Ancient nuclear reactor found in Gabon |
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Wednesday, 18 March 2015
Ancient nuclear reactor found in Gabon
In 1972 a French physicist Francis
Perrin discovered the existence of this phenomenon at Oklo in Gabon, Africa. Oklo is the only known
location for this in the world and consists of 16 sites at which
self-sustaining nuclear fission reactions took place approximately 1.7 billion years ago, and ran for a few hundred
thousand years, averaging 100 kW of thermal power during that time (which would power
about 1,000 lightbulbs).
The energy produced
by these natural nuclear reactors was modest compared to the commercial nuclear
power plants, which produce about 1,000 megawatts that would power about ten
million lightbulbs.
The Gabon nuclear
reactor was discovered when the French who had been mining uranium in Gabon for
use in nuclear power plants. During a routine isotopic measurement of uranium
ore from the Oklo site, the French noticed something very strange: the uranium
ore did not have a uranium-235 content of 0.720%. Rather, the uranium ore was
anomalously depleted in uranium-235, containing only 0.717%. The discrepancy though
quite small was very alarming for the French nuclear officials, as uranium-235
in Earth’s crust, in moon rocks and in meteorites varies very little from the
average value of 0.720%. Since uranium-235 can be used to make nuclear bombs,
it was very important to account for this “missing” uranium-235.
The nuclear
officials and scientists eventually remembered the old publications of Kuroda
and others, and soon realised that the anomalous uranium from Gabon provided
evidence of something extraordinary—the first natural nuclear reactor ever
discovered. Eventually, sixteen natural nuclear reactors were discovered in
uranium mines at Oklo. An additional seventeenth natural nuclear reactor was
also discovered at Bangombé, located about 30 km to the southeast of Oklo.
Since the discovery
of the Gabon natural nuclear reactors in 1972, scientists have been puzzling
over why these reactors developed only in Gabon and no other place on
Earth. Scientists are still working to understand the Gabon reactors, but
over the past forty years, they have managed to tease out some of the details
of how these nuclear reactors operated and were preserved in the geologic
record.
But one question
that is yet to be answered is whether the reactors were operated by intelligent
beings that have inhabited the Oklo area during that period of time.
-
Additional
information from Scientific American
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