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Event Notification Report for December 15, 2009

U.S. Nuclear Regulatory Commission
Operations Center

Event Reports For
12/14/2009 - 12/15/2009

** EVENT NUMBERS **

Power Reactor	Event Number: 45567
Facility: PRAIRIE ISLAND Region: 3 State: MN Unit: [1] [ ] [ ] RX Type: [1] W-2-LP,[2] W-2-LP NRC Notified By: WILLIAM BODIN HQ OPS Officer: KARL DIEDERICH	Notification Date: 12/14/2009 Notification Time: 17:20 [ET] Event Date: 12/14/2009 Event Time: 12:00 [CST] Last Update Date: 12/14/2009
Emergency Class: NON EMERGENCY 10 CFR Section: 50.72(b)(3)(ii)(B) - UNANALYZED CONDITION	Person (Organization): TAMARA BLOOMER (R3DO)

Unit	SCRAM Code	RX CRIT	Initial PWR	Initial RX Mode	Current PWR	Current RX Mode
1	N	Y	100	Power Operation	100	Power Operation

Event Text

UNANALYZED CONDITION RELATED TO CERTAIN FIRE CONDITIONS

"During review of the safe shutdown strategies for NFPA 805 in Fire Area 32, it was identified that fire induced damage to cable 1C-333 could cause a spurious lockout of 1RY transformer. The Appendix R Safe Shutdown Compliance assessment for Fire Area 32 credited the 1RY transformer source to safeguards 4kv bus 16 for safe shutdown. Cable 1C-333 was not previously identified as a required cable for the 1RY source in the Appendix R circuit analysis.

"It was determined that D2 Emergency Diesel Generator could be credited as the safe shutdown power source to safeguards 4kv bus 16. Cabling required to support D2 Emergency Diesel Generator passed through Fire Area 32 but should be protected with a thermal shield as approved by the 5/4/1983 NRC Fire Protection Safety Evaluation Report. While inspecting these thermally shielded cables, it was identified that they are not wrapped after leaving the cable tray and prior to entering the bus room located above.

"A fire watch was established in Fire Area 32 as a compensatory measure. Actions to ensure a power source remains available to achieve safe shutdown have been initiated.

"The discovery of this non-compliance is being reported as an unanalyzed condition as defined by 10 CFR 50.72(b)(3)(ii)(B). An hourly fire watch has already been in place for Fire Area 32 as a compensatory measure for other issues identified in this fire area."

The licensee notified the NRC Resident Inspector of this event.

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