Analysis of Enhanced Heat Flux First Wall behavior under ITER Pulsed Loads

Abstract

Abstract The First Wall (FW) is a component of the Blanket System facing the plasma. Two types of FW panel design have been developed based on the design heat flux: the Enhanced Heat Flux First Wall (EHF FW) panels designed for a 4.7 MW/m2 heat flux, and the Normal Heat Flux First Wall (NHF FW) panels designed for a 2.0 MW/m2 heat flux. The EHF FW panels are sheared by the RF and China. The EHF FW panels as part of the RF Procurement Arrangement 1.6.P1A.RF.01 are manufactured by two institutes: JCS NIIEFA and JSC NIKIET. As part of the technological process qualification, the design of the EHF FW Full Scale Prototype (FSP) was developed and approved. The so-called “pipe option” was taken as a basis for the FW configuration because during the final assembly the fingers are connected to the beam by orbital welding, allowing for acceptably small welding distortions and while providing for the required NDT examinations. At the same time, the previously considered welded attachment of the fingers to the beam was replaced by a mechanical option. This approach allowed for the removal of the Central Slot Insert (CSI) from the FW beam central zone, thereby simplifying the cooling configuration. This design was integrated in representative EHF FW panels located on the top and outboard zones of the vacuum vessel and the cooling configuration in the FW beams was developed to accommodate the additional plasma radiation on the front FW beam surface in the absence of the CSI. This paper summarizes the results of design activity for top and outboard EHF FW panels and presents the results of the thermo-hydraulic and transient thermal analyses which confirm the acceptable performance of the EHF FW panels without the CSI.