Erlangen 2018 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 20: Plasma Wall Interaction II - Poster
P 20.8: Poster
Mittwoch, 7. März 2018, 16:15–18:15, Zelt West
Determining fundamental transport parameters of hydrogen isotopes in tungsten — •G. Holzner1,2, T. Schwarz-Selinger1, Udo von Toussaint1, and F. Hindenlang1 — 1Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, 85748 Garching — 2Technische Universität München, Boltzmannstraße 15, 85748 Garching
Future fusion devices will use the hydrogen isotopes deuterium and tritium as fuel. The first-wall material probably will be tungsten for which retention and transport of hydrogen isotopes needs to be predicted. The key quantity for transport is the diffusion coefficient. The generally accepted value for diffusion of protium in tungsten stems from Frauenfelder derived in the late 60ies. Experimental values determined since scatter by several orders of magnitude, trapping effects are presumably the reason. However, recent simulations even question the Frauenfelder value. Furthermore, that experimental value was not derived for deuterium.
The objective is to measure the solubility of protium and deuterium in tungsten at temperatures between 1200 and 3000 K. At these temperatures, trapping effects are insignificant and diffusion is the governing transport effect. From solubility, the diffusion coefficient can be derived. Hence, an Ultra High Vacuum (UHV) experiment was planned and established. An induction furnace in combination with a water-cooled quartz glass container is used for conditioning by gas loading at pressures of up to one atmosphere. Following the spectra of the gas species in solution are measured by Thermal Desorption Spectroscopy (TDS).