HARTELPOOL nuclear power station is one of four reactors shut down for safety reasons that may not be back online until the end of the year, EDF Energy has said.
The move came after a crack was found in the boiler spine of Reactor 1 at the Heysham 1 site.
Hartlepool’s reactors have been shut down since August 11 as a precautionary measure by EDF.
The power company said there could be a phased return to service between the end of October and the end of December, 2014.
Earlier this week National Grid announced it was seeking emergency supplies of electricity this winter.
It cited concern over potential shortages of power.
EDF said today that it had now had time to assess any work and draw up a timetable.
"Dates for returning the stations to service depend on the findings and completion of the inspections," the company said.
"Depending on the progress of the programme and any necessary modifications, the company expects there to be a phased return to service between the end of October and the end of December, 2014.
Any re-entry into service will have to be approved by the nuclear safety regulator, EDF said.
On Tuesday, National Grid, which runs the power distribution network, said it was seeking additional electricity supplies for winter.
The company said it was accelerating an emergency plan asking providers how much more electricity they could provide to fill a possible shortfall.