ML20101H234

Special Rept 92-06 Re Auxiliary Bldg Fire Doors A-196 & A-197 Being Breached on 920520.Doors Breached for Period Greater than TS Allowable Time Period.Fire Detectors on Each Side of Breaches Verified Operable & Fire Watch Established

ML20101H234
Person / Time
Site:	Sequoyah
Issue date:	06/25/1992
From:	Joshua Wilson TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
92-06, 92-6, NUDOCS 9206290242
Download: ML20101H234 (4)

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l J L. W,:wn vo nemam sew,e toar en June 25, 1992 U.S.-Nuclear-Regulatory Commission ATTN: Document Control Dest Washington, D.C. 20555 Gentlemen In the Matter of ) Docket Nos. 50-327 Tennessee Valley Authority ) 50-328 SEQUOYAll NUCLEAR PLANT (SQN) - UNITS 1 AND 2 - FACILITY OPERATING LICENSES DPR-77 AND,DPR SPECIAL REPORT 92-06 The enclosed special report provides details concerning auxiliary building Fire Doors A-196 and A-197 being breached for a period greater than the technical specification (TS) allowable tf.me period. It also provides details concerning the inoperability of- the fire detection instruments in Fire Zones 364 and 369 for the Unit 1 lower containment in the area of the Nos. 3 and a reactor coolant pumps. This report is being submitted in accordance with TS Action Statements 3.3.3.8.b and 3.7.12.a.

If you have any questions concerning this submittal, please telephone C. H. Whittemore at (615) 843-7210.

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J 2. Wilson Enclosure-cc:- See page 2

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'- U.S. Nuclear Regulatory Commissiot:

Page 2 June.25, 1992 e

cc (Enclosure):

Mr. D. E. LaBarge, Project Manager U.S. Nuclear Regulatory Comhiission One White Flint, North

- 11555 Rockville Pike Rockville, Maryland 20852 NRC Resident Inspector Sequoyah Nuclear Plsnt 2600 Igou Ferry Road Soddy-Daisy, Tennessee 37379

( Mr. B. A. Wilson.-Project Chief

U.S. Nuclear Regulatory Connission Reglen II~

101 Marietta Street WJ. Suite 2500 Atlanta, Georgia 30323 P

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• ENCLOSURE t (

SEQUOYAH NUCLEAR P1 ANT (SQN)

SPECIAL REPORT 92-06

1. FIRE DOORS A-196 AND A-197 Dessrbt101LDLCondi.thn On May 20, 1992, with Units 1 and 2 in Mode 1, auxiliary building Fire Doors A-196 and A-197 were breached to provide room ventilation for the 480-volt (V) board rooms on Elevation 749 of the auxiliary building. .The fire doors will be nonfunctional as fire barriers until the room coolers are repaired and returned to service. Fire >

Door A-196 connects 480-V Board Booms 1B and 2B. Fire Door A-197 connects 480-V Board Rooms 1A and 2A.

Cause of conditinn On May 20, 1992, two of the four air conditioning units (one ,

Train A, one Train B) for the 480-V board rooms were in various stages of maintenance activities and hence inoperable. The four board rooms are cooled by four air conditioning units, two for Train A and two for Train B. When any of the air conditioning systems are not availdhle, it in acceptable to share use of the opposite unit's same trali cir conditioning system by opening the doors between the rooms and c culating cooled air from the unaffected board room with temporary fans. The doors necessary to accomplish this cooling are designated fire barriers and as such are re tricted by technical specifications (TSa) as to the period of time they may remain breached. The time necessary to accomplish the maintenance to return the air conditioning units to service and reestablish the fire barrier has been greater than the TS allowable period to have a fire barrier nonfunctional.

CorteLLLYe AcLL.on In accordance with Limiting Condition for Operation (LCO) 3.7.12 Action Statement-(a),.the fire detectors on one side of each of the breaches were verified operable; a roving fire watch was immediately established and will be maintained until the breaches are removed and the fire barriers are reestablished. The B train air conditioning unit is expected to be- repaired and returned to service by August 1, 1992. The breach will be removed and the fire barrier will be reestablished at that time. The A train air conditioning unit has been repaired and returned to service. Auxiliary building Door A-197-hes been' closed, i.e., breach removed, and the fire barrier reestablished.

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11. FIRE DETECTORS LOCATED IN THE UNIT 1 LOWER CONTAINMENT REACTOR CO01 ANT PUMP (RCP) NOS. 3 AND 4 AREA Descrip.tlon_of_ Condition On hay 19, 1992, with Units 1 and 2 in Mode 1, the thermal fire detection instrumentation in the Unit 1 RCP No. 4 area was declared inoperable -and LCO 3.3.3.8 was entered. Trouble alarms were acknowledged on Panel 629 for Fire Zone 369. Several attempts to l identify and resolve the problem and maintain the operability of the  !

fire detectors were tmsuccessful. The thermal detectors cannot be repaired until the inext outage of adequate duration. The time required to restore the instruments to operable status will exceed the TS allowable timeframe for fire detection instrumentation to be t nonfunctional. On May 21, 1992, the same condition developed in Zone 364 in the RCP No. 3 area.

Caust_of_Condi.tlon The thermal detectors in the Nos. 3 and 4 RCP areas have repeatedly brought in the trouble alarms on the pyrotronics system (Panels 629

-and 631). These alarms are supervisory circuits-that transmit low current signals and monitor the resistance in the ele:trical system to determine if the detector's integrity is good. The cause of the problem is unknown at this time because the instruments are located in the lower containment compartment area, and troubleshooting cannot be performed until an outage of adequate duration.

Corrective _Ac.tlon In accordance with LC0 3.3.3.8 Action Statement (a), the Unit 1 lower containmeat compartment air temperature is being monitored at least once_per hour and will continue to be monitored until_the detectors are restored to operable status. The detectors and system circuits will be inspected and eaaluated as:to the cause of the sporadic operation. Work requeL;s have been written and placed on the forced-outage item list. SQN will remain in LCO 3.3.3.8 until the detectors are repaired and/or replaced. _A problem evaluation report (SQPER 920203) has'been initiated to address the frequent alarms occurring in the RCP zones.

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