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Sn strandNunoya, Yoshihiko; Isono, Takaaki; Koizumi, Norikiyo; Hamada, Kazuya; Nabara, Yoshihiro; Okuno, Kiyoshi
IEEE Transactions on Applied Superconductivity, 17(2), p.2588 - 2590, 2007/06
Times Cited Count：14 Percentile：58.29(Engineering, Electrical & Electronic)Japan Atomic Energy Agency has successfully developed NbSn strand which fulfilled ITER requirement. The achieved Jc value are more than 700A/mm
for bronze process and more than 800A/mm for internal tin process, as well as hysteresis value is less than 1J/cc. Because NbSn are very susceptible to an external strain such as reducing critical current, critical temperature, and critical field, it is necessary to evaluate strain dependency of developed NbSn strand to make the database for optimization of the conductor design. The apparatus to measure the strain dependency was newly developed. It has horseshoe-shaped ring on whose outer surface the strand is soldered. This shape produces uniform axial compressive or tensile strain along strand length by expanding or closing the opening of the ring, furthermore this expanding and closing movement can be transmitted by translation motion without torque, which improves versatility of the ring especially in case of large scale application. The critical current under the magnetic field can be measured by the apparatus in the range of 4.2K to 15K temperature and -0.8% to 0.5% strain. The maximum allowable current is about 250A. Measurement result and the detail of the apparatus will be presented.
Kizu, Kaname; Tsuchiya, Katsuhiko; Ando, Toshinari*; Sborchia, C.*; Masaki, Kei; Sakurai, Shinji; Sukegawa, Atsuhiko; Tamai, Hiroshi; Fujita, Takaaki; Matsukawa, Makoto; et al.
IEEE Transactions on Applied Superconductivity, 17(2), p.1348 - 1352, 2007/06
Times Cited Count：4 Percentile：29.39(Engineering, Electrical & Electronic)no abstracts in English
Takahashi, Yoshikazu; Yoshida, Kiyoshi; Nabara, Yoshihiro; Edaya, Masahiro*; Bessette, D.*; Shatil, N.*; Mitchell, N.*
IEEE Transactions on Applied Superconductivity, 17(2), p.2426 - 2429, 2007/06
Times Cited Count：15 Percentile：58.29(Engineering, Electrical & Electronic)The ITER TF coils consists of 18 D-shape coils. The operating current, the maximum field and the stored magnetic energy are 68 kA, 11.8 T and 41 GJ, respectively. A NbSn cable-in-conduit conductor with a central channel is used, with a cooling length of 380 m. An accurate prediction of the coil performance requires, in addition to assessments of the superconductor behavior, a thermohydraulic analysis of the supercritical He. The overall thermohydraulic conditions were simulated by the full-scale quasi three dimensional code VINCENTA. Analysis of stability and quench was carried out using one dimensional Gandalf electric and thermohydraulic code. An interface was written between these codes. The stability margin against the mechanical disturbance and due to a plasma disruption was estimated. In the quench analysis, the temperature rise during the fast discharge was calculated. According to these results, it is confirmed that the TF coils will be operated with the designed performance.
Sn strand subjected to bending strainMurakami, Haruyuki*; Ishiyama, Atsushi*; Ueda, Hiroshi*; Koizumi, Norikiyo; Okuno, Kiyoshi
IEEE Transactions on Applied Superconductivity, 17(2), p.1394 - 1397, 2007/06
Times Cited Count：19 Percentile：66.01(Engineering, Electrical & Electronic)Critical current of ITER mode coil degraded as increase of electromagnetic force. It was shown that the periodic bending of the strand caused this degradation from analysis based on results of experiments in which periodic transverse load is artificially applied to single strand. However, since the experiments were carried out under a certain condition, general relation between transverse load and critical current was not obtained. The authors therefore developed a numerical simulation code. The simulation results are in good agreement with test results. The general dependence of the critical current on temperature and pitch of periodic load is studied using our code. The simulation results reveal that the reduced critical current depends on the temperature and is a function of the bending strain independent of the pitch of the periodic load.
Zanino, R.*; Astrov, M.*; Bagnasco, M.*; Baker, W.*; Bellina, F.*; Ciazynski, D.*; Egorov, S. A.*; Kim, K.*; Kvitkovic, J. L.*; Lacroix, B.*; et al.
IEEE Transactions on Applied Superconductivity, 17(2), p.1353 - 1357, 2007/06
Times Cited Count：4 Percentile：29.39(Engineering, Electrical & Electronic)The PFCI will be tested at JAEA Naka, inside the bore of the ITER Central Solenoid Model Coil. The main test program are the DC characterization of the conductor, the measurement of AC losses in conductor, the hydraulic characterization, the stability and the quench propagation, and the effects of cycling electromagnetic load. Based on and in support of this test program, an extensive campaign of predictive analysis has been initiated on a subset of the above-mentioned test program items and the results of the comparison of selected predictions from different laboratories will be presented and discussed. A sudden quench at 5.7-6.2 K and 45 kA is predicted. The computed temperature increase at the winding outlet is about 0.5 K for the pulse. These results will be compared with the experiment and used for an accurate prediction of the PF coil performance.
Ando, Toshinari*; Kizu, Kaname; Tsuchiya, Katsuhiko; Tamai, Hiroshi; Matsukawa, Makoto
no journal, ,
no abstracts in English
