The company issued a one-line statement on its website in May, saying a unit of its Dungeness station, near the city of Kent on England's southeastern seacoast, was taken off-line for maintenance. Five months earlier, the environmental website ClickGreen said EDF had admitted to the industry's watchdog organization, the Office of Nuclear Regulation, protections between the nuclear reactors and the sea were "not as robust as previously thought."
A review of flood defenses followed the Fukushima, Japan, nuclear disaster in 2011.
Britain's nuclear power sector has a reputation for secrecy, and EDF released a more detailed statement on the Dungeness plant after media reported the shutdown, the newspaper the Guardian said Wednesday.
"The power station has operated normally in the recent high tides and stormy weather," station director Martin Pearson said.
Doug Parr, policy director of the environmental group Greenpeace, said EDF "does not feel the need to tell the wider community about serious safety worries over flooding."