Southern Company said on October 14, 2026, that the U.S. Department of Energy had approved cost-shared funding to accelerate the final stage of the Molten Chloride Reactor Experiment (MCRE). The company said the funding, through DOE’s Advanced Reactor Demonstration Program, would support work by Southern Company, Idaho National Laboratory and CORE POWER.
The announcement did not disclose a funding amount. CORE POWER chief executive Mikal Bøe said the project was targeting first criticality as early as 2027. Criticality is the point at which a reactor sustains a controlled nuclear chain reaction; the date remains a project target.
The partners intend to use the experiment to collect operating evidence for future reactor development. Southern Company described it as an effort to become the world’s first fast-spectrum molten chloride salt reactor experiment to reach criticality.
Measuring a liquid-fueled reactor
Molten salt reactor designs can dissolve nuclear fuel in liquid salt, unlike conventional reactors that typically use solid fuel. Idaho National Laboratory describes MCRE as a planned chloride-based system using a fast neutron spectrum. Fast neutrons have higher energies than the thermal neutrons used in many conventional reactors, affecting how the fuel behaves and sustains fission.
Jess Gehin, Idaho National Laboratory’s associate laboratory director for Nuclear Science and Technology, said MCRE was intended to provide direct measurements of reactor behavior during sustained fission. He said engineers had relied on models for the operating behavior the experiment would examine.
“Enhancing those models with real-world operating evidence will reduce uncertainty for future reactor designers and regulators,” Gehin said.
The planned measurements concern fuel behavior, operation and performance. Southern Company said the resulting data could support future reactor designs and licensing work. These remain intended uses of the research, with experimental results still to come.
Research goals and limits
Mark S. Berry, Southern Company’s senior vice president of research, environment and sustainability, said collaboration between DOE, the laboratory and industry could expand knowledge of molten salt technology and reduce technical uncertainty for developers.
Southern Company also identified industrial energy, medical isotope production and recovering additional energy from used nuclear fuel as potential applications of future fast-spectrum molten salt systems. Its announcement qualified those possibilities as dependent on reactor design and fuel-cycle configuration.
The company cautioned that these were potential future capabilities. MCRE itself would not use spent fuel or demonstrate a closed fuel cycle.
CORE POWER’s maritime ambitions
Bøe said CORE POWER first committed to building MCRE in 2020. He said the experiment’s data would help guide the engineering, licensing and supply chains needed to pursue commercial deployment of fast-spectrum molten salt reactors.
The company sees a connection between that research and its work on maritime nuclear power. Bøe identified propulsion for large commercial ships as a potential market, presenting long-duration nuclear power as an alternative energy source for shipping.
The funding announcement did not set a date for commercial marine deployment. Southern Company explicitly said MCRE would not test a marine reactor.