426:
the fuel after just 90 days of use. Such rapid fuel cycles are highly impractical for civilian power reactors and are normally only carried out with dedicated weapons plutonium production reactors. Plutonium from spent civilian power reactor fuel typically has under 70% Pu and around 26%
445:, the rest being made up of other plutonium isotopes, making it more difficult to use it for the manufacturing of nuclear weapons. For nuclear weapon designs introduced after the 1940s, however, there has been considerable debate over the degree to which
331:
are more likely to absorb a neutron, and can undergo fission upon neutron absorption more easily than isotopes of even mass number. Thus, even mass isotopes tend to accumulate, especially in a
631:
The energy yield of a nuclear explosive decreases by one and two orders of magnitude if the 240 Pu content increases from 5 (nearly weapons-grade plutonium) to 15 and 25%, respectively
1050:
343:
The inevitable presence of some Pu in a plutonium-based nuclear warhead core complicates its design, and pure Pu is considered optimal. This is for a few reasons:
323:), but only a tiny thermal neutron fission cross section (0.064 barns). When the isotope Pu captures a neutron, it is about 4500 times more likely to become
355:
will cause it to detonate almost immediately, even before it has been crushed to an optimal configuration. The presence of Pu would thus randomly cause
500:
Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert
Hendrik (December 2003). "The Nubase evaluation of nuclear and decay properties".
684:
659:
253:
Pu undergoes spontaneous fission as a secondary decay mode at a small but significant rate. The presence of Pu limits plutonium's use in a
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Isotopes besides Pu produce more decay heat, which can cause phase change distortions of the precision core if allowed to build up.
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where the assembly occurs in a few microseconds. Even with this design, it was estimated in advance of the
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869:"The Effect of the Spontaneous Fission of Plutonium-240 on the Energy Release in a Nuclear Explosive"
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423:
522:
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Isotopes besides Pu release significantly more radiation, which complicates its handling by workers.
832:
Hoddeson, Lillian (1993). "The
Discovery of Spontaneous Fission in Plutonium during World War II".
348:
239:
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that Pu impurity would cause a 12% chance of the explosion failing to reach its maximum yield.
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prematurely, causing an early release of energy that physically disperses the core before full
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701:"Actinide data: Thermal neutron cross sections, resonance integrals, and Westcott factors"
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Atlas of neutron resonances : resonance parameters and thermal cross sections Z=1-100
332:
294:
286:
282:
797:
Chamberlain, O.; Farwell, G. W.; Segrè, E. (1954). "Pu-240 and Its
Spontaneous Fission".
389:
configuration can take up to a millisecond to complete, and made it necessary to develop
898:Şahi̇n, Sümer (1978). "The effect of Pu-240 on neutron lifetime in nuclear explosives".
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513:
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Symposium to
Commemorate the 50th Anniversary of the Discovery of Transuranium Elements
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The spontaneous fission problem was extensively studied by the scientists of the
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611:"Remarks On The Plutonium-240 Induced Pre-Ignition Problem In A Nuclear Device"
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Audi, Georges; Wapstra, Aaldert
Hendrik; Thibault, Catherine (December 2003).
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Mark, J. Carson; Hippel, Frank von; Lyman, Edward (2009-10-30).
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351:. A single stray neutron that is introduced while the core is
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NLM Hazardous
Substances Databank – Plutonium, Radioactive
834:
Historical
Studies in the Physical and Biological Sciences
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poses a barrier for weapons construction; see the article
300:
The isotope Pu has about the same thermal neutron capture
589:"Emilio Segre, Enrico Fermi, Pu-240, and the atomic bomb"
359:, with an explosive yield well below the potential yield.
289:; the remainder of the time, it forms Pu. The longer a
652:
Nuclear Energy: Principles, Practices, and
Prospects
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50:
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741:"Explosive Properties of Reactor-Grade Plutonium"
648:"Nuclear Bombs, Nuclear Energy, and Terrorism"
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327:than to fission. In general, isotopes of odd
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654:. Springer Science & Business Media.
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381:nuclear weapons in which the assembly of
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246:and had important consequences for the
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867:Şahin, Sümer; Ligou, Jacques (1980).
377:. It blocked the use of plutonium in
281:About 62% to 73% of the time when Pu
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550:"The Ame2003 atomic mass evaluation"
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422:(less than 7% Pu) is achieved by
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574:10.1016/j.nuclphysa.2003.11.003
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1:
748:Science & Global Security
912:10.1016/0306-4549(78)90104-4
56:plutonium-240, 240Pu, Pu-240
705:Nuclear Data for Safeguards
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675:Mughabghab, S. F. (2006).
188:Complete table of nuclides
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768:10.1080/08929880903368690
265:is reached. It decays by
182:
900:Annals of Nuclear Energy
646:Bodansky, David (2007).
760:2009S&GS...17..170M
679:. Amsterdam: Elsevier.
587:Farwell, G. W. (1990).
465:Reactor-grade plutonium
420:weapons-grade plutonium
391:implosion-style weapons
238:. The detection of its
819:10.1103/PhysRev.94.156
347:Pu has a high rate of
31:Plutonium-240, Pu
1123:Isotopes of plutonium
1061:isotopes of plutonium
609:Şahin, Sümer (1981).
482:Isotopes of plutonium
293:element remains in a
184:Isotopes of plutonium
948:Plutonium-240 is an
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27:Isotope of plutonium
811:1954PhRv...94..156C
566:2003NuPhA.729..337A
514:2003NuPhA.729....3A
349:spontaneous fission
240:spontaneous fission
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873:Nuclear Technology
615:Nuclear Technology
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283:captures a neutron
277:Nuclear properties
130:6561(7) years
1128:Fertile materials
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686:978-0-08-046106-9
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271:uranium-236
234:captures a
178:5.25575(14)
173:Alpha decay
149:Decay modes
1112:Categories
979:curium-244
805:(1): 156.
714:2016-09-11
488:References
244:Los Alamos
155:Decay mode
1118:Actinides
961:Heavier:
956:plutonium
939:Lighter:
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776:0892-9882
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263:implosion
228:plutonium
115:Half-life
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471:See also
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379:gun-type
222:) is an
79:Neutrons
952:isotope
807:Bibcode
756:Bibcode
562:Bibcode
510:Bibcode
373:during
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304:as Pu (
287:fission
236:neutron
224:isotope
62:Protons
36:General
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42:Symbol
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