ML18004B749

LER 87-011-00:on 870307,auxiliary Bus IE Feeder Breaker 121 Tripped Open,Causing de-energization of Auxiliary Bus IE & Safety Bus 1B-SB.Caused by Procedural Inadequacy.Work Ticket Initiated to Replace diode.W/870406 Ltr

ML18004B749
Person / Time
Site:	Harris
Issue date:	04/06/1987
From:	SCHWABENBAUER, WATSON R A CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
HO-870395-(), HO-870395-(0), LER-87-011, LER-87-11, NUDOCS 8704130111
Download: ML18004B749 (5)

Text

REGULA Y INFORNATION DISTR IBUTI0 YSTEN (R IDS>;ACCESSION NBR: 8704130111 DOC.DATE: 87/04/06 NOTARIZED:

NO FACIL: 50-400 Shearon Harris Nuclear Power Plant>Unit 1>Carolina AUTH.NANE AUTHOR AFF ILI AT I ON BCHWABENBAUER Carol in a P over 8c Light C o.WATSON>R.A.Carolina Poeer 5 Light Co..RECIP.NAME RECIPIENT AFFILIATION DOCKET 05000400

SUBJECT:

LER 87-011-00:

on 870307>auxiliary bus IE feedeY breaker 121 tripped open>causing de-energization of auxiliary bus IE 5 safety bus 1B-SB.Caused bg procedural inadequacy.

Work tic ket initiated to replace diode.W/870406 ltr.DISTRIBUTION CODE: IESSD COPIES RECEIVED: LTR I ENCL I SIIE: TITLE: 50.73 Licensee Event Report (LER)>Incident Rpt>etc.NOTES: App li cation for permit reneu'al f iled.05000400 RECIPIENT ID CODE/NANE PD2-1 L*BUCKLEY>B INTERNAL: ACRS MICHELSON ACRB WYLIE AEOD/DBP/ROAB NRR/ADT NRR/DEBT/ADS NRR/DEBT/ELB NRR/DEST/MEB NRR/DEBT/PSB NRR/DEBT/SGB NRR/DLPG/GAB NRR/DREP/EPB BR/ILRB REG FIL 02 RGN2 FILE 01 EXTERNAL: EQ8cG GROH>N LPDR NSI C HARRIS>J COPIEB LTTR ENCL 1 1 1 1 1 1 2 2 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 5 5 1 1 1 RECIPIENT ID CODE/NAME PD2-1 PD ACRB NOELLER AEOD/DOA AEOD/DSP/TAPB NRR/DEBT/ADE ERR/DEBT/CEB ERR/DEBT/I CSB NRR/DEST/MTB NRR/DEST/RSB NRR/DLPG/HFB NRR/DOEA/EAB NRR/DREP/RAB NRR/PNAS/PTSB RES SPEIS>T H ST LOBBY WARD NRC PDR NSIC MAYS>G COPIES LTTR ENCL 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 TOTAL NU>HER OF COP IES REQUIRED: LTTR 41 ENCL 39 NRC Form 3FS (94)3)LICENSEE EVENT REPORT (LER)U rL NUCLEAR REQULATORY COMMISSION APPROVED OMB NO.31504104 EXPIRES)5/31/SS FACILITY NAME (I)SHEARON HARRIS PLANT UNIT 1 TITLE (4)"6.9 KV ONSITE DISTRIBUTION" DOCKET NUMBER (2)0 5 0 0 0 4 0 PA E 3I 1 QF 0 3 MONTH DAY YEAR EVENT DATE (5)YEAR LER NUMBER (6)SEQUENTIAL Mb NUMBER 5M Rt VISION NUMBER REPORT DATE (7)MONTH DAY YEAR DOCKET NUMBER(S)0 5 0 0 0 FACILITY NAMES OTHER FACILITIES INVOLVED IS)0 3 0 7 8 7 011 0 04 6 87 0 5 0 0 0 OPERATINQ MODE (9)POWER LEVEL 00)0 0 0 20A02(II)20.405[v)(I)(I)20A05(~)(I)(il)20.405(~)(1)(ill)20A05(~)(I)(I v)20.405 (e)(I)(v)20.405(c)50.35(c)(I)50.35(c)(2)50.73(e)(2)(l).50.73(s)(2)(Ii)50.73(s)(2)(lii)LICENSEE CONTACT FOR THIS LEA (12I 50.73 (e)(2)(Iv)50.73(e)(2)(v) 50,73(s)(2)(vii)50.73(e)(2)(vill)(A)50.7 3(e)(2)(vill)(5)50.73(~)(2)(s)THIS REPORT IS SUBMITTED PURSUANT T 0 THE REQUIREMENTS OF 10 CFR (): (Check one or more of the follovy'npl (11)73.71(5)73 71(c)DTHER (specify ln Aortrect helow end ln Test, NRC Form 366A)NAME R.SCHWABENBAUER

-REGULATORY TECHNICIAN TEI.EPHONE NUMBER AREA CODE 919 362-26 69 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCAIBED IN THIS REPORT (13)CAUSE SYSTEM COMPONENT MANUFAC TVRER..EPOATABLE TO NPRDS!NM5 CAUSE SYSTEM COMPONENT MANUFAC.TVRERPORTABLE i.TO NPADS h:.'..Ihr ARIx..B E E JX W12 0 N X hA:cNkprg~.whirr c N~.~.'" P hk h48X h, SVPPLEMENTAI.

REPORT EXPECTED (14)YES llf yet, complNe EXPECTED SUBMISSION DATE)ABsTRAGT ILlmlr to tcOO tpecer, l.e., epproxlmetely fifteen tfnpleepece typewritten linnl (15)EXPECTED SUBMISSION DATE (15)MONTH DAY YEAR ABSTRACT On March 7, 1987, an Auxiliary Operator (AO)was performing a weekly surveillance test (OST-1023) which is for offsite power verification.

One of the requirements of the OST is to ensure the breaker release lever is in the neutral position with the breaker closed.When the AO checked Auxiliary Bus IE feeder breaker 121 the breaker was inadvertently tripped open causing the.de-energization of Auxiliary Bus IE and Safety Bus 1B-SB.This occurred at 2230 hours0.0258 days <br />0.619 hours <br />0.00369 weeks <br />8.48515e-4 months <br /> on March 7, 1987.The de-energization of Bus 1B-SB caused the 1B-SB Diesel Generator to start and the actuation of Sequencer lB-SB on Bus undervoltage.

The AO immediately closed the breaker cabinet and.notified the Control Room of the incident.The Senior Control Operator (SCO)then initiated AOP-025 for the loss of one emergency bus and all plant systems were then returned to normal.At the-time of the incident, the plant was in Mode 4 at 3450F and 350 psig.There were no adverse consequences due to this event and safety systems performed as required.To prevent recurrence, the applicable procedure has been revised.8704130111 870406 PDR*DOCI('5000400 S PDR NRC Form 355 (94)3)

NRC Form 366A (94)3)FACILITY NAME (1)U.S.NUCLEAR REOULATORY COMMISSION APPROVED OMB NO, 3150-0)04 EX PIR ES: 8/31/BS'1'UMBER YEAR FACE (3)LER NUMBER (6):R+: SEQUENTIAL

,8 NUMBER DOCKET NUMBER (2)LICENSEE EVENT REPORT (LER)TEXT CONTINUATION SHEARON HARRIS PLANT UNIT 1 TEXT//F'moro FPoco/4/or/rokod, Iroo/I/Ooro///RC

%%d 36649/(13 I 0 5 0 0 0 4 0 0 011 0 0 02"0 3 TEXT DESCRIPTION On March 7, 1987, an Auxiliary Operator (AO)was performing a weekly surveillance test OST-1023 entitled"OFFSITE POWER AVAILABILITY VERIFICATION WEEKLY INTERVAL MODES 1-2-3 6 4." One of the requirements of the OST is to ensure the breaker release lever is in the neutral position with the breaker closed.The AO did this by checking the release lever with his foot for freedom of movement.The AO had used this method without incident in the past.When the AO went to check the Auxiliary Bus 1E feeder breaker 121 the breaker tripped open causing the de-energization of Auxiliary Bus lE.This also de-energized the 1B-SB safety bus thereby activating the 1B-SB Sequencer and starting the 1B-SB Diesel Generator.

The AO immediately closed the breaker cabinet and notified the Control Room.Upon notification, the Senior Control Operator (SCO)entered Abnormal Operating Procedure AOP-025, entitled"Loss of One Emergency AC Bus (6.9KV)or One Emergency DC (125V)Bus" for the loss of emergency bus and restored all plant systems to normal operation.

At the time of the incident, the plant was in Mode 4 at 345'F and 350 psig.The de-energization of non-safety related Auxiliary Bus 1E also caused the Charging Safety Injection Pumps (CSIP)suction source to automatically transfer from the Volume Control Tank (VCT)to the Refueling Water Storage Tank (RWST).This transfer occurs automatically when both VCT level channels (LT-115 and LT-112)are less than 5X (low low level)or when Safety Injection occurs.This transfer of suction source was due to the de-energization of relays K701 (for LT-115)and K706 (for LT-112)which caused the associated contacts to close and generate a signal to re-position the valves.Relay K701 lost power due to a 7.5 KVA Inverter (the normal power supply)being out of service for a maintenance function, the alternate power supply was via Auxiliary Bus lE.Relay K706 lost power due to a faulty diode which failed to pass the normal power from an uninterruptible source', the backup source was powered via the Auxiliary Bus lE.The VCT/RWST transfer was caused by a combination of both the 7.5 KVA Inverter being out of service, a defective diode in the power supply to the LT-112 relay, and the black out of power panels supplied via Auxiliary Bus 1E.CAUSE The incident was caused by a procedural inadequacy.

The procedure did not clearly state how the check was to be performed.

The AO had performed this by using a,slight amount of pressure on the" release pedal.NRC FORM BBBA (94)3)*U.S.GPO;1986 0-624 538/455 NRC Form 366A (963)LICENSEE EVENT REPORT (LER)TEXT CONTIN'ION U.S.NUCLEAR RECULATORY COMMISSION APPROVEO OMB NO.3150&)04 EXPIRES: 8/31/88 FACILITY NAME (I)SHEARON HARRIS PLANT UNIT 1 DOCKET NUMBER (2)YEAR LER NUMBER (6)SEOVENTIAL NVMSER RroI/REVISION NUMBER PACE (3)TEXT/O'IRors 4/Moo/4 o/O/ISIL Iroo o//SooM/HRC Fo/RI 35546/((7)40 OS7 0 1 1 00 03 OF 0 ANALYSIS There were no adverse consequences due to this incident.The event resulted in actuation of components on the 1B-SB bus as required by plant design.The event is reportable per 10CFR50.73(a)(2)(iv) which requires reporting of manual or automatic initiation of any Engineered Safety Feature.CORRECTIVE ACTION A work ticket has been initiated to replace the faulty diode.ACTION TO PREVENT RECURRENCE To prevent a recurrence of this event, a change to OST-1023 has been completed.

The procedure now contains the caution statement, NDo not depress the breaker release pedal when breaker is closed, pedal will trip breaker." NRC FORM SSSA (963)*U.S.CPO.'1986 0.624 538/455

~4/Carolina Power 8 Light Company HARRIS NUCLEAR PROJECT P.O.Box 165 New Hill, NC 27562 APR 0 6 1987 File Number'SHF/10-13510C Letter Number'HO-870395 (0)U.S.Nuclear Regulatory Commission ATTN: NRC Document Control Desk Washington, DC 20555 SHEARON HARRIS NUCLEAR POWER PLANT UNIT 1 DOCKET NO.50-400 LICENSE NO.NPF-63 LICENSEE EVENT REPORT 87-011"00 Gentlemen.'n accordance with Title 10 to the Code of Federal Regulations, the enclosed Licensee Event Report is submitted.

This report fulfills the requirement for a written report within thirty (30)days of a reportable occurrence and.is in accordance with the format set forth in NUREG-1022, September, 1983.Very truly yours, R.A.Watson Vice President Harris Nuclear Project RAW:skm Enclosure cc.'r.J.Nelson Grace (NRC-RII)Mr.B.Buckley (NRR)Mr.G.Maxwell (NRC-SHNPP)