Mechanical behaviour of cabled superconductors under transverse and longitudinal loads (for NET)

As part of the development for the magnet system for the NET (Next European Torus) Tokamak machine (Next European Torus) for fusion research, 40 kA cable-in-conduit type Nb/sub 3/Sn superconductors are being manufactured and tested. A model has been developed for the behavior of strands randomly oriented in a superconducting cable. The model predicts that frictional heating in such cables, due to either transverse magnetic loading or applied longitudinal strain or both combined, is not a significant heat source compared to AC losses. Under typical operational conditions in the ABB cable, with epsilon /sub leff/=0.0015, sigma /sub teff/=6.4 MPa, and an applied external transverse strain to the jacket of -0.0015, the maximum strains predicted in the strands are (with c=4 mm); due to the transverse stress (longitudinal bending) +or-0.3%, due to the longitudinal strain (direct) 0.15%.<
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