| fissile | Capable of being split, cleft, or divided in the direction of the grain, like wood, or along natural planes of cleavage, like crystals. "This crystal is a pellucid, fissile stone." (Sir I. Newton) Origin: L. Fissilis, fr. Fissus, p.p. Of findere to split. See Fissure. Source: Websters Dictionary (01 Mar 1998) |
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| fissile material | <radiobiology> Material containing a large number of easily fissionable nuclei which give off multiple neutrons in the fission process. Usual meaning is that if a sufficiently large amount of fissile material is put together, a fission chain reaction can occur. Sometimes used synonymously with fissionable material, i.e., material that can be fissioned (though often under restricted circumstances, such as only with thermal (slow) neutrons). A more restricted meaning use of fissile material limits the concept to those materials which can be fissioned by neutrons of all energies (fast & slow). Examples include Uranium-235 and Plutonium-239. (09 Oct 1997) |