Design status of the structural components of the helical fusion reactor FFHR-d1

FFHR-d1 is a conceptual design of the Large Helical Device-type fusion reactor. Several design optimizations for FFHR-d1 have been conducted under a multipath strategy. The structural design began from a radial build design of the components using a system code analysis and considering a shielding/breeding blanket design. The support structure must be sufficiently rigid to hold a constant geometric position of the radial build components. Additionally, large apertures are required for the maintenance work of in-vessel components. The shape of the support structure was carefully chosen and the analytically determined stress level was within the permissible limit. Thus, the basic design of the structural components of FFHR-d1 was established. To accelerate the design activity and achieve a consistent helical reactor system, the high-temperature superconducting joint-winding, liquid metal divertor, a supplemental helical coil addition, a novel divertor structure, and other challenging options are investigated alongside the basic design. This paper describes the structural design status of FFHR-d1 by focusing on the latest radial build design, construction scheme, and effectiveness of the novel divertor structure.