Search results
Results from the WOW.Com Content Network
Uranium-238 (238 U or U-238) is the most common isotope of uranium found in nature, with a relative abundance of 99%. Unlike uranium-235, it is non-fissile, which means it cannot sustain a chain reaction in a thermal-neutron reactor. However, it is fissionable by fast neutrons, and is fertile, meaning it can be transmuted to fissile plutonium-239.
Consequently, uranium-238 is fissionable but not fissile. [4] [5] An alternative definition defines fissile nuclides as those nuclides that can be made to undergo nuclear fission (i.e., are fissionable) and also produce neutrons from such fission that can sustain a nuclear chain reaction in the correct setting.
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.
All three isotopes are radioactive (i.e., they are radioisotopes), and the most abundant and stable is uranium-238, with a half-life of 4.4683 × 10 9 years (about the age of the Earth). Uranium-238 is an alpha emitter, decaying through the 18-member uranium series into lead-206.
Approximately 2.2% of its radioactivity comes from uranium-235, 48.6% from uranium-238, and 49.2% from uranium-234. Natural uranium can be used to fuel both low- and high-power nuclear reactors . Historically, graphite-moderated reactors and heavy water -moderated reactors have been fueled with natural uranium in the pure metal (U) or uranium ...
Uranium-238 is predominantly an alpha emitter, decaying to thorium-234. It ultimately decays through the uranium series , which has 18 members, into lead-206 . [ 17 ] Uranium-238 is not fissile, but is a fertile isotope, because after neutron activation it can be converted to plutonium-239, another fissile isotope.
Some atoms, notably uranium-238, do not usually undergo fission when struck by slow neutrons, but do split when struck with neutrons of high enough energy. [1] The fast neutrons produced in a hydrogen bomb by fusion of deuterium and tritium have even higher energy than the fast neutrons produced in a nuclear reactor. This makes it possible to ...
Fission by-products produced by the operation of commercial light-water nuclear reactors are long-lived and highly radioactive, but they can be consumed using the excess neutrons in the fusion reaction along with the fissionable components in the blanket, essentially destroying them by nuclear transmutation and producing a waste product which ...