EDF missed its 2019 target due to outages, with nuclear output falling 3.5% to 379.5 TWh.

Stephane Feutry, in charge of EDF's nuclear output, told journalists that while EDF was keeping the target the same, output was likely to be affected by the planned closure of Fessenheim, France's oldest operating nuclear plant.

The utility will release its 2019 results and outlook for this year on Feb. 14, and the company's chief executive will give the exact nuclear target for 2020, Feutry said.

The Fessenheim 1 reactor is to halt generation at the end of February and Fessenheim 2 will stop on June 30.

Around seven EDF reactors are also scheduled to undergo planned 10-year maintenance and upgrades, Feutry said.

He said EDF was increasingly flexible in managing the availability of its fleet.

"In the past we used to do it mostly in spring and at night in summer when demand is low. Increasingly now, we sometimes do it in the middle of winter, depending on the weather," he said.

"For example in December there was a lot of wind. On Dec. 23, we could have produced 47 gigawatts (GW) but at certain periods during the day we only produced 35 GW because of market conditions," he added.

EDF operates France's 58 nuclear reactors which cover around 75% of the country's electricity needs.

(Reporting by Bate Felix; Editing by Mark Potter)