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Decay energy from CRC bible
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Reverted my background color change -- the background color codes for half-life!
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| halflife = 87.7 years |
| halflife = 87.7 years |
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| error_halflife = |
| error_halflife = |
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| background = # |
| background = #7F7 |
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| decay_product =Uranium-234 |
| decay_product =Uranium-234 |
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| decay_mass =234 |
| decay_mass =234 |
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| General | |
|---|---|
| Symbol | 238Pu |
| Names | plutonium-238, 238Pu, Pu-238 |
| Protons (Z) | 94 |
| Neutrons (N) | 144 |
| Nuclide data | |
| Half-life (t1/2) | 87.7 years |
| Isotope mass | 238.049553 Da |
| Spin | 0 |
| Parent isotopes | 242Cm (α) 238Np (β−) 238Am (β+) |
| Decay products | 234U |
| Decay modes | |
| Decay mode | Decay energy (MeV) |
| Alpha decay | 5.593 |
| Isotopes of plutonium Complete table of nuclides | |
Plutonium-238, is a radioactive isotope of plutonium with a half-life of 87.7 years. Because it is a very powerful alpha emitter that does not emit significant amounts of other, more penetrating and thus more problematic radiation, this isotope is used for radioisotope thermoelectric generators and radioisotope heater units. One gram of plutonium-238 generates approximately 0.5 watts of power.
Plutonium-238 was the first isotope of plutonium to be discovered. It was synthesized by Glenn Seaborg and associates in 1941 by bombarding uranium-238 with deuterons. Neptunium-238 is made as an intermediate product, which then decays to form plutonium-238. Plutonium-238 decays to uranium-234 and then further along the radium seriestolead-206.
Reactor-grade plutonium from spent nuclear fuel contains various isotopes of plutonium. Pu-238 makes up only a percent or two, but may be responsible for much of the short-term decay heat because of its short halflife. This is not useful for producing Pu-238 for RTGs because difficult isotopic separation would be needed.
Pure plutonium-238 is prepared by irradiation of neptunium-237, one of the minor actinides that can be recovered from spent nuclear fuel during reprocessing, or by the irradiation of americium[1] in a reactor. In both cases, the targets are subjected to a chemical treatment, including dissolution in nitric acid to extract the plutonium-238. A 100 kg sample of light water reactor fuel that has been irradiated for three years contains only about 700 grams of neptunium-237, and the neptunium must be extracted selectively.
The United States currently has limited facilities to produce plutonium-238.[2] Since 1993, all of the plutonium-238 the U.S. has used in space probes has been purchased from Russia. 16.5 kilograms in total have been purchased.[3] The US Department of Energy is requesting funding to restart domestic production, but it is expected to take approximately 5 years to produce substantial amounts.[4]
| Lighter: Plutonium-237 |
Plutonium-238 is an isotopeofPlutonium |
Heavier: Plutonium-239 |
| Decay product of: Curium-242 (α) Americium-238 (β+) Neptunium-238 (β-) Uranium-238 (β-β-) |
Decay chain of plutonium-238 |
Decays to: Uranium-234 (α) |
