OMAHA, Neb. (AP) — Federal regulators have approved a small change in a Fort Calhoun's flood preparations and they plan to re-examine the worst-case scenario for flooding at the Nebraska nuclear plant.
The Nuclear Regulatory Commission license change issued Wednesday should ensure Fort Calhoun shuts down quickly enough to be protected in a flood. NRC spokeswoman Lara Uselding said the change reflects an issue identified before the 2011 Missouri River flooding and it will make the nuclear plant's flood plan more conservative.
The Omaha Public Power District-owned plant will now shut down whenever the river rises to 1,004 feet above sea level. Previously, the plan didn't require shutdown until the water reached 1,009 feet above sea level.
In 2011, flood waters reached 1,006 feet above sea level and surrounded the nuclear plant on the banks of the Missouri River, which had already been shut down for maintenance and several safety violations. Fort Calhoun's main power plant buildings are at 1,004 feet above sea level.
At the height of the flooding, OPPD erected a network of barriers and set up an assortment of pumps to help protect its buildings. But the plant, 20 miles north of Omaha, remained dry inside.
The concern with flooding is that the water could damage a nuclear plant's equipment and possibly disable its electrical and cooling systems. Without cooling for an extended period, a nuclear plant core could be damaged and harmful radiation might be released.
Fort Calhoun remained shut down from April 2011 until December while officials assessed and repaired flood damage and addressed regulatory violations. OPPD had to deal with a small electrical fire in June 2011, address structural concerns and retrain workers to respond aggressively to safety concerns.