Fusion Science and Technology / Volume 52 / Number 3 / October 2007 / Pages 422-426
Technical Paper / The Technology of Fusion Energy - Experimental Devices and Advanced Designs
The complexity of Compact Stellarator (CS) coils made from brittle A15 SC alloys results in a challenging design. Three options of manufacturing the ARIES-CS coils are discussed. The first two options use high performance Nb3Sn superconductor, one with the wind-and-react method, the second with react-and-wind. The magnet protection design philosophies are different for the two winding methods. Wind-and-react uses high conductor current with external dump, while react-and-wind uses low conductor current with internal dump. The use of non-uniform internal quench is explored as a means to minimizing the requirements for internal dump for the case of react-and-wind. Cooling of the superconductor is also fundamentally different in the two cases, as the hydraulic path of the react-and-wind option requires low velocity He in a sheathed Rutherford-like cable, cooled by a heat exchanger in accessible regions. In the third design option, HTS superconductors are deposited directly on the structure, minimizing conductor movement. Coil protection techniques will be described.