We live in a time when we need to increase energy production and reduce CO2 emissions. In this perspective, nuclear energy is characterized by one of the lowest emissions values per unit of energy produced and at the same time it may provide energy in a constant and controllable way. The objective of this thesis is the modelling of the vacuum vessel for Affordable Robust Compact (ARC) fusion reactor: an approximately 190 MWe tokamak reactor of small size in order to reduce the cost and the complexity of such a facility. ARC is under development by the Massachusetts Institute of Technology (MIT) and PSFC (Plasma Science and Fusion Centre).