Fusion Science and Technology / Volume 54 / Number 3 / October 2008 / Pages 694-724
Technical Paper / Aries-Cs Special Issue
A stellarator systems/optimization code is used to optimize the ARIES-CS fusion power plant parameters for minimum cost of electricity subject to a large number of physics, engineering, and in-vessel component constraints for a compact stellarator configuration. Different physics models, reactor component models, and costing algorithms are used to test sensitivities to models and assumptions. The most important factors determining the size of the fusion power core are the allowable neutron and radiative power fluxes to the wall, the distance needed between the edge of the plasma and the nonplanar magnetic field coils for the intervening components, and an adequate tritium breeding ratio. The magnetic field and coil parameters are determined from both plasma performance and constraints on the Nb3Sn superconductor. The same costing approach and algorithms used in previous ARIES studies are used with updated material costs. The result is a compact stellarator reactor with a major radius close to that of tokamaks. A one-dimensional power balance code is used to study the path to ignition and the effect of different plasma and confinement assumptions on plasma performance for the reference plasma and coil configuration. A number of variations are studied that affect the size and cost of the fusion power core: maximum field at the coils, component cost penalties, a different blanket and shield approach, alternative plasma and coil configurations, etc. Comparisons are made with some earlier ARIES power plant studies. A number of issues for the development of compact quasi-axisymmetric stellarators are identified.