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Weapons grade plutonium (with greater than 90% 239 Pu) is used to make nuclear weapons and has many advantages over other fissile material for that purpose. Lower proportions of 239 Pu would make a reliable weapon design difficult or impossible; this is due to the spontaneous fission (and thus neutron production) of the undesirable 240 Pu.
Weapons-grade plutonium is defined as being predominantly Pu-239, typically about 93% Pu-239. [24] Pu-240 is produced when Pu-239 absorbs an additional neutron and fails to fission. Pu-240 and Pu-239 are not separated by reprocessing. Pu-240 has a high rate of spontaneous fission, which can cause a nuclear weapon to pre-detonate. This makes ...
But since plutonium-breeding reactors produce plutonium from U238, and thorium reactors produce fissile U233 from thorium, all breeding cycles could theoretically pose proliferation risks. [61] However U-232, which is always present in U-233 produced in breeder reactors, is a strong gamma-emitter via its daughter products, and would make weapon ...
Fission product yields by mass for thermal neutron fission of U-235 and Pu-239 (the two typical of current nuclear power reactors) and U-233 (used in the thorium cycle). This page discusses each of the main elements in the mixture of fission products produced by nuclear fission of the common nuclear fuels uranium and plutonium.
239 Pu is virtually nonexistent in nature. It is made by bombarding uranium-238 with neutrons. Uranium-238 is present in quantity in most reactor fuel; hence 239 Pu is continuously made in these reactors. Since 239 Pu can itself be split by neutrons to release energy, 239 Pu provides a portion of the energy generation in a nuclear reactor.
Plutonium-239, bred from uranium-238 by neutron capture with intermediate decays steps omitted. Plutonium-241 , bred from plutonium-240 directly by neutron capture. Fissile nuclides do not have a 100% chance of undergoing fission on absorption of a neutron.
The odd numbered fissile plutonium isotopes present in spent nuclear fuel, such as Pu-239, decrease significantly as a percentage of the total composition of all plutonium isotopes (which was 1.11% in the first example above) as higher and higher burnups take place, while the even numbered non-fissile plutonium isotopes (e.g. Pu-238, Pu-240 and ...
The "reactor-grade" plutonium produced by a regular LWR burnup cycle typically contains less than 60% Pu-239, with up to 30% parasitic Pu-240/Pu-242, and 10–15% fissile Pu-241. [127] It is unknown if a device using plutonium obtained from reprocessed civil nuclear waste can be detonated, however such a device could hypothetically fizzle and ...