Back Plutoni 240 Catalan Plutonium-240 Czech Πλουτώνιο-240 Greek پلوتونیم-۲۴۰ FA Plutonium 240 French प्लूटोनियम-२४० HI Plutonium-240 ID プルトニウム240 Japanese Plutônio-240 Portuguese Плутоний-240 Russian
| General | |
|---|---|
| Symbol | 240Pu |
| Names | plutonium-240, 240Pu, Pu-240 |
| Protons (Z) | 94 |
| Neutrons (N) | 146 |
| Nuclide data | |
| Natural abundance | Trace |
| Half-life (t1/2) | 6561(7) years[1] |
| Isotope mass | 240.0538135(20)[2] Da |
| Decay modes | |
| Decay mode | Decay energy (MeV) |
| Alpha decay | 5.25575(14)[2] |
| Isotopes of plutonium Complete table of nuclides | |
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.[3]
240Pu undergoes spontaneous fission as a secondary decay mode at a small but significant rate. The presence of 240Pu limits plutonium's use in a nuclear bomb, because the neutron flux from spontaneous fission initiates the chain reaction prematurely, causing an early release of energy that physically disperses the core before full implosion is reached.[4][5] It decays by alpha emission to uranium-236.
- ^ Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (December 2003). "The Nubase evaluation of nuclear and decay properties". Nuclear Physics A. 729 (1): 3–128. Bibcode:2003NuPhA.729....3A. CiteSeerX 10.1.1.692.8504. doi:10.1016/j.nuclphysa.2003.11.001.
- ^ a b Audi, Georges; Wapstra, Aaldert Hendrik; Thibault, Catherine (December 2003). "The Ame2003 atomic mass evaluation". Nuclear Physics A. 729 (1): 337–676. Bibcode:2003NuPhA.729..337A. doi:10.1016/j.nuclphysa.2003.11.003.
- ^ Farwell, G. W. (1990). "Emilio Segre, Enrico Fermi, Pu-240, and the atomic bomb". Symposium to Commemorate the 50th Anniversary of the Discovery of Transuranium Elements.
- ^ Cite error: The named reference
:1was invoked but never defined (see the help page). - ^ Bodansky, David (2007). "Nuclear Bombs, Nuclear Energy, and Terrorism". Nuclear Energy: Principles, Practices, and Prospects. Springer Science & Business Media. ISBN 978-0-387-26931-3.