France’s most powerful nuclear reactor begins supplying energy to homes

France has successfully connected its most powerful nuclear reactor – the Flamanville 3 European Pressurized Reactor – to the national electricity grid.

The Flamanville 3 EPR has now started providing electricity to homes in France after a nearly 12-year delay.

The EDF power company says the Flamanville power plant has three nuclear reactors. The two operating reactors, ‘Flamanville 1-2’, have a capacity of 1300 MWe.

As per EDF, the newly started Flamanville 3 is an EPR pressurized water reactor of approximately 1,600 MW capacity. This makes Flamanville 3 France’s most powerful reactor.

Steps towards starting supply from the nuclear reactor

Construction on the third unit at the Flamanville nuclear power plant site began in December 2007. The reactor building dome was installed in July 2013, and the reactor vessel was installed in January next year.

The reactor was expected to start operations in a short while, but several setbacks happened along the way.

Finally, on May 8, 2024, EDF loaded the fuel into the reactor vessel of the Flamanville EPR, the 3rd reactor of the Flamanville nuclear power plant. It is a third-generation reactor with stringent safety standards incorporated into its design.

The addition of fuel is the first step in the reactor start-up program.

On September 2, the Nuclear Safety Authority the French nuclear safety authority (Autorité de Sûreté Nucléaire) gave its approval to launch the divergence operations of the Flamanville EPR reactor.

On September 3, 2024, the Flamanville 3 teams carried out the first divergence of the reactor.

A string of start-up tests followed this throughout September.

The start-up of the EPR is a long and complex process that puts the equipment into service for the first time. As per EDF, the activation of other automatic shutdowns and the encounter of hazards remain probable until the reactor reaches full power.

Flamanville unit 3’s capacity and more

According to a report by France 24, the nuclear reactor can supply power to over two million homes when it begins working at full capacity.

The report also states that the start-up has occurred at least 12 years behind schedule. The delay has been attributed to several technical setbacks, leading to the project cost inflating to $13.76 billion (13.2 billion euros) from the initial $3.43 billion (3.3 billion euros) estimate.

The Flamanville 3 is now operating at 25 percent capacity and is generating electricity. Moreover, according to EDF, it produces 100 MW of electricity.

A report by World Nuclear News quotes EDF as saying that the reactor will be operated at different capacity levels until summer 2025, which will conclude the testing phase.

This will be followed by the nuclear reactor operating at its 100 percent capacity until the first planned outage for maintenance and refueling scheduled for 2026.