External vacuum boundary, independent TF coils

A tokamak power reactor configuration is proposed which locates the primary vacuum boundary away from the plasma chamber. The vacuum boundary is the inside surface of the reactor cell. This is expected to eliminate the need for vacuum joints at the torus sector allowing the reactor to be designed as modular units which can be vertically disassembled. All service penetrations into the cell must be vacuum-tight, and special considerations must be designed into electrical joints to prevent arcing. The large surface area exposed to vacuum conditions will require special treatment to avoid outgassing problems. The TF coils, which are an integral part of the reactor modules, must be enclosed in separate cryostats, capable of transmitting out-of-plane loads to the surrounding warm structure. It was found that a 25-cm-thick thermal insulator composed of alumina polyimide chocks with a nitrogen cold shield would result in acceptable peak and average heat loads to the coils. If the outgassing and penetration problems can be solved, the external vacuum boundary and independent TF coils will greatly simplify the topology of the vacuum chamber theme by increasing the availability of the power reactor. 2 figs