In 2008 and 2009, following observations made during inspections at the Flamanville 3 site, ASN requested EDF to implement an action plan to improve quality of liner welds and, while awaiting convincing results, to perform radiographic testing on all welds. The action plan specified rules for welding conditions and training for welders.

During their visit on 7 July 2010, ASN inspectors observed that the ergonomics of the welding position of the horizontal weld in question was the primary cause of the new problems. They also observed that radiographic testing was not performed as welding work advanced: the delay in performing an inspection prevented quick detection of inferior weld quality. On the day of the inspection, EDF had already temporarily suspended new welding activity, reminded those concerned of the 2009 action plan and begun radiographic testing of all questionable welding. Repair of areas showing faults has now been completed.

Welding difficulties caused by the ergonomics of the welder’s post had already been identified as one of the main causes of the 2008-2009 events. ASN also determined that EDF’s treatment of the anomalies detected in 2008 and 2009 was not performed correctly and requested that EDF apply this operating feedback to all welding activities at the site. ASN however wishes to emphasize EDF’s proactive response in implementing preventive measures following detection of the deviation in June 2010.