Fire and rescue services were alerted to a blaze within the grounds of Hunterston B Power Station.
The matter was recently reported on at this month's nuclear site stakeholders group meeting held at The Waterside Inn at Seamill.
The details came out at the briefing involving power station chiefs, nuclear regulators and environmental authorities, and was open to the public.
A spokesperson for EDF said: "Three appliances from Scottish Fire and Rescue Services came to site in the early hours of Sunday 12 January to attend to a fire in one of the contractor cabins on site.
"The fire was brought under control very quickly and at no time was there any risk to nuclear safety or the operation of the plant. The fire was contained within the cabin by fire doors and no one was hurt.
"A full investigation has been carried out to ensure we understand the cause."
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