Bremen 2017 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 15: Helmholtz Graduate School II
P 15.19: Poster
Dienstag, 14. März 2017, 16:30–18:30, HS Foyer
Determining fundamental transport parameters of hydrogen isotopes in tungsten — •Georg Holzner1,2, Thomas Schwarz-Selinger1, and Udo von Toussaint1 — 1Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 — 2Fakultät für Maschinenwesen der Technischen Universität München, Boltzmannstr. 15, 85748
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 60s. 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 1400 and 3000K. At these temperatures trapping effects are vanishing and pure diffusion is the governing transport effect. From solubility the diffusion coefficient can be derived. Hence, an Ultra High Vacuum (UHV) experiment needs to be 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 is measured by Thermal Desorption Spectroscopy (TDS).