The start-up of this reactor, the first of this generation planned on French soil, will thus take place with a total delay of 12 years compared to the initial planning.

Two other EPRs are already operating in China and a third in Finland.

This additional period of six months will lead to an additional cost of 500 million euros which will bring the total amount of the Flamanville EPR, the construction of which was launched in 2007, to 13.2 billion euros, specified EDF, i.e. four times the initial budget of 3.3 billion euros.

The new delay is due to the necessary revision of treatment procedures for some 150 "complex" welds, within the main secondary circuit of the reactor, explained to the press the director of the Flamanville 3 project, Alain Morvan.

The problem appeared this summer, when it was necessary to carry out the heat treatment of "stress relief" of these welds: the process used revealed a "non-conformity of behavior" of sensitive materials nearby, affected by too high temperatures.

"We had a behavior of the temperatures of the valves not in conformity with what one expected", explained Mr. Morvan, from where the resumption of "studies to define a method (...) making it possible to guarantee the good level of carrying out these heat treatments".

These modifications "have been presented to Bureau Veritas, which analyzes them, and by the end of the year we will have the authorization to resume the so-called complex heat treatments", assured the project director.

Postponements of nuclear reactor restarts © Valentin RAKOVSKY / AFP/Archives

These operations should therefore be able to resume at the beginning of 2023, but the entire project schedule is upset, with fuel loading now announced for the 1st quarter of 2024. The reactor will send its first electrons when it has reached nearly 25% of its power. , "about three months later", so by mid-2024.

The additional 500 million euros announced on Friday are mainly related to maintaining staff and subcontracting companies on site.

Winter 2023/24

In addition to these technical hazards, a shutdown of the reactor is already planned to change, by the end of 2024, the lid of its tank which presents anomalies, recalled Mr. Morvan.

However, "the Flamanville EPR has taken new strategic steps in recent months, in its pre-operation phase", welcomes EDF in a press release, citing the resumption of certain welds or the testing of electrical equipment.

Since 2007, the site of this reactor, designed to offer increased power and safety, has been accumulating disappointments, whether it be anomalies on the steel of the lid and bottom of the vessel or welding problems.

The turbines of the third-generation EPR reactor, June 14, 2022 in Flamanville, in the Manche department © Sameer Al-DOUMY / AFP/Archives

The latest come as Emmanuel Macron announced the order of six or even 14 new EPRs and that Parliament must decide on France's energy model.

In the absence of the Flamanville EPR next year, France should therefore once again face tensions over its electricity supply during the winter of 2023-24, while EDF is already facing the aging of its nuclear fleet and that the deployment of renewable energies, solar and wind, is struggling.

The current winter gives a taste of these tensions, with Friday 41 reactors in operation only out of 56.

Among the 15 reactors shut down for maintenance operations and/or for corrosion checks, two - in Penly and Flamanville - should also restart several weeks late, thus depriving France of their production until in February or March, we also learned Friday from EDF.

© 2022 AFP