Behaviour of Li2ZrO3 and Li2TiO3 pebbles relevant to their utilization as ceramic breeder for the HCPB blanket

Li2ZrO3 and Li2TiO3 pebbles are being investigated at. Commissariat q l'Ene rgie Atomique as candidate alternative ceramics for the European helium-coo led pebble bed (HCPB) blanket. The pebbles are fabricated using the extrusi on-spheronization-sintering process and are optimized regarding composition , geometrical characteristics, microstructural characteristics, and materia l purity. Tests were designed and are being performed with other organizati ons so as to check the functional performance of the pebbles and pebble bed s with respect to the HCPB blanket requirements, and, finally, to make the selection of the most appropriate ceramic for the HCPB blanket. Tests inclu de high temperature long-term annealing, thermal shock, thermal cycling, th ermal mechanical behaviour of pebble beds, thermal conductivity of pebble b eds, and tritium extraction. Current results indicate the attractiveness of these ceramics pebbles for the HCPB blanket. (C) 2000 Elsevier Science B.V . All rights reserved.