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Terrestrial Energy, Westinghouse and UK National Nuclear Laboratory Sign Agreement for IMSR Nuclear Fuel Supply

Preston, United Kingdom and Oakville, Ontario – August 17, 2021 – Westinghouse, the UK National Nuclear Laboratory (NNL), and Terrestrial Energy have signed an agreement for nuclear fuel development and supply. The agreement is to advance the industrial scale up and commercial supply of enriched uranium fuel for use in Terrestrial Energy’s Integral Molten Salt Reactor (IMSR®), a Generation IV advanced nuclear power plant, which is under development in Oakville. The Terrestrial Energy IMSR® incorporates the latest in nuclear technology to provide cleaner, safer, more reliable and cost effective energy.

Westinghouse’s UK facility, Springfields, is a global leader in the supply of uranium fuel for today’s commercial nuclear power reactors. The NNL is the UK’s national laboratory for nuclear fission research and provides critical technical support services to Westinghouse from its research facility co-located on the Springfields site.

IMSR® fuel utilizes Standard Assay Low Enriched Uranium (LEU), which over many decades has become the commercial fuel standard. Standard Assay LEU is enriched to up to 5 percent uranium-235, at plants in Germany, the Netherlands, United Kingdom, and United States. Terrestrial Energy’s use of Standard Assay LEU fuel in IMSR® operation, the only Generation IV reactor design to do so today, supports early deployment.

Paul Howarth, Chief Executive of NNL, said: “The development of the IMSR® power plant provides a fundamental platform that showcases the vast potential of the Springfields site. The agreement also harnesses NNL’s expertise in collaboration with Westinghouse global fuels experience and capabilities, which is vital to expand the supply capability for advanced reactor fuels.”

“As the expansion plan continues, we are delighted that the advanced reactor sector recognises our capabilities and Terrestrial Energy has selected Westinghouse and NNL to develop the commercial fuel supply. We look forward to implementing the processes and facilities, creating jobs which will be pivotal in supporting the first operating IMSR® nuclear power plant,” added Howarth.

Sophie Lemaire, Regional Vice President, Westinghouse, said: “We are committed to Shaping Tomorrow’s Energy together for a cleaner, better future, and as a leading global supplier of commercial nuclear fuel, we have the knowledge, technology and capability to develop new fuel manufacturing routes for advanced nuclear technologies. These technologies will support skilled manufacturing jobs at our Springfields site in Lancashire, a strategic national asset for the United Kingdom, employing around 800 high value jobs in the region.”

Simon Irish, Chief Executive Officer, Terrestrial Energy, said: “We have designed IMSR® to use Standard Assay LEU fuel as it is today’s nuclear fuel standard and is readily available for civilian use. This is a major advantage for early deployment. Terrestrial Energy is working on a multiple sourcing strategy for IMSR® fuel supply, and we recognize the world-class fuel expertise and production capabilities at the National Nuclear Laboratory and Westinghouse Springfields. Our agreement is an important step to demonstrate reliable, secure and long-term commercial supply of reactor fuel to utilities operating IMSR® power plants.”

The agreement between Terrestrial Energy, Westinghouse and the National Nuclear Laboratory defines the process for delivering IMSR® fuel for commercial use, concurrent with schedules for commercial operation of IMSR® power plants by electric utility customers.

 About Terrestrial Energy

Terrestrial Energy is a developer of Generation IV advanced nuclear power plants that use its proprietary Integral Molten Salt Reactor (IMSR®) technology. IMSR® technology represents true innovation in cost reduction, versatility and functionality of nuclear power plants. IMSR® power plants will provide zero-carbon, reliable, dispatchable, cost-competitive electric power and high grade industrial heat for use in many industrial applications, such as chemical synthesis and desalination, and in so doing extend the application of nuclear energy far beyond electric power markets. They have the potential to make important contributions to industrial competitiveness, energy security, and economic growth. Their deployment will support rapid global decarbonization of the primary energy system by displacing fossil fuel combustion across a broad spectrum. Using an innovative design, and proven and demonstrated molten salt reactor technology, Terrestrial Energy is engaged with regulators and industrial partners to complete IMSR® engineering and to commission first IMSR® power plants in the late 2020s.

About Westinghouse

Westinghouse Electric Company is the world’s pioneering nuclear energy company and is a leading supplier of nuclear plant products and technologies to utilities throughout the world. Westinghouse supplied the world’s first commercial pressurized water reactor in 1957 in Shippingport, Pa., U.S. Today, Westinghouse technology is the basis for approximately one-half of the world’s operating nuclear plants. For more information, please visit

About the National Nuclear Laboratory

The UK’s National Nuclear Laboratory is the country’s national lab for nuclear fission, owned by the UK Government and operating on a commercial basis. NNL’s purpose is Nuclear Science to Benefit Society and one of its four focus areas is Clean Energy – clearly aligned to this work. NNL is developing advanced fuel cycle solutions through its leadership of the £46m Advanced Fuel Cycle Programme – part of the Department for Business, Energy and Industrial Strategy’s (BEIS) £505m Energy Innovation Programme.

Learn More About Terrestrial Energy

Terrestrial Energy is an industry-leading technology company committed to delivering reliable, emission-free, and cost-competitive nuclear energy with a truly innovative advanced reactor design, the Integral Molten Salt Reactor (IMSR®).