductor. Delivered superconducting cables and jackets are fabricated into CIC conductors at the jacketing facility with the length of 680 m constructed in the Naka site of JAEA. The production of superconductors with 444 m in length for actual EF coils was started from March 2010. The measurements of superconducting performance like current sharing temperature (Tcs) were conducted prior to the mass production. The measured Tcs was agreed with the expectation values from strand values indicating that no degradation was happened by production process.

Journal Articles

Stability margin of NbTi CIC conductor for JT-60SA equilibrium field coil

Murakami, Haruyuki; Ichige, Toshikatsu; Kizu, Kaname; Tsuchiya, Katsuhiko; Yoshida, Kiyoshi; Obana, Tetsuhiro*; Hamaguchi, Shinji*; Takahata, Kazuya*; Yanagi, Nagato*; Mito, Toshiyuki*; et al.

IEEE Transactions on Applied Superconductivity, 21(3), p.1991 - 1994, 2011/06

 Times Cited Count:2 Percentile:79.41(Engineering, Electrical & Electronic)

no abstracts in English

Journal Articles

Stability and quench test for NbTi CIC conductor of JT-60SA equilibrium field coil

Murakami, Haruyuki; Ichige, Toshikatsu; Kizu, Kaname; Tsuchiya, Katsuhiko; Yoshida, Kiyoshi; Obana, Tetsuhiro*; Hamaguchi, Shinji*; Takahata, Kazuya*; Mito, Toshiyuki*; Imagawa, Shinsaku*

IEEE Transactions on Applied Superconductivity, 20(3), p.512 - 516, 2010/06

 Times Cited Count:8 Percentile:50.47(Engineering, Electrical & Electronic)

JT-60SA magnets system consists of 18 toroidal field (TF) coils, 4 stacks of central solenoid (CS) and 6 plasma equilibrium field (EF) coils. The maximum magnetic field and maximum current of EF coils is 6.2 T and 20 kA, respectively. It has been decided that the NbTi cable-in-conduit (CIC) conductor is applied to EF coil conductors. The performance verification test was conducted by Japan Atomic Energy Agency (JAEA) and National Institute of Fusion Science (NIFS). The critical current measurement of this sample under the condition of coil operation was performed in the previous test. In addition, the quench test is conducted in this time to evaluate the stability margin and the coil behavior during quench. The Minimum Quench Energy of this conductor and the velocity of normal conducting state propagation are described in this paper. We also described the Tcs margin and maximum temperature during the quench evaluated by thermo-fluid analysis based on the quench test.

Journal Articles

Critical current measurement of prototype NbTi cable-in-conduit conductor for JT-60SA

Kizu, Kaname; Tsuchiya, Katsuhiko; Obana, Tetsuhiro*; Takahata, Kazuya*; Hoshi, Ryo; Hamaguchi, Shinji*; Nunoya, Yoshihiko; Yoshida, Kiyoshi; Matsukawa, Makoto; Yanagi, Nagato*; et al.

Fusion Engineering and Design, 84(2-6), p.1058 - 1062, 2009/06

 Times Cited Count:11 Percentile:34.85(Nuclear Science & Technology)

The maximum magnetic field and maximum current of EF coils for JT-60SA is 6.2T, 20 kA, respectively. The EF coil conductors are NbTi cable-in-conduit (CIC) conductor with SS316L conduit. In order to confirm the performance of current sharing temperature ($$T$$$$_{rm cs}$$) tests under coil operational condition was performed. As a results, the degradation of $$T$$$$_{rm cs}$$ was 0.01-0.08 K indicating that the conductor design and its fabrication method is appropriate. Experimental results were compared with the $$I$$ and $$T$$ by standard plasma operation scenario. It was confirmed that the conductor has $$T$$$$_{rm cs}$$ margin of $$>$$ 1K.

Journal Articles

Upgrading the NIFS superconductor test facility for JT-60SA cable-in-conduit conductors

Obana, Tetsuhiro*; Takahata, Kazuya*; Hamaguchi, Shinji*; Yanagi, Nagato*; Mito, Toshiyuki*; Imagawa, Shinsaku*; Kizu, Kaname; Tsuchiya, Katsuhiko; Hoshi, Ryo; Yoshida, Kiyoshi

Fusion Engineering and Design, 84(7-11), p.1442 - 1445, 2009/06

 Times Cited Count:18 Percentile:19.98(Nuclear Science & Technology)

The superconductor test facility in National Institute for Fusion Science (NIFS) has been upgraded in order to test cable-in-conduit (CIC) conductors for the JT-60SA equilibrium field (EF) coil. In the test facility, supercritical helium (SHe) lines were newly assembled with transfer tubes and a heat exchanger. The CIC conductor was covered with a thermal insulation vessel filled with gas helium at atmospheric pressure. The temperature of the conductor was varied using a film heater attached to an inlet pipe. The Ic and Tcs measurements of the prototype CIC conductor have successfully been carried out with the upgraded test facility. In the measurements, the conductor temperature was precisely controlled.

Journal Articles

Extended steady-state and high-beta regimes of net-current free heliotron plasmas in the Large Helical Device

Motojima, Osamu*; Yamada, Hiroshi*; Komori, Akio*; Oyabu, Nobuyoshi*; Muto, Takashi*; Kaneko, Osamu*; Kawahata, Kazuo*; Mito, Toshiyuki*; Ida, Katsumi*; Imagawa, Shinsaku*; et al.

Nuclear Fusion, 47(10), p.S668 - S676, 2007/10

 Times Cited Count:34 Percentile:22.29(Physics, Fluids & Plasmas)

The performance of net-current free heliotron plasmas has been developed by findings of innovative operational scenarios in conjunction with an upgrade of the heating power and the pumping/fuelling capability in the Large Helical Device (LHD). Consequently, the operational regime has been extended, in particular, with regard to high density, long pulse length and high beta. Diversified studies in LHD have elucidated the advantages of net-current free heliotron plasmas. In particular, an internal diffusion barrier (IDB) by a combination of efficient pumping of the local island divertor function and core fuelling by pellet injection has realized a super dense core as high as 5$$times$$10$$^{20}$$ m$$^{-3}$$, which stimulates an attractive super dense core reactor. Achievements of a volume averaged beta of 4.5% and a discharge duration of 54 min with a total input energy of 1.6 GJ (490 kW on average) are also highlighted. The progress of LHD experiments in these two years is overviewed by highlighting IDB, high-beta and long pulse.

Journal Articles

Extended steady-state and high-beta regimes of net-current free heliotron plasmas in the large helical device

Motojima, Osamu*; Yamada, Hiroshi*; Komori, Akio*; Oyabu, Nobuyoshi*; Kaneko, Osamu*; Kawahata, Kazuo*; Mito, Toshiyuki*; Muto, Takashi*; Ida, Katsumi*; Imagawa, Shinsaku*; et al.

Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 12 Pages, 2007/03

The performance of net-current free Heliotron plasmas has been developed by findings of innovative operational scenarios in conjunction with an upgrade of the heating power and the pumping/fueling capability in the Large Helical Device (LHD). Consequently, the operational regime has been extended, in particular, with regard to high density, long pulse length and high beta. Diversified studies in LHD have elucidated the advantages of net-current free heliotron plasmas. In particular, an Internal Diffusion Barrier (IDB) by combination of efficient pumping of the local island divertor function and core fueling by pellet injection has realized a super dense core as high as 5$$times$$10$$^{20}$$m$$^{-3}$$, which stimulates an attractive super dense core reactor. Achievements of a volume averaged beta of 4.5 % and a discharge duration of 54-min. with a total input energy of 1.6 GJ (490 kW in average) are also highlighted. The progress of LHD experiments in these two years is overviewed with highlighting IDB, high $$beta$$ and long pulse.

Oral presentation

Critical current measurement of prototype NbTi cable-in-conduit conductor for JT-60SA

Kizu, Kaname; Tsuchiya, Katsuhiko; Hoshi, Ryo; Yoshida, Kiyoshi; Matsukawa, Makoto; Obana, Tetsuhiro*; Takahata, Kazuya*; Hamaguchi, Shinji*; Yanagi, Nagato*; Imagawa, Shinsaku*; et al.

no journal, , 

The maximum magnetic field and maximum current of EF coils for JT-60SA is 6.2 T, 20 kA, respectively. The EF coil conductors are NbTi cable-in-conduit (CIC) conductor with SS316L conduit. In order to confirm the performance of current sharing temperature (Tcs) tests under coil operational condition was performed. As a results, the degradation of Tcs was 0.02-0.07 K indicating that the conductor design and its fabrication method is appropriate.

Oral presentation

Quench test for NbTi CIC conductor of JT-60SA equilibrium field coil

Murakami, Haruyuki; Ichige, Toshikatsu; Kizu, Kaname; Tsuchiya, Katsuhiko; Yoshida, Kiyoshi; Obana, Tetsuhiro*; Hamaguchi, Shinji*; Takahata, Kazuya*; Imagawa, Shinsaku*; Mito, Toshiyuki*

no journal, , 

no abstracts in English

Oral presentation

Estimation of heat generation in prototype joint of JT-60SA equilibrium field coil

Murakami, Haruyuki; Matsui, Kunihiro; Kizu, Kaname; Tsuchiya, Katsuhiko; Yoshida, Kiyoshi; Okuno, Kiyoshi; Obana, Tetsuhiro*; Takahata, Kazuya*; Imagawa, Shinsaku*; Mito, Toshiyuki*; et al.

no journal, , 

no abstracts in English

Oral presentation

Fabrication and tests of superconductors for equilibrium field coil of JT-60SA

Kizu, Kaname; Kashiwa, Yoshitoshi; Murakami, Haruyuki; Tsuchiya, Katsuhiko; Yoshida, Kiyoshi; Obana, Tetsuhiro*; Takahata, Kazuya*; Hamaguchi, Shinji*; Yanagi, Nagato*; Imagawa, Shinsaku*; et al.

no journal, , 

In JT-60SA, magnets system consists of 18 toroidal field (TF) coils, 4 stacks of central solenoid (CS) and 6 plasma equilibrium field (EF) coils. The CS and EF coils are procured by Japan. The maximum magnetic field and maximum current of EF coils is 6.2 T, 20 kA. EF coil conductors are NbTi cable-in-conduit (CIC) conductor. Delivered superconducting cables and jackets are fabricated into CIC conductors at the jacketing facility with the length of 680 m constructed in the Naka site of JAEA. The production of superconductors with 444 m in length for actual EF coils was started from March 2010. The measurements of superconducting performance like current sharing temperature were conducted prior to the mass production. The production and test results of EF conductors will be described.

Oral presentation

Stability evaluation of superconductors for equilibrium field coil of JT-60SA

Murakami, Haruyuki; Ichige, Toshikatsu; Kizu, Kaname; Tsuchiya, Katsuhiko; Yoshida, Kiyoshi; Obana, Tetsuhiro*; Takahata, Kazuya*; Hamaguchi, Shinji*; Yanagi, Nagato*; Imagawa, Shinsaku*; et al.

no journal, , 

no abstracts in English

28 (Records 1-20 displayed on this page)