A reactor at the Penly plant (Seine-Maritime) is now also affected by this defect, which until now had only affected more powerful and recent reactors.
“The faults which have been observed on the latest generation reactors have been observed on another reactor”, that of Penly 1, which is already shut down, told AFP Karine Herviou, deputy director general of the Institute for Radiation Protection and Nuclear Safety (IRSN).
The problem had so far only been identified in 1,450 megawatt reactors. The fault detected at Penly 1, a 1,300 MW reactor, is the first to affect another family of reactors.
EDF announced in mid-December the precautionary shutdown of the two reactors at the Chooz (Ardennes) power plant to check for possible faults on its emergency cooling circuit, after the detection of faults in Civaux (Vienne), a another plant of the same model, the shutdown of which was then extended.
The group has since announced that one of Chooz’s reactors was indeed affected by the same problem. The second is still being investigated.
The problem identified at Penly “would also be due to a phenomenon of stress corrosion, that is to say the same phenomenon that was detected” on the 1,450 MW reactors, said Karine Herviou, referring to “a fault in the ‘order of the millimeter’.
The shutdown of the four Civaux and Chooz reactors in the middle of December deprived France of 10% of its nuclear capacity and caused the already very high electricity prices on the market to jump.
The RTE network manager had increased his level of vigilance concerning the supply of electricity to France while the availability of the nuclear fleet, also upset by the pandemic, is at its lowest.
France, which derives the vast majority of its electricity from nuclear power, had a total of 10 out of 56 reactors unavailable on Thursday and was deprived of 20% of its capacity, at a time when consumption is usually high with the drop in temperatures.
The Penly reactor, where the corrosion problem was identified, had already been shut down, but the question now is whether other reactors in the French fleet are concerned.
“We don’t know if there are no problems elsewhere. EDF is in the process of reviewing all the records ”of checks carried out in the past on the park, said Karine Herviou.
“It is impossible to exclude that other reactors of the 1,300 MW series are affected,” said Yves Marignac, nuclear expert from the NégaWatt association.
“This poses a difficult problem for the authorities, which is whether we apply the same logic (as for the 1,450 MW reactors) and preventively shut down the reactors or if we prioritize electrical safety,” he said. added. Because “closing more 1,300 MW reactors would inevitably lead to supply disruptions”.
The new problems revealed Thursday come at a time when France is wondering about its energy future, between will to fight against climate change and to ensure its security of supply at the best price.
Nuclear power is one of the divisive themes of the presidential campaign, with candidates in favor of this energy (especially the right, the far right but also the PCF) and others hostile (LFI and EELV in particular).
President Emmanuel Macron, who has not yet declared himself a candidate for a second term, has often touted the advantages of nuclear power, especially from a climate point of view. He announced in November that France would launch a new nuclear reactor construction program.
For the moment, it is only building one of the new generation, the Flamanville EPR (Manche), which has experienced many delays. The last has just been announced on Wednesday: fuel loading has been postponed from the end of 2022 to the second quarter of 2023, for a bill increased by 300 million euros.