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  2. Valley of stability - Wikipedia

    en.wikipedia.org/wiki/Valley_of_stability

    In nuclear engineering, a prompt neutron is a neutron immediately emitted by a nuclear fission event. Prompt neutrons emerge from the fission of an unstable fissionable or fissile heavy nucleus almost instantaneously. Delayed neutron decay can occur within the same context, emitted after beta decay of one of the fission products.

  3. Nuclear fission - Wikipedia

    en.wikipedia.org/wiki/Nuclear_fission

    In nuclear fission events the nuclei may break into any combination of lighter nuclei, but the most common event is not fission to equal mass nuclei of about mass 120; the most common event (depending on isotope and process) is a slightly unequal fission in which one daughter nucleus has a mass of about 90 to 100 daltons and the other the ...

  4. Alpha decay - Wikipedia

    en.wikipedia.org/wiki/Alpha_decay

    Alpha decay or α-decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle (helium nucleus) and thereby transforms or "decays" into a different atomic nucleus, with a mass number that is reduced by four and an atomic number that is reduced by two.

  5. Delayed neutron - Wikipedia

    en.wikipedia.org/wiki/Delayed_neutron

    In nuclear engineering, a delayed neutron is a neutron emitted after a nuclear fission event, by one of the fission products (or actually, a fission product daughter after beta decay), any time from a few milliseconds to a few minutes after the fission event. Neutrons born within 10 −14 seconds of the fission are termed "prompt neutrons".

  6. Nuclear chain reaction - Wikipedia

    en.wikipedia.org/wiki/Nuclear_chain_reaction

    In nuclear physics, a nuclear chain reaction occurs when one single nuclear reaction causes an average of one or more subsequent nuclear reactions, thus leading to the possibility of a self-propagating series or "positive feedback loop" of these reactions. The specific nuclear reaction may be the fission of heavy isotopes (e.g., uranium-235 ...

  7. 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

  8. Decay heat - Wikipedia

    en.wikipedia.org/wiki/Decay_heat

    Decay heat as fraction of full power for a reactor SCRAMed from full power at time 0, using two different correlations. In a typical nuclear fission reaction, 187 MeV of energy are released instantaneously in the form of kinetic energy from the fission products, kinetic energy from the fission neutrons, instantaneous gamma rays, or gamma rays from the capture of neutrons. [7]

  9. Photodisintegration - Wikipedia

    en.wikipedia.org/wiki/Photodisintegration

    Photodisintegration (also called phototransmutation, or a photonuclear reaction) is a nuclear process in which an atomic nucleus absorbs a high-energy gamma ray, enters an excited state, and immediately decays by emitting a subatomic particle.