New technique on large superconducting toroidal magnet system coil manufacturing

In large toroidal systems the loads are reacted by the winding pack (WP) and surrounding steel case. The major feature of a proposed WP manufacturing technique is the use of radial and toroidal steel plates, which support the conductors. In the WP cross-section the radial covers and toroidal ribs form steel box cells. Four circular conductor jackets are inserted in each box cell. Plastics inserts between conductors keep structural integrity inside cell. Set of cells forms one single pancake. The toroidal ribs and radial covers transfer the electromagnetic forces acting on each four-conductor group directly to the case without accumulation on conductors and their turn insulation. The process of manufacturing is described in the paper. The performance of the proposed box structure is assessed using detailed finite element examination of the WP of DEMO type thermonuclear reactor.