Research Highlight | Nuclear Technologies and National Security

Turning nuclear waste into a resource
Turning nuclear waste into a resource image
(Image by Argonne National Laboratory).

Every year, the United States produces about 2,000 metric tons of used nuclear fuel (UNF) from its 94 nuclear power plants. Managing this waste is a big challenge. Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory are working on a solution called pyroprocessing, which recycles valuable materials from nuclear waste into fuel for use in advanced reactors, reducing the amount of waste requiring disposal and making nuclear energy more sustainable.

Pyroprocessing uses a special type of chemistry called electrochemistry, which uses electricity to perform the chemical separations. It separates the reusable elements from used nuclear fuel such as uranium, neptunium and plutonium using a molten salt as the working fluid. For example, the used nuclear fuel is submerged into the molten salt and electricity is applied to the fuel to separate and collect the uranium as a purified metal on an electrode. The uranium can be reused as fuel for advanced nuclear reactors. The waste materials remain in the salt and are removed later so they can be encapsulated in a waste form and disposed. 

This process has big benefits. It reduces the amount of high-level nuclear waste and decreases the amount of time that the waste has to be isolated, from 300,000 years to just 300 years. It also allows researchers to recover more energy from the originally mined uranium, which means fewer resources are wasted.

“Pyroprocessing is like giving nuclear waste a second life,” said Bethany Dean-Kersten, an Argonne chemical engineer. ​“It helps us recycle valuable materials and minimizes the creation of waste.”

The researchers are working to scale up this technology so it can be used in the real world. They’ve built larger systems to test the process from start to finish.  They have also incorporated sensors that monitor the molten salt in real time, which help keep the process running smoothly and efficiently.

“We are leveraging the insights we gain from evaluating our technologies at small-scale up to pilot-scale to close technical gaps and make our processes industrially ready,” said Steven DelaCruz, Argonne chemical engineer.

These processes also enable the recovery of other valuable materials, like rare earth elements. These materials are important for other energy technologies, such as electric cars. The team is also adding artificial intelligence (AI) tools to improve safety and track materials during the process.

This work is supported by the U.S. Department of Energy’s Office of Nuclear Energy and the Advanced Research Projects Agency’s (ARPA-E). By advancing pyroprocessing, Argonne is helping to recycle valuable energy resources, support the next generation of nuclear energy systems and reduce the amount of nuclear waste needing to be disposed of.