The debate around Dukovany is dominated by the proposed new reactors, their financing and the political argument over who should build them. The existing plant is less glamorous but economically just as important. At the start of July, all four units were operating at full reactor power, and ČEZ reported lifetime generation of more than 542.8 million MWh since the station entered service in 1985.
Those figures underline the transition problem facing Czech energy policy. New nuclear capacity takes years to finance, license and construct. The country therefore has to keep the current Dukovany units safe and commercially reliable while preparing the next generation of reactors beside them.
Life extension is infrastructure, not maintenance
A nuclear outage is often described as routine maintenance, but the work carried out during refuelling windows goes well beyond replacing fuel. Operators inspect primary-circuit equipment, test safety systems and undertake investment projects designed to support longer operation. ČEZ’s July updates described hundreds of checks and upgrades during the planned outage of Unit 3.
The economics are straightforward. Every additional safe operating year from an existing reactor produces low-carbon electricity from an asset whose original construction cost has largely been absorbed. Replacing that output early with imported power or new gas generation would expose Czech consumers to different price and security risks.
The new-build timetable increases the value of the old fleet
Large nuclear projects rarely arrive exactly when the first political timetable suggests. Permitting, supply-chain constraints, financing negotiations and construction risk all create room for delay. That makes the existing Dukovany units a bridge asset: their reliability affects how much flexibility the system has if the new units take longer than expected.
It also changes the way investors should think about Czech grid spending. Transmission upgrades, reserve capacity and new generation are not separate projects. They are pieces of one transition in which aging nuclear units, renewables and future reactors have to coexist for a prolonged period.
ČEZ has to balance output and ageing risk
Older reactors require rising inspection discipline because components have accumulated decades of thermal and mechanical stress. The answer is not to assume age automatically makes a plant unsafe; it is to spend enough on monitoring, replacement and regulatory oversight that lifetime decisions are evidence-based.
For ČEZ, the operational incentive is strong. Dukovany generated more than 7.3 million MWh in the first half of 2026. Keeping those units available supports earnings and domestic supply, but outages cannot be shortened simply to maximise production. The long-term value of the plant depends on maintenance being conservative rather than opportunistic.
The transition will be measured in decades
Czechia’s nuclear strategy is therefore not a single construction project. It is a sequencing exercise: extend the existing fleet where regulators judge it safe, add new capacity, reinforce the grid and avoid creating a supply gap between the two generations.
The most useful number in the Dukovany story may not be the headline cost of the new reactors. It may be how many dependable megawatt-hours the current four units can deliver while the replacement system is being built.