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The radioactive decay modes of electron capture and internal conversion are known to be slightly sensitive to chemical and environmental effects that change the electronic structure of the atom, which in turn affects the presence of 1s and 2s electrons that participate in the decay process.
The known isotopes of plutonium range from 226 Pu to 247 Pu. The primary decay modes before the most stable isotope, 244 Pu, are spontaneous fission and alpha decay; the primary mode after is beta emission.
Plutonium-239 is the primary fissile isotope used for the production of nuclear weapons, although uranium-235 is also used for that purpose. 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]
Alpha decay, the release of a high-energy helium nucleus, is the most common form of radioactive decay for plutonium. [11] A 5 kg mass of 239 Pu contains about 12.5 × 10 24 atoms. With a half-life of 24,100 years, about 11.5 × 10 12 of its atoms decay each second by emitting a 5.157 MeV alpha particle. This amounts to 9.68 watts of power.
The four most common modes of radioactive decay are: alpha decay, beta decay, inverse beta decay (considered as both positron emission and electron capture), and isomeric transition. Of these decay processes, only alpha decay (fission of a helium-4 nucleus) changes the atomic mass number ( A ) of the nucleus, and always decreases it by four.
Plutonium-241 is a beta emitter with a half-life of 14.3 years, corresponding to a decay of about 5% of 241 Pu nuclei over a one-year period. This decay has a Q-value of 20.78 ± 0.17 keV and a mean of 5.227 ± 0.043 keV, and does not emit gamma rays. [1]
Watchdogs are raising new concerns about legacy contamination in Los Alamos, the birthplace of the atomic bomb and home to a renewed effort to manufacture key components for nuclear weapons. A ...
Plutonium-238 was the first isotope of plutonium to be discovered. It was synthesized by Glenn Seaborg and associates in December 1940 by bombarding uranium-238 with deuterons, creating neptunium-238. 238 92 U + 2 1 H → 238 93 Np + 2 n. The neptunium isotope then undergoes β − decay to plutonium-238, with a half-life of 2.12 days: [6] 238 ...