Fatigue life assessment in lateral support element of a magnet for nuclear fusion experiment 'Wendelstein 7-X'

摘要

Wendelstein 7-X (W7X), a nuclear fusion experiment of modular stellarator type, started operation in 2015 and will be upgraded with a water cooled first wall for steady state operation in 2020. A hot hydrogen plasma of ultra-low density is confined in a plasma vessel by an electromagnetic field generated by specially shaped superconducting coils. Such coils, embedded in a cryostat working at 4 K, are kept by a central support ring and joined together by welded lateral support elements (LSEs). In this paper, a coupled FEM-DBEM (Dual BEM) submodelling approach is adopted for crack-growth simulations of the cracks detected in LSEs and driven by a fatigue load spectra.