Author/Authors :
Roth، نويسنده , , J. and Alimov، نويسنده , , V.Kh. and Golubeva، نويسنده , , A.V. and Doerner، نويسنده , , R.P. and Hanna، نويسنده , , J. and Tsitrone، نويسنده , , E. and Brosset، نويسنده , , Ch. and Rohde، نويسنده , , V. and Herrmann، نويسنده , , A. and Mayer، نويسنده , , M.، نويسنده ,
Abstract :
Plasma-facing carbon fibre composites (CFC) are used for Tore Supra (CFC N11), ASDEX Upgrade (CFC DMS 701) and foreseen for ITER (CFC NB31). Therefore, deuterium retention in the CFC NB31 and N11 was studied by irradiation with 30–200 eV D ions, both from ion beams and plasma devices (PISCES-A, Magnetron plasma device), using methods of the thermal desorption spectrometry and D(3He, p)4He nuclear reaction in a resonance-like technique. It is found that at each irradiation temperatures in the range from 50 to 450 °C the amount of deuterium trapped in the CFCs increases with the ion fluence, Γ. No saturation is reached as observed in pyrolytic graphite. At room temperature the retention at high fluence increases proportional to Γ0.5. Depth profiles show that saturation occurs only within a near-surface layer corresponding to the ion range. The increase in total retention is accompanied by an increasing long profile tail extending beyond 14 μm with the D concentration above 10−1 at.% at fluences above 1024 D/m2. Analysis of CFC and fine-grain graphite tiles removed from identical strike-point positions in the outer ASDEX Upgrade divertor show an order of magnitude higher retention in the CFC and profiles extending into the bulk with concentrations of 0.1 at.% well beyond the measurable depth of 14 μm.
