The recent progress in fields such as High Temperature Superconductors (HTS), Additive manufacturing, new diagnostics, and innovative materials, has led to new scenarios and to a second generation of Nuclear Fusion Reactor designs. The new Affordable Robust Compact (ARC) Fusion Reactor is described in the paper. ARC could be not only the base-load but also a load-following reactor, capable to cover peak requests and other plant shutdowns. In order to investigate this interesting ability of ARC, its more sensitive component has been analyzed: ARC vacuum vessel