Electromagnetic modeling and subsequent structural analysis for ITER core CXRS upper port plug diagnostic structure

Abstract

The upper port of the ITER vacuum vessel contains the core charge exchange spectroscopy (cCXRS) port plug diagnostic system. Electromagnetic (EM) loads caused by plasma transients are critical for the port plug. An ANSYS 3D EM model of the ITER magnet system, addressing main port plug features (conceptual design 2009), was developed by Forschungszentrum Jülich (FZJ). EM forces on main plug components have been calculated and main integral mechanical moments are represented. Two external contracts on independent global EM models were launched and are being successfully benchmarked against the FZJ model. In support of the cCXRS design its components are structurally analyzed under EM loading. Four different approaches to calculate EM loads for detailed structural models have been used and are described. One of them, called an “express” analysis, allows a prompt choice between different design solutions. The “air” elements, which should fill gaps between assembled conducting parts in the electromagnetic FE models, are neglected in this approach. This may save up to 90% of time for building and calculating complex EM models. Applicability and use of this method for small critical plug components like a fast shutter are demonstrated in this paper.