Improvements to physics performance and engineering technology required for a tokamak fusion reactor

Abstract

Abstract The reactor parameters and optimum radial build of a tokamak fusion reactor with an aspect ratio, A, in range from 2.5 to 4.0 were investigated using a tokamak systems analysis coupled with neutron transport calculation which enabled self-consistent determination of radial thicknesses of the reactor components with neutronic constraints. The minimum major radius, R0, and optimum radial build were primarily determined by plasma performance, the ripple requirement, the role of the external current drive system, and the maximum allowable magnetic field at the toroidal field (TF) coil, Bmax. When there was no central solenoid (CS), and an external current drive system was used to drive and maintain the plasma current, the minimum R0 increased with larger A but decreased with larger Bmax and larger normalized plasma beta, βN. When using a CS to drive the plasma current, the minimum R0 and the radial reactor size were larger than without the CS when A ≤ 3.0, but fell between those found in cases without the CS with Bmax = 13 T and 16 T when A > 3.5. Variation of the minimum R0 with A was small. A tokamak fusion reactor with a fusion power of 3000 MW, a fusion gain, Q > 30, and a reactor size comparable to that of ITER is viable using improved physics performance and engineering technology compared to those adapted in the design of the ITER.