As the Water Rises

Flooding along the Mississippi River Valley has sent thousands scurrying for safety. Amid the havoc, three nuclear power plants along the Mississippi are making preparations to deal with rising flood waters. If all goes as planned, they should be able to safely continue operating through the worst of the predicted flooding.

Grand Gulf in Port Gibson, Miss., River Bend near Baton Rouge, La., and Waterford near New Orleans were designed and built to be able to withstand floods, tornadoes, earthquakes and other furies of Mother Nature. Plans are in place at all three facilities to ensure the protection of plant personnel, the public and the environment.

NRC’s resident inspectors at Grand Gulf have been monitoring preparations by Entergy workers. According to projections by the U.S. Army Corps of Engineers, the plant should be able to keep operating safely even as river levels rise. The plant is located 132.5 feet above mean sea level and the river is expected to crest at 95 feet on May 19. No safety-related equipment is expected to be affected by the flooding. But as a preventive measure, plant personnel are sandbagging and applying waterproof sealants to buildings and non-safety related equipment.

Emergency diesel generators have been checked and re-checked as have emergency batteries that would be relied on in the unlikely event the diesels fail. Unlike at Fukushima, the diesels are located in water-proof buildings.

Waterford, which is being re-started from an April 6 refueling outage, can continue to operate until waters reach the 27 foot level, which would affect the plant’s water intake system. Current projections show the Mississippi River may reach this level if spillways and floodgates are not opened, but plans are in place to do so. The level at Waterford is 29 feet. All safety equipment at the plant is housed behind a walled-in enclosure that is more than 29 feet high. Even with a levee breach, flood levels would still be several feet below the top of this enclosure.

River Bend sits 94.5 feet above mean sea level. The Mississippi is expected to crest at 57.5 feet on May 22. A vault housing non-safety related cooling water systems is located in a vault at the 51-foot level, but is designed to operate submerged. The licensee has installed a 7.5 foot tall dam on top of the vault, plugged all external penetrations, and installed sump pumps inside as an extra safety measure.

NRC staff in our Region IV office are closely following flooding conditions along the river and have plans in place to dispatch additional personnel to augment the resident inspectors if needed.

There are currently no known impacts on the hundreds of industrial, commercial and medical users of radioactive materials licensed by the NRC in the affected areas along the Mississippi.

Victor Dricks
Public Affairs Officer, Region IV