A foot-and-a-half, a mere 18 inches, was what was between keeping the Cooper Nuclear Plant in Nebraska running or shutting it down.
The Missouri River has to hit 902 feet above sea level at Brownville before officials will shut down the Cooper Nuclear Plant, which sits at 903 feet.
The river rose to 900.56 feet on Sunday, then dropped to 900.4 feet later in the day and remained at that level Monday morning, said Nebraska Public Power District (NPPD) spokesman Mark Becker. The plant was operating at full capacity, he said.
The utility sent a “notification of unusual event” to the Nuclear Regulatory Commission (NRC) when the river rose to 899 feet early Sunday morning. The declaration is the least serious of four emergency notifications established by the federal commission. “We knew the river was going to rise for some time,” Becker said Sunday. “It was just a matter of when.”
The plant has been preparing for the flooding since May 30. Officials hauled in more than 5,000 tons of sand to construct barricades around it and access roads, according to NPPD.
The Army Corps of Engineers said the river level at Brownville surged 2 feet from Saturday morning to Sunday morning and it continued to rise because of heavy rain on the Nishnabotna River, which flows into the Missouri River from Iowa, and due to some erosion along a levee upstream at Hamburg, Iowa, that created a water pulse.
The Cooper Nuclear Station is one of two plants along the Missouri River in eastern Nebraska. The Fort Calhoun Station, operated by the Omaha Public Power District, is about 20 miles north of Omaha. It issued a similar alert June 6.
The river has risen at least 1.5 feet higher than Fort Calhoun’s 1,004-foot elevation above sea level. The plant can handle water up to 1,014 feet, according to OPPD. A series of protective barriers, including an 8-foot rubber wall outside the reactor building, is holding back the water.
Officials shut down the reactor for refueling and maintenance and said they would not fire it up again until the flooding subsides.
The entire plant still has full electrical power for safety systems, including those used to cool radioactive waste. It also has at least nine backup power sources.
A spokesman for the NRC thinks OPPD managers have “done everything that they need to do to respond to the current conditions” at the nuclear plant.
Flooding remains a concern all along the river because of the massive amounts of water released by the Army Corps of Engineers. The river could 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.