Flamanville EPR: “We just have to be patient”: after the automatic shutdown of the nuclear reactor, checks are underway

The EPR nuclear reactor in Flamanville (Manche) experienced an “automatic shutdown” on Wednesday, September 4, 2024, the day after its start-up, and EDF teams are carrying out technical checks and analyses before being able to restart its “divergence”, i.e. the nuclear reaction.

The EPR, the subject of a construction site with many setbacks, reached an important milestone on Tuesday with the achievement of the first nuclear fission. But several steps are still planned before it can actually supply the grid with electricity, with potential technical hazards.

“This morning, the reactor shut down automatically”, a spokesperson for the EDF group said on Wednesday evening, September 4, 2024.

“The teams are carrying out the necessary technical checks and analyses, following the usual procedures, and will then restart the reactor divergence”, she added.

“Long and complex process”

“Starting up is a long and complex process (which) requires many trials, tests, and this can lead to shutdowns of this type”, she stressed.

“This proves that the security system is working well”, she further indicated. “We know that this can lead to shutdowns of this type.”

According to Nicolas Goldberg, energy expert at Colombus Consulting, “you have to expect this type of hazard. It is a very complex industrial process start-up and it is therefore common to encounter hazards.”

The expert emphasizes that “on the Finnish EPR, there were several setbacks, notably with hydraulic pumps that were defective and had to be replaced”.

“This does not call into question the start-up. We just have to be patient", he notes.

Three million homes

"According to the first elements of the technical diagnosis, the shutdown (on Wednesday) could be linked to an inappropriate configuration of the installation", specified the EDF spokesperson.

The latter "would have led to the automatic shutdown of the reactor in accordance with the device provided for in the design”, she added.

The start-up of this new-generation nuclear reactor is 12 years behind schedule due to numerous technical setbacks that have caused the bill to explode, now estimated at 13.2 billion euros by EDF, or four times the initial estimate of 3.3 billion.

4th EPR of this type installed in the world

After loading the uranium rods into the reactor core in May, EDF has conducted a series of cold and hot tests in recent months that resulted on Monday in obtaining the green light from the Nuclear Safety Authority (ASN) to launch the first fission reaction nuclear.

This crucial stage of the reactor's start-up took place on Tuesday, marking the beginning of its ramp-up in successive stages.

It must reach 25% power to be connected to the electricity grid, which should happen “by the end of autumn", according to EDF. The energy company had hoped to reach this stage by the end of the summer, i.e. by September 21 at the latest, but the group now estimates that these conditions should be reached by the end of the fall.

The EPR, a new-generation pressurized water reactor, is the 4th of its type installed in the world, the 57th reactor in the French nuclear fleet, and the most powerful in the country (1,600 MW). Ultimately, it should supply electricity to around 3 million homes.