The low aspect ratio design concept possibility of an acceptable fusion power system

A scoping design code has been prepared and utilized to evaluate the critical issues of the low aspect ratio (LAR) concept as a design for a fusion power reactor. The physics basis for the A=1.4, κ=3, β_T of 62% and bootstrap fraction of 87% equilibrium design point was derived from earlier work. Using Kr to enhance the radiation from the core, it is shown to be possible to trade off the heat flux between the first wall and the divertor, with corresponding reduction in fusion power. An aggressive technology approach is used to push critical components toward respective design limits. To minimize the reactor size, no inboard shielding of the Cu-alloy TP-coil central column is used. A helium-cooled, V-alloy, LiPb breeder first wall and blanket design that can withstand high heat flux and neutron wall loading is proposed. With this combination of materials and design, the major radius of a 1998 MWe reactor can be as small as 2.9 m. The material fluence lifetime of 15 MW.y/m² is assumed for both Cu and V-alloys. Including the change out cost of the Cu-alloy central column and outboard first wall and blanket during the reactor lifetime of 30 years, the cost of electricity is estimated to be 52.9 mil/k Whr. The total direct cost is $5.3B. This is significant, because at $2650/kWe fusion begins to approach a manageable development cost, supporting the motivation of adopting the LAR development path for the achievement of economic fusion power