ML18153C382

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LER 90-004-00:on 900827,main Feedwater Regulating Valve Closed Following Inadvertent Grounding of Control Signal. Root Cause Not Determined.Computer Multiplexer Testing Procedures changed.W/900920 Ltr
ML18153C382
Person / Time
Site: Surry Dominion icon.png
Issue date: 09/20/1990
From: Kansler M
VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
90-580, LER-90-004-01, LER-90-4-1, NUDOCS 9010100211
Download: ML18153C382 (7)
v • d • e


Text

ACCELERATED D~TRIBUTION DEMONSTB.ATION SYSTEM

*; . . . . REGULAT~ INFORMATION DISTRIBUTION"YSTEM (RIDS) .

!~ ;

!/ ACCESSION NBR:9010100211 DOC.DATE: 90/09/20. NOTARIZED: NO DOCKET#

r FACIL~50-281 Surry Power Station, Unit 2, Virginia Eiectiic ~ Powe 05000281

.AUTH.NAME AUTHOR AFFILIATION KANSLER,M.R. Virginia Power (Virginia Electric & Power Co.)

REC IP. NAME RECIPIENT AFFILIATION *

SUBJECT:

LER 90-004-00:on 900827,unit 2 manual reactor trip tallowing ]

inadvertent gr'ounding of "A" main * *

  • testing. W/900920. 1 tr .*

DISTRIBUTION CODE: IE22T COPIES REC.EIVED:LTR 1 TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

ENCL J SIZE: ' * * .

. . I NOTES:lcy NMSS/IMSB/PM. 05000281 RECIPIENT COPIES RECIPIENT _COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL . j PD2-:-2 LA 1 1 PD2-2 PD 1 1 BUCKLE:Y ,B 1 1 I INTERNAL: ACNW 2 2 ACRS 2 2 I AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 2 NRR/DET/ECMB 9H 1 1 NRR/DE:T /EMEB 7 E 1 1 NRR/DLPQ/LHFBll 1 1 NRR/DLPQ/LPEBlO 1 1 NRR/DOEA/OEABll 1 1 NRR/DREP/PRPBll 2 2 NRR/DST/SELB 8D 1 1 NRR/DST/SICB 7E 1 1 1 1 NRR/DST/SRXB SE RES/DSIR/EIB 1

1 1

1 CJIBG:1*~

ffl~LB8Dl R FILE 01 02 1 1

1 1

EXTERNAL: EG&G BRYCE,J.H 3 3 L ST LOBBY WARD 1 1 NRC PDR 1 1 NSIC MAYS,G 1 1 NSIC M.URPHY,G.A. 1* 1 NUDOCS FULL TXT .1 1 B

NOTES: 1 1 I

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A D

D NOTE TO ALL "RIDS" RECIPIENTS:

s PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK.

ROOM Pl-37 (EXT. 20079) TO ELIMINATE YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

FULL TEXT CONVERSION REQUIRED.

TOTAL NUMBER OF COPIES REQUIRED: LTTR 34 ENCL 34

,,,/

Virginia Electrk and Power Company Surry Power Station P. 0. Box 315 *

. Surry, Virginia 23883 September 20, 1990 U; S. Nuclear Regulatory Commission Serial No.: 90-580 Document Control Desk Docket No.: .. 50-281 Washington, D. C., 20555 . License No.: DPR-37 Gentlemen:

Pursuant to Surry Power Station Technical Specifications, Virginia Electric and Power Company hereby submits the following Licensee Event Report for Unit 2 ..

  • REPORTNUMBER 90-004-00 This report has been reviewed by the Station
  • Nuclear Safety and Operating Committee and will be reviewed by Corporate Nuclear Safety.

Very truly yours,

. (

~uz ansler Station Manager Enclosure cc: Regional Administrator Suite 2900 101 Marietta Street, NW Atlanta, Georgia 30323

/) ,i 9010100211 900'920 PDR ADOCK 05000281 Apv S PNU

.~ \\ \

NRC FORM 366, U.S. NUCLEAR REGULATORY COMMISSION (6-89) APPROVED 0MB NO. 3150-0104 EXPIRES: 4/30/92 ESTIMATED BURDEN PER .RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0* HRS. FORWARD

. l.lCENSEE EVENT REPORT (LER)

/ COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (P-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFI_CE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) GE 131 TITLE 141 Surry Power Station, Unit 2 Unit 2 Manual Reactor Trip Following Inadvertent Grounding of the*

IO 15 Io IO IO 12 I 811 1!0FOl-5

'.'A" Main Feedwater Regulating Valve Con.trol Signal During* Testing EVENT DATE (5) LER NUMBER (6) REPORT DATE 17) OTHER FACILITIES INVOLVED 18)

MONTH DAY YEAR VEAi!

ft? SEQUENTIAL NUMBER \rt REVISION NUMBER MONTH DAY YEAR .FACILITY NAMES DOCKET NUMBERIS) 01s1010101 I I ols 21 7 9 0 9 lo - ol ol 4 - olo ol 9 ii o, 91 0 o,s,o,o,o, I . I OPERATING THIS ltEPORT IS SUBMITTED PURSUANT TO THE R~QUIREMENTS OF 10 CFR. §: (ChtK:k on* or mar* of tho following/ (11) 1111 _ _..._N _ _ :!o.40 21b J J MODE I -- 20.405(cl 60.73(11121 I iv)

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73.71(bl POWER l!0.405(11111111 60.38(cllll 60.73111121M 73.7l(cl L1~~L 1, 0 *I O - l!0.405(1lllllill

--

  • 60.38(cll21 60.731111211viil I--

OTHER (Specify in Abstr1ct b1low and in Toxt. NRC Form

~.40511111 llilll 60.7311112lliJ 60.7311Jl21MIIIIAI 366A}

11111111=  ::0.40511111111*)

2.0.405111(1 JM - IS0.73(1112l(iil 60.7311112lliiil LICENSEE CONTACT FOR THIS LER 1121 60.7311il2Hvllll(BI 60.7311112)1x)

NAME TELEPHONE NUMBER AREA CODE M. R. Kansler, Station Manager s1 o 14 315171-13111814 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT 113)

CAUSE SYSTEM COMPONENT MANUFAC- MANUFAC*

TURER TURER I I I I I I I I I I I I I I I I I I I I I I I I I I I I SUPPLEMENTAL REPORT EXPECTED (14) MONTH DAY YEAR EXPECTED SUBMISSION 11 YES /If yos, complotl EXPECTE£l SUBMISSION DATE/

DATE 1151 I I I ABSTRACT (Limit ro 1400 spact1s, i.a., approximett1/y fifr11t1n single-space rypewrit~n limuJ (16)

On August 27, 1990 at 0925 hours0.0107 days <br />0.257 hours <br />0.00153 weeks <br />3.519625e-4 months <br />, with Unit 2 operating at 100% power, the "A" Main Feedwater Regulating Valve (MFRV) closed following the inadvertent grounding of its control signal during periodic surv,eillance testing.* Closure of the "A" MFRV resulted in a mismatch between "A" Steam Ge:nerator (S/G) feedwater flow and steam flow causing several annunciators to alarm. The reactor operator immediately attempted to reopen the "A" MFRV by increasing the controller demand in manual but the valve did not respond. Since a low S/G level coincident with steam flow-feedwater flow mismatch reactor trip was imminent, the reactor operator manually tripped the reactor at approximately 27% level in the "A" S/G. The operators followed appropriate plant procedures and quickly stabilized the unit following the manual trip. A four hour non-emergency report was made to the Nudear Regulatory Commission in accordance with 10CFR50.72.

NRC Form 366 16-89)

NIICfOIIM .....

CHIii e U.1. NUCLlAII IIEOULATOIIY COMMISSION LIC:ENSEE EVENT REPORT CLER) .

e APPROVED OMI NO. :1150.0ICM IXPIIIU:~

ESTIMATED IUADEN PEIi IIE8'0NIE TO COMPLY WTH THIS IIIIFOIIMATION COLLECTION IIEOUEST: eo.o HAS. ,oAWAIID a-.lENTI IIEGARDING IUIIDEN EITIMATl 10 THE IIECOIIDS TEXT CONTINUATION . NllfJ IIEPOATI MANAGEMENT IIIANCH IP-l301, U.I. NUCL.LUI REGULATORY COMMISSION, WASHINGTON, DC 201151, ANO TO THE PAPEIIWOIIK IIEOUCTION PIIO.IICT 13tlO-OtCMI, OF,ia OF MANAGEMENT ANO IUOGET, WASHI_NGTON, DC 20IOJ.

  • FACILITY NAME 111 DOCKET NUMIEII 121 LEII NUMllll 111 PAGI 1:11 Surry Power Station, Unit 2 o Is I o I o I o 12 1s 11 91 b - o I oI 4 - o Io o 12 oF oI s
1. O DJCSCRIPTION OF THE EVENT On August 27, 1990 at 0925 hours0.0107 days <br />0.257 hours <br />0.00153 weeks <br />3.519625e-4 months <br />, Surry Unit 2 was operating at 100%

power when several annunciators alarmed indicating a mismatch between "A" Steam Generator (S/G) feedwater flow and steam flow. The op,erator observed that the "A" Main Feedwater Regulating Valve (MFRV) (EIIS:-FCV) incficated fully closed, that the valve controller (EIIS-JB) had shifted to manual, and that feedwater flow to the "A" S/G had decreased to approximately zero. The reactor operator immediately att1~mpted to reopen the valve by increasing controller demand in manual, but the

  • valve did not respond. Since a low SIG level coincident with steam flow-feed water
  • flow mismatch* reactor
  • trip was imminent, the reactor operator manually tripped the reactor. At the time the reactor was tripped, the "A" S/G. level was approximately 27%.

FoHowing the trip, all safety systems functioned as designed with the exception that one Individual Rod Position Indicator -(!RPI) (EIIS-ZI) rod bottom bistable light. did not illuminate immediately (Control Rod -M-10).

Additionally, a safety valve - (EIIS-RV) located on the Main Steam Reheater (MSR) cpmmon drain header between the two first point Feedwater Heaters (FWHs) lifted, which caused a portion of the Turbine Building (TB) fire sprinkler system (EIIS-KP) to actuate . on high temperature.

2. 0 SAlrETY CONSEQUENCES AND IMPLICATIONS The reactor trip on main steam flow-feedwater flow mismatch coincident with a low water level (20%) in any S/G provides protection against an anticipated loss of 11ormal feedwater. Since the reactor was manually tripped . before the automatic setpoint was

Emergency Procedures E-0, "Reactor Trip or Safety Injection", and ES-0.1, "Reactor Trip Response" were performed. Step 4 of ES-0.1 requires emergency boration if more than

However, since all but one IRPI rod bottom light illuminated within 30 seconds from the reactor trip, emergency boration was not required.

Control Rod M-10 rod bottom light illuminated approximately 30 seconds after the reactor was tripped.

N11c,-~cM1111

NIICfOIIM . . A CHIii e U.I. NUCLU.11 IIEOULATOIIY COMMISSION

.uc:ENSEE EVENT REPORT (LER) e Al'l'ROVED OMI NO. 31IIO.OICM IXPIIIU: 'l:IOl'82 ESTIMATED IUIIDEN PEIi IIE~NIE TO COMPLY.WTH nus llllf'C>IIMATIDN COLLECTION IIEOUEST: IO.O HRS. FORWAIIC)

GMoalENTI IIEGAJIIDINO IUIIDEN ESTIMATE TD THE IIECORDS

) TEXT CONTINUATION Al/ID IIEl'OIITI MANAGEMENT IIIANCH CP.a:IOI, U.I. NUCLLUI r,

J REGULATORY COMMIDION, WASHINGTON. DC 20HII, AND TO TNE PAPEIIWOIIIC IIEDUCTION l'tlO.IICT 13lll0o01CMI. OFFICE Of' MANAGEMENT AND IUDGET, WASHINGTON, DC :IO!i03.

FACILITY NAME Ill DOCKET NUMIEII 121 LIii .NUMIIII Ill PAOll:11 Surry Power Station, Unit 2 o 1s Io Io Io 12 I s1 1 91 o - oIo I 4 - 01 o 01 3 oF o I Y Operators quickly realigned secondary systems to depressurize system piping and reseat the FWH safety valve, tp.e affected . sprinkler heads replaced and the fire protection system lineup restored

  • with no safety consequences resulting thereof.

Safety related systems and equipment remained op~rable and plant parameters remained well within the bounds of the safety analysis, therefore the health and safety of the public were not affected.

3.0 The* "A" SIG MFRV went shut at 100% power when its

  • controller .

circuitry was inadvertently shorted during an Emergency Response Facility (ERF) computer multiplexer (MUX) (EIIS-MPX) power supply pedodic surveillance test. At the time of the event, a MUX circuit card containing the "A" MFRV control signal was being . removed and repl.aced with an insert extender test card. The test card was being used to measure MUX voltage per the periodic surveillance test procedure. As the card was reinserted, the input to the "A" MFRV controller was shorted, and the valve shifted to manual control and went to . zero demand. This resulted m zero output to the valve positioner, causing the MFJRV to close. The shorting of the MFRV controller output occurred due to a combination of the wiring configuration used to provide the MFRV comttol - signal input to the General Electric Transient Analysis System (GET ARS) computer and

  • the insert extender test card being inserted with the test toggle switch in the "short" -position.

The MFRV demand signal input to GETARS was designed to be derived from the. resultant voltage drop across a 50 Ohm resistor mounted in the controller module. This resistor is wired in series with the output signal to . the MFRV valve electro-pneumatic (E/P) converter (EIIS-CNV).

However, the connection between the signal output and common test jacks on the controller effectively bypassed the output signal to the valv,es when the circuit was shorted. Insertion of the extender test card with the toggle switch in the "short" position caused the 4-20maDC outpiut signal to the E/P converter (EIIS-CNV) to go to zero. The Unit 1 inputs to GET ARS were examined and found to be configured

  • as designed.

It was determined that the difference in wiring configuration between Unit 1 and Unit 2 was the result of insufficient instailation d_eiail in the design documentation which installed the OET ARS.

NIICF_aA..._I

C NIICfOIIM . .A IWIII e U.1. NUCLU.11 IIEOULATOIIY COMMISSION LICENSEE EVENT REPORT CLER) e ,.,,.,.OVED OMI NO. 31l504tlM IXPIIIU:~

IST'IMATED IUIIDEN 'Ell !IE.ONIE. TO COWLY WTH THIS

-<<>IIMATION COLLECTION IIEOUEST: IIO.O HAS. l'ORWAIIO CIDIIMENTI IIEOAIIDIIIIG IUIIDEN EITIMATE TO THE IIECOflCS TEXT CONTINUATION M1ID IIE,OIITI MANAGEMENT IIIANCH r,.uc,1. U.I. NUCLENI

/ REGULATOIIY COMMISSION. WASHINGTON. DC DIii. AND TO THE ,APEIIWOIIK IIEDUCTION NIO.IECT 131!5041CMI. OFl'ICE OF MANAGEMENT AND IUDGET, WASHINGTON, DC DCU.

FACILITY NAME 111 DOCKET NUMIEII 121 LIii NUMalll 11!1 ,ADI C:11 Surry Power Station, Unit 2 o 1s 101010121 s11 91 o - o 10 1.4 - 010 014 OF o Is The delay of the IRPI M-'10 rod bottom light to illuminate has been evaluated by the .Nuclear Steam Supply System vendor to be the result of residual permeability in the control rod drive mechanism housing. This

  • phenomenon is caused by a comhinaiion of factors up to and including material composition and reactor coolant system temperature drop following the trip.
4. O IMMEDIATE CORRECTIVE ACTION<Sl Operators followed appropriate plant procedures and quickly stabilized the unit following the manual reactor trip. The Shift Technical Advisor performed critical safety function status tree reviews to ensure specific plant parameters were within safe bounds.
5. 0 AIDJ1ITIONAL CORRECTIVE ACTION<Sl All MUX testing was halted, and an investigation was initiated to determine the cause of the MFRV malfunction.
6. 0 A..CI;CONS TO PREVENT RECURRENCE The Unit 2 control signal inputs to GET ARS will be disconnected. from the common test jack, and reconnected such that the input is derived from the :resultant voltage drop across a resistor, a more fault tolerant configuration and consistent with the installation in Unit l. Extensive improvements made to the design control program since the GET ARS installation design documents were genera,ted should prevent recurrence.

The a,pplicable MUX testing procedures will be changed to

  • specify which MUX .cards (those that are monitoi::ing
  • indication inputs only) . are allowed to be utilized to perform this testing.
  • The use of insert extender test cards with shorting switches has been restricted to . MUX thermocouple inputs, the only testing which requires the us,e of a shorting test switch.

A root cause analysis has been initiated to further investigate this event and any additional recommendations to prevent recurrence. will be properl.y dispositioned.

NIIC , _ *A c.-1

NIICFOIIM . . A* U.1. NUCLlAII IIEGULATOIIY COMMISSION IW81 APl'ROVEO OMI NO. :1150.0IIM IXPIIIU: 4l1Glfl BTIMATEO IUIIDEN PEIi !IE.ONIE TO COMPLY WTH THIS LIC:ENSEE EVENT REPORT CLER) ~MATION COLLECTION IIEOUEST: ICI.O HRS. l'ORWAIIO Cl>IAIENTI IIEOAADING IUIIDEN ESTIMATE TO THE IIECOIIDIS I

  • i. TEXT CONTINUATION AMO IIE,OIITI MANAGEMENT IIIANCH IP-6:IOI, U.I. NUCLUJI IIEGULATOIIY COMMIIIION, WASHINGTON, DC 20lilll, AND TO THE PAPEIIWOIIIC IIEDUCTION PflO.IICT 1:1150.ollMI. OFl'la OF MANAGEMENT AND IUDGET,WASH.INGTON, DC 2Dli0:I.

FACILITY NAME 111 DOCKET NUMIEII 121 UII NUMIIII Ill PAGI 1:11 Surry Power Station,. Unit 2 0 5 0 0 0 2 8 1 -9 0 - 0 0 .4 - 0 0 0 .5 O_F O 5 TIXT r, ,_. .-a II,....,, - edtllrloNI N/fC Tonn-.,.-., m,

7. O .S.l.MILAR EVENTS The following LERs describe events where MFRV malfunctions led to

LER S2-90-003, The MFRV malfunction was *-due to air blockage. in the valve po_sitioner.

LER S2-86-007, The MFRV malfunction was due to metal debris between

. the plug and valve seat.

LER S2-84-003, The MFRV failed due to broken instrument air. supply piping.

LER Sl-86-001, The MFRV malfunction was due to a loss* of instrument air.

LER S 1-86-010, The MFRV malfunction was due to improper maintenance.

8. O MANUFACTURER/MODEL NUMBER Westinghouse Electric
  • Corp.

Hagan 7100 Series Control System.

Model 124 Controller

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