Transient mechanical defects in internally cooled superconducting cables : Stability criterion and stability of the W 7-X prototype cable from LMI
The stability of superconducting internally cooled cable-in-conduit conductors (CIC) for large magnets is discussed with regard to transient microscopic movements of the multifilamentary strands. The hysteresis loop resulting from a transverse mechanical compression experiment on a cable piece, using stresses corresponding to the magnetic Lorentz forces, is a measure of the overall dissipative mechanical energy (friction, plastic deformation) which might be released during coil loading. It is shown that this energy could serve as a simple and conservative stability criterion for the design of CIC cables. These investigations concern rated field and current values as well as conditions which will prevail during the solenoid tests at the KfK STAR test facility. It is shown that by a modest increase of the strand diameter and a change in the copper/superconductor ratio, the stability margin can be improved significantly.
Bibliographic Reference: Report: IPP 2/320 DE (1993) 30 pp.
Availability: Available from Max-Planck-Institut für Plasmaphysik, 8046 Garching bei München (DE)
Record Number: 199311103 / Last updated on: 1994-11-29
Original language: de
Available languages: de