River Levels on the Rise – The NRC At The Ready

Lara Uselding
Public Affairs Officer
Region IV
 

NEW UPDATE: Currently, river levels are at 1000 feet 6 inches with levels not expected to increase more than a few inches over the next 24 hours. OPPD is returning the plant to full power. NRC inspectors provided around the clock coverage through last weekend and the agency will continue closely monitoring plant operations and river conditions.

UPDATE: Fort Calhoun began decreasing power at midnight, and is currently holding at a reduced power level. The river level is now predicted to crest at 1,002.4 feet on Saturday, which is lower than previously predicted. For comparison, the 2011 flood peaked at about 1,007 feet. Three people from Region IV will begin around the clock coverage today in support of the resident inspectors.

Three years ago this month marks the anniversary of the record Missouri river floods. Now, due to heavy rains, the NRC is once again watching rising Missouri River levels impacting Nebraska’s Fort Calhoun nuclear power plant,  north of Omaha.

Cooper Nuclear Station in Brownville is not anticipating a major impact this weekend.

Fort Calhoun’s procedure requires them to declare a Notice of Unusual Event and be shut down by the time river levels at the site reach 1,004 feet mean sea level. Thursday afternoon, river levels were at 998 and rising. Normally, river levels at the site range from 980 to 990 feet mean sea level.

Over the past week, NRC’s Region IV in Arlington, Texas, has been engaged in routine calls with the United States Army Corps of Engineers, National Weather Service, Federal Emergency Management Agency, National Oceanic and Atmospheric Administration, states, and local response organizations to understand changes in the predicted river levels and assess potential impacts on the plants. 

Simultaneously, the NRC has been overseeing actions that Omaha Public Power District (Fort Calhoun) and Nebraska Public Power District (Cooper) are taking to protect the plant against impending flood waters. At this time, river levels at Cooper are not projected to be high enough to require a plant shutdown.

OPPD’s actions involve the use of sand bags, flood doors, and readying mobile pumps as river levels are projected to rise. They have also ordered equipment to protect certain buildings on site. NRC resident inspectors, who live in the area and work at the plant, have been monitoring the flood preparations.

The NRC is sending more staff to the plant to support the resident inspectors and provide around the clock coverage. During the 2011 flood, river levels at Fort Calhoun reached about 1007 feet and the plant remained in a safe shutdown condition. The plant restarted late last year only after extensive flooding improvements and other safety upgrades mandated by the NRC. Fort Calhoun remains under increased NRC regulatory oversight.

Region IV will continue monitoring the situation for both plants over the weekend.

 

 

NRC Grants Ft. Calhoun License Amendment Request

Lara Uselding
Public Affairs Officer
Region IV
 

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.

Ft. Calhoun Senior Resident Inspector John Kirkland provides "boots on the ground" oversight at the plant.
Ft. Calhoun Senior Resident Inspector John Kirkland provides “boots on the ground” oversight at the plant.

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.