Flamanville 3 weldings found to be sub-standard

26 February 2018

Electricite de France (EDF) said on 22 February some weldings on it’s the EPR reactor under construction at Flamanville 3 did not meet required specifications but that this did not affect safety or the schedule to load it with fuel at the end of 2018. An EDF spokeswoman said 38 of 66 weldings on the reactor’s secondary cooling circuit were not in line with standards aimed at making them rupture-proof, but they met Autorite de Surete Nucleaire (ASN - Nuclear Safety Authority) requirements for nuclear equipment under pressure.

However,  ASN chief Pierre-Franck Chevet told a parliament committee hearing on nuclear safety and security on 23 February that an inspection had revealed that the welding issue was more severe than initially thought. Chevet said the issue was still very much open, and the regulator was far from drawing conclusions. “That given, I cannot confirm EDF’s assertion that there would not be an impact on Flamanville’s schedule,” he said. “The startup of Flamanville is subject to my authorisation, and the safety calendar will be paramount.”  

The Flamanville EPR  is already nine years behind schedule and billions of euros over budget at €10.5bn ($12.4bn). It is scheduled to be loaded with fuel by the end of December and to be at full power by the end of 2019.

A statement on the Flamanville EPR reactor website said deviations had been detected in the quality of the weldings in pipes transferring steam from the steam generator to the power turbine. “EDF has started analysis aimed at proving that the mechanical characteristics of the circuit are in line with expectations, within deadlines compatible with the project planning,” it said.

The problem was identified in the workshops of third-party suppliers to Framatome (formerly Areva), in 2015 and 2017, as well as in weldings on site. EDF informed ASN about the problem in early 2017 and submitted technical dossiers to prove the equipment was fit for service and met regulations. In June 2017 ASN said Flamanville was fit for service despite weak spots in its steel but ordered EDF to replace the reactor cover by 2024 at the latest because of high carbon concentrations, which make the steel brittle.

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