ASN imposes test on more weldings at EDF's Flamanville reactor

PARIS (Reuters) - French state-controlled utility EDF EDF.PA will have to inspect more weldings at the nuclear plant it is building in Flamanville, France after flaws were discovered in the weldings of the reactor's secondary circuit, nuclear regulator ASN said.

EDF said on Tuesday that problems with Flamville's weldings were worse than first expected and may impact the cost and startup of the long-delayed project.

The utility will comment on the start-up schedule at the end of May, after it has verified all 150 weldings in the secondary circuit that conducts steam from the steam generator to the plant’s turbines.

“The ASN considers that EDF will have to extend its controls to other circuits,” the regulator said in a statement.

The ASN did not specify whether it wanted an inspection of weldings on the primary circuit - which conducts steam from the reactor vessel to the steam generator - or an inspection of all weldings on the entire nuclear plant.

The ASN said that its April 10 inspection of the weldings of Flamanville’s secondary circuit had shown that EDF and reactor builder Framatome had not adequately overseen the verification of the weldings by suppliers at the time of their installation.

It said EDF had only discovered the problems with the weldings during an overall pre-launch inspection of the plant in early March.

The reactor is scheduled to load nuclear fuel in December.

Any major further delay to Flamanville’s EPR reactor - the same type EDF is building in Hinkley Point in Britain - could add hundreds of millions of euros to the budget and negatively impact EDF earnings.

Reporting by Geert De Clercq; Editing by Leigh Thomas