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  2. Uranium - Wikipedia

    en.wikipedia.org/wiki/Uranium

    Uranium-236 is not fertile, as three more neutron captures are required to produce fissile 239 Pu, and is not itself fissile; as such, it is considered long-lived radioactive waste. [115] Uranium-234 is a member of the uranium series and occurs in equilibrium with its progenitor, 238 U; it undergoes alpha decay with a half-life of 245,500 years ...

  3. Weapons-grade nuclear material - Wikipedia

    en.wikipedia.org/wiki/Weapons-grade_nuclear_material

    Moreover, different isotopes have different critical masses, and the critical mass for many radioactive isotopes is infinite, because the mode of decay of one atom cannot induce similar decay of more than one neighboring atom. For example, the critical mass of uranium-238 is infinite, while the critical masses of uranium-233 and uranium-235 are ...

  4. Nuclear weapon - Wikipedia

    en.wikipedia.org/wiki/Nuclear_weapon

    Uranium appears in nature primarily in two isotopes: uranium-238 and uranium-235. When the nucleus of uranium-235 absorbs a neutron, it undergoes nuclear fission, releasing energy and, on average, 2.5 neutrons. Because uranium-235 releases more neutrons than it absorbs, it can support a chain reaction and so is described as fissile. Uranium-238 ...

  5. Uranium in the environment - Wikipedia

    en.wikipedia.org/wiki/Uranium_in_the_environment

    Uranium's radioactivity can present health and environmental issues in the case of nuclear waste produced by nuclear power plants or weapons manufacturing. Uranium is weakly radioactive and remains so because of its long physical half-life (4.468 billion years for uranium-238).

  6. Uranium-235 - Wikipedia

    en.wikipedia.org/wiki/Uranium-235

    Uranium-235 (235 U or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exists in nature as a primordial nuclide. Uranium-235 has a half-life of 703.8 million years.

  7. Minecraft: Bedrock Edition - Wikipedia

    en.wikipedia.org/?title=Minecraft:_Bedrock...

    Minecraft This page was last edited on 1 January 2025, at 03:58 (UTC) . Text is available under the Creative Commons Attribution-ShareAlike 4.0 License ; additional terms may apply.

  8. Actinides in the environment - Wikipedia

    en.wikipedia.org/wiki/Actinides_in_the_environment

    The actinide series is a group of chemical elements with atomic numbers ranging from 89 to 102, [note 1] including notable elements such as uranium and plutonium.The nuclides (or isotopes) thorium-232, uranium-235, and uranium-238 occur primordially, while trace quantities of actinium, protactinium, neptunium, and plutonium exist as a result of radioactive decay and (in the case of neptunium ...

  9. Environmental radioactivity - Wikipedia

    en.wikipedia.org/wiki/Environmental_radioactivity

    One of the advantages of this method is that any sample provides two clocks, one based on uranium-235's decay to lead-207 with a half-life of about 703 million years, and one based on uranium-238's decay to lead-206 with a half-life of about 4.5 billion years, providing a built-in crosscheck that allows accurate determination of the age of the ...