Stability and Design Criteria for CICC with a Broad Transition to Normal State

摘要

Stability in cable-in-conduit conductors (CICC) against perturbations is often associated with transient heat removal of heat generated in the normal zone. Based on this approach, stability criterion requires low current density in the strands. This criterion is often used for design of the magnets for fusion devices like ITER, KSTAR and others. We show that this criterion is not a mandatory requirement for serviceability of CICC and that CICC may work reliably at higher current densities. In conditions of limited and well defined perturbations, sufficient stability is provided not by a large amount of copper and high transient heat transfer, but by a smooth transition to the normal state and easy current redistribution. A strand parameter space in terms of Ic and N-value meeting CICC requirements for stability, limited heat generation, and minimum temperature margin is proposed and discussed. The theory predictions are compared with known experimental data on CICC.