Nuclear fission is nothing new. Mankind was introduced to the science of nuclear power at the end of World War II and first learned the peaceful use of nuclear energy in the 1950’s. Since then, nuclear science has evolved into an industry that today stands ready to end the energy crisis that has caused war, suffering, and pollution worldwide.
Did you know that the first fission reaction on Earth actually took place about 2 billion years ago? In 1972 French Physicist Francis Perrin discovered a unique blend of isotopes in the Uranium Ore foud in the Oklo Mine in Gabon, Central Africa. In this location, the correct blend of Uranium and water existed that allowed for the fission of Uranium underground eons before mankind first appeared on Earth. It is estimated that this natural nuclear reactor was “operating” for a few hundred thousand years! This was a billion years before the first multi-celled life forms ever evolved on Earth.
Since the discovery at Oklo, 16 such sites have been located underground and it is suspected that dozens if not hundreds more exist worldwide. For all we know, this could be going on underground at this moment. But what happened? If nuclear fission went uncontrolled on Earth for so long all those years ago, surely the world be a radioactive wasteland by now? If storing fission byproducts underground is unsafe, then how did multi-cellular, animal, vertebrate, primate, and finally human life ever evolve?
Since the 1970’s, the global nuclear industry has done a horrendous job of educating the public about the science and technology of nuclear energy. A policy of “no comment” has been allowed to fester within the men and women who have been operating and researching the cutting edge of nuclear technology. This unfortunate lack of information has been one of the major reasons why mankind is yet to kick the dirty habit of burning fossil fuels.
In the Science and Technology section, we will cover the different types of nuclear reactors, nuclear fuels, radiation, nuclear physics, and even the cutting edge of nuclear research. Here you will learn from the experts about the technology that overcame and harnessed the power of the atom.
Image Credit
Oklo Natural Nuclear Reactor image courtesy of Wikimedia Commons published under the CC license.
Looking forward...
5 Comments
Slight nitpick. It is not really possible today for a natural nuclear chain reaction to start. Back when the natural reactor at Oklo was active, the fraction of uranium-235 was higher than it is today. Today, uranium in a natural form immersed in light water cannot achieve criticality. While it is indeed possible to have fission chain reactions in natural uranium (see CANDUs or MAGNOX designs), those conditions would not occur naturally.
Any and all nitpicking is welcome and encouraged.
Do you think there is a chance that any natural ore deposits still have a high enough U-235 component to go critical. that we haven’t discovered yet?
While it’s certainly possible, it’s highly unlikely. Much of the base material for our solar system came from the same supernova explosion. It was in this event that the heavy elements we find here on Earth were formed. The original isotopic ratio (the initial condition on “enrichment”) depended upon the conditions in the supernova at the time.
For us to have a sample with a higher uranium-235 concentration, it would have had to been in a meteorite from a different supernova. The isotopic ratios here on Earth are remarkably consistent suggesting that only one supernova was responsible for the formation of all the heavy elements here on Earth. Given the vast expanses of space, it is not likely at all that “rogue ejecta” from a more recent supernova (with a higher U-235 concentration) would have been able to reach us.
If natural nuclear fission is the focus, I’m interested in what you think about Marvin Herndon’s belief that the earth’s magnetic field is powered by nuclear fission in what he calls a georeactor at the earth’s core. See http://www.youtube.com/watch?v=O-V3yR2RZUE
The georeactor is an interesting hypothesis. While I don’t think anyone can outright dismiss the idea based on physical grounds, more likely explanations for various observed phenomena exist. Therefore, Dr. Herndon faces a burden of proof to demonstrate that his hypothesis is most likely, which, last I heard, he has not successfully done.
What we would really need to do is measure the antineutrino flux. That would provide a definitive answer. Unfortunately, such measurements are very difficult to make.