PARIS, Jan 6 (Reuters) - The outage of the 1.5 gigawatt (GW) No.2 reactor at the Chooz nuclear power plant in northern France has been extended after an inspection found the same fault as at the Civaux plant in the west of the country, operator EDF (EDF.PA) said on Thursday. The two plants were shut down in December after discovery of corrosion in a safety system at the Civaux plant. read more The reactor outage was extended to Apr. 20 from the previous expected return date of Jan. 23. The repair solution is being investigated with the French nuclear safety authority ASN, EDF said, adding that inspections on the Chooz 1 reactor are still in progress. The extension of the outage did not affect the provisional nuclear production estimate for 2022, currently between 330 to 360 terawatt hours (TWh), the company said. French power grid operator RTE said in December that French nuclear capacity in January was expected to be at its lowest level ever for this time of year. read more The extension of the Chooz 2 reactor outage was accounted for in January analysis published by RTE. Nuclear power accounts for about 70% of France"s electricity mix and the COVID-19 pandemic has delayed maintenance work on some nuclear reactors.