One of the two units at Hunterston B power station was switched off on 1 August for its statutory outage: one of its biggest yet. More than 13,000 separate pieces of work are scheduled to be completed, with a total spend of more than £20 million.
One of the main jobs is replacing the generator transformer, a £5 million project. The three phases were delivered by barge and then reversed down the approach road to Hunterston.
The number of workers on site will nearly double with around 500 specialist workers brought in to assist Hunterston B staff.
Hunterston B nuclear power station, based on two advanced gas-cooled reactors and operated by EDF Energy, has produced more than 255 TWh of low carbon electricity for Scotland since it started producing power in 1976.
Colin Weir, station director said: "Once again Hunterston B will turn to a number of local firms, with whom we have a tried and trusted relationship, to provide essential services during this outage"