ARIES-ST plasma-facing component design and analysis

ARIES-ST is a 1000 MW fusion power plant conceptual design based on a low aspect ratio 'spherical torus' (ST) plasma. The plasma-facing components include the inboard and outboard first wall, divertor plates, and plasma stability plates. Several unique aspects of ST plasma influence the engineering design. The limited inboard space precludes a full inboard divertor slot, such that substantial power and particle flows are expected to impact the inboard first wall. Strong requirements on plasma vertical stability require close-in conductors. The use of He-cooled tungsten for the stability plates allows them to act as plasma-interactive components operating at high temperature and moderately high (1-2 MW/m2) heat flux. High plasma core radiation fraction and a natural tendency for low inboard transport losses help to alleviate these inboard problems, such that the peak power loads are not expected to exceed the capability of He-cooled tungsten and steel structures. The main features of the plasma-facing components are summarized here together with the analysis of their thermal hydraulic and thermomechanical performance