Extending the life of the global nuclear fleet is technically proven and increasingly seen as a cost-effective pathway to meeting net-zero targets. Of the 416 reactors (376.2 GWe) in operation today, half have already reached 38 years of service, according to International Atomic Energy Agency (IAEA) data. Among the oldest reactors are Switzerland’s Beznau 1&2 – 380 MWe Westinghouse pressurised water reactors (PWRs) – that started up in 1969 and 1971. After investing some CHF2.5bn ($3.2bn) in retrofitting and modernisation work over their lifetimes, operator Axpo intends to spend a further CHF350m ($400m) so that with regulatory approval Beznau 2 can remain on grid until 2032 and Beznau 1 until 2033. Many reactors are in a similar position around the globe. Originally designed for 30-40-years of operation, reactors can now be licensed for 60-80 years – and potentially beyond – with upgrades to systems, structures and components (SSCs).
Benefits of plant life extension
Given the lengthy timelines for nuclear new-build, existing reactors are expected to retain an important role in future low-carbon electricity generation. The International Energy Agency (IEA) predicts that life extensions will account for 150 GWe or a fifth of global nuclear capacity in 2040 under its Announced Pledges Scenario. In 2024, the global nuclear fleet generated a record 2,667 TWh of electricity, surpassing the previous high of 2,660 TWh set in 2006, according to the World Nuclear Association’s 2025 World Nuclear Performance Report, released in September. There was no overall age-related decline in capacity factor, giving “a positive indication for the potential of reactors continue to function well when entering periods of extended operation”.
Life extension also has huge economic benefits. The UK’s eight nuclear power stations contributed some £123bn ($166bn) to the UK economy since 1976, according to a study by Economic Insight. EDF Energy recently announced plans to extend the life of Heysham 1 and Hartlepool power stations until March 2028, an extension of 12 months, securing jobs for 1,000 workers. Meanwhile, Bruce Power’s C$13bn ($9bn) Major Component Replacement project in Canada – focused on replacing the key parts such as the steam generators, pressure tubes, calandria tubes and feeder tubes at Bruce 3-8 between 2020 and 2033 – is expected to support around 22,000 jobs and generate C$4bn ($2.9bn) in economic benefit for Ontario every year until 2064.
In South Africa, life extension of the two-unit Koeberg nuclear plant was driven by “the need to preserve reliable, low cost, low-carbon baseload capacity while South Africa scales up new generation”, Eskom told NEi. Koeberg 1 started operating in 1984, followed by Koeberg 2 in 1985. The plant has a generating capacity of roughly 1860 MWe (about 5% of national supply) and extending its life is “faster and far less capital intensive than building a new power station,” the utility added.
Reactor life extension plans
Many countries have ambitious reactor life extension goals.
In the US, the Nuclear Regulatory Commission (NRC) has granted renewals to the original 40-year licences for 87 of the 94 currently operating reactors. The vast majority (95%) of US reactors surveyed by the US Nuclear Energy Institute also anticipate receiving approval to operate for at least 80 years, while 73% are also considering power uprates.
In Canada, Ontario Power Generation and Bruce Power have ongoing refurbishment programmes to extend the lives of CANDU reactors at Bruce, Darlington and Pickering by 30-35 years. Meanwhile, in France, EDF intends to spend €6bn ($7bn) on 20 of its 1300 MWe reactors so they can operate beyond 40 years, with safety reviews due to take place between 2027 and 2035. Belgium, Czech Republic, Finland,
Hungary, Sweden, Romania, South Africa, South Korea and the UK are also among countries seeking life extensions across a range of reactor types.
Two main pathways to life extension
Internationally, there are typically two models for achieving plant life extension, explains Dr Derik Wolvaardt, senior executive at Lesedi Nuclear Services, a South African engineering, procurement and construction (EPC) company involved in supporting life extension works at Koeberg as well as internationally. The US NRC’s License Renewal Rule (10 CFR Part 54) defines a robust programme of evaluation and assessment needed to apply for a renewed licence; it can be applied multiple times, provided each renewal satisfies safety requirements. Outside of the US, utilities typically follow the IAEA Safety Aspects of Long-Term Operation (SALTO) process, an approach that is less prescriptive. The SALTO service provides advice and assistance to countries considering extending the operating lives of their nuclear plants. Since 2005 it has offered peer reviews to compare LTO activities against IAEA Safety Standards and international good practice.
The expert review process typically involves:
A workshop on the IAEA Safety Standards and the SALTO review methodology
A nine-day pre-SALTO mission (anywhere from 10 to two years before LTO)
The SALTO mission (less than two years before LTO)
A follow-up mission (1.5-2 years after the pre-SALTO and SALTO review)
Case study: Koeberg looks to life beyond 40
Africa’s only commercially-operating nuclear plant, Koeberg, took part in the SALTO process. Wolvaardt says that Lesedi was involved in the work at Koeberg, utilising software tools to conduct ageing analysis.
“We started with hundreds of thousands of SSCs in the scoping and screening process. After that process, we ended up with about 80,000 safety-related components for the two Koeberg units (pumps, civil structures, cables, etc.),” he explains. These components were then screened and put into ‘commodity groupings’ based on their materials, environmental and other common properties. Each of the commodity groupings – and some of the larger individual components – then underwent further analysis to determine whether they can achieve a life span beyond 40 years. Lesedi also supported component upgrades at Koeberg, including replacement of the refuelling water storage tanks (RWSTs), the reactor pressure vessel heads and the steam generators (SGs).
Eskom explains that the SALTO review in March 2022 and its follow-up mission in September 2024, focused on aspects essential to safe long-term operation, “in particular ageing-management programmes, certain equipment-condition issues (including cable management and corrosion monitoring), and enhancements to plant-wide monitoring and safety oversight”.
Koeberg 1 received a licence to continue operating until 2044 in July 2024 and Eskom is planning to extend operations of Koeberg 2 until 2045. Koeberg 2’s operating licence runs until 9 November 2025. Eskom has applied for LTO. South Africa’s nuclear regulator plans to hold public hearings on the application in the autumn and will announce its decision before the current licence expires.
The outlook for life extension
Nuclear life extension is an essential part of meeting net-zero ambitions. Momentum for nuclear power continues to build. The IAEA forecasts global nuclear capacity growing from 377 GWe in 2024 to 561-992 GWe by 2050. In the ‘high-case’ scenario most current reactors would receive life extensions, limiting retirements to 20% by mid-century.
Established frameworks and technology demonstrate that existing units can support safe operation beyond 40 years. However, the challenge will be maintaining public confidence and political will alongside engineering progress.
Image: The Beznau nuclear power plant in Dottingen, Switzerland is planning to operate until 2033 (Credit: ToM-5400 / Shutterstock)
