Nuclear energy in France is not a supporting part of the electricity system. It is the system’s central industrial structure. France operates 57 reactors at 19 power stations, with approximately 63 gigawatts of net capacity. Nuclear plants generated about 67% of French electricity in 2024, giving the country the largest nuclear fleet in Europe and one of the most nuclear-dependent power systems in the world.
The scale creates advantages that few countries can reproduce. France has extensive reactor-operating experience, a large engineering workforce, domestic fuel-cycle facilities and a power sector with very low direct carbon emissions. It also creates a difficult replacement problem. Most reactors were built within a relatively short period, meaning that many units are reaching major ageing and modernization decisions at similar times.
French nuclear policy is therefore moving along two tracks. EDF must maintain and upgrade the existing fleet while the state prepares a new generation of EPR2 reactors. The success of the strategy will depend on plant reliability, industrial capacity, project financing and the ability to avoid repeating the construction problems experienced at Flamanville 3.
France Built an Electricity System Around a Standardized Reactor Fleet
The modern French nuclear program expanded rapidly after the oil shocks of the 1970s. The government pursued a centralized construction program based largely on standardized pressurized water reactor designs. EDF developed sites with multiple units, allowing infrastructure, operating staff and technical services to be shared.
The fleet consists mainly of three reactor series. France operates 32 units in the 900-megawatt class, 20 in the 1,300-megawatt class and four larger N4 reactors of around 1,450 megawatts. Flamanville 3, an EPR, is the newest and largest unit.
This standardized structure supported rapid construction and created economies of scale. It also means that a technical issue discovered in one reactor series can affect many units. Inspections, component replacements and safety improvements must sometimes be carried out across several plants within a limited period.
EDF’s French nuclear output rose to 373 terawatt-hours in 2025 as reactor availability improved. This recovery was important after a period in which maintenance delays, inspections and corrosion-related repairs reduced output. Higher nuclear generation strengthened French electricity exports and reduced the need for fossil-fuel generation elsewhere in the interconnected European market.
Nuclear plants must also operate within a changing power system. France is adding wind and solar capacity, while electricity demand is expected to grow through electric vehicles, heat pumps, industrial electrification, hydrogen production and data centres. The fleet increasingly adjusts output to changes in demand and renewable generation rather than operating at maximum power at all times.
Extending Reactor Life Is France’s Immediate Nuclear Priority
New reactors will not replace the existing fleet quickly enough to make lifetime extension optional. France’s oldest operating units entered service in the late 1970s and early 1980s, while most of the fleet was connected during the following decade.
French reactors do not receive a single operating licence that expires after a fixed number of years. Instead, each unit undergoes an extensive periodic safety review every ten years. The nuclear safety authority determines what inspections, modifications and improvements are required before continued operation.
The fourth reviews of the 900-megawatt reactors are particularly important because their original design assumptions were based on approximately 40 years of operation. The regulator concluded that continued operation for another ten-year period was possible if EDF completed major safety improvements. These include measures addressing natural hazards, severe accidents, cooling systems and spent-fuel-pool protection.
A similar process is under way for the 1,300-megawatt fleet. The 20 reactors in this group are approaching their fourth periodic reviews, placing another large set of units into intensive inspection and modernization programs.
EDF’s ability to carry out this work is a national energy issue. Outages must be scheduled without removing too much capacity from the grid at once. Equipment manufacturers, engineering firms and specialized contractors must also support work at multiple sites while preparing for new construction.
Lifetime extension does not mean that every reactor will operate for the same number of years. Decisions are made for individual units, and local conditions, component ageing and safety performance remain important. France nevertheless expects much of the existing fleet to remain active well into the 2030s and 2040s.
Flamanville 3 Connects the Existing Fleet to the EPR Era
Flamanville 3 was intended to demonstrate France’s ability to move from its standardized reactor fleet to a more advanced EPR design. Construction began in 2007, but the project experienced extensive delays, technical problems and cost increases.
The reactor was connected to the grid in December 2024 and reached full nuclear thermal power in December 2025. At full output, it generated approximately 1,669 megawatts gross, making it the most powerful reactor in France.
Its completion adds valuable low-carbon capacity, but its larger importance lies in the industrial lessons it produced. Problems involving engineering coordination, welding quality, component documentation and construction management exposed weaknesses that developed during a long period with little domestic reactor construction.
France is attempting to apply those lessons to the EPR2, a revised design intended to be easier to build than the original EPR. Design simplification, standardized construction, earlier supply-chain preparation and repeated pairs of reactors are meant to reduce project risk.
Flamanville 3 will also test the operating performance of EPR technology within the French system. Reliable generation would strengthen the case for EPR2 construction, while recurring technical problems would increase concern about the cost and schedule of the renewal program.
Six EPR2 Reactors Form the Core of France’s Nuclear Renewal
The first phase of France’s new-build program covers six EPR2 reactors arranged in three pairs. EDF plans to construct them at Penly in Normandy, Gravelines in northern France and Bugey in eastern France. Each site already contains operating reactors, reducing the need to create an entirely new nuclear location.
Penly is expected to host the first pair. EDF’s target is to commission the first reactor in 2038, followed by the remaining units at intervals of approximately 12 to 18 months. The schedule means that new capacity will arrive gradually and cannot replace large parts of the existing fleet during the early 2030s.
EDF placed the forecast cost of the six-reactor program at €72.8 billion in 2020 prices in December 2025. The estimate remains subject to audit, design development and a final investment decision. A financing structure involving the French state and European regulatory approval is central to whether the program can proceed on the planned scale.
The program is intended to rebuild domestic construction skills as well as add generation. Framatome is preparing major reactor components, while Arabelle Solutions is involved in turbines and generators. Civil-engineering firms, electrical contractors and specialist manufacturers will need to expand recruitment and training.
France has also considered a later program of additional EPR2 units. That decision will depend partly on the performance of the first six, future electricity demand and the condition of the existing fleet. The first program is already large enough to test whether France can convert political commitment into predictable nuclear construction.
The Fuel Cycle Gives France Industrial Depth but Not Complete Independence
France’s nuclear sector extends well beyond power stations. Orano operates conversion facilities at Malvési and Tricastin, uranium-enrichment capacity at Georges Besse II, spent-fuel processing at La Hague and mixed-oxide fuel production at Melox.
This infrastructure gives France greater control over the nuclear fuel cycle than most reactor-operating countries. Used fuel is processed at La Hague to separate reusable uranium and plutonium from final waste. Plutonium can then be incorporated into mixed-oxide, or MOX, fuel at Melox for use in approved reactors.
Recycling reduces the quantity of fresh uranium required and makes use of energy materials that would otherwise remain in storage. It does not eliminate radioactive waste, and France must still manage high-level residues produced during reprocessing.
France also depends on imported uranium. Domestic conversion, enrichment and fuel fabrication provide industrial autonomy after the mining stage, but the original uranium comes from international suppliers. Diversifying these sources remains part of French energy security.
For permanent disposal, the country is developing Cigéo in the Meuse and Haute-Marne area. The project is designed as a reversible deep geological repository for high-level and long-lived intermediate-level waste. Its creation-licence application remains under regulatory review, and the facility has not yet entered construction as an operating repository.
France’s Nuclear Future Depends on Execution Across the Entire System
France has already made the political decision to retain nuclear power as a major part of its long-term electricity supply. The unresolved question is whether the industrial system can deliver all parts of that decision at the same time.
EDF must recover dependable output from the existing reactors, complete extensive lifetime-extension work, integrate Flamanville 3 and prepare the EPR2 program. The fuel-cycle industry must support both old and new reactors, while waste facilities and the Cigéo licensing process must progress separately.
The 57-reactor fleet gives France an operating base that no other European country possesses. It also exposes the country to concentrated maintenance schedules and a large future replacement requirement. The EPR2 program will not succeed through reactor design alone. It requires stable financing, qualified workers, experienced project management and a supply chain capable of repeating construction rather than treating each unit as a separate prototype.
For the next decade, existing-plant performance will matter more than new-reactor output. By the late 2030s, the result at Penly will show whether France has created a practical bridge from the reactor fleet built in the twentieth century to the nuclear system it intends to operate during the second half of the twenty-first.
