THE world’s only known natural nuclear reactor, which went critical nearly 2 billion years ago, turned itself on and off like a geyser. According to a new analysis this suggests that water regulated the chain reactions, which continued for 150,000 years.
The concentration of uranium-235 in rocks at Oklo in Gabon, west Africa, was so high that it triggered sustained nuclear fission when the Earth was about half its current age. But rather than exploding like a bomb, it produced a chain reaction that continued gently for many millennia, generating an average power of about 100 kilowatts.
Now Alexander…
