* Says EDF failed to properly oversee Flamanville site
* EDF must review quality of Flmanville materials (Adds ASN comments about oversight failures)
PARIS, Oct (Shenzhen: 000069.SZ - news) 3 (Reuters) - Faulty weldings at the nuclear plant that French utility EDF is building in Flamanville, Normandy, may require more repairs than originally estimated and EDF will have to review materials on the site, the ASN nuclear regulator said in a statement.
In July, problems with the weldings forced EDF (Swiss: EDF.SW - news) again to delay the start-up date for the troubled Flamanville 3 nuclear reactor to the second quarter of 2020. It also pushed its cost estimate up to three times the original budget.
EDF said then that a total of 53 weldings on Flamanville's secondary circuit would have to be redone, while for another 10 it was confident it could convince the ASN that they were fit for service. Another 85 needed no repairs, it said.
The ASN said on Wednesday that a programme of major tests would be necessary to verify whether eight weldings were indeed fit for service, as EDF has argued.
"To the extent that it is not certain that this will be the case, ASN invites EDF to start preparing for possible repair work on the weldings," the regulator said.
The regulator said it would start an investigation of EDF's proposals and it was sharply critical about the way EDF has handled the problems with the weldings.
"The ASN considers that the problems with the weldings show that EDF has failed to properly oversee certain activities on the Flamanville reactor construction site," the regulator said.
It added that it was demanding that EDF will broaden the quality review of materials installed on the reactor.
It also said that, given the fact that the first problems had been identified in July 2015, the management of the situation by EDF had been inadequate.
"Therefore ASN demands that EDF proceed to a thorough analysis of the dysfunctions at EDF and its suppliers," it said.
EDF will also have to explain why it informed the ASN so late, at the start of the 2017.
EDF was not immediately available for comment.
EDF is building two similar EPR reactor models at Hinkley Point, Britain. Three other models under construction in China and Finland have also suffered long delays and budget overruns. (Reporting by Geert De Clercq; Editing by Sudip Kar-Gupta)