PARIS (Reuters) - French utility EDF <EDF.PA> can continue operating nuclear reactors that have generators with defective welding, the head of France's ASN regulator told Les Echos newspaper.
"In view of the analysis we have carried out since the beginning of September ... we believe there is no need to halt the reactors equipped with the steam generators affected by defective welds," Bernard Doroszczuk said in an interview published on Thursday.
He said the investigation was ongoing and could last up to two years, adding that further probes would be carried out when the reactors were shut down during planned maintenance to verify that there were no other defects.
An EDF spokesman said the company welcomed the remarks from the head of the regulatory agency, but would await a formal ruling before commenting further.
EDF shares rose 2.5% in early trade and were among the top gainers on the Paris bourse following Doroszczuk's comments.
Doroszczuk said the regulator had not yet made a ruling on generators that will be installed at EDF's Flamanville 3 EPR nuclear reactor under construction in northern France.
EDF and the steam generator maker Framatome "reacted quickly when the defects were detected, which has not always been the case in the past", Doroszczuk said, adding that EDF seemed to have learned some useful lessons.
EDF said in September that the problems were identified in reactors 3 and 4 at its Blayais plant, reactor 3 at Bugey, reactor 2 at Fessenheim, reactor 4 at Dampierre-en-Burly and reactor 2 at Paluel.
Atomic power from France's 58 nuclear reactors operated by EDF covers around 75% of the country's electricity needs.
A trader said the comments from the ASN head had eased fears in the power market over potentially tight supply during winter.
French front-month power contracts fell in early trade. The November delivery price <TRFRBMX9> fell more than 2% to 51.7 euros ($57.52) a megawatt hour. The contract for delivery in the first quarter of 2020 <TRFRBQH0> slumped 3.6% to 56.50 euros.
In the autumn of 2016, the regulator ordered EDF to halt up to a third of its reactors for weeks for safety checks and repairs following separate problems with components.
($1 = 0.8988 euros)
(Reporting by Bate Felix; Editing by Sudip Kar-Gupta, Edwina Gibbs and Dale Hudson)
