Missouri River soaks Nebraska nuclear plant, but it's no Fukushima
Much of the grounds at Fort Calhoun nuclear plant in Nebraska are under two feet of water from the rising Missouri River. But the plant's critical systems sit six feet above the flood's expected crest.
Flooding along the Missouri River has overspread much of one nuclear power plant's boundaries, forcing it onto emergency generators, and threatens a second plant downstream.Skip to next paragraph
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In both cases, regulators and operators say the plants appear to be in no danger of the kind of sequence of events – exacerbated by plant-design flaws – that led to the tsunami-spawned nuclear disaster in March at Japan's Fukushima Daiichi nuclear power plant.
The two plants, nestled along the Missouri River in Nebraska, "will be annoyed but not destroyed," adds David Lochbaum, a nuclear engineer and nuclear-safety specialist at the Union of Concerned Scientists in Washington.
At the plant facing the biggest challenge, the Fort Calhoun Nuclear Station, about 30 miles north of Omaha, the Missouri River is predicted to crest Wednesday at 33 feet above flood stage – some six feet below the level critical buildings at the plant were designed to handle. That flood crest would put the flood level roughly half an inch higher than it is currently.
Much of the plant's grounds are under at least two feet of water. Through early Saturday morning, the reactor-containment building and its adjacent auxiliary buildings were high and dry, protected by a 2,000-foot-long water-filled berm. But workers operating heavy machinery ruptured the eight-foot-high berm, allowing water to lap at these structures as well. Some water has leaked into the turbine building, which houses no nuclear material.
With the emptying of the berm, the only dry patch remaining is the plant's switch yard, which holds transformers and power lines that ship the plant's electricity to the grid, but which also receive power to operate the plant.
The switch yard is surrounded by a concrete levee. But that barrier has sprung leaks, prompting plant operators to shift to diesel generators for onsite power. Workers are looking at ways to patch the leaks, as well as repair the berm.
Fort Calhoun has been off line since April for a scheduled refueling outage, and officials with the Omaha Public Power District, which owns the plant, say they won't restart it until the flood has subsided.
If something untoward should happen, workers would have more leeway to deal with a problem because the plant is cooler than it would have been if it were online and because some of the most troubling radioactive byproducts in an accident have a quick decay time, says David Lochbaum, a nuclear engineer who tracks nuclear-safety issues for the Union of Concerned Scientists in Washington.
The danger of flooded nuclear plants was thrown into stark relief in March, when an earthquake struck off northeastern Japan, sending a tsunami crashing into the Fukushima Daiichi nuclear plant. The wave easily overtopped a seawall designed to keep tsunamis at bay. The tsunami swamped the plant's emergency generators, which had been installed on the seaward side of the facility, and swept away above-ground storage tanks holding the fuel to run them.