From Longman Dictionary of Contemporary Englishfissilefis‧sile /ˈfɪsaɪl $ -səl/ adjective technical HPable to be split by atomic fission
Examples from the Corpus
fissile• This was done because in theory fusion neutrons could be an alternative to fission reactors for making fissile elements for weapons.• It won't need anything as big and expensive as a nuclear power station to provide the fissile material.• There is a pressing case for the nuclear nations to deny fissile materials to would be customers.• The military bomb boys can churn out their own fissile materials without difficulty.Origin fissile (1600-1700) Latin fissilis, from fissus; → FISSION 