Structural integrity assessment of an ITER ECH&CD Upper Launcher mirror (LM1)

摘要

The Lower Mirror one (LM1) is part of the in-vessel quasi-optical beam propagation system for the ITER Electron Cyclotron (EC) Upper Launcher (UL), in which each of eight gaussian beams of mm-waves is reflected by a group of four mirrors and radiated into the plasma. Ohmic losses at the mirror surfaces with 60'000 thermal cycles are foreseen at frequencies lower than 3 Hz and power levels up to 1.31 MW per beam.This paper reports the means used to accurately ascertain resistance against the following failure modes: 1) plastic collapse, 2) thermal fatigue and 3) ratcheting. Analyses are carried out in accordance with the design-by-analysis approach. Thermo-mechanical effects are investigated via finite elements to support the assessment during the thermal cycle.This structural integrity study of the LM1 mirror using the American Standard of Mechanical Engineer code (ASME) for pressure vessels and piping confirms the compliance of the proposed design for the Normal Operation (NO) scenario.