other “significant” cracks discovered in two reactors

This additional complication could upset the maintenance schedule for French power plants. EDF has detected another fault “not insignificant” due to a phenomenon called thermal fatigue on a weld of an emergency pipe in two reactors, according to the Nuclear Safety Authority (ASN), Thursday, March 9.

These are reactor 2 of the Penly nuclear power plant (Seine-Maritime) and reactor 3 of the Cattenom power plant (Moselle), according to a note from the ASN. At Penly 2, the crack is 57 mm long, representing less than 10% of the circumference, for a maximum depth of 12 mm. “It’s not trivial, it’s a significant depth”, said Julien Collet, deputy director general of ASN, to AFP. The other crack was spotted at Cattenom 3, 165 mm long (representing about a quarter of the circumference) for a maximum depth of 4 mm.

Uncertainties about nuclear production in 2023

This discovery comes two days after the revelation of a crack of size never before seen in the Penly 1 reactor, on an emergency pipe used to flood the reactor with water in the event of a nuclear accident. The phenomenon called “stress corrosion” has been identified since October 2021 on several sites, but generated smaller cracks and on other areas of these pipes.

EDF must submit a revised control strategy to ASN in the coming days. In total, the electrician will have to check 200 welds throughout its fleet, according to ASN. What potentially cause prolonged shutdowns of reactors and raise uncertainties about nuclear production in 2023.