Strikes which were meant to last 48 hours at France's nuclear reactors and fuel refineries have ended after a day, the hardline CGT union told Reuters on Friday.

France is seen as a net exporter of electricity through the day until early evening hours Friday, data from grid operator RTE showed, after being a net importer in early morning hours.

More strikes against the government's plans to make the French retire two years later, at 64, are scheduled in the energy sector and beyond next Tuesday amid a nationwide day of protests.

At nuclear reactors, the strike ended early because grid operator RTE requested that the nuclear supply be returned to the network due to the cold, a spokesperson for the energy branch of the union FNME-CGT said.

While not a legal obligation, unions tend to comply with such requests.

Besides, following on a deal struck with EDF in October, workers have "a lot of expectation on wage negotiations," and that helped bring them back to work, FNME-CGT spokesperson Virginie Neumayer told Reuters.

The strike, which started Thursday, had only a marginal effect on nuclear power supply throughout the day and into the evening compared to the around 10% of total supply removed from the grid on Jan. 19, operator EDF data showed.

Production disruptions at hydropower plants, where strikes tend to be more intermittent, ended on Thursday, the data showed.

On the refining side, the CGT union told Reuters that the strikes disrupting fuel deliveries from several TotalEnergies' sites were also suspended, but will be proposed again at each site for the Jan. 31 national strike. It gave no reason as to why it ended early. (Reporting by Forrest Crellin Editing by Ingrid Melander)