Natural nuclear fission reactor

Natural nuclear fission reactor‏‎

A Natural nuclear fission reactor refers to a phenomenon where nuclear fission occurs naturally, without human intervention. This process is a rare occurrence and has only been observed in two locations on Earth, both in Gabon, Africa, at a site known as Oklo.

History

The existence of natural nuclear fission reactors was first proposed by Paul Kuroda, a Japanese-American chemist, in 1956. However, it was not until 1972 that the first evidence of such a reactor was discovered at Oklo by French physicist Francis Perrin.

Mechanism

Natural nuclear fission reactors operate on the principle of nuclear chain reaction, similar to man-made nuclear reactors. The key difference is that natural reactors utilize uranium-235, a naturally occurring isotope of uranium, as their fuel source.

When a neutron strikes the nucleus of a uranium-235 atom, the nucleus splits, releasing energy and additional neutrons. These neutrons can then strike other uranium-235 atoms, causing them to split and release more neutrons. This chain reaction continues until the uranium-235 is depleted.

Conditions for Formation

The formation of a natural nuclear fission reactor requires very specific conditions. First, there must be a sufficient concentration of uranium-235. Second, there must be a natural moderator, such as water, to slow down the neutrons and increase the likelihood of them causing fission. Finally, the uranium must be in a geological setting that allows for the chain reaction to be sustained over a long period of time.

Significance

The discovery of natural nuclear fission reactors has significant implications for various fields, including nuclear physics, geology, and astrobiology. It provides evidence that nuclear reactions can occur naturally on Earth, and potentially on other planets as well.

Furthermore, the reactors at Oklo have been studied extensively to understand how nuclear waste is naturally stored and contained over geological timescales. This has important implications for the management of man-made nuclear waste.

See Also

• Nuclear fission
• Nuclear chain reaction
• Uranium-235
• Oklo
• Paul Kuroda
• Francis Perrin