Design of the TPX limiter and armor components

The TPX limiter and armor systems are designed for steady-state operation from day one operation, at 18 MW plasma input power, to a possible upgrade to 45 MW. All components are designed for remote handling. Carbon-carbon (C-C) composites are the baseline plasma facing material for all limiter and armor systems. Where applicable, all components are made from low activation materials. The TPX limiter system consists of the inboard toroidal limiter, the outboard toroidal limiter, and three discrete poloidal limiters. These limiters are used for plasma startup and to protect the vessel, passive plates, and equipment in the ports from the energetic particle fluxes during steady-state operation. In addition, the inboard limiter protects the vacuum vessel from steady-state neutral beam shine-though and from neutral beam faults. The TPX armor components consist of two major systems: the neutral beam armor that protects the outer vessel wall and equipment in the ports, and the ripple armor that intercepts the trapped energetic particles that are drifting vertically in the ripple region. Different design concepts are employed for these plasma facing components (PFC) depending on their expected heat loads. Inboard and outboard limiters are designed with mechanically restrained C-C composite tiles mounted on cooled support plates. Components which must withstand higher heat loads, such as neutral beam and ripple armor, are made of C-C composite tiles brazed to actively-cooled copper.