The U.S. Department of Energy’s (DOE) Argonne National Laboratory will be partnering with three companies as part of a voucher program provided by the Gateway for Accelerated Innovation in Nuclear (GAIN) program of DOE’s Office of Nuclear Energy. As part of the projects, Argonne will help industry develop a range of new reactor and fuel cycle concepts that go beyond today’s traditional large, water-cooled reactors.
In one award, Argonne will work with Radiant Industries, a start-up based in California, to perform numerical modeling of heat production and removal in Radiant’s advanced high-temperature gas-cooled microreactor concept. The advantage of this microreactor, called Kaleidos, is that it is portable, said Argonne nuclear engineer April Novak, one of the laboratory’s Maria Goeppert Mayer fellows.
“This type of reactor is quite different from conventional reactors because of its small size; it is targeting diverse applications for nuclear energy, such as remote communities and electric vehicle charging,” Novak said. “I’m very excited to be working on this because I find it rewarding to see Argonne’s research applied to a commercial concept that has potential to expand nuclear energy’s role in addressing climate change.”
Novak will help create high-fidelity computational fluid dynamics models of the microreactor in shutdown conditions, including its passive heat removal systems. One of these heat removal systems is called an air jacket, which consists of a thin layer of ambient air in between the reactor and the shielding. “The air jacket is designed to passively remove decay heat, improving the safety of nuclear power production,” Novak said.
“The air jacket modeling work with Argonne will be truly novel and a critical requirement with unique benefit to passive cooling,” says Radiant CEO Doug Bernauer. “We plan to be the first new commercial reactor design to achieve a fueled test in more than 50 years. Full commercialization for advanced reactors will require widespread, ongoing partnership across DOE and several national labs like Argonne and Idaho National Lab. We’re thrilled about this award because it’s another key step in that direction.”
The award will also help researchers identify the heat sources in the reactor, based on how fuel is burned, Novak said. Argonne’s work on Kaleidos through the GAIN voucher is an extension of earlier work performed through the Nuclear Energy Advanced Modeling and Simulation program.
In another GAIN award project, Argonne nuclear engineer Darius Lisowski will lead a team of researchers working with Oklo, a nuclear company also based in California working on small fast reactors as part of the Aurora product line.
Lisowski’s team will help to test high-flow coolant over pin bundles that have been designed by Oklo. These pins are fabricated and tested using capabilities recently established at Argonne. “We initially built this facility for the Versatile Test Reactor, and our experience will serve us well in helping Oklo bring their reactor concept into reality,” Lisowski said.
Argonne maintains facilities for testing the flow performance of the pin bundles. “Basically because of the internal geometry there’s a lot of interesting physics about how the coolant mixture will flow across the pins,” Lisowski said. “We’re looking at extreme flow conditions — over 800 gallons of water a minute — to look at the pressure drop through various sections of the assembly.”
A third project to receive GAIN funding will involve a team led by Argonne nuclear engineer Melissa Rose to look at reactors powered and cooled by a molten salt mixture. Although no molten salt reactors are currently commercially in use, Rose said that a molten salt reactor is conducive to nuclear fuel recycling via pyroprocessing, a technology Argonne also developed. “About 97% of nuclear fuel can theoretically be used; it’s just contaminated by fission products that have to be separated out,” she said. “A molten salt reactor could get us closer to a closed fuel cycle in which much of the nuclear fuel is used over and over again.”
In a molten salt reactor, the fuel is dissolved in the molten salt and the liquid moves through the reactor. In her GAIN-funded program, Rose is working with Flibe Energy, based in Alabama. Flibe is pursuing a molten fluoride reactor that could be used for both energy generation and to provide medical isotopes for life-saving cancer treatments.
Argonne developed and maintains specialized facilities that Rose and her colleagues will use to measure the properties of these molten salts. From melting point to phase behavior to heat capacity and thermal diffusivity, Argonne’s analysis of these properties will help Flibe bring their reactor closer to construction. This is Argonne’s seventh GAIN voucher measuring properties in support of molten salt reactors.
Funding for the research is provided by DOE’s Office of Nuclear Energy.
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.