The element Americium won’t be the first thing you think of when someone mentions nuclear waste, but it has been a problem all the same.
Director of UNC’s Energy Frontier Research Center Tom Meyer said we have the capability to separate and recycle leftover Plutonium or Uranium, but until now, Americium had remained an issue.
“Separating the Americium, which is radioactive, from these other ions turns out to be very painful,” he said. “It’s not totally obnoxious but you can’t just let it lie around and there are big tanks that contain this solution because there’s been no way to get rid of the Americium.”
Meyer and postdoctoral fellow Chris Dares worked to adapt technology used in solar energy and apply it to nuclear waste.
They added a molecule known as a ligand, which bonds to the Americium and causes it to lose electrons.
“When it does that it really changes it nature,” Meyer said. “All of the sudden it has a lower charge, it has a couple of oxygens stuck on it, the charge goes down and all of the sudden the separation looks an awful lot, at least in principle like you would use for Uranium or Plutonium.”
Once in that state, scientists should be able to use the same processes on Americium as they use on the other elements.
Dares said although the process of removing three electrons sounds simple, the voltage required is large and that had prevented success in the past.
“The reason why we want to get rid of the Americium is because the heat that’s generated during its radioactive decay,” he said. “It really limits how densely you can pack this material into a storage location.”
The two had been working with the Idaho National Laboratory, which gave a safe place to work with radioactive material. UNC and INL are currently discussing extending the research.
“It does not completely remove the need to store nuclear waste,” Dares said. “However it does reduce the time that you need to have it stored away from human contact and it also improves the density with which you can store this material.”
