(Science: radiobiology) proposed nuclear reactor relying on both fusion and fission reactions. A central fusion chamber would produce neutrons to induce fission in a surrounding blanket of fissionable material.
The neutron source could also be used to convert other materials into additional fissile fuels (breeder hybrid). Safer than a plain fission reactor because the fission fuel relies on the fusion neutrons, and therefore cannot achieve criticality.
on the other hand, hybrids are more complex because of the fusion power core, and still generate fission's radioactive byproducts. But a fusion-fission hybrid could be more economical and have less stringent technical requirements than a pure fusion reactor.