B203 Towards a drastic enhancement of operating current density of superconducting coil systems : Mechanism of thermal runaway for RE-based superconducting coil

Abstract

REBCO high temperature superconductors are promising for various superconducting coil systems such as MRI, NMR and Superconducting Energy Storage Systems. However, REBCO coils sometimes shows thermal runaway, resulting in meltdown of the coil in the worst case. In this paper, we investigate the effect of thermal grid method, in which heat channel of high thermal conductive metal are installed in the coil winding, on temperature increase of the REBCO coil due to thermal runaway. We demonstrate that there is a time interval prior to thermal runaway, in which the normal conductive part shrinks if the coil current dump starts.