Event Notification Report for February 13, 2009

UNUSUAL EVENT - ENGINEERING ANALYSIS REQUIRES TECHNICAL SPECIFICATION SHUTDOWN

"On February 13, 2009 at 1526 CST, Fort Calhoun Station declared a Notification of Unusual Event [NOUE] based upon EAL 4.2 - Both Diesel Generators NOT Operable. The station has entered Technical Specification 2.0.1(1) requiring the Unit to be placed in at least HOT SHUTDOWN within 6 hours.

"The cause of the NOUE is a potential common mode failure of the diesel generators. Design Engineering has identified an unanalyzed condition in which a High Energy Line Break in Room 81, Main Steam Lines Containment Penetration Room, or an auxiliary steam leak in Room 82, Turbine Building Ventilation Room, can potentially result in water entering both diesel generator rooms through the floor of Room 82 located directly above the diesel rooms, Rooms 63 and 64. This condition presents a potential common mode failure of the diesel generators due to loss of diesel generator auxiliaries from a single failure. The possibility of water leaking into Rooms 63, 64 and the Switchgear rooms prompted this declaration."

Compensatory measures to exit the NOUE will be to remove auxiliary steam from room 82 and blockading shut the door between rooms 81 and 82. These actions are expected to be completed within one to three hours.

The licensee notified the NRC Resident Inspector.

* * * UPDATE AT 1928 ON 2/13/2009 FROM SCOTT EIDEM TO MARK ABRAMOVITZ * * *

At 1828 CST, Fort Calhoun Station exited the Notification of Unusual Event. Both Diesel Generators were declared operable based upon establishing compensatory measures. Diesel 2 was confirmed operable by running in accordance with approved procedures. Diesel 1 was successfully run on February 11, 2009 per a monthly surveillance tests. No additional water intrusion had occurred into the diesel 1 room since completion of the surveillance test. Compensatory measures to prevent water intrusion into Room 82 include isolating auxiliary steam to room 82 to eliminate a source of water to room 82, installing a temporary barrier at the door between rooms 81 and 82 to prevent water from flowing from room 81 to room 82, should an HELB occur in room 81, and to open the door between room 81 and the turbine building to allow water to flow out of room 81 so as not to flow into room 82. Technical Specification 2.0.1 has been exited as of time 1828 CST."

The licensee will notify the NRC Resident Inspector.

Notified the R4DO (Miller), IRD (McDermott, McMurtray), DHS (Doyle), and FEMA (Via).

* * * UPDATE AT 1539 EDT ON 4/1/2009 FROM ERICK MATZKE TO DONG PARK * * *

"This is a retraction [of the report made under 10 CFR 50.72(b)(3)(ii)(B) - Unanalyzed Condition]

"Fort Calhoun has performed a detailed evaluation of water intrusion through cracks in the floor of room 82 above the emergency diesel generators, as identified in part in the notification of 2/13/2009. This evaluation determined that no common mode failure mechanism existed and that the diesel generators were capable of performing their design safety functions."

The licensee informed the Resident Inspector. Notified R4DO (Rick Deese).

FITNESS FOR DUTY

A non-licensed employee supervisor had a confirmed positive for illegal drugs during a follow-up fitness-for-duty test. The employee's access to the plant has been terminated. Contact the Headquarters Operations Officer for additional details.