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Plutonium-239 is also one of the three main isotopes demonstrated usable as fuel in thermal spectrum nuclear reactors, along with uranium-235 and uranium-233. Plutonium-239 has a half-life of 24,110 years. [1]
half-life seconds seaborgium-263: 1 astatine-198m: 1.0 mendelevium-246: 1.0 thorium-224: 1.05 sodium-26: 1.077 plutonium-228: 1.1 mendelevium-247: 1.12 curium-246m: 1.12 bohrium-271: 1.2 thorium-215: 1.2 radium-208: 1.3 radium-207: 1.3 rutherfordium-268: 1.4 hassium-268: 1.42 polonium-217: 1.47 astatine-218: 1.5 lawrencium-253m: 1.5 fermium-259 ...
Plutonium-244 is the most stable isotope of plutonium, with a half-life of about 80 million years. It is not significantly produced in nuclear reactors because 243 Pu has a short half-life, but some is produced in nuclear explosions. 244 Pu has been found in interstellar space [13] and has the second longest half-life of any non-primordial ...
Half-life (y) Critical mass (kg) Diameter ... plutonium-239: 24,110: 10: 9.9 [4] [8] plutonium-240: 6561: 40: 15 [4] ... If the density is 1% more and the mass 2% ...
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] The ratio of plutonium-239 to uranium at the Cigar Lake Mine uranium deposit ranges from 2.4 × 10 −12 to 44 × 10 −12. [56]
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 nuclear weapon to pre-detonate.
Nonradioactive 133 Cs capturing a neutron and becoming 134 Cs, which is radioactive with a half-life of 2 years 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 ...
At least 3,300 nuclides have been experimentally characterized [1] (see List of radioactive nuclides by half-life for the nuclides with decay half-lives less than one hour). A nuclide is defined conventionally as an experimentally examined bound collection of protons and neutrons that either is stable or has an observed decay mode .