British Energy has said it will extend the lives of two nuclear reactors by five years, a move it says could help the UK to meet climate change goals.
British Energy reactors generate about one-sixth of the nation's electricity
Hunterston B nuclear power station in North Ayrshire and the Hinkley Point reactor in Somerset will now continue operating until at least 2016.
The company expects to spend an additional £90m to get the two nuclear reactors ready.
Both reactors are currently running at reduced capacity due to boiler repairs.
"This decision is based on a comprehensive technical and economic evaluation," said Bill Coley, British Energy's chief executive.
"(It) is important in supporting the UK's climate change goals for the reduction of CO2 emissions."
The UK government will decide next month whether to give the controversial go-ahead to a new generation of nuclear reactors.
British Energy has named eight of its existing sites as possible locations for next-generation nuclear plants.
The firm has earmarked Sizewell in Suffolk, Hinkley in Somerset, Bradwell in Essex and Dungeness in Kent for development.
It also named Heysham in Lancashire, Torness in East Lothian, Hunterston in Ayrshire and Hartlepool as other possible sites.