Design layout and maintenance of the ARIES-IV tokamak fusion power plant

The ARIES-IV fusion power plant is a conceptual, steady-state, D-T burning, 1000-MWe net-power tokamak, operating in the second-stability plasma regime. Design simplicity, maintainability, and reasonable maintenance downtimes are crucial for viable and competitive fusion economics. The ARIES-IV design team developed a maintenance scheme that allows rapid and simultaneous replacement of all of the components in a large, self-contained fusion-power-core (FPC) section. The FPC is divided into 16 self-contained "pie-shaped" sections that can be removed horizontally through large vacuum-vessel access ports located between the outer legs of the toroidal-field (TF) coils. Prior to commitment to service, the entire FPC section assembly is pretested extensively to maximize operating reliability. To facilitate this radial section-removal scheme, the TF coils and the poloidal-field (PF) coils of the ARIES-IV tokamak had to be enlarged. The advantages of the ARIES-IV section-replacement scheme over more traditional approaches, where individual FPC components are removed sequentially from the vacuum vessel, outweigh the cost increases associated with larger TF- and PF-coil systems.