Nuclear Reactors May Be Offline Until 2015

Four nuclear reactors, which each provide 1% of the country's electricity, could be out of action until the end of the year due to safety fears.

The announcement by EDF Energy, which owns the Heysham 1 and Hartlepool power stations, raised further concerns about the chances of blackouts during the winter following confirmation of actions to secure supplies by the National Grid.

Generation was suspended at the reactors last month after the discovery of a crack on a component known as a boiler spine at Heysham 1, a part also used at Hartlepool.

Brian Cowell, director of nuclear operations at EDF told Sky's Ian King:

"We will be back on now between October 31st and December 31st this year."

Mr Cowell also said:

"These reactors make up just four out of fifteen reactors which is roughly 3-4% of the UK's demand. The system copes by bringing in other generation."

It said that in addition to verifying that no other potential defects could lead to cracks, its teams had to identify the cause of the crack at Heysham 1 and develop designs and techniques to implement any necessary modifications.

The shutdowns have put a strain on capacity at a time when the National Grid is worried about the looming winter.

It confirmed earlier this week it was seeking extra electricity from older or mothballed plants to be able to help out in the event of possible shortages and was looking to sign contracts with heavy users to reduce their drain on electricity at peak times.

EDF said it hoped to have both its power stations operating again by the end of December but the dates depended on the findings and completion of the inspections.

UK capacity has been damaged by ageing plants being taken out of service at a quicker than the rate of new plants becoming operational.

A serious fire at Ferrybridge has also contributed to the pressure on generation in northern England.