oklo natural reactor

If you visit the exhibition you will also have the chance to meet Oklo, the Earth’s 2-billion-year-old only known natural #nuclear reactor! We wrote about it some months ago: http://goo.gl/EYd4vs
About two billion years ago, nuclear reactors were created naturally in a West African uranium ore deposit in Oklo (Gabon).
Uranium-​235 (at that time, constituting around 3% of the natural proportion of uranium ore) initiated a self-​perpetuating chain reaction that was moderated by water in the fissures in the uranium rock. This resulted in the generation of several tonnes of high-​level waste (fission products) and plutonium that remained enclosed in the clay rock.
Nature has created a natural nuclear reactor and a functioning “deep geological repository for high-​level waste” in Oklo. Since then, the radioactive substances have barely moved from where they were produced, even in the absence of optimised geological conditions in undisturbed Opalinus Clay and without engineered safety barriers such as bentonite, as are foreseen for a deep geological repository in Switzerland.