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

https://doi.org/10.1016/j.physc.2015.07.009

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

https://doi.org/10.1016/j.fusengdes.2014.11.002

In the cold test of the JT-60SA CS model coil made by NbSn 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 NbSn strands inside the CIC conductor. The calculations were in good agreement with the measurements. Consequently, the validity of magnetic field measurements was confirmed.

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

https://doi.org/10.1109/TASC.2013.2284020

no abstracts in English

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

https://doi.org/10.1016/j.fusengdes.2013.04.022

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 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.

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

https://doi.org/10.1016/j.fusengdes.2011.01.028

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.

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

https://doi.org/10.1109/TASC.2010.2040157

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.

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

https://doi.org/10.1016/j.fusengdes.2008.12.029

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 () tests under coil operational condition was performed. As a results, the degradation of was 0.01-0.08 K indicating that the conductor design and its fabrication method is appropriate. Experimental results were compared with the and by standard plasma operation scenario. It was confirmed that the conductor has margin of 1K.

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

http://www-naweb.iaea.org/napc/physics/FEC/FEC2006/html/node31.htm#5947

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 510m, 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 and long pulse.

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.

Self-magnetic field measurements of JT-60SA CS model coil

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

no journal, , 

The central solenoid (CS) of JT-60SA is composed of 4 modules consisting of a quad-pancake and 6 octa-pancakes. In order to verify the process for the coil manufacturing and the fabrication jigs, the CS model coil was developed. The model coil is composed of one quad-pancake. The cold test of the model coil was conducted at the Nation Institute for Fusion Science (NIFS) test facility. The critical current, joint resistance, and pressure drop of the model coil were measured in the cold test. In addition, self-magnetic field of the model coil was measured using Hall sensors. The magnetic fields were varying slightly while holding coil current of 20 kA. 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.