EDF lowers expected output of Flamanville EPR to 1,585 MW

EDF anticipates a 35 MW decrease in output for the Flamanville EPR between 2026 and 2031, citing a degraded performance level with no official technical explanation to date.

Share:

Comprehensive energy news coverage, updated nonstop

Annual subscription

8.25$/month*

*billed annually at 99$/year for the first year then 149,00$/year ​

Unlimited access • Archives included • Professional invoice

OTHER ACCESS OPTIONS

Monthly subscription

Unlimited access • Archives included

5.2$/month*
then 14.90$ per month thereafter

FREE ACCOUNT

3 articles offered per month

FREE

*Prices are excluding VAT, which may vary depending on your location or professional status

Since 2021: 35,000 articles • 150+ analyses per week

French utility Électricité de France (EDF) has revised downward the expected output of its Flamanville EPR, which is currently in the testing phase. The group informed the Commission de régulation de l’énergie (CRE), France’s energy regulatory authority, that for the period between 2026 and 2031, it expects a maximum power output of 1,585 megawatts (MW), instead of the previously announced 1,620 MW in official public data. This projection is based on an assumption of lower final efficiency than originally anticipated, although no technical details currently substantiate this adjustment.

A power deviation with financial implications

This adjustment, disclosed in a CRE report published on 30 September, was released without technical documentation confirming any structural limitation or voluntary output restriction. The CRE stated that EPR testing is still ongoing, and in the absence of validated information, it continues to base its analysis on the theoretical power output of 1,620 MW. This figure is notably used to calculate nuclear production costs for electricity pricing projections.

The 35 MW difference represents a decrease of approximately 2.2% compared to the initial announced capacity. According to estimates relayed in the press, this reduced output could represent an annual revenue shortfall of around EUR15mn ($15.79mn), if maintained over the plant’s expected 60-year operational lifespan. EDF has not confirmed these figures but stated that the exact power rating will only be known after the full power ramp-up phase is completed.

Ongoing testing of critical components

The Flamanville 3 reactor was connected to the grid in December 2024, following more than 12 years of delays linked to technical and industrial issues. EDF had initially aimed to reach 100% power output during summer 2025. This milestone was postponed to autumn due to further adjustments to the turbogenerator, a key component in converting steam energy into electricity.

Abnormal heating was detected on this equipment earlier in the year. EDF carried out adjustments to the turbine and indicated that their impact would be assessed during the power ramp-up phase. The unit is currently offline for additional valve work and is scheduled to restart on 17 October. The group also stated that the discrepancy between publicly disclosed figures and those used in internal simulations is not expected to have any significant impact.

The environmental review of TerraPower’s Natrium project in Wyoming has been completed, paving the way for a construction permit for this advanced nuclear reactor.
Santee Cooper has selected Brookfield Asset Management to lead a feasibility study aimed at completing two unfinished AP1000 reactors, without relying on public funds or raising consumer rates.
Endesa, Iberdrola and Naturgy have officially requested the Spanish government to delay the closure of the Almaraz nuclear power plant, originally scheduled for 2028, reigniting the debate on nuclear power's role in the national energy mix.
The reactor vessel for Unit 1 at Egypt’s El Dabaa nuclear plant has been delivered following a 20-day maritime transport from Saint Petersburg, marking a critical milestone in the country’s energy project.
Ontario Power Generation secures CAD3bn ($2.1bn) in public equity financing to construct four modular reactors at Darlington, aiming to ease private sector entry into next-generation nuclear infrastructure.
French developer Newcleo launches a joint venture with Nextchem through a EUR70 mn contract to design the conventional island of its upcoming 200 MW modular nuclear reactors.
NANO Nuclear strengthens its North American strategy by acquiring Global First Power in Canada, securing regulatory rights for its KRONOS MMR™ project at Chalk River.
South Korea becomes the first country to submit a safeguards technical report to the IAEA for a small modular reactor, setting a precedent for early integration of non-proliferation requirements in nuclear design.
The Environmental Authority criticises the lack of key data on health risks, chemical discharges and construction safety for EDF's two upcoming EPR2 reactors in Seine-Maritime.
Brazil and China have concluded a three-year agreement to secure access to essential radioisotopes for the medical, industrial and scientific sectors, with no financial exchange between the parties.
US-based developer Last Energy will deploy its first domestic microreactor at Texas A&M-RELLIS, marking a strategic step in the advanced modular reactor race.
PGE acquires ZE PAK's stake in the joint venture responsible for developing Poland’s second nuclear site, consolidating a strategic asset within its energy portfolio.
Amazon unveils new visuals of its upcoming nuclear site, marking a key step in its partnership with X-energy to deploy up to 960 MW of modular nuclear capacity in Washington state.
Canadian uranium producer NexGen Energy has completed a A$1bn ($639mn) equity raise split between North American and Australian markets to support the development of its Rook I project.
Tokyo Electric Power Company Holdings is examining the permanent closure of units 1 and 2 at the Kashiwazaki-Kariwa nuclear power plant, the oldest at the site, while continuing efforts to restart unit 6.
The formal expiration of the 2015 nuclear deal with Iran comes as international sanctions have already been reinstated and diplomatic negotiations remain stalled.
Oklo, newcleo and Blykalla partner to develop advanced nuclear fuel infrastructure in the United States, backed by a planned $2bn investment.
enCore Energy has identified three new uranium roll fronts at its Alta Mesa project, with ongoing drilling aimed at defining their extent and accelerating development work.
California-based Radiant will build its first microreactor production facility in Oak Ridge, on a former Manhattan Project site, with production targeted at 50 units per year by 2028.
EDF restarted the Flamanville EPR reactor after repairing non-compliant valves, delaying the target of reaching full power output of 1,620 MW until the end of autumn.

All the latest energy news, all the time

Annual subscription

8.25$/month*

*billed annually at 99$/year for the first year then 149,00$/year ​

Unlimited access - Archives included - Pro invoice

Monthly subscription

Unlimited access • Archives included

5.2$/month*
then 14.90$ per month thereafter

*Prices shown are exclusive of VAT, which may vary according to your location or professional status.

Since 2021: 30,000 articles - +150 analyses/week.