Nuclear reactor corrosion: France avoids worst for this winter
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The Nuclear Safety Agency on Wednesday confirmed EDF’s strategy to deal with the corrosion problems affecting its power supply prospects this winter. About 30 out of 56 reactors are currently shut down, including 12 for corrosion and 18 for scheduled maintenance.
France has escaped a bleak scenario for its electricity supply, already very tight for next winter, after the nuclear police officer validated on Wednesday July 27 EDF’s strategy to deal with the corrosion problems of certain reactors.
EDF plans to ultrasonically scan all of its reactors by 2025 to look for traces of this problem, which has led to the shutdown of 12 out of 56 reactors.
The group must prioritize controlling the most sensitive areas of the 1,450 MW reactors – the most powerful – and some of the 1,300 MW reactors.
The Nuclear Safety Authority (ASN) “considers EDF’s strategy appropriate in light of the knowledge gained about the phenomenon and the safety issues involved,” according to a press release, without claiming an overall more streamlined control plan.
“Regarding reactor 2 of the Belleville nuclear power plant, however, ASN considers that the inspection of this reactor scheduled for 2024 is too late,” she specifies.
EDF “takes note” and “is studying reprogramming of the controls for this reactor,” the group says in a briefing note.
The test plan is “part of the shutdowns already planned for the years 2022 to 2025,” emphasizes the company. However, “in the event of repairs, these downtimes will probably be extended to a total of up to 25 weeks”.
ASN also believes that knowledge of the phenomenon “is still evolving” and that “if the inspections or analysis uncover new elements, the inspection program needs to be adjusted”.
These corrosion problems have been identified or suspected at the welds of the elbows of the safety injection tubes (RIS) connected to the primary circuit – which allow the reactor to be cooled in the event of an accident. This so-called “stress corrosion” leads to small cracks.
The Shutdown Reactor Cooling Circuit (BRP) of certain reactors is also checked.
30 reactors are currently shut down
This corrosion issue is weighing on nuclear power generation prospects and financial results this year for EDF, whose government has planned 100 percent renationalization.
It has also raised concerns about powering France next winter. Thirty of 56 reactors are currently shut down, including 12 for corrosion and 18 for scheduled maintenance.
From this point of view, Wednesday’s ASN decision does not exacerbate the situation, since the nuclear police officer does not call for faster checks, equivalent to reactor shutdowns, but essentially confirms the EDF roadmap.
“The scenario we escape from is the one where the ASN adds an additional constraint that reduces nuclear availability for the coming winter,” explains Julien Teddé, managing director of broker Opéra Energie. “A negative statement from the ASN could have been bad news,” even “a disaster,” he notes.
“I find it quite reassuring that ASN is making this decision,” Sébastien Menesplier of CGT Mines-Énergie told AFP. “Given today’s energy situation and production fleet, all the better that the ASN validates this, otherwise we would have been in a hell of a mess.”
Supply fears this winter come on top of other factors, starting with soaring gas prices fueled by fears of shortages amid Ukraine’s invasion, sending electricity prices skyrocketing.
Prices have almost doubled in a matter of weeks: electricity for delivery in 2023 in France was trading at around 500 euros per megawatt hour (MWh) on Wednesday, up from less than 300 euros in mid-June.
These futures prices no longer obey their usual economic logic, but likely reflect “expectations of severe shortages” and “a high risk premium in the French electricity market,” according to the sector regulator.
The fears are not limited to the nuclear fleet. “The real question for me is the interconnectors,” says Julien Teddé, while France is dependent on its neighbors for part of the winter.
“If there is gas rationing next winter, with additional questions about solidarity between states, it doesn’t seem entirely won to me that the Germans would agree to burn gas to generate electricity and send it to France,” he warns.