Dynamic behaviour of DEMO vacuum vessel during plasma vertical displacement events

Abstract

© 2020 Elsevier B.V. In tokamaks during plasma vertical displacement events (VDEs) electrical currents occur in the vacuum vessel (VV) and in the in-vessel components (IVCs) that interact with the strong magnetic field generating large electromagnetic (EM) loads. The aim of the present work is the evaluation of the peak displacements and accelerations of the DEMO VV in case of VDEs. Four types of VDEs are investigated that are specified to generate the most severe net loads. The assessment considers also the electromagnetic-mechanical coupling between the VV and the toroidal field (TF) coils whose characteristic stiffness and damping coefficients were determined through a transient EM analysis. In a second step a transient dynamic analysis was performed using a structural finite element (FE) model of the VV to evaluate the displacement and acceleration peaks during the VDEs in relevant locations of the VV.