TY - JOUR
T1 - Comparison of avalanche-like quenches between NbTi and Nb3Sn cables
AU - Seo, K.
AU - Hishinuma, Y.
AU - Nishimura, A.
AU - Nishijima, G.
AU - Watanabe, K.
AU - Nakamura, K.
AU - Takao, T.
AU - Katagiri, K.
N1 - Funding Information:
Part of this work was supported by Grant-in-Aid for Scientific Research (17656098), NIFS collaboration research programs (NIFS05KKMF002) and Fusion Engineering Research Center program at NIFS (NIFS05UCFF008).
Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2006/11
Y1 - 2006/11
N2 - Superconductors carrying currents larger than several 10 kA are required for magnetic confinement fusion systems. A cable-in-conduit-conductor (CICC), which has about 1000 of twisted thin superconducting strands in a ridged conduit, is a promising candidate for such large and high magnetic field superconducting system. A specific phenomenon in the CICC is so called avalanche-like quench (AQ). When some strands become resistive due to current saturation at critical current and/or a mechanical disturbance, the current re-distributes from the strands into neighboring ones, which are electro-magnetically coupled more strongly than the others. This causes current saturation in the neighboring strands. Finally, the whole cable becomes normal. We call this phenomenon an avalanche-like quench. Small multi-strand cables were tested by induced-current methods. Quench behaviors of both Nb3Sn and NbTi cables are observed and compared. In the experiment, for the Nb3Sn cable, the critical current measurement was stably carried out at high field without quench. In contrast, for the NbTi cable, we observed a number of AQs during inductive energization. Consequently, we suspected that the reason is based on the difference of critical temperature (TC) between Nb3Sn and NbTi. The difference of TC is several Kelvins, however, their macroscopic behaviors differ significantly.
AB - Superconductors carrying currents larger than several 10 kA are required for magnetic confinement fusion systems. A cable-in-conduit-conductor (CICC), which has about 1000 of twisted thin superconducting strands in a ridged conduit, is a promising candidate for such large and high magnetic field superconducting system. A specific phenomenon in the CICC is so called avalanche-like quench (AQ). When some strands become resistive due to current saturation at critical current and/or a mechanical disturbance, the current re-distributes from the strands into neighboring ones, which are electro-magnetically coupled more strongly than the others. This causes current saturation in the neighboring strands. Finally, the whole cable becomes normal. We call this phenomenon an avalanche-like quench. Small multi-strand cables were tested by induced-current methods. Quench behaviors of both Nb3Sn and NbTi cables are observed and compared. In the experiment, for the Nb3Sn cable, the critical current measurement was stably carried out at high field without quench. In contrast, for the NbTi cable, we observed a number of AQs during inductive energization. Consequently, we suspected that the reason is based on the difference of critical temperature (TC) between Nb3Sn and NbTi. The difference of TC is several Kelvins, however, their macroscopic behaviors differ significantly.
KW - Avalanche-like quench
KW - Current sustainability
KW - Multi-stage twisted cable
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U2 - 10.1016/j.fusengdes.2006.07.060
DO - 10.1016/j.fusengdes.2006.07.060
M3 - Article
AN - SCOPUS:33750624839
VL - 81
SP - 2497
EP - 2502
JO - Fusion Engineering and Design
JF - Fusion Engineering and Design
SN - 0920-3796
IS - 20-22
ER -