FT/P3-20 Physics and Engineering Basis of Multi-functional Compact Tokamak Reactor Concept

An important milestone on the Fast Track path to Fusion Power is to demonstrate reliable commercial application of Fusion as soon as possible. Many applications of fusion, other than electricity production, have already been studied in some depth for ITER class facilities. We show that these applications might be usefully realized on a small scale, in a Multi-Functional Compact Tokamak Reactor based on a Spherical Tokamak with similar size, but higher fields and currents than the present experiments NSTX and MAST, where performance has already exceeded expectations. The small power outputs, 20-40MW, permit existing materials and technologies to be used. The analysis of the performance of the compact reactor is based on the solution of the global power balance using empirical scaling laws considering requirements for the minimum necessary fusion power (which is determined by the optimized efficiency of the blanket design), positive power gain and constraints on the wall load. In addition, ASTRA and DINA simulations have been performed for the range of the design parameters. Our studies show that increased toroidal field in a spherical tokamak can be possibly achieved by use of commercially available high temperature superconductors. This multi-functional compact reactor will also contribute to the mainstream GW Fusion power concept by providing data on burning plasma, test of diagnostics, remote handling, blanket design and operation, reactor integration etc. In this paper, the motivation for the concept as well as physics and technological challenges of the multi-functional compact reactor are discussed.