The Bill Gates-chaired company has also announced the creation of TerraPower UK, a UK subsidiary, its first office outside the USA.
Chris Levesque, President and CEO of TerraPower, said: “TerraPower is entering the UK market with a long-term commitment to supporting the nation’s clean energy future and establishing ourselves as a serious and reliable deployment partner.”
He said that creating the UK-based firm and beginning Step 1 of the Generic Design Assessment (GDA) process “advances our mission to bring the Natrium technology to Britain”.
A Generic Design Assessment is the process to assess nuclear power plant designs, notably the safety, security and environmental implications. It looks at this aspect separately from applications to build them at specific sites.
The ONR says that by assessing at the design stage, any potential safety, security or environmental concerns can be identified and highlighted so “they can be addressed before commitments are made to construct any reactors based on that design. GDA is also designed to be generic, allowing the results of the regulators’ assessment to potentially be applied to multiple sites where that design is subsequently constructed”.
TerraPower submitted its GDA application in October, the first regulatory filing for Natrium technology in a market outside the USA. It was accepted into the process in February and the UK’s Office for Nuclear Regulation (ONR), the Environment Agency and Natural Resources Wales have now begun the GDA process.
Over the coming months the ONR will discuss with Terrapower, the Environment Agency, and Natural Resources Wales, “to prepare and agree interface arrangements, undertake reactor familiarisation activities, and develop and define the GDA scope, project delivery strategy and assessment plans needed to guide future formal assessment activities”.
Alan McGoff, the Environment Agency’s Policy Lead New Nuclear Build, said: “GDA’s purpose is to de-risk future Natrium projects by ensuring that environmental protection is built into the design from the start. This is the first GDA where we can take advantage of our arrangements for enhanced cooperation between international regulators following the UK and US governments’ signing last year of the Atlantic Partnership for Advanced Nuclear Energy.”
Yeliz Marshall, Natural Resources Wales’s Radioactivity and Industry Policy Senior Specialist Advisor, said: “It provides a valuable route to embed environmental protection early in the Natrium design and address key risks ahead of any future deployment.”
Diego Fernandez Lisbona, ONR Head of Regulation for the TerraPower Natrium GDA and Advanced Nuclear Technologies, said: “Our focus is on agile and timely delivery of a robust, risk-informed and proportionate assessment of the design’s safety, security and safeguards aspects, to ensure it meets UK regulatory requirements and expectations.”
Ian Hudson, who has been appointed as head of Terrapower UK, said: “Establishing a permanent presence enables us to work closely with our partners to deliver the critical energy infrastructure needed to support the UK’s clean energy transition and economic prosperity.”
Background
In terms of small modular reactors (SMRs), Rolls-Royce SMR Limited’s SMR design entered the GDA process in 2022 and is currently in Step 3 – the final step – of the process; Holtec’s SMR-300 entered the GDA process in December 2023 and is currently in Step 2; and GE Vernova Hitachi’s BWRX-300 entered the process in January 2024 and completed Step 2 in December 2025.
Microsoft co-founder Bill Gates has been chairman of TerraPower since 2006. The firm’s molten salt-based energy storage system means the Natrium plant can temporarily boost output to 500 MWe when needed, enabling the plant to follow daily electric load changes and integrate seamlessly with fluctuating renewable resources.
TerraPower began non-nuclear construction for its first Natrium plant, in Kemmerer, Wyoming, in June 2024, and expects construction of the plant – which it says will be the first commercial-scale, advanced nuclear project in the USA – to be complete in 2030. The first Natrium project is being developed through the US Department of Energy’s Advanced Reactor Demonstration Program.
Earlier this year, social media giant Meta announced that its future nuclear energy plans included funding to support the development in the USA of up to eight Natrium sodium fast reactors – two new units capable of generating up to 690 MW of firm power with delivery as early as 2032, plus the rights for energy from up to six other Natrium units capable of producing 2.1 GW and targeted for delivery by 2035.
The Natrium reactor is a TerraPower and GE Vernova Hitachi Nuclear Energy technology.
