NRC NEWS U. S. NUCLEAR REGULATORY COMMISSION

 Office of Public Affairs Region IV 

 611 Ryan Plaza Drive - Suite 400

 Arlington, TX 76011-4005

No. IV-07-025 June 28, 2007

Contact: Roger Hannah E-Mail: opa4@nrc.gov

Phone: 404-562-4417

NRC TO INCREASE OVERSIGHT OF FORT CALHOUN NUCLEAR PLANT

The Fort Calhoun nuclear plant will receive additional oversight from the U.S. Nuclear

Regulatory Commission based on a performance indicator and an inspection finding involving

the improper installation of a valve that degraded the condition of a safety system for 454 days. 

The plant, located near Omaha, Neb., is operated by the Omaha Public Power District (OPPD).

“The NRC remains confident in the ability of the Omaha Public Power District to operate

Fort Calhoun safely,” said NRC Region IV Administrator Bruce S. Mallett. “But there are

performance problems that need to be addressed by the licensee.”

The NRC uses a color-coded system to categorize inspection findings and performance

indicators, which are objective measures of plant performance. The colors range from “green”

and then increase to “white,” “yellow” and “red” depending on the safety significance of the

issue. In this case, the Fort Calhoun performance indicator and inspection finding were

determined by the NRC staff to be “white,” or a safety issue of low to moderate significance. 

Both of these “white” inputs into the NRC’s reactor oversight process involved mitigating

systems, a group of components, like valves, pumps or electrical breakers, that are designed to

mitigate, or minimize the consequences of an accident. As a result, Fort Calhoun is being

moved to the Degraded Cornerstone Column of the NRC’s Action Matrix, which will result in a

higher level of scrutiny by the NRC. This is the third highest level of NRC oversight and eight

other nuclear power plants in the U.S. are currently in this category. The NRC Action Matrix is

available on the NRC web site at: 

www.nrc.gov/NRR/OVERSIGHT/ASSESS/FCS/fcs_chart.html.

An NRC inspection, described in a report released on March 2, determined a valve in the

containment spray system was improperly installed on May 11, 2005. The system sprays water

in the building containing the reactor to reduce pressure under some accident conditions. 
The valve remained improperly positioned for 454 days until the problem was discovered

during a refueling outage in October 2006. The NRC staff is satisfied that the licensee completed

a thorough review and analysis of the event and has taken appropriate corrective actions. 

“The improper installation resulted in a condition in which the actual position of the

valve was nearly opposite of the indicated position,” Mallett said. “The violation involved the

conduct of maintenance activities and a failure by the licensee to conduct appropriate postmaintenance testing prior to returning the valve to service.”

At the request of the licensee, a regulatory conference was held on April 16 to discuss

OPPD’s position on the safety significance of the finding and corrective actions. In response to

questions, the licensee submitted additional information to the NRC on April 23. Nevertheless,

the NRC has determined that the safety significance of the violation is best characterized as

“white.”

Fort Calhoun has also accumulated seven reportable failures of various components in

mitigating systems that count towards the safety system functional failure performance indicator. 

This performance indicator tracks the number of events or conditions that alone prevented, or

could have prevented the fulfillment of the safety function of structures or systems. 

The NRC will conduct a supplemental inspection at a future date to provide assurance

that the causes for the performance issues are understood, to independently assess the extent of

the problems, to determine if safety culture contributed to the problems, and to verify that

corrective actions are sufficient to prevent recurrence.

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