Re: Repository analogues -Reply

["William Kolb" <William_Kolb_at_SETA@mail.hq.faa.gov>]

>Forgive the following but some radsafers might be unfamiliar with the
>"fossil reactor" at Oklo:  Oklo is a uranium deposit in Gabon. Around 1800
>million years ago, it went critical and "operated" for approximately
>700,000 years releasing about 15,000 megawatt years of energy. This
>was possible because the U-235 levels were higher then, than they are
>today. Water in the ground served as the moderator. The fission
>products seem to have migrated only very small distances,  say less
>than 100 m. There are a ton of references, all of mine are old though.

To put this in perspective, the average output was about 2.5 watt-hours, 
sufficient for a night-light.  In reality, however, the reactor zones (there 
were about 6) would have surged as ground water started it up then boiled away. 
Still, it's a remarkable phenomenon and is likely to have occurred in other 
places but migration of the reaction products has long since oblitered the 
evidence.

bill kolb
bkolb@arinc.com