The integrated-blanket-coil concept applied to the spherical torus

The purpose of this study is to investigate the potential of reactor embodiments based on the combination of two novel concepts, the integrated-blanket-coil (IBC) concept and the spherical torus (ST) concept. The IBC concept involves the combination of blanket and coil functions into a single component. The ST concept is based on the operation of the tokamak magnetic configuration at low aspect ratio. Two applications of the IBC concept to the ST are presented: (1) the IBC as the outer blanket and TF coil return legs (Application 1); and (2) the IBC as the inner blanket and OH solenoid coil set (Application 2). The application 1 IBC/ST yields reactor embodiments operating with high mass power density (≅500 kWe/MT) while, at the same time, yielding moderate neutron wall loading (≅5 MW/m/sup 2/) and modest electrical output (400-500 MWe). It is anticipated that fusion reactors operating in the above parameter space will exhibit attractive economic potential. When compared with a conventional ST design (copper TF coils and separate blanket), the Aplication 1 IBC/ST design exhibits a factor of two improvement in mass power density. The Application 2 IBC/ST provides an inductive current drive option which yields burn times in the range 3-4 minutes with no penalties in inboard breeding and energy recovery