Improved support concept for the Helias reactor coil system

For the Helias reactor (HSR) a system of non-planar superconducting coils has been developed. The distributions of the magnetic field and the forces are calculated. In order to support the magnetic forces a scheme of mutual support of the coils is applied. The common vault support concept of earlier studies has been modified: Two toroidal support rings, connected to each other, are introduced at the inner part of the coil system. These new rings connect the coils and carry the main part of the centripetal forces. Finite element computations are done with half a field period, taking into account the stellarator symmetry. The mechanical stress and strain distributions inside the coil support structure are analyzed.