The “Americium Problem”

Obtaining power from nuclear fission is one of the cleanest and most efficient ways to feed our energy-thirsty civilization; however, there is the thorny issue of what to do with the toxic, radioactive waste that the method inevitably produces.

But by adapting a technique used in the solar power industry, a team of researchers from the University of North Carolina at Chapel Hill have shown that it’s possible to isolate and safely remove some of the most dangerous elements in nuclear waste. The discovery points the way to finally laying to rest the stifling shade of toxic, radioactive waste—waste that lingers for tens of thousands of years—which has done so much to prevent the widespread adoption of nuclear power.

“In order to solve the nuclear waste problem, you have to solve the americium problem,” explains Tom Meyer, leader of the new study. And that is precisely what his team did.

Closing the Nuclear Fuel Cycle

The problem with “cleansing” nuclear waste is that, while plutonium and uranium can be removed with current technologies, americium is far more difficult. Previously, teams had claimed to have solved the problem, but these attempts were thwarted by issues that developed further “downstream”—issues that overthrew the solutions altogether.

But Meyer’s team hit upon a different solution: they used a technology used in solar power applications to strip electrons from water molecules. “Cracking” americium is slightly more difficult—the process requires twice as much energy as with water—but the results are well worth the expenditure.

The technique was used to strip three electrons from the americium atoms, which then behave identically to uranium and plutonium. These elements are easily cleansed from spent fuel by dissolving the nuclear pellets in acid, and now the americium can be filtered out along with them.

So there is an “americium problem” no more—and a great obstacle to the further development of nuclear energy is removed.

“With a scaled up solution,” says Chris Dares, a member of the team, “not only will we no longer have to think about the dangers of storing radioactive waste long-term, but we will have a viable solution to close the nuclear fuel cycle and contribute to solving the world's energy needs. That's exciting.”

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