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The Molten Chloride Reactor Experiment will provide crucial operational data for fast-spectrum salt reactors and unlock this uniquely flexible advanced reactor technology for use in a net-zero future

BELLEVUE, Washington – February 23, 2022 – TerraPower and Southern Company recently finalized a subrecipient agreement to design, construct and operate the Molten Chloride Reactor Experiment (MCRE) – the world’s first critical fast-spectrum salt reactor – at Idaho National Laboratory (INL).

“TerraPower is eager to continue its partnership with Southern Company – an established energy company that offers a crucial perspective and expertise to further position our Molten Chloride Fast Reactor technology for success,” said Chris Levesque, TerraPower’s president and CEO. “We are honored to be part of a team that is dedicated to advancing next-generation, low-cost, carbon-free nuclear technology to help meet global emissions-reduction targets and provide reliable power.”

Selected for funding under the U.S. Department of Energy’s (DOE) Advanced Reactor Demonstration Program (ARDP), the MCRE project will advance TerraPower’s Molten Chloride Fast Reactor (MCFR)— a technology that could provide low-cost, clean energy for a sustainable future. Southern Company research and development will lead the effort in a collaboration that includes TerraPower, INL, CORE POWER, Orano Federal Services, the Electric Power Research Institute and 3M Company. The team’s ongoing alliance with DOE’s Office of Nuclear Energy through the ARDP is essential for delivering this key technology and will be supported by a five-year, $170 million cost-shared funding agreement.

“Southern Company is honored to work with DOE, TerraPower, INL and our other team members to advance next-generation nuclear as part of a comprehensive strategy to deliver clean, safe, reliable, affordable energy to the customers and communities we serve,” said Dr. Mark S. Berry, Southern Company vice president of R&D. “The Molten Chloride Reactor Experiment will advance a revolutionary technology that promises to address climate change benchmarks on a timescale to deliver on Southern Company’s goal of net-zero greenhouse gas emissions by 2050.”  

The Molten Chloride Reactor Experiment will be the world’s first fast-spectrum, salt-fueled nuclear fission reactor to go critical, meaning that it is operating on a self-sustaining nuclear chain reaction. The MCRE project represents a significant inflection point in the technology demonstration roadmap for TerraPower’s MCFR, as the project will inform the design, licensing and operation of an MCFR demonstration reactor. MCRE is targeted for operation at INL, the nation’s premier nuclear energy laboratory, and will be authorized by DOE.

The MCRE project will not generate electricity, but it will operate at a power of up to 500 kilowatts and demonstrate key physics performance important to the broader MCFR program. An environmental review will be completed for the MCRE project in accordance with the National Environmental Policy Act before final design and construction begin. MCRE first criticality is scheduled for late 2025.

TerraPower’s MCFR technology has the potential to provide low-cost, clean energy for the future. It offers many performance and economic benefits including flexible, highly efficient clean power generation as a complement to the increased use of intermittent renewables on the grid. The MCFR technology also has the potential to provide carbon-free, high-grade process heat and thermal storage for difficult-to-decarbonize industrial markets and ocean transportation sectors.

Through a public-private partnership that was initiated in 2015, Southern Company and TerraPower joined DOE and others in the nearly $80 million project building integrated infrastructure necessary to support early development of the MCFR technology. The newly selected Molten Chloride Reactor Experiment will further advance this development.

About TerraPower
TerraPower is a leading nuclear innovation company that strives to improve the world through nuclear energy and science. Since it was founded by Bill Gates and a group of like-minded visionaries, TerraPower has emerged as an incubator and developer of ideas and technologies that offer energy independence, environmental sustainability, medical advancement and other cutting-edge opportunities. It accepts and tackles some of the world’s most difficult challenges. Behind each of its innovations and programs, TerraPower actively works to bring together the strengths and experiences of the world’s public and private sectors to answer pressing global needs. Learn more at

About Southern Company

Southern Company (NYSE: SO) is a leading energy company serving 9 million customers through its subsidiaries. The company provides clean, safe, reliable and affordable energy through electric operating companies in three states, natural gas distribution companies in four states, a competitive generation company serving wholesale customers across America, a leading distributed energy infrastructure company, a fiber optics network and telecommunications services. Southern Company brands are known for excellent customer service, high reliability and affordable prices below the national average. For more than a century, we have been building the future of energy and developing the full portfolio of energy resources, including carbon-free nuclear, advanced carbon capture technologies, natural gas, renewables, energy efficiency and storage technology. Through an industry-leading commitment to innovation and a low-carbon future, Southern Company and its subsidiaries develop the customized energy solutions our customers and communities require to drive growth and prosperity. Our uncompromising values ensure we put the needs of those we serve at the center of everything we do and govern our business to the benefit of our world. Our corporate culture and hiring practices have been recognized nationally by the U.S. Department of Defense, G.I. Jobs magazine, DiversityInc, Black Enterprise, Forbes and the Women’s Choice Award. To learn more, visit

About Idaho National Laboratory

Battelle Energy Alliance manages INL for the U.S. Department of Energy’s Office of Nuclear Energy. INL is the nation’s center for nuclear energy research and development, and also performs research in each of DOE’s strategic goal areas: energy, national security, science and the environment. For more information, visit Follow us on social media: TwitterFacebookInstagram and LinkedIn.