a natrual reactor

[stephens@lamar.ColoState.EDU (John Stephens)]

> bill kolb
> bkolb@arinc.com
> I'm not convinced this is the correct lesson from Oklo.  The rarity (or absence)
> of similar depleted deposits argues that the fission products are indeed likely
> to work their way into the environment over eons.  Perhaps the issue is whether
> the material is "safer" when concentrated in one spot or uniformly distributed
> over the globe.

Yes, distribution can have a dramatic effect on pathway exposure analysis.
However, it actually the opposite of your suggestion that many deposits
might have formed but we only see a few because the fission products are
transported.

It was thought that the evolution of bacteria back when the % abundance
was high enough was insufficient to produce oxygenated water to form the
uranyl ions in the groundwater.  So this places a fairly rigid window
along the timeline of when this deposit could have formed!

John Stephens
one of those still unemployed HP grads...