OSLO, Nov 21 (Reuters) - Test production of electricity at Finland's much-delayed Olkiluoto 3 nuclear reactor will restart on Dec. 11 at the earliest, while regular output is at best set to begin on Jan. 22, operator Teollisuuden Voima (TVO) said on Monday.

TVO in October revealed that cracks were found in the OL3 reactor's four feedwater pumps after test production, again delaying startup of the plant which was originally meant to begin operations in 2009. (Reporting by Nora Buli, editing by Terje Solsvik)