ML17227A403

Special Rept:On 920403,EDG 1B Output Breaker Would Not Close During Weekly Operational Check.Caused by Failure of Underfrequency Permissive Circuit Relay.Failed Relay Replaced & EDG Successfully Started

ML17227A403
Person / Time
Site:	Saint Lucie
Issue date:	04/28/1992
From:	SAGER D A FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LD-92-117, NUDOCS 9205040230
Download: ML17227A403 (3)

Text

ACCELERATED DI~~RIBUTION DEMONS'ITION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)ACCESSION NBR-9205040230 DOC.DATE: 92/04/28 NOTARIZED:

NO.FACIL:50-335 St.Lucie Plant, Unit 1, Florida Power&Light.Co.AUTH.NAME AUTHOR AFFILIATION SAGER,D.A.

Florida Power&Light Co.RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Special rept:on 920403,EDG 1B output breaker would not close during weekly operational check.Caused by failure of underfrequency permissive circuit relay.Failed relay replaced&EDG successfully started.DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR

!ENCL/SIZE:2 TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.NOTES: DOCKET iI 05000335 RECIPIENT ID CODE/NAME PD2-2 LA NORRIS,J INTERNAL'CNW AEOD/DOA AEOD/ROAB/DSP NRR/DLPQ/LHFB10 NRR/DOEA/OEAB NRR/DST/SELB 8D NRR/DST-: RBESD1 REG-'Ei" RGii2 PILE 01 EXTERNAL Ed&G BRYCE T J~H NRC PDR NSIC POORE,W.COPIES LTTR ENCL 1 1 1 1 2 2 1 1 2 2 1 1 1 1 1 1 1 1 1 1 1 1 3 3 1 1 1 1 RECIPIENT ID CODE/NAME PD2-2 PD ACRS AEOD/DSP/TPAB NRR/DET/EMEB 7E NRR/DLPQ/LPEB10 NRR/DREP/PRPB1 1 NRR/DST/SICB8H3 NRR/DST/SRXB 8E RES/DSIR/EIB L ST LOBBY WARD NSIC MURPHY,G.A NUDOCS FULL TXT COPIES LTTR ENCL 1 1 2 2 1 1 1 1 1 1 2 2 1 1 1 1 1 1 1 1 1 1 1 1 NOTE TO ALL"RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE!CONTACT THE DOCUMENT CONTROL DESK, ROOi~l Pl-37 (EXT.20079)TO ELliblINATE YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!TOTAL NUMBER OF COPIES REQUIRED: LTTR 32 ENCL 32 P.O.Box 128, Fr.Pierce, FL 34954-0128 APL April 28, 1992 L-92-117 10 CFR 50.36 1 U.S Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Re: St.Lucie Unit 1 Docket No.50-335 Special Report Date of Event: April 3, 1992 1B Emer eric Diesel Generator Failure The attached'pecial Report is being transmitted pursuant to the requirements of St.Lucie Unit 1 Technical Specifications 4.8.1.1.3 and 6.9.2.This report provides notification that the 1B Emergency, Di'esel Generator was declared inoperable due to the 1B Emergency Diesel Generator output breaker failing to close.Should there be any, questions on this information, please contact us~Very truly yours, D.A.ger Vice.r sident St.Lu ie Plant DAS/JJB/kw Attachment cc: Stewart D.Ebneter, Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, St.Lucie Plant DAS/PSL 1677-92/5~(9205040230 920428 PDR ADOCK 05000335 S PDR r i l,~:~.;," cruhr/E 2g NRC SPECIAL REPORT DIESEL GENERATOR VALID FAILURE On 3 April 1992, at 0947, the St.Lucie Unit One 1B Emergency Diesel Generator (EDG)was started for the weekly operational check.The RCO attempted to close the 1B EDG output breaker but the breaker would not close.The 1B EDG was shutdown at 1017 and declared out of'service.St Lucie Unit One was in Mode 1 at 100%Power and entered the 72 hr.action statement for Technical Specification 3',8.1.1.The 1B EDG was restarted for troubleshooting at 1325 and shutdown at 1400.The problem was traced to the underfrequency permissive circuit relay.The underfrequency permissive circuit is designed to prevent the EDG output breaker from closing in the event of an underfrequency condition in the EDG.In accordance with the NRC Regulatory Guide 1.108,C.2.e.5, this event was evaluated as a valid failure.Corrective Actions: The failed relay was replaced and at 1316 on 4 April 1992 the EDG was successfully started.After performing the operational check the 1B EDG was declared back in service at 1352.The 1B EDG was unavailable for 28 hrs.Failure Summary: This is the second valid failure of the 1B EDG in the previous 20 valid'tests.The 1B EDG has accumulated 42 valid tests since the implementation of Technical Specification 3.8.1.1 (July 1990).The current surveillance interval is once per seven days per Technical Specification 4.8.1.2.2.