Bremen 2017 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 24: Plasma Wall Interaction
P 24.5: Vortrag
Donnerstag, 16. März 2017, 09:45–10:00, HS 1010
Plasma exposure of W-based smart alloys for the fusion power plant — •Janina Schmitz1,2, Felix Klein1, Tobias Wegener1, Xiaoyue Tan1, Andrey Litnovsky1, and Christian Linsmeier1 — 1Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung - Plasmaphysik, 52425 Jülich — 2Department of Applied Physics, Ghent University, Ghent
Although the final design of the fusion power plant DEMO has not been specified yet, there is no doubt that the plasma-facing wall will be subject to extreme conditions.
Tungsten (W), featuring among others low tritium retention and sputter yield, is preferred as first wall material. In case of a LOCA (Loss-of-Coolant-Accident) the wall temperature rises above 1200 K for up to 3 months due to nuclear decay heat. With additional air ingress, radioactive volatile WO will be formed and its mobilisation into the environment poses a severe threat.
Smart alloys aim at suppressing the WO3-sublimation while, thanks to preferential sputtering, behaving like pure W during plasma operation. Experiments in the linear plasma device PSI-2 help understanding the plasma influence onto the developed alloys. First experiments with W-Cr-Ti alloys and pure W showed comparable sputter yields (W: 1 mg, smart alloy: 1.1 mg mass loss) and confirmed the expected depletion of the alloying elements at the plasma-facing surface. In addition, the results of studies of new W-Cr-Y-systems under plasma impact, including changes in microstructure and oxidation behaviour, will be presented and discussed.