ML20196H368

Special Rept:On 880531 & 0601,diesel Generators 1B & 1A Identified as Being Above Tech Spec 3/4.7.8 Limit of 104 F. Cause Not Yet determined.Safety-related Equipment Susceptible to Thermal Aging Mechanisms Replaced

ML20196H368
Person / Time
Site:	River Bend
Issue date:	06/24/1988
From:	Booker J GULF STATES UTILITIES CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
NUDOCS 8807060144
Download: ML20196H368 (3)

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ib GULF STATES UTILITIES COMPANY R'VER eENO STAYsON POST OFFICE BOX 220 Si FRANCISVILLE.LOUISLANA 70175 arf A COOC 504 635 6094 346 8651 l

June 24, 1988 RBG- 28160 File Nos. G9.5, G9.25.1.4 U.S. Nuclear Regulatory Commitsion Decament Control Desk Washington, D.C. 20555 Gentlemen:

River Bend Station Unit 1 Docket No. 50-451 Enclosed is Gulf States Utilities Compcny's Special Report concerning exceeding diesel generator c on t. *ol room Technical Specification temperature limits. This report is being submitted pursuant to River Bend Station Technical Specif ication 3/4.7.8 and 6.9.2.

Sincerely,

. [- 3 J. E. Booker Manager-River Bend Oversight River Bend Nuclear Group cc: U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76011 NRC Resident Inspector P.O. Box 1051 St. Francisville, LA 70775 8807060144 880624 8 PDR ADOCK 0500 S

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Page 1 of 2 Special Report Reported Condition At approximately 2035 hours0.0236 days <br />0.565 hours <br />0.00336 weeks <br />7.743175e-4 months <br /> on 5/31/88, and 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br /> on 6/1/88, during the performance of Surveillance Test Procedure (STP)-000-0001 "Daily Operating Logs", temperature in the Diesel Generator IB Control Room, and in the Diesel Generator IA Control Room were 8

identified as above the Technical Specification (3/4.7.8) limit of 104 F. This spcial report is being submitted because temperatures have remained aMye the limit for greater than 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. This is the first occurrence where temperatures have exceeded the Technical Specification limit in the Diesel Generator Control Room.

Investigation Design Engineering is reviewing the design of the heating and ventilating system for Diesel Generator Control Rooms. When completed, the design review will determine what corrective actions, if any, are necessary.

The following temperature shows the peak temperature recorded daily during perform nce of STP-000-0001 from 5/31/88 through 6/22/88.

Date DG1A CONTROL ROOM TEMP ( F) DG1B CONTROL ROOM TEMP F (O )

573I/88 101 100 6/1/88 105 107 6/2/88 106 108 6/3/88 105 108 6/4/88 106 108 6/5/88 105 106 6/6/88 103 101 6/7/88 103 105 6/8/88 105 106 6/9/88 105 107 6/10/88 105 109 6/11/88 105 108 6/12/88 107 108 6/13/88 105 108 6/14/88 102 108 6/15/88 105 109 6/16/88 107 110 6/17/88 107 106 6/18/88 93* 110 6/19/88 100 110 6/20/88 102 110 6/21/88 104 110 6/22/88 106 105 6/23/88 105 108

• Room was cooled during maintenance activities.

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.. r' Page 2 of 2 Analysis and Corrective Action Investigation of the cause of the elevated temperatures has not been completed. The apparent cause of the high temperatures is nonnal heat sources concurrent with seasonal high exterior temperatures.

There is no effect on the qualified lives of safety-related equipment' located in the Diesel Generator Control Rooms because the thennal aging portion of the qualification test0 program used as its basis a normal temperatum distribution gf 125 F for 25% of plant life and an average ambient temperature of 85 F for 75% of plant life.

Furthermore, the Diesel Generator Control Room is considered a mild environment as defined in 10CrT;b0.49 (c)(iii), and as such is excluded from the final rule for environmental qualification. Safety-related equipment located with the Diesel Generator Control Rooms which has been identified to be susceptible to significant thennal aging mechanisms (e.g. Agastat relays, electrolytic capacitors) are periodically replaced on an EQ PM to ensure operability of the equipment.

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