Behavior of NbSn cable assembled with conduit for ITER central solenoid

Nabara, Yoshihiro; Suwa, Tomone; Takahashi, Yoshikazu; Hemmi, Tsutomu; Kajitani, Hideki; Ozeki, Hidemasa; Sakurai, Takeru; Iguchi, Masahide; Nunoya, Yoshihiko; Isono, Takaaki; et al.

IEEE Transactions on Applied Superconductivity, 25(3), p.4200305_1 - 4200305_5, 2015/06

https://doi.org/10.1109/TASC.2014.2360562

Establishment of production process of JK2LB jacket section for ITER CS

Ozeki, Hidemasa; Hamada, Kazuya; Takahashi, Yoshikazu; Nunoya, Yoshihiko; Kawano, Katsumi; Oshikiri, Masayuki; Saito, Toru; Teshima, Osamu*; Matsunami, Masahiro*

IEEE Transactions on Applied Superconductivity, 24(3), p.4800604_1 - 4800604_4, 2014/06

https://doi.org/10.1109/TASC.2013.2281536

Cable twist pitch variation in NbSn conductors for ITER toroidal field coils in Japan

Takahashi, Yoshikazu; Nabara, Yoshihiro; Hemmi, Tsutomu; Nunoya, Yoshihiko; Isono, Takaaki; Hamada, Kazuya; Matsui, Kunihiro; Kawano, Katsumi; Koizumi, Norikiyo; Oshikiri, Masayuki; et al.

IEEE Transactions on Applied Superconductivity, 23(3), p.4801504_1 - 4801504_4, 2013/06

https://doi.org/10.1109/TASC.2013.2239693

Japan Atomic Energy Agency (JAEA) is the first to start the mass production of the TF conductors in March 2010 among the 6 parties who are procuring TF conductors in the ITER project. The height and width of the TF coils are 14 m and 9 m, respectively. The conductor is cable-in-conduit conductor (CICC) with a central spiral. A circular multistage superconducting cable is inserted into a circular stainless steel jacket with a thickness of 2 mm. A total of 900 NbSn strands and 522 copper strands are cabled around the central spiral and the cable is inserted into a round-in-round stainless steel jacket. It was observed that the cabling pitch of the destructive sample is longer than the original pitch at cabling. The JAEA carried out the tensile tests of the cable and the measurement of the cable rotation during the insertion to investigate the cause of the elongation. The cause of elongation was clarified and the results will be described in this paper.

Mass production of NbSn conductors for ITER toroidal field coils in Japan

Takahashi, Yoshikazu; Isono, Takaaki; Hamada, Kazuya; Nunoya, Yoshihiko; Nabara, Yoshihiro; Matsui, Kunihiro; Hemmi, Tsutomu; Kawano, Katsumi; Koizumi, Norikiyo; Oshikiri, Masayuki; et al.

IEEE Transactions on Applied Superconductivity, 22(3), p.4801904_1 - 4801904_4, 2012/06

https://doi.org/10.1109/TASC.2011.2178053

Japan Atomic Energy Agency is the first to start the mass production of the TF conductors in Phase IV in March 2010 among the 6 parties who are procuring TF conductors in the ITER project. The conductor is cable-in-conduit conductor with a central spiral. A total of 900 NbSn strands and 522 copper strands are cabled around the central spiral and then wrapped with stainless steel tape whose thickness is 0.1 mm. Approximately 60 tons of NbSn strands were manufactured by the two suppliers in December 2010. This amount corresponds to approximately 55% of the total contribution from Japan. Approximately 30% of the total contribution from Japan was completed as of February 2011. JAEA is manufacturing one conductor per month under a contract with two Japanese companies for strands, one company for cabling and one company for jacketing. This paper summarizes the technical developments including a high-level quality assurance. This progress is a significant step in the construction of the ITER machine.

Examination of Japanese mass-produced NbSn conductors for ITER toroidal field coils

Nabara, Yoshihiro; Nunoya, Yoshihiko; Isono, Takaaki; Hamada, Kazuya; Takahashi, Yoshikazu; Matsui, Kunihiro; Hemmi, Tsutomu; Kawano, Katsumi; Koizumi, Norikiyo; Ebisawa, Noboru; et al.

IEEE Transactions on Applied Superconductivity, 22(3), p.4804804_1 - 4804804_4, 2012/06

https://doi.org/10.1109/TASC.2011.2178990

no abstracts in English

Technology development and mass production of NbSn conductors for ITER toroidal field coils in Japan

Takahashi, Yoshikazu; Isono, Takaaki; Hamada, Kazuya; Nunoya, Yoshihiko; Nabara, Yoshihiro; Matsui, Kunihiro; Hemmi, Tsutomu; Kawano, Katsumi; Koizumi, Norikiyo; Oshikiri, Masayuki; et al.

Nuclear Fusion, 51(11), p.113015_1 - 113015_11, 2011/11

https://doi.org/10.1088/0029-5515/51/11/113015

Japan Atomic Energy Agency is procuring the NbSn superconductors for Toroidal Field (TF) Coils under the ITER project. Because manufacturing amount of NbSn strands is quite large compared with the past experience and required superconducting performance is higher than that of the model coils which have been fabricated and tested in the ITER-EDA, quality control technique is very important for the manufacture of the strands. Sophisticated control technique is also required for the jacketing, in order to fabricate the conductors with the precise outer diameter and without leakage at welding part. This paper summarizes the technical developments leading to the first successful mass production of ITER TF conductors.

Technology development for the manufacture of NbSn conductors for ITER Toroidal Field coils

Takahashi, Yoshikazu; Isono, Takaaki; Hamada, Kazuya; Nunoya, Yoshihiko; Nabara, Yoshihiro; Matsui, Kunihiro; Hemmi, Tsutomu; Kawano, Katsumi; Koizumi, Norikiyo; Oshikiri, Masayuki; et al.

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

http://www-naweb.iaea.org/napc/physics/FEC/FEC2010/html/node89.htm#21018

Japan Atomic Energy Agency is procuring the NbSn superconductors for Toroidal Field (TF) coils under the ITER project. Because manufacturing amount of NbSn strands is quite large compared with the past experience and required superconducting performance is higher than that of the model coils which have been fabricated and tested in the ITER-EDA, quality control technique is very important for the manufacture of the strands. Sophisticated control technique is also required for the jacketing, in order to fabricate the conductors with the precise outer diameter and without leakage at welding part. Cu dummy conductor with full length (760 m) has been fabricated successfully and all jacketing technology was confirmed through this fabrication. The fabrication of the NbSn conductor for TF coils will start in March 2010.

Installation and test programme of the ITER poloidal field conductor insert (PFCI) in the ITER test facility at JAEA Naka

Nunoya, Yoshihiko; Takahashi, Yoshikazu; Hamada, Kazuya; Isono, Takaaki; Matsui, Kunihiro; Oshikiri, Masayuki; Nabara, Yoshihiro; Hemmi, Tsutomu; Nakajima, Hideo; Kawano, Katsumi; et al.

IEEE Transactions on Applied Superconductivity, 19(3), p.1492 - 1495, 2009/06

https://doi.org/10.1109/TASC.2009.2019551

The ITER Poloidal Field Conductor Insert (PFCI) was constructed to characterize the performance of selected cable-in-conduit NbTi conductors for the ITER Poloidal Field (PF) under relevant operating conditions. The PFCI was installed and tested inside the bore of the ITER CS model coil, which provides the background magnetic field. The PFCI is a single-layer solenoid, wound from about 50 m of a full-size ITER cable-in-conduit conductor. The winding diameter and height are about 1.5 m and 1 m, respectively. The nominal design current of the conductor is 45 kA at 6 T and 5 K. The main items in the PFCI test programme are current sharing temperature (Tcs) measurements, critical current (Ic) measurements and AC loss measurement. The key technology of the installation, the test methods and procedures, and some preliminary results of the testing campaigns are described and discussed in this paper.

Performance of Japanese NbSn conductors for ITER toroidal field coils

Takahashi, Yoshikazu; Isono, Takaaki; Koizumi, Norikiyo; Nunoya, Yoshihiko; Matsui, Kunihiro; Nabara, Yoshihiro; Hemmi, Tsutomu; Oshikiri, Masayuki; Uno, Yasuhiro*; Okuno, Kiyoshi; et al.

IEEE Transactions on Applied Superconductivity, 18(2), p.471 - 474, 2008/06

https://doi.org/10.1109/TASC.2008.921866

The ITER TF coil system consists of 18 D-shape coils. The operating current and the maximum field are 68 kA and 11.8 T, respectively. A NbSn cable-in-conduit conductor with a central channel is used, with a unit length of about 380 m. A cable consists of 900 NbSn strands and 522 Cu strands with a diameter of 0.82 mm. Superconducting performance of full-size conductors manufactured was measured at the operating condition of the TF coils with the maximum field. The strands made by bronze and internal-Sn methods were used for the sample conductors with a void fraction of 29% and 33%, respectively. The measured current sharing temperatures Tcs are 6.5-6.7K for the bronze route method and 5.7-5.9K for the internal-Sn method. The Tcs of the conductor with small void fraction is relatively higher with 0.1-0.2K than that with large void fraction. It is confirmed that Tcs of both strands is higher than the design value (5.7K). It is shown from the results that the strain on the conductor, estimated by the strand data, is about -0.7%. This value seems to be reasonable.

Technology development for the construction of ITER superconducting magnet system

Okuno, Kiyoshi; Nakajima, Hideo; Sugimoto, Makoto; Isono, Takaaki; Kawano, Katsumi; Koizumi, Norikiyo; Hamada, Kazuya; Nunoya, Yoshihiko; Nabara, Yoshihiro; Kitamura, Kazunori; et al.

Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03

http://www-naweb.iaea.org/napc/physics/FEC/FEC2006/html/node462.htm#91406

The ITER superconducting magnet system consists of 18 TF coils, one CS and six Poloidal Field (PF) coils. Among six PTs, Japan, EU and US will be responsible for major part of the superconducting magnets, and Japanese contribution will be the largest, including the following four areas: part of TF conductors, about half (9 out of 19) of TF coil winding packs, most of TF coil structures and part of CS conductor. Since 2004, Japan Atomic Energy Agency (JAEA) started preparation activities for procurement, including manufacturing studies to identify detailed fabrication processes and tools for critical components, such as TF coil winding and case, and manufacturing demonstrations at full scale level on NbSn strands and conductors and cryogenic structural materials, such as coil case segments and radial plates. Details are described in the following sections.