from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. An isotope of uranium, used for energy generation and in atomic weapons, containing one hundred and forty-three neutrons. It has a half-life of 7·038×108 years, whereupon it decays into thorium-231.


from Wiktionary, Creative Commons Attribution/Share-Alike License

uranium + 235 the atomic mass of this isotope.


  • But they would still rely on uranium-235, a limited resource with safety and proliferation concerns.

    Calculating the speed of light; building nuclear reactors

  • Richard Wakeford of the Dalton Nuclear Institute, at the University of Manchester, called such fears science fiction, pointing out there is not enough uranium-235 in the reactor to create a nuclear blast.

    Blast rocks Fukushima reactor No. 2; radioactive leak feared

  • But President Obama is talking about building new ones, massive gigawatt-sized reactors, and even smaller ones that would use thorium, rather than uranium-235.

    Lee Schneider: Will We See Nuclear Progress in Japan?

  • Today's reactors use dried wood—enriched uranium-235—that burns hot and quickly.

    A Window Into the Nuclear Future

  • The essence of a conventional nuclear power reactor is the controlled fission chain reaction of uranium-235 (235U) and plutonium-239 (239Pu).

    Accelerator-driven nuclear energy

  • Natural uranium has the same elemental composition as when it was mined (0.7% uranium-235 (235U), over 99.2% uranium-238 (238238U)), whereas enriched uranium has the proportion of the fissile isotope 235U increased by a process called enrichment, commonly to 3.5 - 5.0%.

    Nuclear power reactor

  • These numbers compare with 200-210 MeV released by the fission of one uranium-235 or plutonium-239 atom.

    Accelerator-driven nuclear energy

  • As uranium-235 molecules are lighter than the uranium-238 molecules, they move faster and have a slightly better chance of passing through the pores in the membrane.

    Uranium enrichment

  • Uranium found in nature consists largely of two isotopes, uranium-235 (235U) and uranium-238 (238U).

    Uranium enrichment

  • Both decay much more rapidly than uranium-235 and uranium-238, and one of the daughter products of 232U emits very strong gamma radiation, which means that shielding is necessary in the plant handling material with more than very small traces of it.

    Uranium enrichment


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