Dungeness reactor shut down for £25m maintenance
One of two reactors at Dungeness B nuclear power station in Kent has been shut down for maintenance.
EDF Energy said the "outage" had been planned for two years and would allow £25m of maintenance on the reactor and machinery, including the turbine.
The company was criticised earlier this week by campaigners who claimed it did not give enough information about two shutdowns last year.
EDF said it had ensured that everyone knew about what was happening.
The latest shutdown, which began on Friday, is a three-yearly event. The other reactor and turbine will continue to generate electricity.
During the outage the number of workers on site will double, with about 550 specialists assisting Dungeness B staff.
A spokeswoman said she could not say for legal and commercial reasons how long the outage would last, because the price of energy might be affected.
But she said the last outage of this type was for 72 days.
Dungeness B started operating just over 30 years ago. It is currently scheduled to close in 2018, but EDF hopes to extend its life for a further 10 years.
"This is a huge programme of works which will help to ensure Dungeness B can continue to operate," said director Martin Pearson.
"The significant investment from the company shows EDF Energy's confidence in the future of Dungeness B."
Campaign group Kent Against a Radioactive Environment claimed EDF did not give enough information when the Dungeness reactors were taken offline for two months last May.