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Does Uranium-235 Always Fission in to Kr-89 and Ba-144?

  1. Nov 5, 2015 #1
    If it does, why is that so?
  2. jcsd
  3. Nov 5, 2015 #2


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    No, that is one of numerous possibilities.

    The atomic numbers of the fission products must = 92, and the masses would sum to 234 or 233, depending on whether fission produces 2 or 3 free neutrons. One could find Br and La, or Zr-100 and Te-134, which is one of the most probable results for thermal fission. In fast fissions, the fission is more symmetric and one will find higher proportions of transition elements centered around Pd.

    Plots from NNDC at BNL - showing nuclide yields (fractions) from thermal fisson of U-235.

    http://www.nndc.bnl.gov/chart/temp/z52n81zl1c235ufy249.png [Broken]
    http://www.nndc.bnl.gov/chart/temp/z40n58zl1c235ufy5304.png [Broken]
    Last edited by a moderator: May 7, 2017
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