Speaker
Simone Pupeschi
(Institute for Applied Materials (IAM))
Description
All solid breeder concepts, considered to be tested in ITER, make use of lithium-based ceramics in the form of pebble-packed beds as tritium breeder. A thorough understanding of the effective thermal conductivity of the ceramic breeding pebble beds in fusion relevant conditions is essential for the design of the breeder blanket modules of the future fusion reactors. An experimental set-up for the investigation of the effective thermal conductivity of ceramic pebble beds was designed and assembled. The hot wire method was selected to measure the thermal conductivity of ceramic pebble beds. Measurements of the effective thermal conductivity of polydispersed lithium orthosilicate pebble beds with different lithium metatitanate contents were performed. The EU reference tritium breeding material was investigated as well. The effective thermal conductivity was investigated in the temperature range between RT and 600 °C. Experiments were performed in helium atmosphere in the pressure range 0.12-0.4 MPa with a compressive load up to 6 MPa. The initial packing factor of the beds was approx. 64 %. The results show no significant influence of the chemical composition of the solid material on the bed’s effective thermal conductivity. An increase of the effective thermal conductivity with the temperature was observed for all investigated compositions. The results show a slight increase of the effective thermal conductivity with the applied load. The halving of the helium pressure results in a slight reduction of the effective thermal conductivity at all investigated temperatures. However, the reduction of the helium pressure from 0.4 to 0.12 MPa leads to a significant reduction of the bed’s effective thermal conductivity.
Co-authors
Marc Kamlah
(Institute for Applied Materials (IAM), Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany)
Regina Knitter
(Institute for Applied Materials (IAM), Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany)
Simone Pupeschi
(Institute for Applied Materials (IAM), Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany)
