Deuterium trapping indivertor tiles at ASDEX-upgrade
The report discusses surface analysis and thermodesorption as methods for studying the gas content of inner wall components of fusion devices. The following problems are considered: (I) calibration of the thermodesorption, (ii) parasitic adsorption and reaction of released gases at inner walls of the of the analysing chamber, (iii) gas absorption during storage of the samples in air, (iv) influence of the surface morphology, and (v) influence of deposited layers of carbon and boron. A large number of tiles from the inner and outer divertor of ASDEX-Upgrade have been studied. The tiles consisted of pure graphite, massive tungsten, and graphite with sprayed tungsten coatings.Large regions of the inner divertor tiles show thick deposition layers of carbon, boron and the hydrogenic isotopes containing up to 12(23) deuterium atoms/m2 in the regions of the outer divertor, where erosion processes prevail, the gas content is less by about one order of magnitude, depending in a complicated way on the surface structure and being laterally inhomogeneous. Codeposition trapping is favoured by the surface roughness even in the erosion zones.
Bibliographic Reference: Article: Deuterium trapping in divertor tiles at ASDEX-upgrade, 1998, 1-19
Record Number: 199910297 / Last updated on: 1999-03-12
Original language: en
Available languages: en