Deuterium trapping and release in JET ITER-like wall divertor tiles

Selected set of samples from JET-ILW divertor tiles exposed in 2011-2012 has been analysed using thermal desorption spectrometry (TDS).The highest amount of deuterium was found on the regions with the thickest deposited layers, i.e. on the High Field Gap Closure (HFGC) tile and on the apron and top part of Tile 1, which resides deep in the scrape-off layer.Outer divertor Tiles 6, 7 and 8 had nearly an order of magnitude less deuterium.The remaining fractions of D in the analysed samples at ITER baking temperature 350 o C are rather high implying that co-deposited films may be difficult to be de-tritiated.In these cases other cleaning techniques such as oxygen discharges, laser/flash lamp heating or arcdischarge cleaning may have to be considered.Experimental TDS spectra for samples from the top horizontal and sloping parts of Tile 6 were modelled using TMAP program.Reasonable agreement between experimental and TMAP calculations was obtained.