Bochum 2015 – scientific programme
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P: Fachverband Plasmaphysik
P 3: Plasma Wall Interactions
P 3.8: Talk
Monday, March 2, 2015, 16:25–16:40, HZO 50
Development of Smart Self-Passivating Tungsten Alloys as Passive Safety Measure for Future Fusion Reactors — •Tobias Wegener1, Andrey Litnovsky1, Jens Brinkmann1, Freimut Koch2, and Christian Linsmeier1 — 1Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung - Plasmaphysik, 42425 Jülich, Germany — 2Max-Planck-Institut für Plasmaphysik, D-85748 Garching
Due to its high melting point, low tritium retention and low erosion yield tungsten is a candidate material for the first wall of a future fusion reactor. In case of a so-called loss-of-coolant accident (LOCA) wall temperatures of about 1200 ∘C are predicted due to nuclear decay heat. The worst case scenario of the LOCA accompanied with air and water ingress, would lead to formation of highly volatile and radioactive tungsten trioxide (WO3). A solution for this issue could be smart self-passivating tungsten alloys, which may prevent the formation of WO3. Presently, ternary material systems with chromium and titanium are well characterized and show the best performance. In this contribution we show first results of new yttrium containing W-Cr-Y alloys produced by magnetron sputtering. These alloys are supposed to show oxidation rates similar to those of W-Cr-Ti, but with a higher content of W. First experiments of the new Ti-free alloy show an oxidation rate of kp=4.7·10−6 mg2 cm−2 s−1, which is about four orders of magnitude lower compared to those of pure W at 800 ∘C. Experimental results and simulations of evaporated material in the case of LOCAs will be presented.