Nuclear Materials and Energy (Aug 2017)

Studies of dust from JET with the ITER-Like Wall: Composition and internal structure

  • E. Fortuna-Zaleśna,
  • J. Grzonka,
  • M. Rubel,
  • A. Garcia-Carrasco,
  • A. Widdowson,
  • A. Baron-Wiechec,
  • L. Ciupiński,
  • JET Contributors

DOI
https://doi.org/10.1016/j.nme.2016.11.027
Journal volume & issue
Vol. 12
pp. 582 – 587

Abstract

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Results are presented for the dust survey performed at JET after the second experimental campaign with the ITER-Like Wall: 2013–2014. Samples were collected on adhesive stickers from several different positions in the divertor both on the tiles and on the divertor carrier. Brittle dust-forming deposits on test mirrors from the inner divertor wall were also studied. Comprehensive characterization accomplished by a wide range of high-resolution microscopy techniques, including focused ion beam, has led to the identification of several classes of particles: (i) beryllium flakes originating either from the Be coatings from the inner wall cladding or Be-rich mixed co-deposits resulting from material migration; (ii) beryllium droplets and splashes; (iii) tungsten and nickel-rich (from Inconel) droplets; (iv) mixed material layers with a various content of small (8–200nm) W-Mo and Ni-based debris. A significant content of nitrogen from plasma edge cooling has been identified in all types of co-deposits. A comparison between particles collected after the first and second experimental campaign is also presented and discussed. Keywords: Dust, JET, ITER-Like Wall, Beryllium, Tungsten, Material mixing