UK Signs Landmark Contract With Rolls-Royce SMR to Build Three Small Modular Reactors at Wylfa, Backed by 2.6 Billion Pounds in Public Funding
Great British Energy-Nuclear and Rolls-Royce SMR signed a contract on April 13 to begin design and delivery of three 470 MW pressurised water reactors at Wylfa in North Wales, targeting grid connection by the mid-2030s.
Overview
Great British Energy-Nuclear (GBE-N) and Rolls-Royce SMR signed a contract on April 13, 2026, formally beginning site-specific design and delivery work for the United Kingdom’s first small modular reactor (SMR) fleet, according to the UK Government. Three 470-megawatt pressurised water reactors will be built at Wylfa on the coast of Ynys Mon (Anglesey) in North Wales, a site with nuclear heritage dating back to the 1960s. The project is backed by 2.6 billion pounds allocated in the 2025 Spending Review, with grid connection targeted for the mid-2030s.
The contract marks the culmination of a two-year competitive selection process in which Rolls-Royce SMR was chosen over GE Hitachi and Holtec International as the UK’s preferred SMR technology partner in June 2025, as CNBC reported at the time.
What We Know
The two-stage contract enables Rolls-Royce SMR to commence site-specific, high-resolution engineering to adapt its standardised modular design to the geological, hydrological, and logistical conditions at Wylfa, according to the UK Government announcement. The deal also authorises the ordering of long lead-time equipment from the supply chain, with key consortium partners including BAM Nuttall, Laing O’Rourke, and Atkins.
Each reactor is designed to generate 470 megawatts of low-carbon electricity, which Rolls-Royce SMR says is equivalent to the output of more than 150 onshore wind turbines, according to Interesting Engineering. The three-unit project will produce at least 1.4 gigawatts combined, enough to power approximately three million homes for more than 60 years. The reactor design is approximately 90 percent factory-built using modular components, an approach intended to reduce costs and accelerate construction compared to conventional large-scale nuclear plants.
The National Wealth Fund is committing up to 599 million pounds to Rolls-Royce SMR in the form of a loan to support generic design work applicable to the Wylfa project, future UK sites, and potential exports, according to the UK Government. GBE-N has additionally awarded over 350 million pounds in supply chain contracts this year.
The project is expected to create approximately 3,000 jobs at the Wylfa site during peak construction and an additional 5,000 positions across the national supply chain, according to the UK Government.
Simon Bowen, Chair of GBE-N, called the signing “an immense moment for the UK nuclear programme,” while Energy Secretary Ed Miliband described it as “a major milestone for Britain’s energy security” that supports “clean, homegrown power for decades,” according to the UK Government announcement.
What We Don’t Know
The contract does not yet constitute a Final Investment Decision, which is expected in 2029. No firm date has been set for when construction will physically begin at Wylfa, and the final cost of the three-unit project has not been disclosed beyond the 2.6 billion-pound programme allocation. The Rolls-Royce SMR design is the only one to have reached the final stage of the UK’s Generic Design Assessment, conducted by the Office for Nuclear Regulation, the Environment Agency, and Natural Resources Wales, but completion of that regulatory review remains outstanding.
While GBE-N has assessed that the Wylfa site could potentially host up to eight reactors in the future, according to Interesting Engineering, no timeline or commitment has been announced for units beyond the initial three. It is also unclear how the SMR programme will interact with Sizewell C, the separate large-scale nuclear project in Suffolk for which the UK government announced 14.2 billion pounds in funding.
Analysis
The Wylfa contract positions the UK as the first country in Europe to move a domestic SMR programme from selection to formal engineering delivery. Rolls-Royce SMR has also secured commitments from Czech utility CEZ for up to 3 gigawatts of capacity, and a selection process is underway in Sweden, giving the company a growing European order book. The factory-built modular approach is designed to avoid the cost overruns and schedule delays that have plagued conventional nuclear construction in the West, most notably at Hinkley Point C in Somerset.
However, the mid-2030s target for grid connection means the project will not contribute to the UK’s near-term energy security challenges. The programme’s success will depend on the Generic Design Assessment proceeding smoothly, the supply chain delivering modular components at the anticipated cost, and the Final Investment Decision in 2029 confirming that the economics remain viable at scale.