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Plutonium-238 (238 Pu or Pu-238) is a radioactive isotope of plutonium that has a half-life of 87.7 years. Plutonium-238 is a very powerful alpha emitter ; as alpha particles are easily blocked, this makes the plutonium-238 isotope suitable for usage in radioisotope thermoelectric generators (RTGs) and radioisotope heater units .
Uranium-238. Uranium-238 (238U or U-238) is the most common isotope of uranium found in nature, with a relative abundance of 99%. Unlike uranium-235, it is non-fissile, which means it cannot sustain a chain reaction in a thermal-neutron reactor. However, it is fissionable by fast neutrons, and is fertile, meaning it can be transmuted to fissile ...
In nuclear science a decay chain refers to the predictable series of radioactive disintegrations undergone by the nuclei of certain unstable chemical elements. Radioactive isotopes do not usually decay directly to stable isotopes, but rather into another radioisotope. The isotope produced by this radioactive emission then decays into another ...
Plutonium-238 has a half-life of 87.74 years [11] and emits alpha particles. Pure 238 Pu for radioisotope thermoelectric generators that power some spacecraft is produced by neutron capture on neptunium-237 but plutonium from spent nuclear fuel can contain as much as a few percent 238 Pu, originating from 237 Np, alpha decay of 242 Cm, or (n,2n ...
Trace amounts of plutonium-238, plutonium-239, plutonium-240, and plutonium-244 can be found in nature. Small traces of plutonium-239, a few parts per trillion, and its decay products are naturally found in some concentrated ores of uranium, [52] such as the natural nuclear fission reactor in Oklo, Gabon. [53]
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.
Isotopes of uranium. Uranium (92 U) is a naturally occurring radioactive element (radioelement) with no stable isotopes. It has two primordial isotopes, uranium-238 and uranium-235, that have long half-lives and are found in appreciable quantity in Earth's crust. The decay product uranium-234 is also found. Other isotopes such as uranium-233 ...
The thorium fuel cycle is a nuclear fuel cycle that uses an isotope of thorium, 232 Th, as the fertile material. In the reactor, 232Th is transmuted into the fissile artificial uranium isotope 233 U which is the nuclear fuel. Unlike natural uranium, natural thorium contains only trace amounts of fissile material (such as 231 Th), which are ...