Its economy is dominated by oil, followed by timber and manganese exports.
A billet of highly enriched uranium-235.
The most common form is uranium-238, which accounts for 99 percent of all uranium on earth.
About 0.72 percent is uranium-235 and a very small amount, about 0.006 percent, is uranium-234.
However, this concentration is too low to induce nuclear fission.
There must also be a moderator, something that can slow down the neutrons produced when uranium fissions.
Such a natural reactor was discovered sixteen years later, in 1972, in Gabon.
At that time the French had been mining uranium in Gabona former French colonyfor use in nuclear power plants.
(There is acting like some disagreement on how less the figures were.
The uranium-235 in the ore was depleted because some of that uranium had been used up in the fission.
A natural nuclear reactor in Oklo, Gabon.
Uranium oxide remains are visible as the yellowish rock.
This allowed uranium to be converted from its insoluble form to its soluble oxide.
The water in the mine itself played a critical role in sustaining the reaction.
The water slowed the ejected neutrons so that they could be absorbed by other nuclei and trigger fission.
Without the water, the neutrons would have simplybounced off the atoms.
Once the water returned the process started again.
These periods of activity and inactivity were probably very short.
Themath suggestthe reactors switched on for 30 minutes and off for about 3 hours.
The Gabon natural nuclear reactors remain truly unique.
