During a major plasma disruption event, the structural components of the NET (Next European Torus) tokamak reactor are subjected to strong electromagnetic transient loads arising from the interaction of the induced eddy currents with large magnetic fields. In the NET design, relatively many removable internal segments facing the plasma are assembled from the top inside of the vacuum vessel. This paper considers the NET reference design aspects for the fastening and guiding systems of the removable internal segments and illustrates the structural analysis of the first wall modules, including the behaviour of their supports during a major plasma disruption. In particular, for three outboard segments, a complete transient dynamic numerical simulation of the first wall structure will be described using a thin shell formulation.