Design of the ITER PF Coils
ITER magnets are all designed using superconducting conductors with a high current carrying capability. The Poloidal Field (PF) coils are operated in pulsed mode with maximum operating currents of 48 kA for PF 1 and 6, 55 kA for PF 2,3, and 4 and 52 kA for PF 5. The PF system consists of 6 ring coils, PF1 through PF6, that serve to stabilize the position and control the shape of the plasma in the tokamak. The six PF coils are attached to the outside of the Toroidal Field (TF) coil cases through flexible plates or sliding supports allowing radial displacements. The PF coil positions and sizes have been optimized for the plasma requirements consistent with the constraints imposed by allowing access to the vacuum vessel and by considering pumping ducts to the in-vessel components. The PF coils will all be wound with Niobium-Titanium (NbTi) cable-in-conduit conductors (CICC), and range in diameter from ~8 m to ~24 m. The winding pack consists of stacked double pan cakes, with joints only on the outer radius for access/repair and eddy current/AC loss reasons, while the helium inlets are located at the inner radius. Since the 2001 design option, the PF coil windings and their sub components have been redesigned to satisfy new operational requirements. The final detailed design has been established in 2009 and validated by the design review held the same year. In this paper, the up-to-date design of the PF coils and each sub-component such as winding pack, electrical insulation, joints and terminations, helium inlet, jumpers, and coils' supports are discussed together with their fabrication methods.