The surrounding blanket can be a fissile material ( enriched uranium or plutonium ) or a fertile material ( capable of conversion to a fissionable material by neutron bombardment ) such as thorium, depleted uranium or spent nuclear fuel.
32.
Almost every other episode of " The Simpsons " wrings more laughs out of the fertile material of a venal, corrupt children's-show host who goes through money faster than a gambler on a cold streak than the new satire " Death to Smoochy ."
33.
With this embarrassment of fertile material, it's hard not to imagine what a director like Peter Weir or Sydney Pollack or Goldman's old partner, George Roy Hill, would do with this movie : what a classic of adventure, history and environmental mysticism it might have been.
34.
Using steel reflectors instead of U-238 blankets, the reactor operates in pure burner mode and is not a net creator of fissile material; on balance it will consume fissile and fertile material and, assuming loss-free reprocessing, output no actinides but only fission products and activation products.
35.
After the reactor is started, four zones form within the core : the depleted zone, which contains mostly fission products and leftover fuel; the fission zone, where fission of bred fuel takes place; the breeding zone, where fissile material is created by neutron capture; and the fresh zone, which contains unreacted fertile material.
36.
It is not fissile, but is a fertile material : it can capture a slow neutron and after two beta decays become fissile plutonium-239 . Uranium-238 is fissionable by fast neutrons, but cannot support a chain reaction because inelastic scattering reduces neutron energy below the range where fast fission of one or more next-generation nuclei is probable.
