A very small fraction of the energy available in nuclear fuel is used during the production of nuclear energy. The amount that remains can be recovered and recycled to create a lot of electricity. The U.S. Department of Energy’s (DOE) Advanced Research Projects Agency-Energy (ARPA-E) estimates that the untapped energy remaining in used nuclear fuel, sometimes referred to as spent nuclear fuel, can generate enough clean energy to power more than 70 million homes.
Recently, ARPA-E awarded more than $6 million to DOE’s Argonne National Laboratory to develop and demonstrate innovative processes and technologies that focus on recycling used nuclear fuel (UNF). The funding is awarded through the Converting UNF Radioisotopes Into Energy (CURIE) program.
Nuclear energy is the source of approximately one-fifth of total electricity used in the U.S., and it provided half of the nation’s carbon-free electricity in 2021. Improving electrochemical separation and other UNF recovery and recycling technologies could help nuclear energy do more. More efficient use of nuclear energy would significantly decrease domestic reliance on fossil fuels and the related greenhouse gases that contribute to climate change. It would reduce waste and produce new fuel for advanced reactors. This last benefit would lead to deployment of new advanced reactors, which would provide even more safe, clean, reliable electricity.
“Our partnerships with ARPA-E and industry are incredibly important to closing remaining technology gaps.” — Krista Hawthorne, section manager, pyroprocess engineering
Argonne will use ARPA-E’s funding to advance two projects. The larger project will combine Argonne’s leadership in nuclear research and development with the experience of nuclear industry partners Oklo Inc. and Deep Isolation. Argonne will collaborate with Case Western Reserve University on both projects.
The larger project was awarded $4.9 million. It focuses on increasing the efficiency and, therefore, the economics of nuclear fuel recycling processes. Argonne, Oklo Inc. and Deep Isolation are working to improve a process that converts UNF oxide fuel to a metal that can then be processed to provide usable materials for advanced reactor fuel. The project will combine improvements in stable, next-generation anode materials and sensors used to control the process to maximize the amount of material that can ultimately be recovered.
Krista Hawthorne, the pyroprocess engineering section manager in Argonne’s Chemical and Fuel Cycle Technologies division, leads the effort.
“Improving the efficiency of fuel recycling processes will help recover and recycle valuable resource materials remaining in used nuclear fuel,” said Hawthorne. “Our partnerships with ARPA-E and industry are incredibly important to closing remaining technology gaps.”
The second project was awarded $1.52 million. With this project, Argonne researchers will develop, produce and test more efficient industrial chemical processing equipment to reprocess UNF. The project lead is Argonne radiochemist Anna Servis.
State-of-the-art facilities that reprocess light water nuclear reactor fuels use equipment known as packed bed columns. Packed bed columns are tall canisters filled with a packing material that mixes the fluids flowing from one end to the other during chemical separations.
Servis’ team’s design instead uses PACERs (PAcked Centrifugal Equipment for Radiochemical separations). PACERs are rotating packed bed contactors that are considerably more efficient than the columns. They use centrifugal forces much greater than the pull of gravity to boost the speed and efficiency of chemical separations. They are also notably smaller. For scale, imagine replacing a water tower-sized packed bed column with a shed-sized PACER.
“Used nuclear fuel contains a treasure trove of raw materials, including energy-rich uranium that can be recycled into new fuel, precious metals and versatile radioisotopes,” said Servis. “Mining our existing UNF stockpiles reduces demand for non-renewable minerals and conserves resources for future generations.”
Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science.
The U.S. Department of Energy’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://energy.gov/science.