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Title: Material migration studies with an ITER first wall panel proxy on EAST

The ITER beryllium (Be) first wall (FW) panels are shaped to protect leading edges between neighbouring panels arising from assembly tolerances. This departure from a perfectly cylindrical surface automatically leads to magnetically shadowed regions where eroded Be can be re-deposited, together with co-deposition of tritium fuel. To provide a benchmark for a series of erosion/re-deposition simulation studies performed for the ITER FW panels, dedicated experiments have been performed on the EAST tokamak using a specially designed, instrumented test limiter acting as a proxy for the FW panel geometry. Carbon coated molybdenum plates forming the limiter front surface were exposed to the outer midplane boundary plasma of helium discharges using the new Material and Plasma Evaluation System (MAPES). Net erosion and deposition patterns are estimated using ion beam analysis to measure the carbon layer thickness variation across the surface after exposure. The highest erosion of about 0.8 µm is found near the midplane, where the surface is closest to the plasma separatrix. No net deposition above the measurement detection limit was found on the proxy wall element, even in shadowed regions. The measured 2D surface erosion distribution has been modelled with the 3D Monte Carlo code ERO, using the local plasmamore » parameter measurements together with a diffusive transport assumption. In conclusion, excellent agreement between the experimentally observed net erosion and the modelled erosion profile has been obtained.« less
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  1. Chinese Academy of Sciences (CAS), Anhui (People's Republic of China)
  2. ITER Organization, St. Paul Lez Durance Cedex (France)
  3. Forschungszentrum Julich GmbH, Association EURATOM-FZJ, Julich (Germany)
  4. Univ. of Toronto Institute for Aerospace Studies, Toronto (Canada)
  5. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0029-5515; 537443
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 55; Journal Issue: 2; Journal ID: ISSN 0029-5515
IOP Science
Research Org:
Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
Country of Publication:
United States