Oklo

thumb|The natural nuclear fission reactors of Oklo:

Oklo is a geological region near Franceville in the Haut-Ogooué Province of Gabon. Several natural nuclear fission reactors were discovered in the uranium mines in the region in 1972.

Natural nuclear fission reactor

Some of the mined uranium was found to have a lower concentration of uranium-235 than expected, as if it had already been in a nuclear reactor. When geologists investigated they also found products typical of a reactor. They concluded that the deposit had been in a reactor: a natural nuclear fission reactor, around 1.8 to 1.7 billion years BPin the Paleoproterozoic Era during Precambrian times, during the Statherian periodand continued for a few hundred thousand years, probably averaging less than 100 kW of thermal power during that time. At that time the natural uranium had a concentration of about 3% ²³⁵U and could have reached criticality with natural water as neutron moderator allowed by the special geometry of the deposit.

See also

• List of uranium projects

References

Further reading

• Alt URL