Nucl. Fusion 51 (2011) 113013 (6pp)
In a spherical tokamak (ST) reactor, the radial build of toroidal field coil and the shield play a key role in determining
the size of the reactor. For self-consistent determination of the reactor components and physics parameters, a
system analysis code is coupled with a one-dimensional radiation transport code. A conceptual design study of a
compact superconducting ST reactor with an aspect ratio of up to 2.0 is conducted and the optimum radial build is
identified. It is shown that the use of an improved shielding material and high-temperature superconducting magnets
with high critical current density opens up the possibility of a fusion power plant with compact size and small
re-circulating power simultaneously at a low aspect ratio, and that by using an inboard neutron reflector instead of
a breeding blanket, tritium self-sufficiency is possible with an outboard blanket only and thus a compact-sized all
superconducting coil ST reactor is viable.
