Structural analysis of a prototype fast shutter for ITER cCXRS diagnostic

Abstract

Optical lifetime of the first mirror is a critical issue for the ITER upper port plug core charge exchange spectroscopy diagnostic (cCXRS). A fast shutter is engaged to protect the mirror from depositions between measurements. The prototype shutter will be examined in a test vacuum vessel that is now under development in the Forschungszentrum Jülich, Germany. Being located near the plasma, the shutter operates under severe thermal and electromagnetic (EM) loads. The multi-field analyses conducted for the shutter are presented in the paper. Since the fast shutter can operate within 1 second, its static structural analysis should be accompanied by dynamic studies. The paper pays attention to numerical strategy used for a multi-field ANSYS modeling of a complex structure. The shutter structural performance under the service, thermal and EM loading is in line with requirements. Solution for a problem of high local thermo-stresses revealed by the analysis is proposed. Problems connected with other possible port plug - shutter layouts are discussed.