Microanalysis of deposited layers in the inner divertor of JET with ITER-like wall

Y. Zhou, H. Bergsåker, I. Bykov, P. Petersson, G. Possnert, J. Likonen, J. Pettersson, S. Koivuranta, A. Widdowson

    Research output: Contribution to journalArticleScientificpeer-review

    Abstract

    In JET with ITER-like wall, beryllium eroded in the main chamber is transported to the divertor and deposited mainly at the horizontal surfaces of tiles 1 and 0 (high field gap closure, HFGC). These surfaces are tungsten coated carbon fibre composite (CFC). Surface sampleswere collected following the plasma operations in 2011-2012 and 2013-2014 respectively. The surfaces, as well as polished cross sections of the deposited layers at the surfaces have been studied with micro ion beam analysis methods (µ-IBA).Deposition of Beand other impurities, and retention of D is microscopically inhomogeneous. Impurities and trapped deuterium accumulate preferentially in cracks, pits and depressed regions, and at the sides of large pits in the substrate (e.g. arc tracks where the W coating has been removed). With careful overlaying of µ-NRA elemental maps with optical microscopy images, it is possible to separate surface roughness effects from depth profiles at microscopically flat surface regions.
    Original languageEnglish
    Pages (from-to)412-417
    Number of pages6
    JournalNuclear Materials and Energy
    Volume12
    Early online date2017
    DOIs
    Publication statusPublished - 1 Aug 2017
    MoE publication typeA1 Journal article-refereed

    Keywords

    • carbon
    • carbon fibers
    • fusion reactor divertors
    • Ion beams
    • surface roughness
    • deposited layer
    • elemental maps
    • flat surfaces
    • horizontal surfaces
    • Ion beam analysis
    • plasma operations
    • surface roughness effects
    • tungsten coated carbon

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  • Cite this

    Zhou, Y., Bergsåker, H., Bykov, I., Petersson, P., Possnert, G., Likonen, J., Pettersson, J., Koivuranta, S., & Widdowson, A. (2017). Microanalysis of deposited layers in the inner divertor of JET with ITER-like wall. Nuclear Materials and Energy, 12, 412-417. https://doi.org/10.1016/j.nme.2017.02.015