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Encyclopedia of Geochemistry pp 1–4Cite as

Oklo Natural Nuclear Reactors

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Part of the book series: Encyclopedia of Earth Sciences Series ((EESS))

Synonyms

Fissiogenic isotopes; Fission products

Definition

Natural nuclear reactors have been discovered in the Oklo and the associated Okelobondo and Bangombe uranium ore deposits in the Republic of Gabon on the coast of Equatorial West Africa. The reactors occur as small lenticular bodies of high-grade uranium ore (20–60% by weight) in the uranium ore deposits. The natural reactors reached criticality and began fission reactions 1.95 billion years ago. They operated for as long as 140,000 years. The primary fuel for the natural reactors was a fissionable isotope of uranium, 235U. The reactors were discovered in 1972 when it was realized that 235U was consumed and fission products were produced within seventeen high-grade uranium ore bodies, the Oklo and the associated Okelobondo and Bangombe uranium ore deposits. Today, these natural nuclear reactors serve as useful analogs for on-going research in the development of nuclear waste containment strategies...

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References

  • Bentridi, S.-E., Gall, B., Gauthier-Lafaye, F., Seghour, A., Pape, A., and Medjadi, D.-E., 2013. Criticality of Oklo natural reactors: realistic model of reactor zone 9. IEEE Transactions on Nuclear Science, 60, 278–283.

    Article  Google Scholar 

  • Bros, R., Turpin, L., Gauthier-Lafaye, F., Holliger, P., and Stille, P., 1993. Occurrence of naturally enriched 235 uranium: the implications for Pu behavior in a natural environment. Geochimica et Cosmochimica Acta, 57, 1351–1358.

    Article  Google Scholar 

  • Bros, R., Carpena, J., Sere, V., and Beltritti, A., 1996. Occurrence of Pu and fissiogenic REE in hydrothermal apatites from the fossil nuclear reactor 16 at Oklo. Radiochimica Acta, 74, 277–282.

    Article  Google Scholar 

  • Cowan, G. A., 1976. A natural fission reactor. Scientific American, 235, 36–47.

    Article  Google Scholar 

  • Curtis, D., Benjamin, T., Gancarz, A., Loss, R., Rosman, K., and DeLaeter, J., 1989. Fission product retention in the Oklo natural fission reactors. Applied Geochemistry, 4, 49–62.

    Article  Google Scholar 

  • Gauthier-Lafaye, F., 2002. 2 billion year old natural analogs for nuclear waste disposal: the natural nuclear fission reactors in Gabon (Africa). Comptus Rendus Physique, 3, 839–849.

    Article  Google Scholar 

  • Gauthier-Lafaye, F., and Weber, F., 1989. The Francevillian (Lower Proterozoic) uranium ore deposits of Gabon. Economic Geology, 84, 2267–2285.

    Article  Google Scholar 

  • Gauthier-Lafaye, F., Weber, F., and Ohmoto, H., 1989. Natural fission reactors of Oklo. Economic Geology, 84, 2286–2295.

    Article  Google Scholar 

  • Hidaka, H., and Gauthier-Lafaye, F., 2008. Ba isotopic signature for early differentiation between Cs and Ba in natural fission reactors. Geochimica et Cosmochimica Acta, 72, 4123–4135.

    Article  Google Scholar 

  • Hidaka, H., Sugiyama, T., Ebihara, M., and Holliger, P., 1994. Isotopic evidence for the retention of 90Sr from excess Zr in the Oklo natural fission reactors: implication for geochemical behavior of fissiogenic Rb, Sr, Cs and Ba. Earth and Planetary Science Letters, 122, 173–182.

    Article  Google Scholar 

  • Holliger, P., 1992. Geochemical and isotopic characterization of the reaction zones (uranium, transuranium, lead and fission products). Proceedings of the Joint Commission European Communities-Commissariat a l'Energie Atomique, 2nd Meeting, Brussels, EUR, pp. 27–38.

    Google Scholar 

  • Holliger, P., and Devillers, C., 1981. Contribution a l’etude de la temperature dans Jes reacteurs fossiles d’Oklo par la mesure du rapport isotopique du lutetium. Earth and Planetary Science Letters, 52, 76–84.

    Article  Google Scholar 

  • Janeczek, J., and Ewing, R., 1995. Mechanisms of lead release in the natural fission reactors in Gabon. Geochimica et Cosmochimica Acta, 59, 1917–1931.

    Article  Google Scholar 

  • Koroda, P. F., 1956. On the nuclear physical stability of the uranium minerals. The Journal of Chemical Physics, 25, 781–782.

    Article  Google Scholar 

  • Nagy, B., and Rigali, M. J., 1993. Newly discovered, organic matter­rich natural fission reactors at Oklo and Bangombe: are they useful analogs for long-term anthropogenic nuclear waste containment? Waste Management ‘93 Conference Proceedings, pp. 897–900.

    Google Scholar 

  • Nagy, B., Gauthier-Lafaye, F., Holliger, P., Mossman, D. J., Leventhal, J. S., and Rigali, M. J., 1993. Role of organic matter in the Proterozoic Oklo natural fission reactors, Gabon, Africa. Geology, 21, 655–658.

    Article  Google Scholar 

  • Naudet, R., 1991. Oklo: Des Reacteurs Nucleaires. Paris: Commissariat a l’Energie Atomique, p. 695.

    Google Scholar 

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Author information

Authors and Affiliations

  1. Sandia National Laboratories, Albuquerque, NM, USA

    Mark J. Rigali

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  1. Mark J. Rigali
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Correspondence to Mark J. Rigali .

Editor information

Editors and Affiliations

  1. Department of Earth, Cornell University Department of Earth, Ithaca, New York, USA

    William M. White

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Rigali, M.J. (2016). Oklo Natural Nuclear Reactors. In: White, W. (eds) Encyclopedia of Geochemistry. Encyclopedia of Earth Sciences Series. Springer, Cham. https://doi.org/10.1007/978-3-319-39193-9_125-1

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  • DOI: https://doi.org/10.1007/978-3-319-39193-9_125-1

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  • Publisher Name: Springer, Cham

  • Online ISBN: 978-3-319-39193-9

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