EDF delayed the restart of 1,300 megawatt (MW) Flamanville 1 in the north of France by more than a month to Dec. 15 from Nov. 11. The reactor has been offline since Sept. 18 for planned maintenance.

Restart of Flamanville 2, which has similar capacity and has been offline since last January, was delayed by two months to Jan. 31, 2020. The reactor is undergoing its third 10-year overhaul.

A spokesman for state-controlled EDF, which operates France's 58 nuclear reactors, said there were no major issues at the reactors but the company is contending with a massive backlog of maintenance operations.

EDF lowered its 2019 nuclear power generation forecast in France by 1.2 percentage points to about 390 terawatt hours (TWh) last week, citing prolonged maintenance outages at its reactors.

It cited the overlapping of some intensive operations in several plants that have resulted the extension of planned shutdowns, including at the Flamanville plant.

French nuclear regulator ASN put the Flamanville 1 and 2 reactors under increased surveillance in September over shortcomings in maintenance and contractor oversight.

Nuclear power from France's reactors covers about 75% of the country's electricity needs. Of the 58 reactors, 19 are currently offline for planned maintenance, according to grid operator RTE.

A trader said reactor availability for this time of the year is at its lowest in eight years, though mild temperatures and low gas prices are easing the pressure.

(Reporting by Bate Felix; Editing by David Goodman)