Two reactors at Heysham power station which were shut down after cracks appeared could be restarted by the end of the year, EDF Energy said.
The reactors at Heysham 1 and Hartlepool power stations were shut in August following a routine inspection.
They could return to service at 75-80% power because defects such as that found at Heysham 1 “can only develop into cracks at very high temperatures”. Each power station has 16 boilers supported by a boiler spine component, where the crack was found.
“As boiler spine defects can only develop into cracks at very high temperatures, two reactors at Hartlepool and one at Heysham 1 could be returned to service at 75%-80% power to reduce the temperature to which the boiler spines are exposed,” an EDF spokesman said.
The phased return could begin between the end of October and December.
The dates will also be subject to approval from the independent nuclear regulator, the Office for Nuclear Regulation.
There will be planned maintenance periods in 2015 and 2016 to allow the reactors to be returned to full power.
EDF Energy said boilers affected by the defect at Heysham 1 would be isolated.