ML20116D109

Special Rept 92-702:on 921005,determined That Fire Damper 2-FP-FDMP-1011 Had Only Partially Closed During Performance of Halon Sys Pressure Switch Testing.Caused by Carpeting Obstructing Cable Link.Carpeting Removed

ML20116D109
Person / Time
Site:	North Anna
Issue date:	11/02/1992
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
92-702, NUDOCS 9211050188
Download: ML20116D109 (2)

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' VIHOINI A El.lCCTHIC AND POWCH COMPANY HIC 11MOND, VIRGINIA 20201 Noventer 2, 1992 U. S. Nuclear Regulatory Commissicn Serial No.92-702 Attention: Document Control Desk NAPS /JHL, Rev.1 Washington, D. C. 20555 Docket Nos. 50-338 50 339 License Nos. NFP-4 NFP-7 Gentlemen:

ylRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS 1 AND_2 SPECIAL REPORT FOR AN INOPERABLE FIRE DAMPER On October 5,1992, it was determined that a fire damper,2 FP-FDMP-1011, located in the Unit 2 Control Room had only partially closed during the performance of Halon System pressure switch testing. The abnormality was discovered while manually resetting the fire dampers following testing.

The fire damper is located in the exhaust ventilation ducting between the Un. 2 Emergency Switchgear Room and the Control Room. it is an accordion type fire damper which closes on a Halon System actuation via the release of a restraining cable from a solenoid actuated latch. Upon actuation, the damper restrining cable link was released from the solenoid latch, however, the cable we.s obstrucWJ from its path of full travel by a piece of newly installed carpeting on the Control Room subfloor.

The carpeting prevented the restraining cable link from dropping through the floor, which resulted in the failure of the fire damper to come to a fully closed position (the fire damper was four.d approximately three inches open). The carpeting that prevented the restraining cable link from functioning pagt.rly was removed and the fire damper was subsequently tested satisfactorily on October 5,1992. It was also verified that other fire dampers in the Control Room were unaffected. Although the fire damper was returned to operable status on the same day it was determined to be inoperable, it is apparent t:1at the inoperable condition ocurred when the new carpeting was installed in the Control Room in early September 1992. Therefore, the fire desper which functions as a fire barrier was inoperable for greater than the 7 day allowance specified by UFSAR Section 16.2.1.3 and administrative procedures. An evaluation will be performed to determine the method to prevent the damper restraining cable link from being obstructed in the event carpeting is replaced in the control room.

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• No hgnificant safety consequences resulted from this condition becauso 'he Control Room had fire detection and suppression equipment that were f:s 'y operable.

Additionally, the small area of the duct not blocked by the fire darnier did not significantly affect the Emergency Switchgear Room Halon System's 3 bey to maintain

adequate gas concentrations. In addition, the Control Room 's continuously manned and a fire would be identified and intmediataly extinguished. Tlierefore, the health and safety of the public were not affected as a result of this condition.

This Special Report has been revie ved by the Station Nuclear Safety ar.d Operating Committee and will be provided to the Manageraent Safety Review Committee, if you have any questions or require additionalinformation, please contact us.

Very truly yours, I i st L fdWg W. L. Stewart Senior Vice President - Nuclear cc: U. S. Nuclear Regulatory Commission Region ll 101 Marietta Street, N. W.

Suite 2900 Atlanta, Georgia 30323 Mr. M. S. Lesser NRC Senior Resiuent inspector North Anna Powar Station

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