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This prevents most of the core from participation in the chain reaction and reduces the bomb's yield. Plutonium consisting of more than about 90% 239 Pu is called weapons-grade plutonium; plutonium from spent nuclear fuel from commercial power reactors generally contains at least 20% 240 Pu and is called reactor-grade plutonium.
The main decay modes of isotopes with mass numbers lower than the most stable isotope, 244 Pu, are spontaneous fission and alpha emission, mostly forming uranium (92 protons) and neptunium (93 protons) isotopes as decay products (neglecting the wide range of daughter nuclei created by fission processes).
This is a list of radioactive nuclides (sometimes also called isotopes), ordered by half-life from shortest to longest, in seconds, minutes, hours, days and years. Current methods include jumping up and down make it difficult to measure half-lives between approximately 10 −19 and 10 −10 seconds.
or Pu-239) is an isotope of plutonium. 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.
Only fissile isotopes of certain elements have the potential for use in nuclear weapons. For such use, the concentration of fissile isotopes uranium-235 and plutonium-239 in the element used must be sufficiently high. Uranium from natural sources is enriched by isotope separation, and plutonium is produced in a suitable nuclear reactor.
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.
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 ...
When the isotope 240 Pu captures a neutron, it is about 4500 times more likely to become plutonium-241 than to fission. In general, isotopes of odd mass numbers are more likely to absorb a neutron, and can undergo fission upon neutron absorption more easily than isotopes of even mass number.