Flamanville 3 EPR
Flamanville, France [INTERNATIONAL] · Construction 2007-2024, Operations began 2024 · ~£20.4bn (2020 prices, based on €23.7bn and ~0.86 GBP/EUR)
The judgement call
Account-gated at launchThe project faced numerous technical challenges and delays, leading to substantial cost increases from an initial estimate of €3.3 billion to €13.2 billion (and later €23.7 billion). - Lessons learned regarding the need for robust project management, supply chain oversight, and early identification of technical issues in complex nuclear new build projects. - The experience has influenced the design and construction strategies for other EPR projects, including Hinkley Point C.
Key engineering challenges
Significant cost overruns and delays, highlighting the complexities of building Generation III+ reactors. - Technical issues with critical components, such as the reactor pressure vessel and steam generators. - Managing a large and diverse international workforce and supply chain. - Ensuring stringent safety and regulatory compliance throughout construction and commissioning.
Project facts
- Client / owner
- EDF (Electricité de France)
- Lead contractor
- EDF, Framatome
- Lead designers
- Areva, Siemens (EPR design)
- Project type
- new build
- Scale
- 1650 MWe (EPR reactor)
- Disciplines
- nuclear; civil; structural; mechanical; electrical; process; safety
- Standards & frameworks
- ASN (French Nuclear Safety Authority) regulations
Sources: World Nuclear News: France’s Flamanville EPR starts supplying power (https://www.world-nuclear-news.org/articles/french-epr-starts-supplying-power) - World Nuclear Association: Flamanville 3 (https://world-nuclear.org/nuclear-reactor-database/details/flamanville-3) - ANS Nuclear News: Flamanville-3 reaches full power (https://www.ans.org/news/article-7625/flamanville3-reaches-full-power/) - ITIF: Lessons From France’s Nuclear Program (https://itif.org/publications/2025/09/02/lessons-from-frances-nuclear-program/) - Reddit: France’s new Nuclear power plant Flamanville EPR costed (https://www.reddit.com/r/europe/comments/1i2qy3f/frances_new_nuclear_power_plant_flamanville_epr/) - Assystem: Construction and commissioning activities for the (https://www.assystem.com/en/references/configuration-construction-commissioning-activities-flamanville-3/)