ML18153B627

LER 89-005-00:on 890204,auto Start of Emergency Diesel Generators 1 & 3 Occurred Upon Loss of Transfer Bus F.Caused by 4,160-volt Supply Circuit Breaker Failure.Circuit Breaker Cleaned & Tested satisfactory.W/890303 Ltr

ML18153B627
Person / Time
Site:	Surry
Issue date:	03/03/1989
From:	KANSLER M R VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
89-006, 89-6, LER-89-005, LER-89-5, NUDOCS 8903090182
Download: ML18153B627 (7)

Text

POW 28-06-01 NRC Form 366 SJI LICENSEE EVENT REPORT (LER) U.S. NUCLEAR REGULATORY COMMISSION APPROVED 0MB. NO. 3150-0104 EXPIRES: 8/31/88 FACILITY NAME (11 PAGE (31 Surry Power Station. Unit 1 !DOCKET NUMBER 121 o I s I o I o I o I 'J ,~ In 1 I OF n I c; TITLE l*l Auto Start of #1 and #3 EDGs Upon The Loss Of 'F' Transfer Bus EVENT DATE (5) LER NUMBER (61 REPORT DATE 171 OTHER FACILITIES INVOLVED IBI MONTH DAY YEAR YEAR )l' see~~~~~AL t<

MONTH DAY YEAR FACILITY NAMES DOCKET NUMBERISI 0!2 ol4 89 slg-olols-oloob ol38 l9 OPERATING MODE (91 N THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Chock on* or more of th* folloV(ing)

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--20.406(al(1Jllvl 60.73(all2Jliil 50.73(al (21 (vliil (Bl -,--20.40lilall1 IM 60.73(al(2111ill 50.73(all211xl LICENSEE CONTACT FOR THIS LER (121 73.71(bl 73.71(cl OTHER (Spacify in Abstract below and in TtJxr. NRC Form 366A) NAME TELEPHONE NUMBER AREA CODE M. R. Kansler, Station Manager COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (131 CAUSE SYSTEM COMPONENT TURER TURER D F I A IB IK I R 11 n I n I c; V I I I I I I I X I I L IM 10 IN KI OI 2 I 0 N I I I I I I I SUPPLEMENTAL REPORT EXPECTED 1141 MONTH DAY YEAR EXPECTED SUBMISSION h DATE (151 YES (If yes, complot* EXPECTED SUBMISSION DATE) ND I I I 1--.l......-------------~..L.---------~-------'--.......,__

ABSTRACT (Limit to 1400 sptJctJs, i.tJ., approxim*ta/y fiftetJn sing/e-spact1 typ11written lines} (18) NRC Farm 366 (9-831 On February 4, 1989, at 2345 hours0.0271 days <br />0.651 hours <br />0.00388 weeks <br />8.922725e-4 months <br />, with Units 1 and 2 in cold shutdown, the #1 and #3 Emergency Diesel Generators auto-started and loaded onto the lH and 2J emergency busses respectively.

This event is reported pursuant to 10 CFR 50.73(a)(2)(iv).

The diesels started due to the de-energization of the lH and 2J emergency busses due to the failure of a 4160 volt supply circuit breaker. The running Residual Heat Removal (RHR) pump de-energized during the event. The redundant RHR pump was started approximately three minutes later to supply RHR flow. The failed circuit breaker was cleaned and tested satisfactory.

Safety-related 4160 volt supply circuit breaker operator mechanisms will be refurbished.

The preventive maintenance program for 4160 volt circuit breakers is being evaluated.

NRC Form 36r.A 19-.<?3) *\ FACILITY NAME (1) LICENSE-ENT REPORT (LERI TEXT CONTINU-ON DOCKET NUMBER (2) .!:'OW :.::'.8 06-01 U.S. NUCLEAR REGULATORY COMMISSION APPROVED OMS NO. 3150-0104 EXPIRES: 8/31 /88 LER NUMBER (61 PAGE (3) Surrv Power Station, Unit 1 TEXT /ff mom ,pace is n,quimd, u/111 additioMI NRC Form 366A 's/ (17) NRC FORM 366A 19-83i 1.0 Description of the Event On February 4, 1989 at 2345 hours0.0271 days <br />0.651 hours <br />0.00388 weeks <br />8.922725e-4 months <br />, with Units 1 and 2 in cold shutdown, operators were removing the 'C' Reserve Station Service Transformer (RSST) {EIIS-XPT}

from service in preparation for a special test. To power the electrical busses supplied from the 'C' RSST, operators closed the applicable circuit breakers {EIIS-BKR}

to establish backfeed from the main transformer and the station service transformer (Figure 1). In accordance with the governing procedure, the backfeed lineup was established and the 'C ' RSST output breaker (15Fl -Figure 1) was opened. When 15Fl was opened the lH and 2J emergency busses and the lC and 2C station service busses de-energized.

Upon de-energization of the above busses, circuit breakers 15C2, 25Cl, 25C2, 15H8, and 25J8 tripped open on undervoltage.

The running residual heat removal (RHR) {EIIS-BP}

pump and component cooling (CC) water pump {EIIS-P} on Unit two tripped. The #1 and #3 Emergency Diesel Generators (EDGs) {EIIS-DG}

auto-started and loaded onto the dead lH and 2J emergency busses, respectively.

The EDGs restored power to the components powered from these emergency busses with the exception of the RHR and cc system pumps for which the "stub bus" supply breaker must be manually reset. Other problems that were associated with the event are as follows: -The backup service air compressor

{EIIS-CMP}

failed to auto start when power was lost to the running service air compressor.

Station instrument air was being supplied from service air. Instrument air header pressure consequently decreased causing the auxiliary ventilation system to realign to its safety injection configuration.

-The memory and setpoints for the process vent and ventilation vent radiation monitors were lost when power was lost to these instruments.

-The sample pumps for both units' containment particulate and gas radiation monitors tripped when power was lost to the 1 and 2 'C' station service busses. *U.S. GPO. 1988-520-58~

llOtl7l1 NRC Form 366A 19-<'3) LICENSEE-NT REPORT (LERI TEXT CONTINUA.N POW 28-06-01 U.S. NUCLEAR REGULATORY COMMISSION APPROVED 0MB NO. 3150-0104

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___ 1 I FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3) Surry Power Station, Unit 1 0 1 5 1°1°1°12la lo al 9 o lo Is ol o ol 3oF ols TEXT /If man, space is requiffJd, u.,, additional NRC Form 366A 's/ (17) NRC FORM 388A (9-83) This event is being reported as an unplanned actuation of engineered safety features (EDG starts and auxiliary ventilation realignment).

2.0 Safety

Consequences and Implications The consequences of this event were minimal because the EDGs auto-started and loaded as designed to

• provide power to the affected emergency busses. Although RHR flow to Unit 2 was lost when the 2J bus de-energized, the redundant pump was started approximately three minutes later to provide the required RHR flow. The RCS temperature increased less than two degrees Fahrenheit due to the loss of the running RHR pump; therefore, the health and safety of the public were not affected by the event. 3.0 Cause The cause of the event was the failure of 4160 volt circuit breaker 25C2 (Figure 1). Breaker 25C2 indicated fully closed, but its main contacts had stopped approximately two inches from full closure. Since 25C2 was not closed (but indicated closed), busses lH, 2J, lC, and 2C de-energized when breaker 15Fl was opened. The failure of 25C2 was due to an accumulation of dust and dirt in its closing mechanism.

The preventive maintenance procedure used to clean the bre.aker did not include steps for cleaning the closing mechanism.

The backup service air compressor failed to start due to a low oil pressure signal. The cause of the low oil pressure signal is being investigated.

The auxiliary ventilation system realigned to its safety injection configuration as designed on low air pressure.

The loss of memory and setpoints to the process vent and ventilation vent radiation monitors was due to the failure of the instruments' backup battery supply. The cause of the backup battery supply failure is under investigation.

• u.s. GPO, 1988-520-589,00070 NRC Form 360::A 19-83) FACILITY NAME (1) LICENSE~ENT REPORT (LER) TEXT CONTINU-ON DOCKET NUMBER (2) U.S. NUCLEAR REGULATORY COMMISSION APPROVED 0MB NO. 3150-0104 EXPIRES: 8/31 /88 LER NUMBER (6) PAGE (3) Surry Power Station, Unit 1 o Is Io Io I o I 2 la lo a I 9 olo Is o I o o I q oF o Is' TEXT (ff more space is required, Ullil additiafllJ!

NRC Fonn Jti6A 's) (17) NRC FORM 366A 19-83) 4.0 Immediate Corrective Actions Approximately three minutes after the Unit two 'B' RHR pump had tripped, operators started the 'A' pump to provide RHR flow in accordance with the appropriate abnormal procedure.

The reactor coolant system (RCS) {EIIS-AB}

temperature had increased by less than two degrees Fahrenheit to approximately 96 degrees F. At 2349 hours0.0272 days <br />0.653 hours <br />0.00388 weeks <br />8.937945e-4 months <br /> operators reclosed the "stub bus" supply breaker to the Unit 2 J bus RHR and cc pumps. At 2356 hours0.0273 days <br />0.654 hours <br />0.0039 weeks <br />8.96458e-4 months <br /> operators reclosed the "stub bus" supply breaker for the Unit 1 H bus RHR and CC pumps. By 0016 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> (2-5-89) breakers 15Fl, 15Cl, and 25Cl had been reclosed restoring power to both units' 'C' station service busses, and normal power was restored to the affected emergency busses. 5.0 Additional Corrective Action(s)

The 25C2 breaker was cleaned and tested satisfactorily.

Operators reset the low oil pressure trip on the backup service air compressor and it was started satisfactorily.

Operators realigned the auxiliary ventilation system to its normal configuration after instrument air pressure had been returned to normal. The sample pump for each unit's containment particulate and gas radiation monitor was restarted.

Instument technicians restored the setpoints to the process vent and ventilation vent radiation monitors.

6.0 Action(s)

Taken to Prevent Recurrence Prior to the restart of either unit, safety related 4160 volt feeder breaker operator mechanisms will be refurbished.

The preventive maintenance program for 4160 volt breakers is being evaluated.

• u.s. GPO: 1988-520-58':)

Ll0070 NRC Form 366A 19-oJI FACILITY NAME (1) LICENSE.ENT REPORT (LERI TEXT CONTINU-ON DOCKET NUMBER (21 U.S. NUCLEAR REGULATORY COMMISSION APPROVED 0MB NO. 3150-0104 EXPIRES: 8/31 /88 LER NUMBER (6) PAGE (31 YEAR rrr SEQUENTIAL

[ft REVISION NUMBER NUMBER Surry Power Station, Unit 1 01s101010121s10 slg-olols-olo ols°Fols TEXT /If mom space is required, U5" additional NRC Form 366A's) (171 Troubleshooting on the process vent and ventilation vent radiation monitors' battery backup system will be performed to identify the failure mode. The cause of the oil pressure signal in the backup service air compressor is being investigated.

Instructions will be added to the Abnormal Procedures for loss of station service bus voltage to direct operators to restart the containment particulate and gas radiation monitor sample pumps after power is restored if power is lost to the 'C' station service bus. 7.0 Similar Events None 8.0 Manufacturer/Model Numbers Circuit Breaker 25C2 Process Vent and Ventilation Vent Radiation Monitors Service Air Compressor ITE Circuit Breaker Company Model SHK-350 Kaman Sciences Corporation Model KMG-HRN & HRH Atlas Copco Model ZT 3 A NRC FORM 3BBA (9-831 *u.s. GPO, 1988-520-589100070

• e FIGURE 1 e Surry Power Station Docket # 05000280 LER # 1-89-005 SIMPLIFIED ELECTRICAL SCHEMATIC BACKFEED LINEUP GRID UNIT 2 GENERATOR___.

OUTPUT --_. BREAKERS MOAB (CLOSED) ...--'-L_, 500 KV M!'~~--~ XFRMR~ 'C' GRID 15C2 15C1 UNIT 1 'C' STATION SERVICE BUS 25J8 25J3 2J EMERG8'JCY BUS RESERVE STATION SERVICE 1RNSFRMR 25C1 25C2 UNIT 2 'C' STATION SERVICE BUS 15H8 15H3 1H EMERGENCY BUS D OPEN CIRCUIT BREAKER I CLOSED CIRCUIT BREAKER -----ii

• 22 KV 22 KV *4160 V GENERATOR DISCONNECT

\ e VIRGl!'4IA ELECTRIC ANO .POWER COMPANY Surry P_, Station March 3, 1989 U.S. Nuclear Regulatory Commission Docmnent Control Desk 016 Phillips Building Washington, D.C. 20555 Gentlemen:

P. 0. Box 316 Surry, Virginia 23883 Serial No.: Docket Nos. : License No: 89-006 50-280 DPR-32 Pursuant to Surry Power Station Technical Specifications, Virginia Electric and Power Company hereby submits the following Licensee Event Report for Unit 1. REPORT NUMBER 89-005-00 This report has been reviewed by the Station Nuclear Safety and Operating Committee and will be reviewed by Safety Evaluation and Control. Very truly yours, Enclosure I I cc: Regional Administrator Suite 2900 101 Marietta Street, NW Atlanta, Georgia 30323 ,f&r\-z,.

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