Nuclear chiefs are investing £300m in Sizewell B power plant over the next two years as they look at giving it a longer lifespan.

Owner EDF is pouring a total of £1.3bn into the UK’s five generating nuclear power stations over 2024 to 2026 - taking the total sum invested in the fleet to nearly £9bn since 2009. Across the plants it plans to hire more than 1,000 people, it said.

Sizewell B power station at Leiston - which has been in operation now for 29 years - has so far generated more than 250TWh (terawatt hours).

According to the energy giant, the plant has the potential to continue to generate for at least a further 20 years beyond its current expiry date end of 2035.

EDF said it was investing in the station to allow a final investment decision to be taken on this during 2025 - but says this would need "a sustainable commercial model".

Sizewell B - which provides 3% of the nation's electricity - differs from the other seven stations in the nuclear fleet as it uses standard Pressurised Water Reactor (PWR) technology.

Combined with the other nuclear plants, it produces 13% of the electricity the country needs.

It was initially intended to be one of a fleet of PWR stations to be built in the UK - but the programme was cancelled by the government more than 30 years ago.

Last year, EDF invested more than £80m in planned maintenance and inspections- including the station’s statutory outage - at the plant.

"The focus for the Sizewell B power station is on operational excellence and investing to enable a potential 20-year life extension, taking the lifetime out from 2035 to 2055. This decision is subject to agreeing the appropriate commercial model to ensure such an extension is viable," the company said.

In its stakeholder update - published on January 9 -  the company set out five priorities over the decade for its Nuclear Operations generation business – one of which is delivering value from the Sizewell B power station.

Another of its priorities was to develop its long-term future "recognising that by the mid-2030s seven of the eight power stations will be owned by the UK government".

UK nuclear output in 2023 was 15% lower than in the previous year at 37.3TWh, it said. It put this down to station closures and statutory outages.

EDF said it plans to maintain output around this level until at least 2026 after life extensions for Heysham 1 and Hartlepool power plants were announced in March 2023.

Its plan is to extend the lives of its four generating Advanced Gas-cooled Reactor (AGR) stations - Hartlepool, Heysham 1 and 2 and Torness - with a decision due to be taken by the end of 2024.

Through its nuclear operations business, EDF will pay around £600m in taxes for 2023, including £200m through the new Electricity Generator Levy.

Dr Mark Hartley, managing director of EDF’s Nuclear Operations business, said “EDF has built a strong track record of safely operating the UK’s existing nuclear fleet, delivering over 35% more clean power than initially forecast.

"Looking ahead, our aim is to maintain output from the four AGR stations for as long as possible and extend Sizewell B by a further 20 years, out to 2055.

"Maximising output also helps preserve the critical nuclear skills and capabilities that will be valuable for future nuclear projects.”