Cooper Nuclear Station, an electric power plant in southeast Nebraska, declared a “Notification of Unusual Event” this morning at 4:02 a. m. The declaration was anticipated throughout Saturday by the power plant’s operators, who closely tracked the river’s steady increase in elevation due to the U.S. Army Corps of Engineers’ releases from dams upstream.
The notification was made as part of safety and emergency preparedness plan the station follows when flooding conditions are in effect. The plan’s procedures dictate when the Missouri River’s water level reaches 42.5 feet, or greater than 899 feet above sea level, a notification of unusual event is declared.
There is no threat to plant employees or to the public; the plant continues to operate safely. Appropriate local, county, state, and federal agencies were also notified.
Cooper staff continuously monitors the river’s water levels as part of normal operations. However, on May 30, site personnel began additional preparations in anticipation of the Corps’ release of higher volumes of water. Personnel have been proactive in preparing the station for flood conditions by filling sandbags, constructing barricades, procuring materials and supplies, and reinforcing the access road plant staff use to get to the station. More than 5,000 tons of sand was brought in for constructing barricades, such as Hesco barriers placed around the station’s switchyard of transformers and other electrical equipment.
Should the river’s level increase to 900 feet above sea level, plant personnel will also barricade internal doorways as another layer of protection for facility equipment. If the river’s level increases to 45.5 feet or 902 feet above sea level, plant operators would take the station offline as a protective safety measure. The plant was built at 903’ MSL, which is 13 feet above natural grade.
A Notification of Unusual Event is the lowest and least serious of four emergency classifications established by the Nuclear Regulatory Commission for nuclear power plants. If placed on a scale of 1 to 4, with 1 being the least serious level of an emergency and 4 being the most serious level of an emergency, a “Notification of Unusual Event” would equal a 1.
Cooper Nuclear Station is located three miles southeast of Brownville, Nebraska, near the Missouri River. It is owned and operated by the Nebraska Public Power District, with headquarters in Columbus, Nebraska.