ML19332B991

Special Rept:On 890620,temp in Diesel Generator Control Room Identified as Above Tech Spec 3/4.7.8 Limit for Greater than 8 H.Similar Event Noted on 890626.Caused by Heat,High Outside Ambient Temps & Insufficient Ventilation

ML19332B991
Person / Time
Site:	River Bend
Issue date:	11/14/1989
From:	Booker J GULF STATES UTILITIES CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RBG-31770, NUDOCS 8911220163
Download: ML19332B991 (2)

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GULF STATES UTELETIES COMPANY mve n e.two st um aust omet eox m St inmcisvut,uosu nm Af;( A CODE (O4 f.3's f4he4 $46 M M f s

s November .14 , '1989  !

= RBG- 31770  :

File Nos.'G9.5,'G9.25.1.4 ,

i E U.S. Nuclear.PegulatoryCommishion, ,

Document Control Desk '.  :

Washington,-D.C.~20555, Gentlemen ,

-i River / Bend Station -? Unit 1 5 -

i Docket'No. 50-458 l

1. .

l' Enclosed is' Culf , States - Utilities Company's Special ' Report concerning diesel" generator control room temperature in excess of  !

the limits of Technical Specification 3.7.8 for greater'than eight hours.' This supplement'al report: is being submitted purttuant to River Bend Technical' Specification 3.7.8.

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b- Sincerely, i.

E. Booker

~ Manager-River Bend Oversight. ..

River Bend Nuclear Group JEB/TFP/.GW/JHM/?PB/ch cc: U. S. Nuclear Regulatory Commission .

Region IV l 611 Ryan Plaza Drive, Suite 1000- i Arlington, TX 76011. -

NRC Resident Inspector  :

. Post Office Box 1051  ;

St. Francisville, LA 7')775 l

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) r19h g?911220163991334ADOCK DR 0500o43g ~

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m .i d SPECIAL REPORT ,

REPORTED CONDITION As identified in GSU's Special Report dated 7/19/89 (RBG-31263), at approximately 0135 hours0.00156 days <br />0.0375 hours <br />2.232143e-4 weeks <br />5.13675e-5 months <br /> on 6/20/89,_ temperature in the diesel generator IB control room was identified as above the Technical Specification (3/4.7.8) limit of 104'F for greater than eight hours. The diesel generator IB control room temperature returned within the Technical Specification limit on 6/21/89. At approximately 0215 hours0.00249 days <br />0.0597 hours <br />3.554894e-4 weeks <br />8.18075e-5 months <br /> on 6/26/89, temperature in the diesel generator IA and IB control rooms were again identified as above the Technical Specification (3/4.7.8) limit of 104*F for greater than eight hours. The temperature excursions were noted during the performance of STP-000-0001, " Daily Operating Logs". This supplemental report provides the record peak temperature in the diesel generator control rooms for 10/14/89 through 10/20/89. The temperature has been maintained within the Technical Specification limit since 10/17/89 and no further supplements will be provided until the temperature again exceeds the Technical Specification limit.

INVESTIGATION The following table shows the peak temperature recorded daily during the performance of STP-000-0001 from 10/14/89 through 10/20/89. ,

DATE DGI A CONTROL ROOM TEMP (*F) DGIB CONTROL ROOM TEMP ('F) 10/14/89 102 101 10/15/89 101 102 10/16/89 101 102 10/17/89 100 106 10/18/89 96 103 10/19/89 94 92 10/20/89 90 90 ANALYSIS AND CORRECTIVE ACTION The apparent cause of the elevated temperatures is a combination of heat generated inside the building by the standby diesel generator " Keep Warm" system, high outside ambient temperatures, and insufficient ventilation in the diesel engine room due to undersizing of the engine room's normal exhaust fans. A modification request has been prepared to increase the capacity of the engine room normal exhaust fan.

The elevated temperatures has no effect on the operability of safety-related equipment located in the diesel generator control room. The diesel generator control room is a mild environment as defined in 10CFR50.49(c)(iii), and as such, is excluded from the final rule on environmental qualifications.

Safety-related equipment located within the diesel generator control rooms which has been identified to be susceptible to significant thermal aging mechanisms (e . g. , Agastat relays) are periodically replaced under an equipment qualification preventive maintenance task to er.sure operability of the equipment.