IN Brief:
- ČEZ expects annual investment in its operating nuclear fleet to rise to CZK10–12 billion.
- Modernisation covers major mechanical equipment, control and safety systems, digitalisation, and longer operating cycles.
- Dukovany and Temelín are being prepared for potential operating lives of up to 80 years.
ČEZ expects annual investment in its existing Czech nuclear fleet to rise to CZK10–12 billion as the utility prepares Dukovany and Temelín for substantially longer operating lives. The spending will cover replacement of ageing equipment, control-system modernisation, safety upgrades, and further digitalisation, with dozens of technical projects expected each year. The programme builds on ČEZ’s decision to prepare its existing units for operation for as long as 80 years from commissioning.
The proposed service-life extension would take the four Dukovany units, commissioned between 1985 and 1987, into the 2065–2067 period if plant condition and regulatory approvals continue to support operation. The two Temelín units, commissioned in 2000 and 2002, could remain in service into 2080 and 2082 under the same approach. ČEZ had previously planned around 60 years of operation for the plants, extending the period over which major components, electrical systems, instrumentation, and safety equipment must remain qualified and maintainable.
The higher annual spending marks a step up from the roughly CZK7 billion a year that ČEZ said in April was being directed towards safety improvements and upgrades at its nuclear stations. The company is not treating the 80-year plan as a single refurbishment campaign with a fixed completion date. Long-term operation instead depends on continuing inspection, component replacement, engineering assessment, and periodic safety review, with investment decisions changing as equipment condition and regulatory requirements evolve.
Dukovany is already moving into a heavier phase of that work. ČEZ has identified replacement of major turbine-hall equipment, including turbo sets and generators, alongside reconstruction of selected piping, valves, electrical equipment, and control and safety systems. The reactor pressure vessels are subject to long-term monitoring and are not currently expected to require replacement, placing much of the engineering burden on maintaining and renewing the large body of replaceable plant around the reactor systems while demonstrating that non-replaceable components remain within acceptable limits.
Instrumentation and control is one of the most consequential areas because several additional decades of operation extend well beyond the practical life of much of the plants’ original electronics and control hardware. Modernisation projects at Dukovany are replacing elements of the control architecture, while Temelín is progressing a multi-year transition to a new Westinghouse control system. At Temelín, that work is scheduled to continue through 2029 and is being introduced progressively during planned outages rather than through one long shutdown.
ČEZ has separately allocated CZK3.8 billion to Temelín modernisation projects in 2026, covering 237 planned investment actions. The work includes control-system upgrades, changes supporting longer fuel cycles, and wider use of digital tools and artificial intelligence. Since Temelín entered operation, ČEZ says almost CZK38 billion has been invested in modernisation, illustrating the cumulative capital requirement of maintaining a large nuclear asset even before an additional two decades of potential service life are considered.
Longer fuel cycles form another part of the operating strategy. Reducing the frequency of refuelling outages can increase the proportion of time that units are available to generate electricity, although the change also affects fuel management, maintenance scheduling, and the volume of work concentrated into each outage. The company is targeting long-term average annual generation of around 32TWh from its Czech nuclear plants, so availability improvements and life-extension work are being pursued alongside safety and reliability.
Extending the existing fleet also buys time while Czechia develops new nuclear capacity. New units at Dukovany will take years to build and commission, whereas continued operation of the present reactors can preserve a large block of dispatchable low-carbon generation through that construction period. The value of that continuity depends on periodic safety assessments and the State Office for Nuclear Safety continuing to support operation as the plants age.
That regulatory condition is central to the 80-year ambition. ČEZ carries out detailed annual evaluations of the conditions for continued operation, while the plants undergo more extensive periodic safety assessments on a ten-year cycle. An extended planning horizon does not itself confer permission to run for that period; the technical case has to be demonstrated repeatedly as components age, standards develop, and operating experience accumulates.
The shift from around CZK7 billion of annual nuclear upgrades towards a CZK10–12 billion investment range gives a clearer measure of the capital intensity behind the life-extension strategy. The spending supports replacement of large mechanical assets, modern digital control, safety systems, and the engineering evidence needed to keep ageing reactors within their licensing basis. For Dukovany and Temelín, an 80-year operating life will be earned through decades of sustained plant work rather than secured by a single decision in 2026.
