Violations at Fla. Plant Highlight NRC Concerns Over Flooding

"On Jan. 9, a freak storm dumped a record rainfall on central Florida's Treasure Coast, inundating the St. Lucie nuclear power plant facing the Atlantic Ocean. Storm drains failed, and 50,000 gallons of water flooded the plant's Unit 1 reactor auxiliary building through improperly sealed electrical passages, disabling core cooling pumps.

Had the reactor tripped during that storm, all of the emergency core cooling pumps would have been submerged. Under that scenario, "after 24 hours, the plant would not achieve a 'safe and stable' condition and reactor core would be damaged, unless emergency recovery action succeeded," according to a Nuclear Regulatory Commission notice of violation against the St. Lucie plant owner, Florida Power & Light Co. (FPL), a subsidiary of NextEra Energy. The NRC notified FPL on Nov. 19 that it would be subject to increased safety inspections because of the violations.

The incident surprised and jarred the NRC, which has made flooding threats to U.S. reactors a top regulatory priority following the 2011 tsunami at the Fukushima Daiichi nuclear plant in Japan. Walls of water sweeping through the plant on Japan's east coast wiped out first- and second-line systems for bringing reactors to a safe shutdown, leading to an explosion of leaking hydrogen gas and three reactor meltdowns."

Peter Behr reports for EnergyWire December 1, 2014.