When someone sees the words Fort Calhoun and flooding in the same document, it gets attention. So we thought we’d provide some insight into a document — issued this week — with that very word combination.
The Fort Calhoun Station, located north of Omaha, Neb., and operated by the Omaha Public Power District (OPPD), recently restarted after a long hiatus. But months before that happened, in April 2012, OPPD asked permission to implement a license change involving actions to protect the plant at high and low river levels.
On Jan. 28, 2014, the NRC granted the request and issued a license amendment officially changing when the plant should be powered down during a flood scenario. Simply put, the change involves powering down at 1004 feet mean sea level versus the previously set level of 1009 feet. In addition to setting the river rising to a lower level, the NRC document also specifies that the plant must shutdown within six hours of river levels dropping below 976 feet 9 inches mean sea level.
This all started back in 2010 when NRC inspectors identified concerns with the plant’s flood protection strategy. So this is not a newly identified item and it does not change the plant’s design basis flood. It is an official change to the plant’s license during flood conditions and provides a more conservative level of action.
It is important to note that prior to restart, the licensee made modifications to the plant and had plans in place to protect the plant from rising river levels.
There is still ongoing and important work being done by OPPD, NRC and the U.S. Army Corps of Engineers to evaluate flood risks at the site in accordance with the post-Fukushima actions. The current target date for OPPD providing this information to the NRC is March 12, 2014. In the meantime, the plant is safe and has measures in place to respond to flooding events.
U.S. NRC Blog 
At Fort Calhoun, the dry cask storage area sits back from the river and is north of the plant. There, spent fuel is enclosed inside stainless steel and placed inside concrete casks. The pads are at 1009 feet and 10 inches. During the 2011 floods, the water rose to 1006 feet. It’s important to note that the dry casks have been analyzed to withstand submersion in water, although that did not happen.
I’ve reached out to you directly to address any other questions you have about Ft. Calhoun.
Lara Uselding
How close was the water to the fuel casks?
The spent fuel pools are located inside the Auxiliary Building and the elevation of the pools is much higher than was reached by the flood waters.
Lara Uselding
Where are the fuel pools? The films I seen it looked like the pools where in the ground and river water was higher then the top of the pool. Didn’t the river water flow into these pools cooling the fuel?
No, the spent fuel pools did not have contact with the flood waters.
Lara Uselding
Gavins Pt. Dam was considerably damaged in the 2011 flood and is still being repaired in 2014. The NRC has made no changes to Calhoun’s sandbags and innertube “flood protection” plan since the 2011 flood. Even after multiple instances of water getting into secured areas of the plant. It is still at risk in a flood and even more so if there is a dam failure. Everyone in the region is forced to put up with this risk so OPPD can run this old plant they don’t really need.
Did the fuel pools fill with water when the plant was flooded as I did not see a above ground fuel pool?