ML17279A553

LER 87-025-00:on 870808,reactor Protection Sys (RPS) Div a Half Scrammed & Multiple ESF Isolations & Actuations Occurred.Caused by Spurious Trip of RPS Breaker 3A.Breaker Sent to GE for analysis.W/870903 Ltr

ML17279A553
Person / Time
Site:	Columbia
Issue date:	09/03/1987
From:	Powers C, Washington S WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
LER-87-025, LER-87-25, NUDOCS 8709100408
Download: ML17279A553 (9)

Text

,ULA,Y INFORMATION DIST UTI YSTEM (R IDS)

ACCESSION NBR 8709100408 DQC. DATE: 87/09/03 "NOTARIZED: NO DOCKET i) FACIL: 50-397 WPPSS Nuclear Pro Ject> Unit 2> Washington Public Poee 05000397 AUTH. NAME AUTHOR AFFILIATION WASHINGTON> S L. Washington Public Poeer Supply System POWERS> C. M. Washington Public Power Supply System

'REC IP. NAME REC IP IENT AFFILIATION SUBJECT LER 87-0>;5-00: on 870808> reactor protection sys (RPS) dlv A hal f scrammed 8c mul tip le ESF isolations 8c actuations occurr ed. Caused by spurious trip of RPS breaker 3A. Breaker sent to GE for analysis. W/870903 ltr.

DISTRIBUTION CODE: IE22D COPIES RECEIVED: LTR i ENCL Q SIZE:

TITLE: 50. 73 Licensee Event Report (LER) Incident Rpt>

> etc.

NOTES:

REC I P I ENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 1 PD5 PD 1 1 SAMWORTH. R 1 1 INTERNAL: ACR S Ml CHELSQN 1 1 ACRS MOELLER AEOD/DQ* 1 AEOD/DSP/NAS AEQD/DSP/RQAB 2 2 AEOD/DSP/TPAB DEDRO 1 1 NRR/DEST/ADS NRR/DEBT/CEB 1 1 NRR/DEST/ELB NRR/DEST/ I CSB 1 1 NRR/DEST/MEB NRR/DEST/MTB NRR/DEST/PSB NRR/DEBT/RSB NRR/DLPG/HFB 1, 1 1

1 NRR/DEST/SGB NRR/DLPG/GAB NRR/DQEA/EAB 1 1 NRR/DREP/RAB N D EP/RPB 2 2 NRR/PMAS/ ILRB REG F ILE 02 1 1 RES DEPY GI P9 T D> J 1 1 RES/DE/E I 8 RGN5 FILE 01 1 1 EXTERNAL: EGSG GROH M 5 5 H ST LOBBY WARD 1 1 LPDR 1 NRC PDR 1 1 NSIC HARRIS> J 1 1 NSIC MAYS> G 1 1 TOTAL NUMBER OF COPIES REQUIRED: LTTR 43 ENCL 42

x I ARC Form 345

~ 0 US. NUCLEAR REOULATORY COMIBISSION (543) APPROVED OMB NO. 31600104 EXPIRES: d/31/dd LICENSEE EVENT REPORT (LER)

FACILITY NAME (I) DOCKET NUMBER (2) PA E Washin ton Nuclear Plant - Unit 2 0 5 0'0 0 397 1 OF 04

"'"'"'ngineered Safety Feature Isolations and Actuat~ons Cause y Reactor Protection System E ui ment Failure EVENT DATE (51 LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (Sl MONTH OAY YEAR YEAR P?EQUENTIAL ~C'EVISION MONTH

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OAY YEAR FACILITYNAMES DOCKET NUMBER(S)

NUMBER '?? NUMBER 0 5 0 0 0 0 8 0 8 8 7 87 Or 5 0 0 0 9 0 3 8 7 0 5 0 0 0 THIS REPORT IS SUBMITTED PURSUANT T 0 THE REOUIREMENTS OF 10 CFR (I: IChech ona or mors of ths IOIlovfinPI (11 OPERATINQ MODE (5) 20.402 (BI 20.405(c) 50.73(a)(2)(lv) 73.7)(B) 1 POWER 20.405( ~ I (1 l (ll SO M(c) (1 I 50.73(s) (2) (r) 73.71(c)

LEVEL 20AOS(al(1 )(B) SOW(c)(2) 50.73(e) (2)(rill OTHER (Specify ln Ahttrsct Below snd In Text NIIC Form

'ging'3 cc+ w'io:@j 20.405( ~ l(1 I(IIl) 50,7 3(a) (2) (ll 50.73(s) (2) (rllI) (Al 366AI 20AOS( ~ ) (1 )(lv) 50.73(e l(2) (II) 50.73(e) (2) (rid) (Bl c.) . c rx x re r Sgk, s r x. 20AOS(e)(ll(vl 50.73(a) (2) (ill) 50.73(e) (2) (x)

LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER AREA CODE S.L. Washinqton, Compliance Enaineer 50 93 77- 208 0 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCAIBED IN THIS REPORT (13)

MANUFAC. AEPOATABLE ckUsE rvrrrM COMPONENT MANUFAC. EPOATABLE CAUSE SYSTEM COIIAPONENT TUAER TO NPADS TVRER "N'"DS.......@.4'.5%

N X JC BKR G08 0 NYZhEBI I

co:.

SUPPLEMENTAL REPORT EXPECTED (14) MONTH DAY YEAR EXPECTED SUB MISS ION DATE (151 YES IIIyat, cornplata EXPECTED SVBSIISSION OATEI NO 1 8 0 8 7 ABSTRACT ILImlt to 1400 tpacn, I sapproximately li ltaan tinplscpscs typewritten linn) (id)

On August 8, 1987 the plant was at 85Ã power and on a gradual power ascension when, at 1855 hours, a spurious trip of the Reactor Protection System (RPS) Electrical Protection Assembly (EPA) 3A Breaker caused a loss of power to RPS Bus A. The loss of power on RPS Bus A caused a half-scram in RPS Division A and multiple Engineered Safety Feature (ESF) isolations and actuations.

The loss of RPS A power causes an Outboard Nuclear Steam Supply Shutoff System (NSSSS) isolation of Groups 1 (Hain Steam Line Drains only), P, 5, I7, and 7. NSSSS Group 7 isolates the Reactor Water Cleanup System (RWCU). In addition, the loss of RPS A power causes a NSSSS Group 3 (Primary and Secondary Containment Ventilation and Purge Systems) isolation and Standby Gas Treatment (SGT) System and Control Room Emergency Fil tration System actuation.

Plant operators switched RPS Bus A to its alternate power supply and restored all systems to their pre-event lineup within RO minutes.

The cause of the event was a spurious trip of the RPS-EPA-3A Breaker.

The root cause of the spurious trip has not been determined. The Supply System sent the breaker to General Electric (breaker manufacturer) for analysis. The root cause information will be provided in a supplemental report.

8709100408 870908 PDR S

ADOCK 05000~7 PDR NRC Form 355 ro.n'lI

~ e NRC Form 355A V.S. NVCLEAR REGULATORY COMMISSION (84)3)

LICENSEE EVENT REPORT ILER) TEXT CONTINUATION APPROVEO OMS NO. 3)50WI OE EXPIRES: 8/31/88 FACILI'TY NAME (1) OOCKET NVMSER (21 LER NVMSER (Sl PAGE (3)

YEAR g8 SEOVENTI*L REVISION NVM ER NVMSER Washington Nuclear Plant - Unit 2 0 5 0 0 0 3 7 8 7 0 2 5 0 0 2 0 4 TEXT ///more t/roteir /I//rirerL eet /reo/ko'on/I //RC Forrrr 355tr't/((7)

There is no safety significance associated with this event as no actual Plant condition requiring the Engineered Safety Feature isolations and actuations existed, and all isolations and actuations occurred as designed. Further, the ESF isolations and actuations had no adverse affect on Plant operation and all systems were restored to their pre-event lineup within 20 minutes.

Plant Conditions a) Power Level - 85 b) Plant Mode - 1 (Power Operation)

Event Description On August 8, lq87 the plant was at 85% power and on a gradual power ascension when, at 1855 hours0.0215 days <br />0.515 hours <br />0.00307 weeks <br />7.058275e-4 months <br />, a spurious trip of the Reactor Proteption System (RPS)

Electrical Protection Assembly (EPA) 3A Breaker caused a loss of power to RPS Bus A. The loss of power on RPS Bus A caused a half-scram in RPS Division A and multiple Engineered Safety Feature (ESF) actuations.

The loss of RPS A power caused a NSSSS Containment Outboard Isolation. The outboard isolations occurred for NSSSS Group 1 (Main Steam Line drains only),

Group 2 (Reactor Water Sample Valves), Group 5 (Residual Heat Removal (RHR) and Traversing In-Core Probe (TIP) Systems), Group 6 (RHR Shutdown Cooling), and Group 7 (Reactor Water Cleanup). The RWCU System was in operation at the time of the event and was tripped off by the event.

In addition, the loss of RPS A power causes a NSSSS Group 3 (Primary and Secondary Containment Ventilation and Purge System) isolation. The NSSSS Group 3 isolation is caused by loss of power to the Reactor Building Exhaust Plenum Process Radiation Monitors, a non-NSSSS ESF tr ip signal. All required Group 3 actions occurred as designed including the automatic start of the Standby Gas Treatment System and the Control Room Emergency Filtration System and a Reactor Building HYAC Isolation.

Plant Operators responded by switching RPS-Bus A to its alternate power supply and by restoring all systems to their pre-event lineup within 20 minutes.

Plant Engineers and Electricians performed a series of diagnostic'tests to determine the cause of the breaker trip. The cause could not be determined.

The tests verified the incoming voltage and frequency were within allowable toler ances and that the logic board outputs were correct. The circuit breaker was reclosed with no problems; however, because of recurrin'g problems with these breakers it was decided to replace the breaker with a new model breaker.

The failed RPS-EPA Breaker was manufactured by General Electric Company and the part number is TFJ226175W6. RPS Bus A power was returned to the preferred source RPS-MG-1A through the new RPS-EPA-3A Breaker at 1421 hours0.0164 days <br />0.395 hours <br />0.00235 weeks <br />5.406905e-4 months <br /> on August 9, 1987.

NRC FORM SEER e V.S.GPO.'1()85.0 524 538/455 (583)

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NRC form 3OSA U.S, NUCLEAR REOULATORY COMMISSION (9431 LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVEO OMS NO. 3)50&)04 EXPIRES: 8/31/88 fACILITYNAME (1) OOCKET NUMSER (21 LER NUM8ER (Sl PACE (3)

SEQUENTrAL rrov IorON NVMeerl /R NUM ER Washington Nuclear Plant - Unit 2 0 5 0 0 o39 787 0 2 5 0 03>>0 4 TEXT ///more e/roco )r )erReire/, ooe ~ /oeo'oo/ HRC form 3/)/A3/ (IT)

The root cause of this event has not been determined. The Supply System sent the breaker to General Electric (breaker manufacturer) for analysis, hut to date the cause of the breaker trip has not been determined. In addition, Plant Engineers have been discussing EPA breaker problems with other BWR Plants. The root cause information will be provided in a supplemental report.

Immediate Corrective Action Plant Operators switched RPS Bus A power to its alternate power supply and all Plant systems were restored to their pre-event lineup within 20 minutes.

Further Evaluation and Corrective Action As part of the root cause investigation Plant Electricians installed a line disturbance analyzer to monitor the line input to the RPS-EPA-3A Breaker.

Points monitored included power supply current, voltage, and frequency; neutral to ground potential; and radio frequency interference. The line was monitored for twenty days during which no abnormal indications were observed.

The three remaining old model EPA breakers were replaced with new model breakers. There are six EPA breakers in the Plant and, prior to this event, three had been replaced with the new model. To date, the plant has not experienced any spurious actuations with the new breakers.

The Supply System will continue to attempt to determine the root cause of this EPA breaker trip. Root cause information will be provided in a supplemental report.

Safety Si nificance There is no safety significance associated with this event because no Plant condition requiring the ESF isolations and actuations existed and all ESF isolations and actuations occurred as designed. The ESF isolations and actuations had no adverse affect on Plant Operations, and all Systems'ere restored to their pre-event lineup within 20 minutes. The recurring problems caused by spurious trips of the EPA breakers is not adverse to Plant s'afety because these trips do not prevent the Reactor Protection System from performing its safety function. This event posed no threat to the safety of the public or Plant personnel.

Similar Events86-008 and 87-019 NRC PORM 3OOA o U.S.OPO:1988.042O 838/488 (983)

U.S. NUCLEAR REOVLATORY COMMISSION NRC Form 300A I8 831 LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVEO OMS NO. 3150M/00 EXPIRES: 8/31/88 FACILITYNAME Ill OOCKET NVMSFR Ill LER NVMSER IS> PACE 13)

YEAR SEQUENTrAL RSVISrON NUM SR NUM00R Washington Nuclear Plant - Unit 2 o s o o o3g 0 2 5 0 04 OF 0 4 TEXT //F moro 0/roco /0 /o/r/wor/ rroo al/R//oM/ /VRC hvm 308AS/117)

EI IS Information Text Reference EIIS Reference System Component Reactor Protection System (RPS) JC Reactor Protection System Electrical Protection Assembly (RPS-EPA-3A) JC BKR RPS-Bus-A JC BU Nuclear Steam Supply Shutoff System (NSSSS) BD Standby Gas Treatment (SGT) System BH Residual Heat Removal (RHR) System BD Reactor Water Cleanup (RWCU) System CE Traversing In-Core Probe (TIP) System IG Reactor Building Exhaust Plenum Process Radiation Monitor IL Reactor Building HVAC VA Control Room Emergency Filtration System VH NRC FORM 300A 0 U.S OPO.I SSbb820 538/055

$ 831

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WASHINGTON PUBLIC POWER SUPPLY SYSTEM P.O. Box 968 ~ 3000 George Washington Way ~ Richland, Washington 99352 Docket No. 50-397 September 3, 1987 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

NUCLEAR PLANT NO. 2 LICENSEE EVENT REPORT NO.87-025

Dear Sir:

Transmitted herewith is Licensee Event Report No.87-025 for the WNP-2 Plant.

This report is submitted in response to the report requirements of 10CFR50.73 and discusses the items of reportability, corrective action taken, and action taken to preclude recurrence.

Very truly yours, Q/f[ guiicA.

C.H. Powers (H/D 927H)

WNP-'2 Plant Hanager CHP: ac

Enclosure:

Licensee Event Report No.87-025 cc: Hr. John B. Hartin, NRC - Region V Hr. C. J. Bosted, NRC Site (H/D 901A)

INPO Records Center - Atlanta, GA Hs. Dottie Sherman, ANI Hr. D. L. Williams, BPA (H/D 399)

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