Hurricane Dorian could be a test for nuclear plant on Florida’s Treasure Coast

Florida’s Treasure Coast is home to a Club Med resort, the popular Jonathan Dickinson State Park and 17th century shipwrecks that attract divers from all over the world.

It’s also where two of South Florida’s four nuclear reactors are located — just across State Road A1A from a beachfront stretch of South Hutchinson Island that remained in fierce Hurricane Dorian’s cone of uncertainty on Saturday.

While tourists and divers will likely stay away from the area this Labor Day week, workers at the St. Lucie nuclear plant were battening down the hatches and making sure that flood-control systems and generators were ready to go before Dorian nears the coast early Tuesday.

Thought Dorian grew in power overnight, reaching Category 4 strength with 150 mph sustained winds, the threat of a direct hit seemed to lessen as forecasters shifted the track offshore. Still, even a brush along the Treasure Coast could bring ripping winds, massive rainfall and potentially destructive storm surge, which could worsen with the king tide forecast for this weekend.

St. Lucie, which started operation in 1976 and is owned by Florida Power & Light, was built to withstand hurricanes. But Dorian’s projected intensity looms as a test for a facility built right off the Atlantic Ocean.

“If it’s a large system, and the current forecasts are pointing to a large, slow-moving storm, St. Lucie would be on the side where storm surge is worse, north of the storm,” said Edwin Lyman, a senior scientist and acting director of the Nuclear Safety Project at the Union of Concerned Scientists. “FPL has to consider both storm surge and heavy precipitation at the same time when implementing its strategy to deal with the hurricane.”

Like most nuclear power facilities in the U.S., St. Lucie has steel-enforced concrete structures that are considered some of the most solid in the country. It went through numerous extreme storms in its lifetime without sustaining significant damage. And it was built 20 feet above sea level, with its reactor vessels and emergency generator buildings elevated slightly more than the 20 feet, said Peter Robbins, director of nuclear communications at FPL.

“We designed the plant beyond the worst hurricanes that have ever been experienced,” Robbins said, adding that enhancements made to generator and pump systems after the 2011 Fukushima nuclear disaster improved the plant’s capacity to operate in case of flooding.

In March 2011, the Japanese plant was hit by an earthquake, leading the reactors to shut down and the power supply to fail. Emergency generators kicked in to power the cooling systems, but a tsunami swept over the plant’s seawall less than an hour later. The tsunami knocked out all backup power supplies, leading to a meltdown that resulted in radioactive material being released into the air and contaminated cooling water running into the Pacific Ocean.

Robbins said FPL may decide to shut down both of St. Lucie’s reactors as a safety measure, not so much due to a risk of damage to the reactors themselves, which he said was low, but because other structures around the plant, such as transmission lines, could be affected by the storm. Another reason to shut down the reactor is to conserve energy for the nuclear plant’s cooling systems.

FPL could close the reactors a day before hurricane-force winds are set to reach the facility, Robbins added. Halting the reactors wouldn’t significantly affect power supply during the storm as energy consumption usually drops due to damage to distribution lines.

An outside view of the FPL St. Lucie Nuclear Power Plant on Friday, August 30, 2019. MATIAS J. OCNER

A failure of cooling systems for reactors and used or “spent” fuel storage pools is the biggest concern for nuclear power plants. Overheated fuel in the reactor core or storage pools potentially could melt, which could lead to explosions and the potential leak of radioactive material.

FPL has multiple generator systems and backup equipment ready to respond to the cooling demands of St. Lucie’s reactor and fuel cooling systems, Robbins said.

Nearby residents also seem to be confident the nuclear plant can weather the huge storm. Pete Tesch, who lives on Hutchinson Island, said the community dodged bullets before with hurricanes Matthew and Irma. He said he was encouraged after 100 mile-per-hour wind gusts measured at the power plant during Irma didn’t cause any problems.

“It held up,” he said.

When Hurricane Irma threatened South Florida in 2017, FPL shut down one of the two reactors at its Turkey Point nuclear plant in south Miami-Dade as a safety move. It left one reactor running because hurricane-force winds lost intensity as the storm approached the state. Even with the shutdown during Irma, other non-nuclear plants powered by fossil and natural gas generated enough to power to make up for losses.

Before that, last time a major hurricane had hit the Turkey Point nuclear power plant was during Hurricane Andrew in 1992; it caused $90 million in damage but left the nuclear reactors along southern Biscayne Bay unscathed. The reactors were shut down for a week, and cooling systems ran on generators for six days.

Staff writer Joey Flechas contributed to this report.