Development of beryllide pebbles with low-hydrogen generation as advanced neutron multipliers

Hydrogen generation via an oxidation reaction of Be with water vapor at high temperatures should reduce the safety associated with fusion reactors. Advanced neutron multipliers with higher stability at high temperatures are desired as replacements for the existing Be neutron multipliers for the pebble bed blanket design using a water coolant. Beryllium intermetallic compounds (beryllides) are the most promising material for advanced neutron multipliers. In this study, prototypic beryllide pebbles, Be12Ti and Be12V, were successfully fabricated using the rotating electrode granulation method with a plasma-sintered beryllide electrode. The beryllides pebbles were much more resistant to water vapor than pure Be pebbles. The surface BeO layer on the beryllide pebbles was shown to act as a protective barrier against hydrogen generation reaction.