The plan, she said, is to shut the 1,870-megawatt plant two hours before tropical storm-force winds reach the facility, which could happen as early as Thursday morning, according to the National Hurricane Center. Meanwhile, the company is providing extra personnel to monitor the plant.

9 nuclear facilities within Florence's project path

Overall, there are at least nine nuclear facilities within Florence's projected impact area. "Brunswick is closest to the eye, but every reactor exposed to hurricane-force winds will be shut down," said Joey Ledford, a spokesman for the U.S. Nuclear Regulatory Commission. "We've got inspectors at every plant."

Still, the boiling water reactors used at Brunswick are similar to ones that melted down at the Fukushima nuclear plant in Japan in 2011, according to Edwin Lyman, a nuclear expert with the Union of Concerned Scientists. They have "a particular vulnerability to flooding," he said.

Flood risk

Federal regulators added measures to prevent a similar accident in the U.S., including re-evaluating flood risk. But if Florence "truly is significantly greater than anything experienced at these plants, it may exceed even their re-evaluated hazard," Lyman said.

"We don't expect any impact from the storm surge," Duke's Williams said by phone. "We've been through many hurricanes since operations began in 1975."

Got photos to share? We'd like to see them. PropertyCasualty360.com readers who have images of Florence's path can send them via e-mail to [email protected], for inclusion in our coverage.