The makeshift flood berm “holding floodwaters from” Ft. Calhoun Nuclear Plant collapsed at 1:30 Sunday morning and the plant was operating on emergency generators as workers hooked up an off-site source of electricity later in the day. According to Reuters, more than 2 feet (60 cm) of water rushed in around containment buildings and electrical transformers at the 478-megawatt facility located 20 miles (30 km) north of Omaha. Missouri River floodwater seeped into the turbine building on Monday, but plant officials said the seepage was expected and posed no safety risk because the building contains no nuclear material.
The auxiliary building at Ft. Calhoun, listed among the nation’s 14 most dangerous nuclear plants, was surrounded by water after the 2,000-foot berm failure according to a federal Nuclear Regulatory Commission (NRC) letter.
While meltdown danger continuing at Japan’s Fukushima Daiichi is equivalent to about twenty Chernobyls, Fort Calhoun constitutes about twenty Fukushimas. This because it stores an immense amount of nuclear fuel in its cooling pool. Not arranged like Fukushima’s elevated bathtub-pools, this structure is eighty feet deep (forty feet under ground).
The NRC letter stated that if water entered the auxiliary building, there could have been a station blackout with core damage in hours. Federal regulators said they had inspectors at the plant monitoring the situation and there was no danger according to AP.
Water surrounded the auxiliary and containment buildings at the plant, NRC said in a statement.
AP reports that Jeff Hanson said the aqua dam wasn’t critical to protecting the plant but a crew will look at whether it can be “patched.”
Flooding remains a concern all along the Missouri because of massive amounts of water the U.S. Army Corps of Engineers has released from upstream reservoirs,” reported AP today.
[…] At 1,010 feet, water would begin to enter the auxiliary building, “shorting power and submerging pumps. The plant could then experience a station blackout with core damage estimated within 15 to 18 hours,” under a worst-case scenario, the NRC said. […]
Update as of July 7, 2011 – Aqua Dam Reinstalled… http://www.highschoolstoday.com/article/20110707/NEWS01/707079880/0#oppd-reinstalls-nuke-plant-dam
Yet, still consider these issues:
Virtually every article about the flooding mentions that the Fort Calhoun plant was shut down on April 9. On May 27, the Omaha World-Herald reported, “The Omaha Public Power District said its nuclear plant at Fort Calhoun, which is shut down for maintenance, is safe from flooding.” The implication is that being shut down makes a plant safe. But as the ongoing crisis in Fukushima demonstrates, nuclear fuel remains hot long after a reactor is shut down.
When Fort Calhoun is shut down for maintenance and refueling, only one-third of the fuel in the reactor core is removed. Besides the hot fuel remaining in the core, there is even more fuel stored in the spent-fuel pool, which is not shut down. According to a May 2011 report PDF by Robert Alvarez at the Institute for Policy Studies, there are an estimated 1,054 assemblies of spent fuel, weighing 379 tons, at Fort Calhoun. The oldest of these assemblies are in dry-cask storage, which does not require any water or electricity for cooling. Like the dry casks at Fukushima, which survived the tsunami unscathed, the Fort Calhoun casks do not appear to be in any danger from flooding.
Many news outlets copied this sentence from a June 6 OPPD press release announcing a low-level emergency: “According to projections from the US Army Corps of Engineers, the river level at the plant site is expected to reach 1,004 feet above mean sea level later this week, and is expected to remain above that level for more than one month.” Though hardly reassuring news so far, missing from these reports (and from the original release) was the elevation of the plant itself, which turns out to be — surprise! — 1,004 feet.
According to NRC Senior Public Affairs Officer Victor Dricks, the river in the end of June was at 1,005.7 feet and is expected to crest at 1,006.4 feet. By then, the plant will be standing in more than two feet of water; luckily, the eight-foot-tall Aqua Dams should keep the water at bay. And the river is still well below the worst-imaginable scenario that OPPD is required to prepare for: a flood reaching 1,014 feet above sea level. Nevertheless, in the absence of any context, the press-release language is meaningless to any reader in the neighboring communities.
Almost every article about the fire and power loss at Fort Calhoun has quoted an OPPD spokesman who said that a diesel-powered backup pump was “available” but not needed. None of these articles, however, told readers how much diesel fuel is stored at the plant, how many generators and batteries are on site, and how long they could keep coolant circulating through both the reactor and spent-fuel pool. For the record, there are two emergency diesel generators at Fort Calhoun. According to Dricks, there is usually enough fuel on site to provide cooling for two weeks, but currently the plant has sufficient fuel for four weeks. Of course, the average newspaper reader would never know any of that or be privy to the timeline of potential events.
Finally, many articles have reported that the temperature in the spent-fuel pools rose 2 degrees during the recent power outage. That may not sound like much, but only a few articles told readers the actual temperature of the pool. And a 2 degree rise from, say, 210 degrees Fahrenheit to 212 degrees Fahrenheit (the boiling point for water) would be catastrophic. The pool is normally kept at about 80 degrees Fahrenheit. OPPD estimated that, in the absence of any power to circulate coolant, it would take about 88 hours before water in the pool would begin boiling.