In July 2026, the UK government extended the life of the Sizewell B nuclear power plant in Suffolk by another 20 years, meaning it will now generate electricity until 2055 instead of closing in 2035. The decision—part of a broader push to revive the UK's nuclear industry—raises questions about how long reactors can safely operate and why the country is betting on ageing plants.
A nuclear power plant's lifespan is originally set by its design and regulatory licence. When a plant approaches its planned closure date, the owner can apply for a life extension, subject to safety checks and government approval. Sizewell B, a pressurised water reactor that started generating in 1995, is the UK's newest completed nuclear plant. It produces about 3% of the country's electricity, enough to power 2.5 million homes. Owner EDF employs 620 staff and around 300 contractors there, and the extension will enable about £800 million of plant investment.
“Explains why the UK is extending nuclear plant lifetimes and what it means for energy.”
The UK's existing nuclear fleet is ageing. Most reactors were built in the 1970s and 1980s. Heysham 2 in Lancashire and Torness in East Lothian—originally due to close in 2018—will now run until March 2030. Heysham 1 and Hartlepool in Teesside, which were initially slated for closure in 2008, have been extended to March 2028. Sizewell B's extension to 60 years is unusual: the country's other reactors are either advanced gas-cooled reactors (AGR) or the more modern pressurised water design, which can be more easily upgraded.
For UK readers, life extensions mean a steady supply of low-carbon electricity while new nuclear projects are built. The government says nuclear is vital for energy security as the country electrifies transport, heating, and AI data centres. Energy Secretary Ed Miliband called the extension "clean power our country needs". Chancellor Rachel Reeves said it was "a real vote of confidence" in the Suffolk workforce. However, campaigners warn of long-term costs. Chris Wilson of Together Against Sizewell C said the extension leaves "multi-generational financial and environmental liability", including flood defences and radioactive waste storage.
The economics also shift: from 2035, EDF will receive £70.50 per megawatt-hour for Sizewell B's power, compared to the original contract. Centrica, which owns a 20% share in EDF's UK reactors, will help fund extra maintenance. Meanwhile, the first new nuclear plant in a generation—Hinkley Point C in Somerset—is under construction but years from completion. Sizewell C, a twin reactor planned next to Sizewell B, has also started preparatory work.
Q: Why does the UK need to extend the life of old nuclear plants? A: The UK wants to reduce carbon emissions while keeping the lights on. Nuclear provides steady, low-carbon power. New plants like Hinkley Point C are expensive and slow to build, so extending existing reactors bridges the gap until they come online.
Q: Is it safe to keep a nuclear plant running beyond its original design life? A: Yes, if it passes rigorous safety checks. Extensions require upgrades—Sizewell B will undergo "major plant modifications and upgrades" paid for by EDF and Centrica. The UK's nuclear regulator must approve any continued operation.
Q: How does this affect my energy bills? A: The deal sets a fixed price of £70.50 per megawatt-hour for power from Sizewell B from 2035, which is higher than recent wholesale prices but intended to provide long-term cost certainty. Life extensions also avoid the cost of decommissioning and building replacement capacity.
What happens next: The Sizewell B deal is due to be finalised later in 2026. Other ageing plants—Heysham 1, Hartlepool, Heysham 2, and Torness—will continue running until the end of this decade. The government is also pushing for new nuclear projects, including Hinkley Point C and Sizewell C, to secure the UK's long-term electricity supply.