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Al cable-in-conduit conductorKoizumi, Norikiyo; Matsui, Kunihiro; Hemmi, Tsutomu; Nakajima, Hideo; Takeuchi, Takao*; Banno, Nobuya*; Kikuchi, Akihiro*
Teion Kogaku, 46(8), p.495 - 499, 2011/08
JAEA and NIMS has been collaborating in development of high performance Rapid-Heating-Quenching-Transformation (RHQT) NbAl CIC conductor, aiming at the application of this conductor to DEMO plant. The technical issue of the RHQT NbAl strand in the application to a fusion magnet is stabilization against perturbation. NIMS developed technique to attach copper stabilizer by using electroplating and a sub-scale CIC conductor is developed using this conductor. JAEA performed stability test of the developed CIC conductor to demonstrate efficiency of this copper stabilization technique. The measured stability margin is sufficiently high compared to the one of similar NbTi CIC conductor previously tested by the authors. Then, it can be concluded that the copper stabilizer works efficiently from view point of stability, resulting in solving the remained technical issues in the RHQT CIC conductor. Therefore, we can say that the RHQT NbAl CIC conductor is the most promising candidate for application to magnet in DEMO plant.
Sn strands under bending strainBanno, Nobuya*; Takeuchi, Takao*; Koizumi, Norikiyo; Okuno, Kiyoshi
IEEE Transactions on Applied Superconductivity, 20(3), p.1455 - 1458, 2010/06
Times Cited Count：8 Percentile：45.71(Engineering, Electrical & Electronic)no abstracts in English
Al strands subjected to an axial-strain for fusion DEMO reactorHemmi, Tsutomu; Koizumi, Norikiyo; Nunoya, Yoshihiko; Okui, Yoshio*; Matsui, Kunihiro; Nabara, Yoshihiro; Isono, Takaaki; Takahashi, Yoshikazu; Okuno, Kiyoshi; Banno, Nobuya*; et al.
IEEE Transactions on Applied Superconductivity, 19(3), p.1540 - 1543, 2009/06
Times Cited Count：16 Percentile：62.11(Engineering, Electrical & Electronic)NbAl cable-in-conduit (CIC) conductors have been developed as one of candidates for the fusion DEMO reactor. The performances of superconducting strands in the CIC conductor are affected by transverse electromagnetic force and thermal strain at reaction heat treatment. In order to accurately design the conductors for the fusion DEMO reactor, the performance evaluation of the NbAl strands, which is processed by a rapid heating, quenching and transformation (RHQT) method, was performed under various temperature, magnetic field and axial-strain conditions. The measured and parameterized results of the NbAl strands are presented.
Al developmentTakeuchi, Takao*; Kikuchi, Akihiro*; Banno, Nobuya*; Kitaguchi, Hitoshi*; Iijima, Yasuo*; Tagawa, Kohei*; Nakagawa, Kazuhiko*; Tsuchiya, Kiyosumi*; Mitsuda, Shiori*; Koizumi, Norikiyo; et al.
Cryogenics, 48(7-8), p.371 - 380, 2008/07
Times Cited Count：62 Percentile：87.99(Thermodynamics)NbAl has advantages of better tolerance to strain/stress and a higher critical magnetic field (30 T at 4.2 K) for stoichiometric composition over NbSn. The rapid-heating, quenching and transformation annealing (RHQT) process enables to form a stoichiometric NbAl with fine grain structures via metastable bcc supersaturated-solid-solution. As a result a large critical current density of NbAl is achieved over the whole range of magnetic fields without trading off the excellent strain tolerance. A long-length of RHQ processing has been established, and a rectangular but Cu stabilized NbAl strand is about be commercially available for NMR uses. Ag or Cu internal stabilization and Cu ion-plating/electroplating techniques have been also developed to enable the stabilized round wire for accelerator and fusion magnets. Successfully energized test coils that were manufactured with a wind-and-react technique have demonstrated that a long piece of Cu stabilized RHQT NbAl wire is really available for practical applications.
Al superconductors with Ta matrixTakeuchi, Takao*; Tagawa, Kohei*; Noda, Tetsuji*; Banno, Nobuya*; Iijima, Yasuo*; Kikuchi, Akihiro*; Kitaguchi, Hitoshi*; Kosuge, Michio*; Tsuchiya, Kiyosumi*; Koizumi, Norikiyo; et al.
IEEE Transactions on Applied Superconductivity, 16(2), p.1257 - 1260, 2006/06
Times Cited Count：6 Percentile：37.33(Engineering, Electrical & Electronic)Next generation nuclear fusion magnets would require a high-current conductor in fields more than 16 T. A CIC conductor of the rapid RHQT processed NbAl may be a promising candidate. Good deformability of intermediately-formed bcc supersaturated-solid solution indeed allowed fabricating such a CIC conductor, which would be subsequently transformation annealed. Ag has been internally included as a basic constituent of a round strand so far, because Ag is almost non-reactive with Nb matrix during the RHQ. However, both of Ag and Nb are not suitable nuclei from the viewpoint of radioactivity when irradiated with neutrons. Recently, we have succeeded in replacing the Nb matrix with Ta that has the advantage of shorter half-life of radioactivity. In the present study, an attempt has been made to replace the Ag internal stabilizer with Cu, in the aim of further reducing radioactivity, based on anticipation that Ta would be less reactive with Cu than Nb did.
Al strandNabara, Yoshihiro; Nunoya, Yoshihiko; Matsui, Kunihiro; Hemmi, Tsutomu; Koizumi, Norikiyo; Isono, Takaaki; Uno, Yasuhiro*; Okui, Yoshio*; Oshikiri, Masayuki; Seo, Kazutaka; et al.
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Sn conductorBanno, Nobuya*; Takeuchi, Takao*; Koizumi, Norikiyo; Okuno, Kiyoshi
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Sn filamentsTakeuchi, Takao*; Banno, Nobuya*; Iijima, Yasuo*; Tsuchiya, Kiyosumi*; Koizumi, Norikiyo
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no abstracts in English
Al CIC conductorKoizumi, Norikiyo; Matsui, Kunihiro; Nakajima, Hideo; Takeuchi, Takao*; Banno, Nobuya*
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no abstracts in English
