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  2. Nuclear fission - Wikipedia

    en.wikipedia.org/wiki/Nuclear_fission

    e. Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioactive decay. Nuclear fission was discovered by chemists Otto Hahn and Fritz Strassmann and physicists Lise ...

  3. Discovery of nuclear fission - Wikipedia

    en.wikipedia.org/wiki/Discovery_of_nuclear_fission

    The nuclear reaction theorised by Meitner and Frisch and observed by Hahn and Strassmann. Nuclear fission was discovered in December 1938 by chemists Otto Hahn and Fritz Strassmann and physicists Lise Meitner and Otto Robert Frisch. Fission is a nuclear reaction or radioactive decay process in which the nucleus of an atom splits into two or ...

  4. Critical mass - Wikipedia

    en.wikipedia.org/wiki/Critical_mass

    In nuclear engineering, a critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction. The critical mass of a fissionable material depends upon its nuclear properties (specifically, its nuclear fission cross-section), density, shape, enrichment, purity, temperature, and surroundings.

  5. Nuclear fission product - Wikipedia

    en.wikipedia.org/wiki/Nuclear_fission_product

    The sum of the atomic mass of the two atoms produced by the fission of one fissile atom is always less than the atomic mass of the original atom. This is because some of the mass is lost as free neutrons, and once kinetic energy of the fission products has been removed (i.e., the products have been cooled to extract the heat provided by the reaction), then the mass associated with this energy ...

  6. Natural nuclear fission reactor - Wikipedia

    en.wikipedia.org/wiki/Natural_nuclear_fission...

    A natural nuclear fission reactor is a uranium deposit where self-sustaining nuclear chain reactions occur. The conditions under which a natural nuclear reactor could exist were predicted in 1956 by Paul Kuroda. [1] The remnants of an extinct or fossil nuclear fission reactor, where self-sustaining nuclear reactions have occurred in the past ...

  7. Nuclear physics - Wikipedia

    en.wikipedia.org/wiki/Nuclear_physics

    Nuclear fission is the reverse process to fusion. For nuclei heavier than nickel-62 the binding energy per nucleon decreases with the mass number. It is therefore possible for energy to be released if a heavy nucleus breaks apart into two lighter ones. The process of alpha decay is in essence a special type of spontaneous nuclear fission. It is ...

  8. Nuclear explosion - Wikipedia

    en.wikipedia.org/wiki/Nuclear_explosion

    A nuclear explosion is an explosion that occurs as a result of the rapid release of energy from a high-speed nuclear reaction.The driving reaction may be nuclear fission or nuclear fusion or a multi-stage cascading combination of the two, though to date all fusion-based weapons have used a fission device to initiate fusion, and a pure fusion weapon remains a hypothetical device.

  9. Nuclear reactor - Wikipedia

    en.wikipedia.org/wiki/Nuclear_reactor

    The Chernobyl sarcophagus, built to contain the effects of the 1986 disaster. A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. When a fissile nucleus like uranium-235 or plutonium-239 absorbs ...