Design and analysis of the structural components in the ITER ECH upper port plug

Abstract

The structural components of the ITER ECH upper port plug are presented which integrates the mm-wave beam lines of the front steering launcher for the control of plasma instabilities. The design of the main structure considers two alternatives. Firstly, a double wall configuration for the port plug frame responds to homogeneous baking requirements at 240 °C. Secondly, an alternative frame is presented with a single wall in sections that do not require active cooling. The blanket shield module (BSM) is designed as a double-wall housing with a first wall panel (FWP) and individual shield blocks respecting the open space for the mm-wave beams. The cut-out sections to the design of the FWP and the neighbouring lower regular blanket module are defined for the beams of the actual front steering model. The thermo-mechanical stresses of the FWP and the BSM housing caused by nuclear heating and plasma radiation were analysed for the more severe case of the earlier remote steering (“3/8 RS”) reference model. As a result of the calculations for stationary loads and for transient loads during a typical plasma burn of 400 s, no critical stresses have to be expected in the BSM housing.