In April 2015, the ASN said nuclear group Areva had found weak spots in the steel of the EPR reactor it is building for EDF in Flamanville, due to concentrations of carbon which weaken the mechanical resilience of the steel and its ability to resist the spreading of cracks.

"We are continuing our investigations to verify whether the anomalies found on the (Flamanville) vessel could concern reactors currently in operation, The answer is that yes, there are," ASN chief Pierre-Franck Chevet told a senate hearing about nuclear safety on Wednesday.

He added that the ASN is in talks with EDF to see what impact these anomalies could have on safety.

At the presentation of the ASN's annual report about nuclear safety in France, Chevet said the safety of France's 58 nuclear reactors was "globally good" but that he was worried about the state of the nuclear industry in France.

Areva had to be saved by French state after years of losses had wiped outs its equity and its reactor division will be bought by EDF. EDF itself if struggling under the weight of its debt and will get a capital increase from the state to boost its finances.

Chevet also said that by end 2018-early 2019 the ASN expects to give a general ruling on whether EDF will be allowed to extend the life of its ageing nuclear plants beyond 40 years.

EDF hopes to get the ASN's authorisation to extend the lifespan of its nuclear plants to 50 years, and already wants to extend the depreciation period on these assets from this year onwards - several years ahead of the ASN go-ahead - as this would boost its bottom-line profit.

(Reporting by Geert De Clercq and Benjamn Mallet; editing by Leigh Thomas and David Evans)

Stocks treated in this article : EDF, Areva