It took humans until the 20^th century to build a nuclear reactor. Mother Nature, on the other hand, built one that turned itself off and on, stored its waste, never threatened a meltdown—and did it 2 billion years ago.
Nuclear reactions in zone 9 of the Oklo natural fossil fission reactor lasted an estimated 220,000 years. | Courtesy of François Gautheir-Lafaye/Centre de Gèochimie de la Surface
François Gautheir-Lafaye/Centre de Gèochimie de la Surface
Physicists analyzing a tiny sample of this ancient georeactor—discovered in the African country of Gabon in 1972—have now determined how it worked. Alexander Meshik at Washington University in Saint Louis and his colleagues conclude that river water trickling into uranium-rich bedrock acted like the control rods in a modern reactor, increasing the efficiency of fission and causing the uranium to produce a chain reaction. The reaction released heat that boiled the water. Once all the water was ...
