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.