Nuclear reactorSee 'reactor'. which generates fissile materialAny substance which can be fissioned by neutrons, during whi..., but less than it uses. This term is also used for a reactorSystem used to initiate, maintain and control a fission chai... that generates fissile materialAny substance which can be fissioned by neutrons, during whi... which differs from the spent fuelSee 'nuclear fuel'.. In both meanings the process is called conversionIn nuclear technology the conversion of a substance in a fis.... (See also ‘breedingConversion of non-fissionable into fissionable material, e.g... reactor’)