Speaker
Rainer Wesche
(SPC)
Description
The present study aims to minimise the outer radius of the CS coil of European DEMO in order to reduce the size and the cost of the whole tokamak. In a previous study, it has been demonstrated that the outer radius of the CS coil can be reduced maintaining the generated magnetic flux at 320 Vs using high-temperature superconductors (HTS). This first study was based on a uniform current density in the winding pack. In a next step, a layer-wound CS coil with superconductor grading has been considered. It is envisaged to subdivide the winding pack of the CS coil into 10 sections each consisting of a double layer. Depending on the magnetic field at the section in question it is foreseen to HTS in the highest field sections, Nb3Sn at medium fields and NbTi at the lowest fields. Furthermore, a superconductor grading will be implemented in order to reduce the cross-section of superconductor in the lower field sections. A procedure to determine the dimensions of the sections and the relevant cross-sections has been developed including the calculation of the hoop stress in a non-uniform current density winding. An outline design of the winding pack of the CS1 module, experiencing the highest magnetic field, is presented.
Co-authors
Boris Stepanov
(SPC, EPFL, Villigen PSI, Switzerland)
Davide Uglietti
(SPC, EPFL, Villigen PSI, Switzerland)
Kamil Sedlak
(SPC, EPFL, Villigen PSI, Switzerland)
Nikolay Bykovsky
(SPC, EPFL, Villigen PSI, Switzerland)
Pierluigi Bruzzone
(SPC, EPFL, Villigen PSI, Switzerland)
Rainer Wesche
(SPC, EPFL, Villigen PSI, Switzerland)
