Multiscale modeling of thermomechanical properties of ceramic pebbles [Elektronische Ressource] / von Shuo Zhao

Multiscale Modeling of Thermomechanical Properties of Ceramic Pebbles Zur Erlangung des akademischen Grades Doktor der Ingenieurwissenschaften Der Fakultät für Maschinenbau Karlsruher Institut für Technologie (KIT) genehmigteDissertationvonM. Eng. Shuo Zhao Tag der mündlichen Prüfung: 25. Nov. 2010Hauptreferent: Prof. Dr. -Ing. habil. M. Kamlah Korreferent: Prof. Dr. rer. nat. O. Kraft AbstractCeramic pebbles are foreseen to be used as tritium breeder in helium cooled pebble bed (HCPB)blankets in fusion reactors. The pebbles will be subject to severe conditions, such as high tem-perature and irradiation. They may fail during thermomechanical loading. The failure of pebbleswill influence the macroscopic thermomechanical response of pebble beds. Moreover, fragmentsof crushed pebbles could block the evacuation of purge gas. As a result, the tritium produced inpebble beds could not be brought away for continuous fusion reaction. Therefore, it is importantto investigate the influence of pebble failure in pebble beds. As for the thermal properties ofpebble beds, the thermal stress and thermal conductivity is of big concern for the blanket design.We aim to derive the pebble strength for pebble-pebble contact like that in pebble beds. Atfirst, crush tests for single pebbles are carried out to supply the crush load for plate-pebble contact.A strength or failure model is desired to explain the influence of plate material.