Is There Such a Thing as a Natural Nuclear Reactor?

In 1972, scientists found evidence that nuclear fission had occurred naturally on Earth nearly 2 billion years ago. This natural nuclear fission reactor, in which a uranium deposit and ideal geological conditions triggered self-sustaining chain reactions, was discovered in the African nation of Gabon by French physicist Francis Perrin. The Gabon reactor is the only one of its kind to have been discovered anywhere on Earth. It consists of 16 sites where natural nuclear fission reactions took place, each lasting for a few hundred thousand years.

More about ancient power plants:

• The energy produced by these natural nuclear reactors was modest. The average output was about 100 kilowatts, which would power about 1,000 light bulbs today. A typical nuclear power plant produces about 1,000 megawatts, enough to power about 10 million light bulbs.
• The radioactive byproducts of the fission reactions in Gabon have been safely contained for almost 2 billion years, providing evidence that long-term geological storage of nuclear waste is feasible.
• The possibility that natural nuclear reactors may have occurred on prehistoric Earth was hypothesized by scientists in the 1950s, two decades before evidence of their existence was found in Gabon.