The Cooper plant also has two main lines of outside power, at least three generators on site and a battery system that can power the plant in an emergency.
Flooding remains a concern all along the Missouri because of the massive amounts of water the U.S. Army Corps of Engineers has released from upstream reservoirs. The river is expected to rise as much as 5 to 7 feet above flood stage in much of Nebraska and Iowa and as much as 10 feet over flood stage in parts of Missouri.
The corps expects the river to remain high at least into August because of heavy spring rains in the upper Plains and substantial Rocky Mountain snowpack melting into the river basin.
Both nuclear plants issued flooding alerts earlier this month, although they were routine, as the river’s rise has been expected.
The main building at Fort Calhoun is at 1,004 feet above sea level, which is about 2 feet below the level of the Missouri River. That’s why floodwaters have been able to get so close to the plant.
The main building complex at Fort Calhoun is surrounded by floodwaters at least 2 feet deep, and employees use an elevated catwalk more than a quarter-mile long to cross the flooded parking lot. But the utility has been able to keep the inside of its buildings and key equipment mostly dry with a network of flood barriers and a number of pumps.
Fort Calhoun workers can remain dry when walking into the plant, but OPPD has invested in about 300 life jackets and a couple hundred pairs of waders for times when employees must enter the water to check a flood barrier or build more scaffolding. Boats also are used to ferry equipment around the complex.
OPPD officials and Mr. Jaczko said the fact that Fort Calhoun has been shut down since April helps make the plant significantly safer during the flooding because the radioactive fuel has been cooling off since then.
“The risk is really very low at this point that anything could go wrong,” Mr. Jaczko said.
Associated Press writers Nelson Lampe and Timberly Ross contributed to this report from Omaha.