In a statement Friday, TVA also said the refueling came in under budget.
The reactor at the plant in Soddy-Daisy, Tenn., near Chattanooga was scheduled to be down for 90 days when the planned outage began Oct. 15. TVA said the refueling and the replacement of four massive steam generators were completed Jan. 6 - 83 days after the project began.
Final costs are being tallied, but the federal utility said it expects to be under the $376 million budgeted for the project.
TVA provides electricity for business customers and distribution utilities that serve 9 million people in parts of seven southeastern states.