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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 ...
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 ...
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
Many of the fission products with mass 147 or greater such as 147 Pm, 149 Sm, 151 Sm, and 155 Eu have significant cross sections for neutron capture, so that one heavy fission product atom can undergo multiple successive neutron captures. Besides fission products, the other types of radioactive products are
Trace amounts of plutonium-238, plutonium-239, plutonium-240, and plutonium-244 can be found in nature. Small traces of plutonium-239, a few parts per trillion , and its decay products are naturally found in some concentrated ores of uranium, [ 54 ] such as the natural nuclear fission reactor in Oklo , Gabon . [ 55 ]
Long-lived fission products (LLFPs) are radioactive materials with a long half-life (more than 200,000 years) produced by nuclear fission of uranium and plutonium.Because of their persistent radiotoxicity, it is necessary to isolate them from humans and the biosphere and to confine them in nuclear waste repositories for geological periods of time.
Decay chain of 240 Pu. Plutonium-240 (240 Pu or Pu-240) is an isotope of plutonium formed when plutonium-239 captures a neutron.The detection of its spontaneous fission led to its discovery in 1944 at Los Alamos and had important consequences for the Manhattan Project.