Assessment of the structural integrity of in-vessel ELM control coils located on the high field side of the TCABR tokamak

The use of Resonant Magnetic Perturbations (RMP) is a well-established technique to control Edge Localized Modes (ELM) in tokamak plasmas. Uncontrolled ELM instabilities can dissipate high energy fluxes that are not withstood by the most advanced materials. In-vessel RMP coils on the low field side (LFS) are usually employed to suppress/mitigate ELMs, but research indicates that applying RMP fields on the high field side (HFS) may improve ELM control. To investigate the effects of RMP fields on both sides, the Tokamak à Chauffage Alfvén Brésilien (TCABR) is being upgraded. Among the improvements, a set of 108 RMP coils will be installed inside the vacuum vessel: 54 coils on the LFS and 54 coils on the HFS. These coils will have to operate with both direct (up to 2 kA) or alternating (up to 1 kA) currents, high voltages (up to 4 kV), and frequencies up to 10 kHz. Consequently, high stress levels due to temperature gradients and electromagnetic loads act in the coils casing. This work presents structural analyses of the in-vessel coils that will be installed on the HFS, for operations in direct current. In these analyses, finite element simulations using the software ANSYS were carried out to evaluate the feasibility of installing this set of coils. The maximum stresses in the CP coil components were obtained and compared with the allowable stresses for each component, showing that the proposed set of CP coils can be safely installed and operated in TCABR.