Pictures of the Fort Calhoun nuclear power plant north of Omaha, Neb., show it encircled by the swollen waters of the Missouri River, which reached a height of nearly 1,007 feet above sea level at the plant yesterday.
The plant's defenses include new steel gates and other hard barriers protecting an auxiliary building with vital reactor controls, and a water-filled berm 8 feet tall that encircles other parts of the plant. Both systems are designed to hold back floodwaters reaching 1,014 feet above sea level. Additional concrete barriers and permanent berms, more sandbags and another power line into the plant have been added. The plant was shut down in April for refueling and will remain so until the flood threat is passed.
"Today the plant is well positioned to ride out the current extreme Missouri River flooding while keeping the public safe," Nuclear Regulatory Commission spokesman Victor Dricks said on an agency blog this week.
But a year ago, those new defenses were not in place, and the plant's hard barriers could have failed against a 1,010-foot flood, the Nuclear Regulatory Commission contends in a yearlong inspection and enforcement action against the plant's operator, the Omaha Public Power District (OPPD).
"This is the first test of the revised flood preparations for Fort Calhoun," OPPD spokesman Michael Jones said.
NRC inspectors concluded that at flooding levels above 1,008 feet, the plant "would experience a loss of offsite power and loss of intake structure" and water pumps providing essential cooling water to the plant. In that case, "the plant would be incapable of reaching cold shutdown" with normal operations -- a fundamental safety requirement imposed by the NRC. The commission's Region IV office in Arlington, Texas, issued a notice of violation against the plant on Oct. 6 last year, finding that the issues were of "substantial importance" to the plant's safety.
OPPD challenged the NRC's inspectors' conclusions in a series of conferences before bowing to the commission staff's demands and agreeing to install the additional defenses this year. The AquaDam water berm was installed beginning June 4.
http://www.nytimes.com/cwire/2011/06/24/24climatewire-a-nuclear-plants-flood-defenses-trigger-a-ye-95418.html?amp
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