A report by Entergy, the site operator, pointed the finger at a bird "streamer" as the cause of the shutdown, which tripped a safety breaker and took a reactor at the site out of commission for three days from December 14.
There was no leak of radiation as a result of the accident, and at no time was public health and safety in jeopardy, the report to the US Nuclear Regulatory Commission noted.
If a streamer contacts an energised conductor, the current can travel up the stream of poop back to the bird or its perch, resulting in "bird electrocution, power outage and/or line trip," CNN quoted the report as saying.
The document reported that no bird carcasses were found in the vicinity of the transmission tower.
Additional anti-avian security will be put in place to minimise the chances of another poop-related outage.
