Electromagnetic analysis of ITER equatorial Wide Angle Viewing System (WAVS) in-vessel components

In the framework of ITER diagnostics, the visible and infrared equatorial Wide Angle Viewing System (WAVS, referenced as 55.G1.C0 in ITER Plant Breakdown Structure) plays a key role. Indeed, this system is devoted to monitor the surface temperature of the plasma facing components by infrared thermography and to image the edge plasma emission in the visible range. As a consequence, it is mandatory to verify that WAVS components are able to withstand all the foreseen loads and load combinations. This paper is dedicated to present the methods and results of electromagnetic (EM) and Transient Structural (TS) analyses for determining the loads due to Eddy Currents and the associated stresses and displacements in the in-vessel components of WAVS at its Preliminary Design Review (PDR) stage. Specifically, the analysed WAVS in-vessel components comprise First Mirror Units, shutters and Hot Dog Legs of the EPP#12 (Equatorial Port Plug). The selected EM loads derive from the IO-assumed worst EM scenario for EPP#12 (specifically a plasma exponential major disruption). Given the variation maps of the global magnetic field in the regions of interest during the transient, the EM loads have been estimated using a local 3D EM model of the WAVS components by means of the ANSYS Electromagnetics Suite v.19.2, employing the tool ANSYS Maxwell. Successively, the obtained results have been used as inputs to the corresponding TS analyses (carried out using ANSYS Workbench v.19.2). Therefore, the related outcomes can be combined with the set of all other structural studies (i.e. thermal and seismic analyses) to assess the overall mechanical behaviour of the components under study for the WAVS PDR level. Moreover, the results obtained have shown how EM loads are often design driving loads for the WAVS components.