A low-level alert issued last month as Missouri River floodwaters approached a southeast Nebraska nuclear power plant has been lifted as water recedes, while a similar alert remains in effect for a second plant along the river that has been shut down since April.
The Nebraska Public Power District said the "notification of unusual event" alert put in place June 19 for the Cooper plant, about 70 miles south of Omaha, officially ended Tuesday. Omaha Public Power District's Fort Calhoun nuclear power plant about 90 miles north remains under an alert because floodwaters there are higher, but officials say the plant remains safe, shut down and dry inside.
The Nuclear Regulatory Commission has said both utilities took appropriate steps to fight the flooding and maintain safety at the power plants.
The base of the Cooper plant, which has continued operating throughout the flood threat, sits at 903.5 feet above sea level, nearly three feet above the highest point reached by the Missouri River's floodwaters. The alert was issued when the river rose to above 899 feet above sea level nearby, but it had fallen to 895.5 feet by Wednesday morning.
Nebraska Public Power District officials said it appears the river near the Cooper plant will continue a slow decline without unexpected major rainfall in the river basin. The utility plans to keep most of the flood barricades in place at Cooper as a precaution.
Workers meanwhile were pumping floodwater from behind a new barrier installed around the Fort Calhoun plant by the Omaha Public Power District. The new 8-foot-tall, water-filled barrier replaced a similar one that failed last month after a worker inadvertently punctured it with a bobcat.
Both public power district officials and federal regulators have said Fort Calhoun remains safe even without the additional barrier, noting that all the key areas of the plant stayed dry inside even as floodwaters surrounded the outside of the plant's main complex.
The Missouri River was about 1005.9 feet above sea level near Fort Calhoun on Tuesday, down slightly from its 1,006-foot peak. The plant is designed to withstand flooding up to 1,014 feet above sea level.
Fort Calhoun has been shut down since a planned refueling outage in April, and the power district plans to keep the plant shut down until after floodwaters subside sometime in the fall.
Nebraska Public Power District: www.nppd.com
Omaha Public Power District: www.oppd.com
Nuclear Regulatory Commission: www.nrc.gov