Thermal mechanical analysis of the Enhanced Heat Flux First Wall panel

► Two FW contact pad design systems have been analyzed. ► The separated pad design is more preferable than single one. ► The pads self-positioning avoids negative effects of FW beam bending under preload. ► The bulk plastic flow in separated pads is localized in near contact spot zones. ► The separated pad design protects electrical insulation from cracking and wearing. According to Blanket Procurement Change Request (PCR-244) about 40% of the FW panels (176 Enhanced Heat Flux panels) shall be delivered to ITER by Russian Federation Domestic Agency (RF DA). Each FW panel includes two main sub-assemblies: plasma facing component which is called FW finger and the load-bearing structure which is called FW beam. There are two RF institutes are involved in the development and manufacturing of the EHF FW panels: D.V. Efremov Scientific Research Institute of Electrophysical Apparatus (NIIEFA) and N.A. Dollezhal Research and Development Institute of Power Engineering (NIKIET). NIIEFA is responsible for the FW fingers design and performs the different testing in order to satisfy the ability to operation for plasma facing components of FW panels. NIKIET develops the design of FW beam, performs necessary and sufficient number of calculations in order to confirm the ability to operation for the FW beam and develops the manufacturing process for it. Also NIKIET is responsible for design development and analyzing of two attachment systems: between FW fingers and FW beam and between the FW beam and Shield Block. Each FW finger is mechanically attached to FW beam by pinned joint. In its turn the FW panel is fixed on the Shield block by deeply installed central bolt and different types of keys are provided on the beam structure to carry the radial and poloidal moments. Each key is equipped with electrically insulated contact pad. This article is devoted to design development and analyses of contact pads to be used in attachment system between FW beam and SB. At the first stage attachment system between FW panel and SB proposed by IO ITER has been analyzed. The structural analyses have been performed in elastic and elasto plastic approaches. Basing on structural analyses results some modifications for contact pads have been proposed. The main intentions of these modifications are:-to provide the necessary cooling and sufficient value of central bolt axial forces during different phases of inductive I operation mode;-to avoid the sliding between electrical insulation coated