Nuclear reactors have been shut down for the second time in three months at a plant in Lancashire.
Two reactors at Heysham 1 nuclear power station were shut down after an electrical fault in a gas turbine set off a sprinkler system on Thursday.
Firefighters were called at 22:27 BST and four crews were sent to the scene from Lancaster, Bispham and Fulwood.
EDF Energy, which operates the plant, said it had been shut down as a precaution.
Lancashire Fire Service said 20 firefighters attended the scene but were not needed.
Ian Stewart, Heysham 1 station director, said: "We will be assessing the generators today, and we will then be looking at bringing the two reactors back on line."
A reactor was shut down in May after smoke was seen coming from a turbine due to smouldering lagging.