Ancient Natural Fission Reactor Helps Scientist Learn How to Better Store Radioactive Waste


Researchers from the U.S. Naval Research Laboratory and Washington University found out about a new way to store nuclear waste by observing the ancient natural Oklo nuclear reactor and analyzing its cores.

They wrote their findings in the paper titled “Discovery of fissionogenic Cs and Ba capture five years after Oklo reactor shutdown,” which was published in Proceedings of the National Academy of Sciences.

It’s the era of searching for new ways to generate energy and make it environmentally friendly, but there is still an old technology that continues to generate waste – the one from nuclear power plants. Scientists are now looking for a way to store waste, starting with learning what happens as it decays in time. Evan Groopman (US Naval Research Laboratory) and his team went to West Africa, in the Oklo region of Gabon.

A Natural Nuclear Reactor – the Answer for Storing Nuclear Waste

They wanted to analyze a sample of uranium ore which was found in a rare geologic formation deep underground. That site was a naturally occurring fission that started taking place almost 2 billion years ago. The uranium-235 which made those reactions possible in the past has decayed after about 24,000 years, and scientists had to learn how it happened to apply the knowledge to modern day nuclear waste.

“It takes an incredible confluence of conditions for these natural nuclear reactors to occur,” says Groopman.

They took the sample to their lag and used the Naval Ultra Trace Isotope Laboratory’s Universal Spectrometer to find out the history of the material – paying great attention to the cesium which was produced as a byproduct in the uranium fission. After their analysis, researchers discovered that cesium was absorbed by ruthenium at almost five years after fission ceased and held the cesium in place for about 2 billion years.

“Perhaps nuclear fuel storage casks could be lined with an additional mineral or element that binds with and captures the caesium. Then the caesium can be stored over a longer term, so it has time to decay,” concludes Groopman, who thinks that ruthenium compounds are very useful, but also too rare to use.


Recommended For You

Leave a Reply

Your email address will not be published. Required fields are marked *