PARIS (Reuters) – EDF will have to demonstrate the resistance of the pipes of certain nuclear reactors and respond to an seismic risk for the Cruas power plant (Ardèche) in order to potentially be able to extend their operating life up to 60 years, indicated the Nuclear Safety Authority (ASN) in a notice published on Wednesday.

This opinion, which mentions other technical issues to be resolved, comes after the government validated in February the launch of studies to prepare for the extension of the life of French power plants to 60 years and beyond.

According to a note quoted by the ASN, EDF considers that the mechanical resistance of certain portions of the primary circuit piping of certain reactors could be “insufficient” and proposes “courses of action” which, according to the authority, “require further developments”.

For five reactors – Tricastin 4, Saint-Laurent 2, Dampierre 4, Blayais 3 and Paluel 2 -, the ASN notes that the demonstration of the effectiveness of the solutions envisaged “is not acquired at this stage” in the perspective of continued operation beyond 50 years.

Regarding the Cruas power plant, taking into account the feedback from an earthquake that occurred in 2019 calls, according to the ASN, for “additional investigations”, currently being carried out by EDF, in order to “better characterize the geology around this site”.

“If these investigations showed the presence, under the Cruas site, of a fault capable of inducing a surface rupture, the safety demonstration (…) would be complex to establish and could require substantial work, or even restore causes the continued operation of the reactors (…), regardless of the deadline for the periodic reviews”, warns the ASN.

The authority adds that other subjects, such as the aging of vessels and containments, the effects of climate change or the operation of fuel cycle facilities, may have “significant consequences on the availability of nuclear power plants ” and must also be the subject of “special attention” for operation up to 60 years.

EDF IS “CONFIDENT”

In response to ASN’s opinion, EDF said it was “confident in its ability to meet the safety conditions necessary for the continued operation of all its reactors” beyond 50 years.

“Some reactors present a particular technical sensitivity, but for each situation, treatment or modification solutions exist or are under development”, added the group, referring in particular to potential repairs to pipes based on “mechanization and ‘process automation’.

EDF clarified that it paid “particular attention” to the Cruas power plant, with in particular a “significant program of investigations and studies” seismic.

ASN asked EDF to present its hypotheses on the extension of the nuclear fleet up to 60 years before the end of 2024 in order to be able to take a position by the end of 2026, to allow decisions on French energy policy on the horizon. 2040 and beyond.

The executive plans for next fall a new energy and climate law which would serve as the basis for Emmanuel Macron’s project, announced in February 2022, to launch the construction of at least six new EPR 2 type reactors and to extend all the power stations that can be extended.

ASN recalled on Wednesday that the significant standardization of the French nuclear fleet presented the risk that a “serious generic defect could lead to the simultaneous suspension of the operation of several reactors”, as may have been the case in 2022 when the discovery of so-called “stress corrosion” problems.

The authority therefore considers that this type of event must be taken into account when verifying compliance with France’s electricity supply security criteria, so that the potential shutdown of several reactors over a short period be “appropriately anticipated” in a long-term vision of energy policy.

(Report Benjamin Mallet; edited by Blandine Hénault)

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