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I_c Analysis of Nb₃Sn Strand Cable-In-Conduit Conductor under the Electromagnetic Force by the Structural Mechanics

Tsuyoshi YAGAI and Takataro HAMAJIMA¹⁾

Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan

1)

Tohoku University, 6-6-05 Aramaki, Aoba, Sendai 980-8579, Japan

(Received 9 December 2011 / Accepted 10 February 2012 / Published 10 May 2012)

Abstract

The Cable-In-Conduit Conductor (CICC) is the most promising one for large scale fusion magnets. Now it has been adopted as conductors for ITER magnets. Although the conductor has good mechanical strength against large electromagnetic force, the performance is not so good because the Nb₃Sn strands are fragile and the critical current density is sensitive to strain. Because the conductor is composed of hundreds or thousands of strands which are twisted and become tangled, the strands experience extra-bending during energizing magnets. It seems so difficult to analyze plastic deformation of the strands of whole conductor. Our approach to calculate it is unique in terms of using structural mechanics called “Beam Model” based on the measured strand traces inside the conduit. The calculated traces provide us the local curvatures of strands under electromagnetic force. This leads to the evaluate the conductor performance such as I_c degradation.

Copyright (c) 2012 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

cable-in-conduit conductor, Nb₃Sn strand, beam model, bending strain analysis, I_c degradation

DOI: 10.1585/pfr.7.2405026

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References

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This paper may be cited as follows:

Tsuyoshi YAGAI and Takataro HAMAJIMA, Plasma Fusion Res. 7, 2405026 (2012).