Oklo, Gabon

Savary, V. Pagel, M. 1997. The effects of water radiolysis on local redox conditions in the Oklo, Gabon, natural fission reactors 10 and 16. Geochimica et Cosmochimica Acta, 61, 4479-4494. 

Bros, R., Carpena, J., Sere, V. Beltritti, A. 1996. Occurence of Pu and fissiogenic rare earth elements in hydrothermal apatites from the fossil natural nuclear reactor 16 of Oklo (Gabon). Radio-chimica Acta, 74, 277-282. 

Made, B., Ledoux, E., Salignac, A.-L., Le Boursicaud, B. Gurban, I. 2000. Modeli-sation du transport reactif de l uranium autour du reacteur naturel de Bangombe (Oklo, Gabon). C R de I Academie des Sciences, Paris, 331, 587-594. 

In 1972, evidence of a past "natural nuclear reactor" was found by a French mining geologist while assaying uranium samples in a uranium mine at Oklo, Gabon, West Africa It "went critical" about 1.7 billion years ago, released 15,000 megawatt-years of energy by consuming six tons of uranium, and was critical (at low power) for several hundred thousand years. 

In 1972 it was found that uranium in ore deposits at Oklo, Gabon, contains significantly smaller concentrations of than other deposits of natural uranium (<0.5% compared with 0.72%). At these places, the isotopic composition of other elements is also different from the mean composition in nature. For instance, natural Nd contains 27% " Nd and xl2% " Nd, whereas Nd at Oklo contains <2% Nd and up to 24% Comparison with the yields of nuclear fission leads to... 

French scientists discover ancient natural nuclear reactor in Oklo, Gabon. 

One namral analogue for geological disposal of nuclear waste is at a site near Oklo, Gabon, West Africa. About 2 billion yr ago, a uranium ore body sustained fission for a period of about 100,000 yr. Most of the fission and activation products from this namral reactor migrated only a short distance from the fission sites, which gives natural supporting evidence for the potential of radionuclide transport from underground waste disposal facilities. 

Myers WD, Swiatecki WJ (1966) Nuclear masses and deformations. Nucl Phys 81 1 Neuilly M, Bussac J, Frejaques C et al (1972) Sur Fexis-tence dans un passe recule d une reaction en chaine natureUe de fissions, dans le gisement d uranium d Oklo (Gabon). Compt Rend D 275 1847 Nier AO (1935) Evidence for the existence of an isotope of potassium of mass 40. Phys Rev 48 283 Nier AO (1938) Variations in the relative abundances of the isotopes of common lead from various sources. J Am Chem Soc 60 1571... 

Photo showing the natural nuclear reactor site (lower right-hand eomer) at Oklo, Gabon RepubUe. 

Tabular U,V,Pb,Cu,Se, Mo,C,S Flat-lying, controlled by palaeo-stream channels, in lithic to arkosic arenites associated with organic-rich rocks epigenetic Grants, U.S.A. Oklo, Gabon... 

It is interesting to note that the natural nuclear reactor discovered in Oklo, Gabon, Africa, operated for about 7 x 10 years and released about 15 GW years of energy about 1.8 x 10 years ago. The study showed that the fission products could lie immobile in the ground at the original reactor site during these many years. It is evident that responsible disposal of nuclear waste is feasible and will eventually be accomplished. 

Kuroda PK (1982) The origin of the chemical elements and the Ohio phenomenon. Springer Heidelberg, Ch. 3.10, 3.11. The fascinating story of the discovery of promethium (element 61) in Earth s crust, a product of the pre-Fermi natural nuclear reactor discovered in Oklo, Gabon. 

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