Center conductor design for the compact spherical torus reactor

The spherical torus (ST) concept has been previously proposed as a means of achieving high plasma β at low aspect ratio and low magnetic field. The center post performance is presently analyzed as a function of operating time for a representative spherical torus reactor with the following parameters: (1) 2000-MW thermal power; (2) 1.43-m major radius; (3) 1.17-m minor radius (A = 1.22); (4) elongation, 2.2; and (5) toroidal field on axis 0.824 T. The key engineering issues for the center post design are the resistive loss, magnet coolant velocity, conductor temperature, and physical erosion of the magnet by the coolant flow. Specifically, resistive loss can be as high as 111 MW, with peak conductor temperature under 300°C, requiring a peak coolant velocity of approximately 12 m/s.