Investigation of tungsten-coated divertor tiles at the JET tokamak with the ITER‐Like Wall

Materials migration in fusion plasma devices and fuel retention in plasma-facing components are issues of great importance for the safe operation of fusion devices. The underlying mechanisms require a good understanding in order to make predictions regarding the lifetime of wall components and to assess the amount of fuel retained in the machine mainly in co-deposited layers. To reduce fuel inventory and to investigate plasma-wall interactions a large-scale experiment at the JET (Joint European Torus) tokamak is realized: operation with the ITER-Like Wall (JET-ILW) which comprises beryllium and tungsten. The current work reports on the post-mortem analysis of W/CFC tiles retrieved after the first deuterium-deuterium campaign at JET-ILW. Specimens from different areas of the divertor have been analyzed by means of several techniques including nuclear reaction analysis and Rutherford backscattering employing a deuterium beam. In addition, X-ray fluorescence spectroscopy and scanning electron microscopy with energy dispersive X-ray analysis are used to assess the sample surface morphology and analyze the stoichiometry of the surface of the samples in order to compare with the results from the ion beam analytical techniques.