ML20202C176

Special Rept:On 980101,CR Vestibule to Turbine Bldg Door 401 Failed to Automatically Close as Designed.Caused by Increased Vestibule Pressure.Util Made Adjustments to Doors Automatic Closure Mechanism

ML20202C176
Person / Time
Site:	Calvert Cliffs
Issue date:	02/05/1998
From:	Katz P BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9802120185
Download: ML20202C176 (2)

Text

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, te l't:Tt::2 E. K ATr. Britimore Gas end Electric Company Plant General Manager Calvert Cliffs Nuclear Power Plant

' Calven Cliffs Nuclear Power Plant 1650 Calven Cliffs Pukway Lusby, Maryland 20657 410 495-4101 February 5,1998 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION: Document Control Desk SUILIECT: Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50 318

! Penetration Fire Barriers Special Report

{ Technical Soccification 3.7.12. Action State mentA__

Per the requirements of Technical Specification 3.7.12, . Action Statement a, we hereby submit the attached Special Report concerni'ig inoperable fire barrier penetrations. Specifically, the Control Room Vestibule to Turbine Building Door, No. 401, was inoperable for greater than seven days.

Should you have questions regarding this matter, we will be p; eased to discuss them with you.

Very truly yours, f

PEK/JKK/bjd i Attachment cc: R. S. Fleishman, Esquire 11. J. Miller, NRC A J. E. Silberg, Esquire Resident Inspector, NRC Director, Project Directorate 1 1, NRC R.1. McLean, DNR A. W. Dromerick, NRC J. II. Walter, PSC as 4* o 9802120185 980205 PDR ADOCK 05000317 S eoa 3 I.l'l.l!. .!!!.a.

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. .- ATTACIIMENT (1)

PENETRATION FIRE BARRIERS - SPECIAL REPORT We submit this Special Report due to an inoperable penetration Gre barrier, as requiied by Technical Speci0 cations 3.7.12, Action Statement a.

ACTION TAKEN On January 1,1998, the Control Room Vestibule to Turbine Building Door, No. 401, failed to automatically close as designed. Subsequent investigation determined that the door was held open by air pressure from the ventilation system, At 2135, Technical Speci0 cation 3.7.12, Action Statement a was entered, because Door No. 401 is part of the Gre barrier that separates the Control Room complex from the Turbine Building. In accordance with Technical Specification 3.7.12, Action Statement a, the operability of the fire detectors on at least one side of the inoperable Dre barrier was verined within one hour, and an hourly Hre watch patrol was established. The function of the door as a Dre barrier separation was maintained by placing a sign on the door directing personnel using the door to verify the the door closes and latches. The Action Statement for Door No. 401 remained in effect in excess of seven days, thereby requiring a Special Report to be submitted.

CAUSE OF. INOPERABILITY The Control Room ventilation system was operating in the Winter mode, and the maximum amount of outside air was being pulled in. The ventile. ion configuration increased vestibule pressure, preventing Door No,401 from properly closing and Jatching.

The potential for fire spread between the Turbine Building and the Connoi Room Complex via tne open door is considered small. The vestibule has other doors between Dooc No. 401, the Control Room, and the stair tower that remained in the closed position. The combustible loading in the vestibule is less than one hour, preventing Gre propagation through the vestibule. There is fire detection in the Control Room, and in the Control Room ventilation system, which will identify a fire in an incipient stage. Door No.401 was Operable as long as the door was maintained closed and latched. However, the Action Statement continued to be implemented as a conservative measure.

PLANS AND SCHEDULES FOR RESTORING TIIE SYSTEM TO OPERABLEJ rATUS The Action Statement for Door No. 401 was exited on January 12,1998, after adjustments were made to the door's automatic closure mechanism. A modi 0 cation to reduce the outside air flow to the Control Room to 10 percent of full system Dow has been deveioped and is scheduled to be completed in March 1998. The modification will reduce the air Dow that is holding open Door No. 401, 1

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