As innovative nuclear technologies enter the national conversation, one category of reactor may present a unique opportunity for Arizona—not only for its passive safety features and potential waste-recycling capabilities, but also for its alignment with the state’s long-term water security and natural resource goals: molten salt reactors.
At its core, every nuclear reactor must continuously remove heat to operate safely and prevent a meltdown. Traditionally, water has served as the primary coolant, but using water requires extremely high-pressure systems and complex safety infrastructure—which have led many advanced reactor designers to pursue lower-pressure alternatives, reimagining the very nature of a nuclear meltdown at its core: instead of using a solid fuel and trying to prevent a meltdown, what if the fuel is already molten by design?
Enter molten salt.
First pioneered in the 1960s, molten salt reactors use chloride salts—such as sodium chloride, potassium chloride, or magnesium chloride—that are heated to roughly 1,000°F until they melt into a circulating liquid coolant, enabling high-temperature operation and passive safety features at or near atmospheric pressure that do not require massive high-pressure systems.
While 1,000°F sounds too hot to “cool” anything, in basic thermodynamics, a coolant only needs to be cooler than the system it regulates. Inside a nuclear core—where fuel temperatures can exceed 2,000°F—even glowing red-hot liquid magma can serve as an effective heat-transfer medium.
In some molten salt designs, the nuclear fuel itself is dissolved directly into the circulating salt, creating a dynamic reactor environment, which some experts have described as “meltdown-proof,” while also enabling the recycling and reuse of spent nuclear fuel to extract more energy per unit of fuel and improve the system’s overall energy efficiency.
Several leading developers are actively working to commercialize chloride-salt technologies.
TerraPower, backed by the U.S. Department of Energy and Bill Gates, is developing a molten chloride fast reactor that uses high-assay low-enriched uranium (HALEU) dissolved in sodium chloride and magnesium chloride to generate power using radioactive material derived from spent nuclear fuel.
Moltex Energy’s Stable Salt Reactor—the company’s “wasteburner” design—dissolves spent nuclear waste in a mix of potassium chloride and sodium chloride salts to extract additional energy from existing fuel while reducing the volume of long-lived nuclear waste.
Stellaria’s molten chloride fast reactor places uranium chloride fuel directly into a mix of molten sodium chloride and potassium chloride, where the liquid fuel serves as both the heat-transfer medium and fission environment, enabling low-pressure operation with passive safety features suitable for future grid and industrial heat applications.
Taken together, these efforts illustrate a clear trend: molten chloride salt systems are moving steadily from laboratory theory toward commercial reality.
The use of molten salt at industrial-scale is not new. The Solana Generating Station in Arizona uses molten salt to store thermal energy from concentrated solar power and generate electricity after sunset. Despite early economic and permitting challenges, Solana continues to operate safely today, demonstrating that large-scale molten salt systems can function reliably in the Arizona desert.
Aside from the passive safety features and potential recycling capability, there is another component of molten salt reactors that may work particularly well for Arizona: the salt itself.
Studies conducted by the Arizona Department of Water Resources (ADWR) and the U.S. Geological Survey show that Arizona contains more than 600 million acre-feet of brackish groundwater, including an estimated 236 million acre-feet in the Little Colorado River Plateau basin.
These waters contain high levels of total dissolved solids (TDS)—including sodium, magnesium, and potassium—many of the same elemental building blocks that are used in chloride salt reactors. According to ADWR, the TDS in the Little Colorado River Plateau basin exceed 10,000 milligrams per liter, making the basin “the largest brackish groundwater area in the state.”
For many policymakers, the challenge with brackish groundwater desalination has been what to do with the brine. But with thoughtful planning and continued research, strategically desalinating Arizona’s brackish groundwater supply could provide a steady stream of in-state chloride-salt feedstocks for next-generation reactors—linking Arizona’s water, energy, and natural resource strengths to help power the next generation of advanced nuclear technologies.
While no one is suggesting piping raw brackish water directly into a reactor, taking the steps to separate and purify these chloride salts to reactor-grade specifications could present a meaningful economic opportunity for our state, creating jobs and new sources of revenue for rural areas.
Arizona has never failed by thinking big. As energy demands rise, water scarcity increases, and mineral needs mount, advanced nuclear reactors with molten salt designs could present the innovative, multi-faceted solution that Arizona needs to power its clean energy future.
Michael Carbone is a Republican member of the Arizona House of Representatives representing Legislative District 25 and serves as House Majority Leader. Follow him on X at @MichaelCarbone. Gail Griffin is a Republican member of the Arizona House of Representatives serving Legislative District 19, which includes areas of Greenlee, Graham, Cochise, and eastern Pima and Santa Cruz Counties. She also serves as Chairman of the House Natural Resources, Energy & Water Committee.