A High Performance Insulated REBCO Pancake With Conductive Cooling Capability

Abstract

REBCO Coated Conductors have high tensile strength along their length. They are however sensitive to delamination when traction force is applied on the tape surface, which in a pancake winding corresponds to radial tensile stress. For this reason, most REBCO magnets are dry-wound (not impregnated). One of the drawbacks of dry winding is that conduction cooling to low temperature (below 20 K) would be inefficient. Edge impregnation structures were developed to mitigate this problem but retaining a soft non-stick insulating layer in between the turn. In this paper, we propose an improved pancake structure with the benefits of edgeimpregnation but using Hastelloy tape with thin insulation coating to reinforce the winding. The mechanical behavior of such structure is first estimated then validated with high current tests under large background magnetic field. The insulation performance is then tested by rapid ramping and fast discharge.

First Validation of Robust REBCO Insert Concept on a Large 20-Pancake Prototype Reaching Up to 25 T

“…The process is repeated until no soft interface is under pressure anywhere. The same modelling approach was already used successfully to match experimental results in [5,6] and [14]. The tensile strength of the Polyimide layer being negligible compared to that of the REBCO tapes, it is ignored in the model.…”