United Kingdom - World Nuclear Outlook Report

Projection of future nuclear capacity in the United Kingdom in 2050

The UK has nine operational nuclear reactors with a total capacity of 5900 MWe at five locations, eight advanced gas-cooled reactors (AGRs) and one pressurized water reactor (PWR).

The country's Labour government (since July 2024) has not indicated any change in the goal set by the previous administration to deliver 24 GWe nuclear capacity by 2050. Great British Nuclear (GBN), a non-departmental public body sponsored by the Department for Energy Security and Net Zero, was set up in 2024 to help deliver the 24 GWe target. It was renamed Great British Energy – Nuclear (GBE-N) in June 2025.

Long-term operation

Operation of the UK’s AGR reactors been extended several times. However, the design is susceptible to gradual cracking of graphite bricks comprising the reactors’ moderators and limiting their operational lifetimes. Hartlepool 1&2 and Heysham I-1&2 are due to close in 2028, and Heysham II-1&2 and Torness 1&2 are due to close in 2030.

EDF Energy plans to operate the Sizewell B PWR reactor for 60 years, to 2055.¹⁷⁴

New capacity

Large-scale reactors

Two EPR reactors are under construction at Hinkley Point C, with start-up of the first reactor expected around 2030.

A second set of two EPRs are planned at Sizewell C. Following the 2025 UK Spending Review, in which the UK government announced a £14.2 billion investment in the project,^175,176 a final investment decision is expected later in 2025.

Small-scale reactors

In 2024 the UK government, and GBN began the selection process for which SMR technology to would be supported for deployment to help reach the UK’s 24 GWe capacity goal.

In June 2025 the government announced that Rolls-Royce SMR had been selected as the preferred bidder, subject to final government approvals.¹⁷⁷ A site is due to be allocated later in 2025, with first grid connection expected in the mid-2030s. A final investment decision is expected to be taken in 2029.¹⁷⁸