STABILITY OF CABLE-IN-CONDUIT INTERNALLY-COOLED SUPERCONDUCTOR SUBJECT TO LOCAL DISTURBANCE-STABILITY ANALYSIS BASED ON MEASURED TRANSIENT HEAT-TRANSFER OF SHE IN NARROW CHANNEL

It is likely that a quench in the cable-in-conduit internally cooled s uperconductor (CCICS) is initiated by a quench of a single strand due to strand motion. The disturbance due to the strand motion is highly l ocalized and has short duration time of less than 1 ms. We have been s tudying the stability of CCICS assuming that the disturbance energy is abruptly put into a small part of a single strand. To perform this an alysis, the heat transfer characteristics of supercritical helium(SHE) confined to narrow channels formed by strands were measured. The pape r presents the experimental heat transfer data which well agree with c alculated values based on a conduction model in short time range while a normal zone caused by a disturbance disappears or grows to propagat e. The transient heat transfer in narrow channels is affected by energ y input to SHE in the channels. According to our stability analysis of a model conductor, energy released during initiation of a quench is n ot large enough to induce SHE flow affecting the heat transfer.