Hochwaermeflussverhalten von Berylliummaterialien und -komponenten fuer zukuenftige Fusionsreaktoren

Plasma facing materials and components for future fusion devices are subjected to high thermal and thermomechanical loads due to radiation and particle bombardment from the burning plasma. Beryllium is a plasma compatible and therefore promising candidate material for plasma interfacing components for fusion reactors. In this work the behaviour of beryllium materials and components is investigated. Short time, pulsed high heat flux loading (thermal shock), as occurring during plasma instabilities like disruptions in tokamak operation, as well as slow cyclic high heat flux loading, as expected in the normal operation of tokamak type fusion reactors is considered. High heat flux simulation experiments using electron beam irradiation were performed. Resulting temperature and stress distributions in the material were estimated by analytical and numerical methods, including finite element modeling. A swelling effect of beryllium surfaces near the lower relevant heat flux bound could be detected by precise metallographic and profilometric examinations of the test samples. Mass loss and volume changes of beryllium test samples could be determined as a function of high heat flux loading parameters. A numerical model has been established, tested and successfully applied to thermal shock simulation on extremely short time scales especially for the thermal response of beryllium. (orig.)Dissertation submitted by Schuster, A., 243 refs.Available from TIB Hannover: RA 831(3437) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman