Beryllium is considered to be basically an excellent material for moderators and reflectors in nuclear reactors, because of its nuclear properties and many of its other physical and mechanical properties.

A test reactor that utilizes beryllium is generally designed to include a “moderator” material to reduce the energy of “fast” neutrons to the extent that they become “thermal” neutrons that are desirable for sustaining the fission process.

Beryllium and beryllium oxide are attractive candidate materials for neutron reflector application in space reactors due to their beneficial combination of low density and high neutron moderation and reflection capabilities.