The EPR nuclear reactor in Flamanville experienced an “automatic shutdown” on Wednesday, the day after it was started up, and EDF teams are carrying out technical checks and analyses before being able to restart its “divergence”, i.e. the nuclear reaction.
Having just started up, the Flamanville EPR, which has been eagerly awaited for 12 years, went into automatic shutdown on Wednesday, a hazard that hardly surprises energy experts given the complexity of the process of starting up a reactor. The head of EDF also wanted to be reassuring on BFM Business: “It’s a very good week since we not only started up the Flamanville reactor by doing the divergence but we also announced that we were increasing our nuclear electricity production target this year.”
“Then it’s operational life: we start this reactor, we shut it down temporarily and we’re going to restart it.”
The energy company’s new-generation reactor, the subject of a construction site marked by setbacks, had reached an important milestone the day before, with the achievement of the first nuclear fission. But several stages are still planned before it can truly supply the grid with electricity, by the end of autumn according to EDF. Until then, hazards are always possible, such as this false start that the EPR in La Manche, the first installed in France and the fourth in the world, has just experienced…
Why this automatic shutdown?
According to initial analyses by EDF, still “in progress”, the shutdown “could be linked to an inappropriate configuration of the installation”, indicated a spokesperson for the group. The latter “would have led to the automatic shutdown of the reactor in accordance with the device provided for in the design”. For the electrician, this could be linked to “an adjustment”. “Start-up is a long and complex process (which) requires numerous trials, tests, and this can lead to shutdowns of this type”, specified the EDF spokesperson. “This proves that the safety system is working well”, she added.
For Nicolas Goldberg, energy expert at Colombus Consulting, “it is a very complex industrial process start-up and it is therefore common to encounter hazards.” The expert points out that there have been precedents in the French electro-nuclear park and other EPRs installed abroad. The Finnish EPR at Olkiluoto, for example, had experienced “several setbacks, particularly with hydraulic pumps that were defective and had to be replaced.”
“Starting up a nuclear reactor is not a long, quiet river and the Flamanville EPR is no exception (and will not escape it in the days/weeks/months to come)”, also commented Michaël Mangeon, nuclear historian on X.
Is an EPR more complex to start up?
Designed to offer greater power (1,600 MW) and increased safety compared to older generations of reactors, the EPR includes “a greater number of systems and circuits”. “With an EPR, there are therefore more checks and tests during start-up than for a conventional reactor”, EDF stresses. “This is the start-up of a first reactor” of this type in France “and it is a complex machine”, the electrician summarises.
“The particularity with the EPR is that the equipment is doubled,” declared a union source the day after the first nuclear reaction. “On a 1,300 or 900 (MW) reactor unit, you have two safeguards (safety and security devices), in the EPR there are four.” “So, we are doubling the volume of equipment, so inevitably, twice as likely to have a problem when we start up the unit,” concluded this source.
The start-up steps, however, remain the same. In the end, for the Finnish EPR, “there were 3 months between the divergence and the connection to the network, which is standard if we look at old reactors”, underlines Nicolas Goldberg. Thierry Charles, former deputy director general of IRSN, technical expert in nuclear safety, points out that EDF “has not started a reactor for 25 years”. The energy company “must do things by taking the time to check that the systems respond as expected, that is the goal of a start-up”, he believes.
What are the consequences for electricity production?
For the time being, EDF teams are “carrying out the necessary technical checks and analyses, following the usual procedures, and then they will restart the reactor divergence,” the group’s spokesperson said on Wednesday evening.
“Barely started, already stopped… the Flamanville EPR is not ready to produce its first electrons,” reacted Pauline Boyer, Energy Transition campaign manager at Greenpeace, on Thursday.
With its delays and difficulties, the EPR construction site has become for opponents of nuclear power a symbol of the inability of nuclear power, an energy that emits almost no CO2, to respond quickly to the climate emergency. EDF has not given any details on the consequences of this hazard for the electricity production schedule. The EPR must reach 25% of power to be connected to the electricity grid, a deadline planned “by the end of autumn”.
