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Pu cannot be found in nature?

  1. Feb 21, 2009 #1
    Is it correct that Pu cannot be found in nature?
    What I mean acctually is that while Uranium can be mined, Pu from what I have searchd on wikipedia cannot be mined.

    I know that Pu is produced in nuclear reactors(or other facilities) from Uranium.
     
  2. jcsd
  3. Feb 21, 2009 #2
    Re: Pu

    The question is difficult to answer, because there are plenty of "natural" reactor out there. So yes, you can find Pu which has not been produced by a human reaction.
     
  4. Feb 21, 2009 #3
    Re: Pu

    I think humanino is probably right but it hasn't been discovered yet and I would assume that there are only tiny quantities of it.
     
  5. Feb 21, 2009 #4

    Astronuc

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    Staff: Mentor

    Re: Pu

    Oklo: Natural Nuclear Reactors
    http://www.ocrwm.doe.gov/factsheets/doeymp0010.shtml [Broken]
    http://www.ans.org/pi/np/oklo/

    There are very few 'natural reactors' or deposits of U ores that went critical. Natural U is about 99.3% U-238 and ~0.7% U-235. But the U oxide content of U-bearing ores is very low - at most a few %.

    The half-lives of the fissile or fissionable Pu-isotopes are relatively short, so if they do form by neutron capture in U-238 (with subsequent beta decay U-239 -> Np-239 -> Pu-239), there will be very little Pu remaining after millions or billions of years, i.e. trace quantities (ppm levels) that would not be economical to mine.

    Pu 239, T1/2 = 24110 y
    Pu 240, T1/2 = 6561 y
    Pu 241, T1/2 = 14.29 y
    Pu 242, T1/2 = 3.75E+5 y

    U 238, T1/2 = 4.468E9 y
     
    Last edited by a moderator: May 4, 2017
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