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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.
Plutonium-240, in addition to being a neutron emitter after fission, is a gamma emitter, and so is responsible for a large fraction of the radiation from stored nuclear weapons. Whether out on patrol or in port, submarine crew members routinely live and work in very close proximity to nuclear weapons stored in torpedo rooms and missile tubes ...
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
The fission cross section for 239 Pu is 747.9 barns for thermal neutrons, while the activation cross section is 270.7 barns (the ratio approximates to 11 fissions for every 4 neutron captures). The higher plutonium isotopes are created when the uranium fuel is used for a long time.
The high short-term radioactivity of spent nuclear fuel is primarily from fission products with short half-life.The radioactivity in the fission product mixture is mostly due to short-lived isotopes such as 131 I and 140 Ba, after about four months 141 Ce, 95 Zr/ 95 Nb and 89 Sr constitute the largest contributors, while after about two or three years the largest share is taken by 144 Ce/ 144 ...
The sum of the atomic mass of the two atoms produced by the fission of one fissile atom is always less than the atomic mass of the original atom. This is because some of the mass is lost as free neutrons, and once kinetic energy of the fission products has been removed (i.e., the products have been cooled to extract the heat provided by the reaction), then the mass associated with this energy ...
PUREX is applied to spent nuclear fuel, which consists primarily of very high atomic-weight (actinoid or "actinide") elements (e.g. uranium, plutonium, americium) along with smaller amounts of material composed of lighter atoms, notably the fission products produced by reactor operation. A simplified plutonium extraction flow chart.
As opposed to the standard practice worldwide of PUREX separation, plutonium is not separated on its own in this pilot-scale, reprocessing cycle, rather all actinides are "electro-won" or "refined" from the "true waste" of fission products in spent fuel. The plutonium therefore instead comes over mixed with all the gamma and alpha emitting ...