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Despite the Fort Calhoun, NE, nuclear reactor surrounded by flood waters, the plant is in a safe cold shutdown and can remain so indefinitely, the reactor’s owners and federal regulators said.

“We think they’ve taken adequate steps to protect the plant and to assure continued safety,” said Victor Dricks, spokesman for the Nuclear Regulatory Commission (NRC).

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The plant’s flood barriers are being built to a level that will protect against rain and the release of record amounts of water from upstream dams on the Missouri River, said Tim Burke, vice president at Omaha Public Power District (OPPD).

“We don’t see any concerns around the Fort Calhoun Nuclear Station,” Burke said at a briefing.

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The nuclear plant, 20 miles north of Omaha, shut down April 9 for refueling. Officials did not restart it because of the imminent flooding.

Cooper Nuclear Station, which is about 70 miles south of Omaha near Brownville, NE, continues to operate even as it makes similar flood protections. Nebraska Public Power District also owns Cooper. The river would have to rise about 6 feet higher for the plant to go into a cold shutdown.

Time has been on Fort Calhoun’s side, said David Lochbaum, director of nuclear safety at the Union of Concerned Scientists. The group is a leading watchdog of the nuclear industry.

Lochbaum is among the handful of outside experts whom Congress taps for perspective on nuclear problems, including the crisis caused by the March earthquake and tsunami in Japan.

At the Fukushima Dai-ichi plant, operators had less than an hour to react to the quake before the tsunami hit, Lochbaum said. Fort Calhoun has had weeks to ready itself for flooding.

That is what OPPD has been doing.

Dricks said the NRC has taken the unusual step of sending more inspectors and a branch chief to Fort Calhoun. A branch chief is a top regional regulator. In this case, it’s the individual responsible for overseeing Fort Calhoun inspections and compliance.

Also, OPPD is bringing in additional boats, food and water for employees, Dricks said.

During routine inspections in June 2010, the NRC concluded deteriorating conditions during catastrophic flooding could make sandbagging near the river difficult.

Regulators required OPPD to improve flood defenses and signaled in April that those improvements were taking the plant in the right direction.

At that time, the plant was putting the finishing touches on the improvements, and utility officials were hopeful that this would be the month that the federal agency signed off on Fort Calhoun’s flood upgrades.

Instead, the nuclear plant is in an all-out battle with the river.

In May, OPPD learned from the Army Corps of Engineers of the imminent flooding.

Since then, the utility:
• Installed an approximately 8-foot-tall, 16-foot-wide water-filled tubular rubber dam. The dam encircles the reactor building, like a black snake, and holds the floodwaters at bay.
• Built an earthen berm around the switchyard, and other berms or sandbag walls around other electrical structures. Protecting the structures allows continued electrical power to the plant.
• Trucked in two more fuel oil tanks that will supplement those on site and provide four weeks’ fuel for the backup diesel generators. The plant is developing plans for additional supplies of fuel.

In addition, the plant’s backup batteries can provide power for eight hours, Dricks said. The plant’s daily source of electricity is brought in from outside via transmission lines. The plant has six power lines coming into the plant, and any one of those is sufficient to run it.

John Remus of the Corps of Engineers said the river level at Fort Calhoun had yet to reflect the full release of water from Gavins Point Dam.

When that happens, and given normal rainfall, the river level at the plant will most likely rise about 6 inches higher than it has been for much of this week, he said. Should higher-than-normal rainfall occur this summer, the river might rise 2.5 feet higher than it currently is, he said.

River levels and other flood measurements at the plant are made in terms of feet above sea level.

Earlier this week, the river stood at 1,005.6 feet elevation, Remus said, and has been mostly unchanged since then. The corps’ projections place the river crest this summer, barring extraordinary rains, between roughly 1,006 and 1,008 feet.

Burke said OPPD’s flood barriers would protect the plant to 1,010 to 1,012 feet elevation. The reactor itself is in a watertight container and the spent fuel pool is at 1,038.5 feet elevation.

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