Could a Natural Nuclear Reactor Have Destroyed an Ancient Civilization?

[BadBrain]

Right now I'm watching "Civilization Lost" on the H2 CHannel, and they just discussed an idea I've heard before, concerning the possibility of a nuclear fission detonation of natural origin having destroyed an African civilization.

I don't buy that.

I mean, even those of us who have never helped design nuclear reactors are still physicists, and we know how difficult it would be to come up with a design that would reach critical mass, and how we would bite our fingernails hoping the thing would actually work.

What they appear to be suggesting is that the combination of uranium ore (NOT elemental uranium, but uranium ore) and water created a natural nuclear reactor, so that you essentially have an uncontained controlled nuclear fission reaction à la Fukushima or Chernobyl.

Sorry about the nice civilization, but I just can't buy this explanation for its disappearance.

Then again, someone on another site to which I regularly post said that I was one lab accident short of becoming a comic-book super-villain!

 

[D H]

What they appear to be suggesting is that the combination of uranium ore (NOT elemental uranium, but uranium ore) and water created a natural nuclear reactor,

This did happen long ago. It's the Oklo natural reactors. See http://www.ans.org/pi/np/oklo/. By "long ago" I meant 1.5 billion years ago, just a tiny bit older than the oldest civilization.

The History Channel has found that producing nonsense makes a whole lot of sense in terms of what is important to them ($$$$).

 

[PatrickPowers]

Nuclear fission did occur naturally. There was no explosion: some steam was released. The radioactive decay products were found in our time.

Sadly the History channel has gone the National Enquirer route. I guess that is where the money is. They had a broadcast about the teleportation of a Navy destroyer, this allegedly due to the consequences of Einstein's Unified Field Theory.

 

[BadBrain]

Nuclear fission did occur naturally. There was no explosion: some steam was released. The radioactive decay products were found in our time.

Sadly the History channel has gone the National Enquirer route. I guess that is where the money is. They had a broadcast about the teleportation of a Navy destroyer, this allegedly due to the consequences of Einstein's Unified Field Theory.

So what you're saying is that what happened wasn't Fukushima nor Chernobyl, but, rather, Three Mile Island.

That must have been one rich concentration of uranium ore!

D.H.:

Thanks for the link!

 

[BadBrain]

Well, anyways, here's my musical salute to that poor lost civilization in Gabon (even though it's a Brazilian Santerist song that refers to Cameroon (which is, at least, adjacent to Gabon)).

Well, here it is:

 

[PatrickPowers]

So what you're saying is that what happened wasn't Fukushima nor Chernobyl, but, rather, Three Mile Island.

That must have been one rich concentration of uranium ore!

D.H.:

Thanks for the link!

It was a small scale event. At the time the concentration of U-235 (or is it 238, I don't recall) was high enough (5%?)that reactions could occur naturally. Since then enough has decayed that the concentration is 3% or so and must be enriched artificially.

 

[Hattattack]

It was a small scale event. At the time the concentration of U-235 (or is it 238, I don't recall) was high enough (5%?)that reactions could occur naturally. Since then enough has decayed that the concentration is 3% or so and must be enriched artificially.

Yeah, 1.5 -1.7 billion years ago, Uranium ores would have contained significantly higher concentrations of fissile U-235, as it's half-life is ~700 million years. A cave lined with this rich ore, and periodically filling with a neutron moderator could in theory (and evidently) become a natural reactor.

 

[MarcoD]

By "long ago" I meant 1.5 billion years ago, just a tiny bit older than the oldest civilization.

Uh, looks to me that you're off by at least three orders here.

 

[Ryan_m_b]

By "long ago" I meant 1.5 billion years ago, just a tiny bit older than the oldest civilization.

Uh, looks to me that you're off by at least three orders here.

Only 3? I make it 5 at least.

 

[D H]

Uh, looks to me that you're off by at least three orders here.

If I was only off by three orders of magnitude, that would place the lost culture of Atlantis at about 1.5 million years ago. Shoot! Everyone knows that Atlantis was founded no earlier than 15,000 years ago. I was off by at least five orders of magnitude.More seriously, do I really need to add some smiley or a /sarc tag every time I make an obvious attempt at humor? (And that “By "long ago" I meant 1.5 billion years ago, just a tiny bit older than the oldest civilization” should have been obvious.)

 

[mplayer]

I think we all know what is REALLY going on here...

 

[FlexGunship]

I think we all know what is REALLY going on here...

Love it.

F**kin' love it.

 

[Pengwuino]

I think we all know what is REALLY going on here...

You'll fit in well here.