Resources & Stats

August 2011

In every instance of a natural challenge, including hurricanes, U.S. nuclear energy facilities’ safety systems and emergency equipment have, without exception, effectively protected public health and safety.

Nuclear energy facilities are the most robust in the U.S. infrastructure, with reactor containment structures of steel-reinforced concrete that have proven their ability to withstand extreme natural events. In addition, nuclear plant operators are trained one out of every six weeks to safely manage extreme events such as hurricanes.

Hurricanes produce a consistent wind speed of at least 74 miles per and can reach as high as 160 miles per hour.

Operators of nuclear energy facilities track hurricanes days in advance of making landfall to take actions as mandated by the independent U.S. Nuclear Regulatory Commission’s guidelines and the plants’ emergency preparedness plans. These include:

• Plant personnel monitor storm conditions, paying close attention to the path of a storm and wind speeds at the site.

• Personnel inspect the entire facility and secure or move any equipment that could possibly become airborne due to high winds. They also verify weather-tight doors and ensure water intakes are prepared.

• Each plant site has numerous emergency backup diesel generators that are tested and ready to provide electricity for critical operations if electric power from the grid is lost. As part of the pre-storm inspection, diesel fuel tanks are checked and topped off to ensure there is a minimum of seven days of fuel to power the generators.

• As a precaution, a reactor will be shut down at least two hours before the onset of hurricane-force winds at the site, typically between 70 and 75 miles per hour.

Beginning 12 hours before a hurricane reaches a nuclear energy facility, operators provide status updates to the NRC.

If there is a loss of off-site power, reactors automatically shut down as a precaution and the emergency backup diesel generators begin operating to provide electrical power to plant safety systems. Operators also may manually shut down the reactor as a precaution, even if off-site power is still available.

There are several examples of nuclear energy facilities that have shut down safely due to a loss of off-site power during or following a hurricane:

• In 2005, staff safely shut down Waterford 3 in Louisiana after Hurricane Katrina, a category 5 hurricane, knocked out off-site power and damaged the regional electrical infrastructure. All emergency equipment functioned as designed and the plant operated on emergency diesel generators for 4.5 days.

• In 2004, staff safely shut down St. Lucie 1 and 2 in Florida after Hurricane Jeanne caused loss of off-site power. Manual shutdown progressed according to procedure and all emergency equipment, including emergency diesel generators functioned as intended.

• In 1992, staff safely shut down Turkey Point 3 and 4 in south Florida after Hurricane Andrew, the most powerful hurricane ever to hit a nuclear energy facility, knocked out off-site power and damaged electrical infrastructure. Emergency diesel generators were used for six days.