In a major milestone for British energy policy and the UK’s nuclear ambitions, Rolls-Royce SMR announced on April 13, 2026 that it has signed a contract to build three small modular reactor (SMR) units in the United Kingdom. The deal marks a significant step forward for a programme that has been developing for several years and represents a bet on nuclear power as a cornerstone of the UK’s long-term clean energy strategy.
What Has Been Agreed?
The contract covers the construction of three SMR units, each capable of generating enough electricity to power approximately one million homes. Combined, the three units would provide power for around three million households — a meaningful contribution to the UK’s electricity grid at a time when the country is working to reduce its dependence on fossil fuels and secure long-term energy resilience.
Rolls-Royce SMR has previously indicated that the most likely site for the first UK units is Wylfa in Anglesey, Wales — a former nuclear power station site that already has much of the infrastructure required for a new nuclear installation. However, final site selection has not been confirmed and further planning and environmental assessments are still required before construction can begin.
Regulatory Approval Already Secured
The contract award comes on the back of a significant regulatory milestone achieved in March 2026, when Rolls-Royce SMR became the first small modular reactor design to receive regulatory justification in the United Kingdom. This approval from the government means that the design has been assessed as having sufficient safety and regulatory merit to proceed toward construction — a hurdle that many competing SMR designs are still working to clear.
The Generic Design Assessment (GDA) process, run by the Office for Nuclear Regulation and the Environment Agency, is a rigorous technical review that all new nuclear reactor designs must pass before they can be built in the UK. Clearing this process gives Rolls-Royce SMR a significant head start over rival designs.
How Does the Technology Work?
Small modular reactors are, as the name suggests, smaller versions of conventional nuclear power stations. A traditional large-scale nuclear plant might generate several gigawatts of power and require a decade or more to construct; an SMR is designed to be factory-manufactured in standardised modules and then assembled on site, which is intended to reduce construction time and cost significantly.
Rolls-Royce SMR’s design uses pressurised water reactor technology — the most widely proven nuclear technology in the world — and is rated at approximately 470 megawatts of electrical output per unit. Each unit is roughly a tenth the size of a conventional large reactor, but the modularity of the design means that multiple units can be deployed at the same site to achieve larger total output.
The UK’s Nuclear Ambitions
The UK government has committed to expanding nuclear power as part of its clean energy targets, with an ambition to generate 24 gigawatts of nuclear power by 2050 — roughly triple the current installed capacity. SMRs are seen as a key part of achieving that ambition, offering faster deployment timelines and lower upfront capital costs than traditional large-scale nuclear projects like Hinkley Point C, which has been plagued by cost overruns and delays.
SMRs are also being positioned as a complementary technology to renewable energy, providing reliable baseload power that can run continuously regardless of weather conditions — something that wind and solar power cannot do on their own. As the UK builds out its offshore wind capacity, having reliable nuclear generation in the mix is seen as essential for keeping the lights on when the wind doesn’t blow.
Timeline and Investment Decision
Despite the progress, the path to operational SMRs in the UK is still a long one. A final investment decision on the construction of the first units is not expected until 2029, and the reactors themselves are not anticipated to begin supplying power to the grid until the mid-2030s. That timeline means that SMRs will not help with the UK’s immediate energy challenges, but they represent a significant long-term bet on a low-carbon, reliable power source.
Rolls-Royce SMR has also been in discussions about deploying its reactor design internationally, with the Czech Republic among the countries expressing interest. A global export success for a British nuclear technology would be a significant industrial achievement — one that the government has been keen to encourage as part of its broader industrial strategy.