At three ore deposits at Oklo in Gabon, sixteen sites (the so-called Oklo Fossil Reactors) have been discovered at which self-sustaining nuclear fission took place approximately 2 billion years ago.
I 3 malm-aflejringer ved Oklo i Gabon, er der opdaget 16 steder (de såkaldte Oklo Fossil Reactors) hvor selvkørende kernefission har fundet sted for omkring 2 milliarder år siden.