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• 3D ANSYS Maxwell FEM model developed for the EM analysis of the OH ORU at FDR level. • ISS modelled to calculate the flowing eddy currents between OH ORU and structure. • A new simplified approach to model the spherical shells has been proposed. • Calculated OH ORU forces are not design driving so do not compromise the final design. • Studies performed to validate key aspects of the methodology developed for EM analyses. An electromagnetic (EM) analysis of the Optical Hinge (OH) and Optical Relay Unit (ORU) has been performed for the validation of their Final Designs. OH and ORU are reflective optical systems, being the starting ex-vessel components of the ITER diagnostic Wide Angle Viewing System (WAVS). These two components share a support structure, attached in turn to the Interspace Support Structure (ISS). The methodology for the realization of the EM analyses for components in fusion devices is not standardized. The choice of the method highly depends on the goals of the study, on the required accuracy of results and on the available resources. A methodology to perform the EM analysis has been developed and validated. In the EM analysis, the arising EM forces have been calculated with a finite element 3D model, and the results obtained were used for the successive structural analysis. The publication presents the methodology developed, its implementation to the OH ORU components, the results obtained for the validation of their Final Designs and additional studies for the methodology validation. [ABSTRACT FROM AUTHOR]

• 3D ANSYS Maxwell FEM model developed for the EM analysis of the IAM at FDR level. • ISS modelled to calculate the flowing eddy currents between IAM and structure. • Found presumed convergence errors in sharp inner boundary corners of Maxwell models. • Calculated IAM forces are not design driving so do not compromise the final design. The ITER Visible and Infrared Wide Angle Viewing System (WAVS) is a diagnostic aiming to optically monitor the tokamak first wall and divertor for machine protection, plasma control and physics analysis. The Interspace Afocal Module (IAM) is a refractive optical system, being one of the WAVS components located in the Interspace area. In order to assure the optical performance, the IAM has to withstand all the relevant loads defined for the Final Design, including the electromagnetic (EM) loads developed in the Interspace area under EM events. Volumetric forces during transient EM events arise from the interaction of the background magnetic field with the eddy currents induced in the conductive components when they experience time-varying magnetic fields. In case of Category III and IV loads, including load combinations with certain Major Disruption and Vertical Displacement Event cases, the IAM integrity has to be ensured since its structure is classified as Safety Relevant. The EM volumetric loads are calculated through a 3D Finite element model and will serve as inputs for the later structural analysis. The paper summarizes the EM analysis of the IAM, performed by CIEMAT, to validate its Final Design. [ABSTRACT FROM AUTHOR]