UNC researchers develop safer nuclear waste storage

Researchers from UNC have developed a safer way to store nuclear waste — and they plan to take it to a larger scale.

Chemistry professor Tom Meyer and postdoctoral research associate Chris Dares teamed up with other researchers to discover a safer way to store nuclear waste — remove a certain element, americium, from the solution. 

Meyer and Dares said the current method for storing nuclear waste involves condensing the solution down into a container and burying it underground. Currently, when nuclear waste is stored, the americium in the solution causes the waste to be radioactive and give off heat.  

“What is going to happen when it gets too hot in this room where you are storing this stuff?” Dares said. 

“Right now, the waste is typically stored in big pools of water inside of a container, but that’s because the water helps to remove a lot of the heat that’s generated. But if you can remove the americium, then you don’t have to worry about the heat.”

Dares said the problem is americium looks and behaves like other elements in the waste, which makes it difficult to identify and separate. UNC researchers were able to develop molecules using electrochemistry to remove electrons from the americium, causing it to undergo a chemical change. This change causes the element to be more distinct in the solution, making it much easier to selectively remove the americium.

“A problem needs to be solved because the waste is building up," Meyer said. "Here is a technique of taking the waste and putting it in a form that is more easily disposable.”

Jeffrey Johnson, chairperson of the chemistry department, said this discovery could be instrumental to the future of chemical nuclear waste. 

“A lot of what drives our faculty is the excitement of scientific discovery,” Johnson said. “What motivates our faculty is, really, curiosity-driven research and asking questions that, I think, can be highly impactful to science in general, but to society as well.”

Dares and Meyer said there were some obstacles when they first started the research.

“I knew nothing at the time about nuclear energy (or) about the nuclear waste problem,” Dares said. “I had always been of the belief that you only had to know up to element number 92 on the periodic table because after that they are all man-made, and here I was working with a man-made element.”

Dares said other scientists’ previous experiments trying to find a way to more safely store nuclear waste have not been as effective.

“This was more than a year and a half in the making, and this was a problem that was not given a high probability of success. So when it first worked, we were very apprehensive if it actually worked,” Dares said.

“There was a lot of going back and trying to be good scientists to make sure that we were dotting our i’s, crossing our t’s, and making sure that the results are actually real. But after we had essentially been able to do this on a regular basis, we were very excited about this.”

Dares credited Meyer with being instrumental in making sure the project ran smoothly.

“It crept up slowly,” Meyer said. “You have a project, you start, get the results and it's pretty interesting. After we got done and saw that you can do it, you then sit down and write it up a form that you can share with the scientific community. At that point, I think for the first time, it struck me that this really could be an important advance.”

Dares said the next step would be to contact Idaho National Laboratory, where they did a majority of their work, to see how effective this form of nuclear waste storage could be on a larger scale. 

“They have been instrumental in all of this,” Dares said. “They are the premier place to do nuclear research in the United States. We’ve been blessed to work with some of the best.”

Now that Dares, Meyer and their team of researchers have shown they are able to do this on a consistent basis, they plan to spend more time thinking about the implications.

Dares said the next steps are to hopefully get funding to find new ways that will more selectively and effectively remove the oxidized americium.

“Hopefully it provides a new platform for a more complete fuel cycle,” Dares said. “Reduce, reuse, recycle. Works with nuclear as well.”

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