Hurricane Isaac soaked the Gulf Coast of Louisiana and Mississippi after making landfall Tuesday night with sustained winds of up to 80 mph, leaving thousands without power in five states. On Tuesday, Entergy took its Waterford 3 nuclear plant offline as a precautionary measure.

Three plants owned by Entergy Nuclear are in the hurricane’s path. The Waterford plant is about 20 miles west of New Orleans; River Bend is about 25 miles northwest of Baton Rouge, La.; and Grand Gulf is near Port Gibson, Miss. Entergy said Tuesday that its River Bend Station in St. Francisville, La., and Grand Gulf Nuclear Station in Port Gibson, Miss., “are operating under severe weather procedures that involve plant walk-downs, equipment checks and detailed staffing plans.”

An Entergy release issued Aug. 28 said that both Waterford 3 in Killona, La., and River Bend Station had “sequestered roughly 100 core employees each, not including security staff. Other employees have been released until after the storm.” Waterford 3, it said, “is designed to withstand the impact of 200 mph hurricane winds and will provide safe shelter for employees remaining at the plant.”

The U.S. Nuclear Regulatory Commission (NRC) activated its Incident Response Center in Arlington, Texas, to track Hurricane Isaac and monitor the activities of the nuclear plants in the storm’s projected path. On Monday, the NRC sent additional inspectors to support the resident inspectors at all three nuclear plants in the storm’s path; they will remain at the plants to monitor plant conditions until the storm is no longer a threat.

Although Isaac was classified as a Category 1 hurricane and Katrina was a Category 3 at the time it hit New Orleans on the same date in 2005, Isaac has done considerable damage that includes widespread flooding and downed power lines and trees. The National Weather Service issued flash flood warnings and tornado watches for the area affected by the hurricane. Before reaching the Gulf, Hurricane Isaac killed more than 20 people and caused significant damage in Haiti and the Dominican Republic. The U.S. National Hurricane Center has now downgraded Isaac to a tropical storm.

At 9 a.m. yesterday, Entergy reported that “more than 495,000 customers were experiencing power outages, with the vast majority in Louisiana.” Overall, as many as a third of the state’s residents and two-thirds of New Orleans residents were without power Wednesday afternoon. At 8:30 a.m.Thursday, Entergy reported that nearly 763,000 customers were experiencing power outages, the vast majority in Louisiana, but nearly 63,000 in Mississippi.

An update from Entergy’s Storm Center on Wednesday noted that “Continued high winds, floodwaters and other hazards” were preventing restoration workers from restoring electrical service. The company said it is “using the time to sharpen our plans and process donor crews.” The utility is gathering more than 10,000 company and contract workers from 24 states to help restore power. States of donor crews include Alabama, Arizona, Arkansas, Connecticut, Florida, Georgia, Illinois, Kansas, Kentucky, Louisiana, Maryland, Mississippi, Missouri, New Jersey, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, and Wisconsin. By Thursday morning, Entergy was able to start restoring service to affected customers.

Because the storm is moving slowly, Entergy said customers should prepare for extended power outages. The company noted: "Every storm is different and Isaac has certainly been a storm unlike any we’ve ever seen before. It’s already left its mark on southeast Louisiana, and it’s making its way across other parts of the state as we speak, leaving its mark as it goes."

Specifically, Entergy said today, "The number of damaged substations in our transmission system as of 6 p.m. yesterday included 12 in Entergy Louisiana, one in Entergy New Orleans and four in Entergy Gulf States Louisiana. In addition, the number of damaged transmission lines included, one in Entergy Mississippi, 28 in Entergy Louisiana, six in Entergy New Orleans and 10 in Entergy Gulf States Louisiana." The company also warned customers to stay away from downed power lines and flooded areas and to call a licensed gas fitter or plumber If gas appliances have been under water.

The New Orleans Times-Picayune reported that the city’s 24 drainage pump stations were being powered by the city Sewerage & Water Board’s own on-site generation.

This story originally ran on 8/29 and was updated and re-dated 8/30.
Sources: POWERnews, NRC, Entergy, National Hurricane Center, Times-Picayune, NBC, National Weather Service

—Gail Reitenbach, Managing Editor (@POWERmagazine)