Oklo

This article is about the region in Gabon. For the company, see Oklo Inc.

Region containing uranium ore in Haut-Ogooué, Gabon

The natural nuclear fission reactors of Oklo:

1. Nuclear reactor zones
2. Sandstone
3. Uranium ore layer
4. Granite

Oklo is a 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

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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 BP – in the Paleoproterozoic Era during Precambrian times, during the Statherian period – and 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.[1][2][3][4][5][6][7]

## See also

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* List of uranium projects

## References

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1. ^ Kean, Sam (12 July 2010). The Disappearing Spoon: And Other True Tales of Madness, Love, and the History of the World from the Periodic Table of the Elements. Little, Brown. pp. 324–. ISBN 978-0-316-05164-4.
2. ^ Lederman, Leon; Hill, Christopher (2004). Symmetry and the Beautiful Universe. Amherst: Prometheus Books. pp. 40-42. ISBN 9781591022428.
3. ^ Zoellner, Tom (2009). Uranium. Viking Penguin. pp. 291–292\. ISBN 9780670020645.
4. ^ Cowan, George (1976). "A Natural Fission Reactor". Scientific American. Vol. 235, no. 1\. pp. 36–47\. Bibcode:1976SciAm.235a..36C. doi:10.1038/scientificamerican0776-36. JSTOR 24950391. Archived from the original on 15 August 2023. Retrieved 15 August 2023.
5. ^ Cowan, George (1976). "Oklo – A Natural Fission Reactor" (PDF). Federation of American Scientists. Los Alamos Scientific Laboratory. Archived (PDF) from the original on 29 March 2024. Retrieved 15 August 2023.
6. ^ Gauthier-Lafaye, F.; Holliger, P.; Blanc, P.-L. (December 1996). "Natural fission reactors in the Franceville basin, Gabon: A review of the conditions and results of a 'critical event' in a geologic system". Geochimica et Cosmochimica Acta. 60 (23): 4831–4852\. doi:10.1016/s0016-7037(96)00245-1. ISSN 0016-7037.
7. ^ Meshik, Alex P. (2005-11-01). "The Workings of an Ancient Nuclear Reactor". Scientific American. Vol. 293, no. 5\. pp. 82–91\. doi:10.1038/scientificamerican1105-82. Archived from the original on 2024-03-25. Retrieved 2024-03-25.

## Further reading

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* Yucca Mountain Project (YMP) (Nov 2004). "Oklo: Natural Nuclear Reactors". Office of Civilian Radioactive Waste Management (OCRWM). Fact sheets. DOE. YMP-0010. Archived from the original on 2004-02-19.
* Manaugh, Geoff (Dec 8, 2009). "One Million Years of Isolation: An Interview With Abraham Van Lu". World Changing. Archived from the original (pdf) on December 12, 2009. Alt URL

1°23′40″S 13°9′39″E﻿ / ﻿1.39444°S 13.16083°E﻿ / -1.39444; 13.16083