REVIEW OF STABILITY EXPERIMENTS ON CABLE-IN-CONDUIT CONDUCTORS

The stability of a cable-in-conduit conductor (CICC) cooled with supercritical helium can be very high if it is operated below a certain limiting current. This limiting current can be determined by a Stekly type heat balance equation. However, an effective heat transfer coefficient that depends not only on the conductor and the coolant, but also on the heating condition, should be used in the equation. By reviewing the stability experiments performed on CICCs, it is shown that, depending on the effectiveness of the heating induced flow, the effective heat transfer coefficient can be as low as 400 W m(-2) K-1 or as high as 1400 W m(-2) K-1. Based on this review, conclusions and comments are made with regard to the permissible current density, ramp rate limitation and dual cooling channel in a CICC.