Compressive pre-strain in Nb3Sn strand by steel tube and effect on the critical current measured on standard ITER barrel

A. Nijhuis, W.A.J. Wessel, H.G. Knoopers, Yu. Ilyin, A. Della Corte, H.H.J. Ten Kate

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Abstract

The large Cable-In-Conduit Conductors (CICC) designed for the magnet coils in the International Thermonuclear Experimental Reactor (ITER), are composed of Nb3Sn strand bundles in a Stainless Steel (SS) or Incoloy conduit. Both, the thermal contraction of the strand composite and the conduit material, define the final pre-strain after cooling down and thus affect the strand critical current (Ic). The transverse forces, introduced when charging a coil, in addition affect the overall strain state due to bending and pinching of strands. Recently, periodic bending tests were applied on strand samples without additional axial compressive pre-strain. Here we explore the method of swaging a SS-tube around a strand to imitate the cool-down strain effect of the conduit. The experimental results of the Icmeasurements at 12 T and 4.2 K are presented for a Nb3Sn PIT strand with and without swaged SS tube on both Ti-6Al-4V and SS standard ITER sample holder (barrels). The effect of gluing the sample to the barrel is also investigated. The intrinsic strain state of the samples is verified by measurement of the Icversus applied strain with the Pacman spring. © 2005 IEEE.
Original languageEnglish
Pages (from-to)3466 - 3469
Number of pages4
JournalIEEE Transactions on Applied Superconductivity
Volume15
Issue number2 PART III
DOIs
Publication statusPublished - Jun 2005
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering
  • Physics and Astronomy (miscellaneous)

Cite this

Nijhuis, A., Wessel, W. A. J., Knoopers, H. G., Ilyin, Y., Della Corte, A., & Ten Kate, H. H. J. (2005). Compressive pre-strain in Nb3Sn strand by steel tube and effect on the critical current measured on standard ITER barrel. IEEE Transactions on Applied Superconductivity, 15(2 PART III), 3466 - 3469. https://doi.org/10.1109/TASC.2005.849060