Measurements of effective thermal conductivity of ceramic breeder pebble beds

The use of lithium ceramic pebble beds in the design of blankets for fusion reactors makes the mechanical and thermal properties of ceramic pebble beds key issues to be investigated. In the last years measurements of the effective thermal conductivity of lithium oxide, lithium orthosilicate, lithium metatitanate and lithium metazirconate pebble beds were performed at the Research Centre of Karlsruhe (Germany), at University of California (USA) and at JAERI (Japan). The measurements performed at FZK and at UCLA were based on steady-state methods, at JAERI a transient method (Hot wire method) was used instead. In the present paper, the results from these experiments are compared and discussed.