The nuclear energy session at New Orleans is FD, not FC; sorry for the
error. As I look at the program I see the presentation FD9 on Oklo. This
reminds me of a question. Was there at least one more uranium mine like
Oklo found somewhere in the world?
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For those who never heard about the topic. Oklo, is a mine in Gabon, Africa,
where the U-235 concentration is significantly less than everywhere else
in the world. Sometimes as little as 0.4% instead of 0.72%. The explanation
is shocking; Oklo was a nuclear reactor, about 2 billion years ago. The
mine is a natural geological "repository" of spent reactor fuel.
The natural abundance of U-235 was close to 3%, as in most man-made reactors
today. Why? Because the half-life of U-235 is 7.1*10^8 years while that of
U-238 is 4.5*10^9 years. The U235/U238 ratio is a time-dependent function;
it was close to 1.0 when elements were formed (meaning 50% entichment). High
concentration of nuclear fuel plus water resulted in a natural reactor. All
isotopic ratios confirmed this explanation.
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Scientists were looking for other natural reactor sites; I read about this
at the time when Oklo was discovered and explained (about 25 years ago ?).
But I never heard about the outcome. The above explanation suggests that
many uranium deposits should have been reactors, especially soon after
solidification of our planet. How old are oceans? How old is water? Why is
the isotopic abundance of U-235 so uniform on earth, except for Oklo?
I can guess what Van Daneken (?sp) would write about this.
Ludwik Kowalski