Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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


    User Avatar
    Staff Emeritus
    Science Advisor

    Re: Pu

    Oklo: Natural Nuclear Reactors
    http://www.ocrwm.doe.gov/factsheets/doeymp0010.shtml [Broken]

    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
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook