Fertile material

Naturally occurring fertile materials that can be converted into a fissile material by irradiation in a reactor include: Artificial isotopes formed in the reactor which can be converted into fissile material by one neutron capture include: Some other actinides need more than one neutron capture before arriving at an isotope which is both fissile and long-lived enough to probably be able to capture another neutron and fission instead of decaying.

A fast-neutron reactor, meaning one with little or no neutron moderator and hence utilising fast neutrons, can be configured as a breeder reactor, producing more fissile material than it consumes, using fertile material in a blanket around the core, or contained in special fuel rods.

Since plutonium-238, plutonium-240 and plutonium-242 are fertile, accumulation of these and other nonfissile isotopes is less of a problem than in thermal reactors, which cannot burn them efficiently.

A subcritical reactor —regardless of neutron spectrum— can also "breed" fissile nuclides from fertile material, allowing in principle the consumption of very low grade actinides (e.g.

If in situ resource utilization is desired to fuel nuclear power plants on the moon, converting fertile material to fissile material could be a way to make the resources last longer and to reduce the need for uranium enrichment which requires the chemically aggressive volatile fluorine to prepare uranium hexafluoride as used in the current enrichment technology.

Transmutation flow between 238 U and 245 Cm in LWR . [ 1 ] Speed of transmutation varies greatly by nuclide, and percentages are relative to total transmutation and decay. After removal of fuel from reactor, decay will predominate for shorter-lived isotopes such as 238 Pu, 241 Pu, 242–244 Cm; but 245–248 Cm are all long-lived.