05000413/LER-1989-001, :on 890107,Train a Blackout Due to Inappropriately Installed Protective Relay.Apparently Relays Were Swapped During Initial Installation During 1978.RHR Reestablished by Placing Nd Train B in Svc

:on 890107,Train a Blackout Due to Inappropriately Installed Protective Relay.Apparently Relays Were Swapped During Initial Installation During 1978.RHR Reestablished by Placing Nd Train B in Svc

ML20247M099
Person / Time
Site:	Catawba
Issue date:	07/28/1989
From:	Glover R, Owen T DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-89-001, LER-89-1, NUDOCS 8908010436
Download: ML20247M099 (6)

LER-1989-001, on 890107,Train a Blackout Due to Inappropriately Installed Protective Relay.Apparently Relays Were Swapped During Initial Installation During 1978.RHR Reestablished by Placing Nd Train B in Svc

Event date:
Report date:
4131989001R00 - NRC Website

text

N.:

\\\\

\\;

Duke !buir Company ;

(803) 831J000 ^

r; Carou:ba NuclearStation bI P0. Box 2%

i Clocer, S C 29T10 -

l

~

f DUKEPOWER.

L July 28,f1989 Document Control Desk U. S. Nuclear-Regulatory Commission Washington, D. C.

20555-

Subject:

Catawba Nuclear Station, Unit 1

~

Docket No.-50-413 LER 413/89-01, Revision 2 Gentlemen:

Attached is' Revision 2 to' Licensee Event Report 413/89-01, concerning a Train A" blackout due to an ' inappropriately installed protective relay.

This: revision.is being submitted to correct the sequential number that'was erroneously typed on Revision 1 as -012 submitted' 05/22/89.

This event was considered to be of no significance with respect-to the

' health:and safety of the public.

Very t'ruly yours, L

- b

. Tony

. Owen Station Manager KEB\\LER-NRC.TBO xc:

Mr.'S, D. Ebneter American Nuclear Insurers Regional. Administrator, Region II c/o Dottie Sherman, ANI Library U. S. Nuclear Regulator Commission The Exchange, Suite 245 101 Marietta Street, NW, Suite 2900 270 Farmington Avenue Atlanta, GA 30323 Farmington, CT 06032 M & M Nuclear Consultants Mr. K. Jabbour 1221 Avenues of the Americas U. S. Nuclear Regulatory Commission New York, NY 10020 Office of Nuclear Reactor Regulation Washington, D. C.

20555 INPO Records Center Suite 1500 Mr. W. T. Orders 1100 circle 75 Parkway NRC Resident Inspector Atlanta, GA 30339 Catawba Nuclear Station f

l 8908010436 890728 PDR ADOCK 05000413 l

i S-PDC

hRC Form aos U.S. NUCLEAR E E0ULATG2V COMMeetsON APPROVED OMS teO.3190 4 108 LICENSEE EVENT REPORT (LER)

• • '****'8'**

P AC.LITY NAME (11 DOCKET NUMSER (2)

PAGE43e L

Catawba Nuclear Station, Unit 1 0 l 5 l 0 l 0 l 0 l4 l1 13,1 loFl Ol5 TITLE (41 Train A Blackout Due to Inapropriatcly Installed Protective Relav EVENT DATE 10)

LER NUMBER 101 REPORT DATE (7)

OTHER 7 ACILITIES INVOLVED (8)

MONTH DAY YEAR YEAR 88(U h^ '

' 7/u",$ MONTH DAY YEAR PaciLITV NAwas DOCKET NUMBERig) 0l5l0l0l0l l l O! 1 0l 7 89 8!9

~ 0l0l1[ 0l2 0l 7 '2l8 8l 9.

0l5lol0;o; l l Twis MerORT is sueMiTTEo evRsuANT TO THE REQUIREMENTS or 30 CrR c: c>.ca ene e, ee,e er ran reerew,asi tit)

Moos is) 5 ao.

m

.w

,,,73,n nm 73.,, m so.sasi. Hum e0. sewn) no.7 mH2im 73.rt u nei O f or o 30 m mnim

.0.sewH2>

.0.rawaHvui g,w,Egs.;-7,,,,ag;g7;,,

20.405(sH1HHI) 90.731sH2HO 30.734sH2HvillHA)

Js6Al 20.40eleH1Hav) to.73teH2HN) 00,73teH2HvHlHS) 30.40BisH1Hv) 90.73Isnt2HHO 90.73laH2Hal LICE 8eSEE CONTACT POR THl8 LER (12)

,,,g TELEPHONE NUMOER ARE A CODE R. M. Glover, Cosop11ance Manager 8l0 3 8l3 l 1 - 13 l2l3l6 1

1 COMPLETE ONE LINE FOR EACM COMPONENT FAILURE DEPCRISED IN THIS REPORT (13) c,y,,

,y,7,,

go,,,,,,,

uANg;AC.

,,ORTAge l

,g

"^"X;AC.

nge,OR,T,Aggt

CAusE

sysTEu COurONENT o

l l l l 1 l l l

l 1 I I I I l

l 1 l i I l l l

l ! I I I 1 suceLEMENTAL nEeORT ExrECTEo n4)

MONTw oav vfAR

'WMe"

~] vEs air y m,=a, exercrro suewss,0N nares

- lNO Ol9 0l1 8l9 ASSTaACT iLim/t to 76 apsces. LA, appmmmiserty fsfwen s/nate spect typewrerms imes/ (18)

On January 7, 1989, at approximately 0302 hours0.0035 days <br />0.0839 hours <br />4.993386e-4 weeks <br />1.14911e-4 months <br />, 6900V Tie Breaker ITC-7 tripped after Reactor Coolant (NC) Pump IC had been started, and power to 4160 Essential Bus 1 ETA was lost. The loss of power caused an isolation of the bus with no back-up power available due to Diesel Generator 1A being out of service. The Blackout resulted in a loss of power to Residual Heat Removal Pump 1A, Fuel Pool Cooling Pump 1A, and Component Cooling Pump 1A2. Subsequently, due to a charging flow control valve failing open, NC System pressure increased and caused a Pressurizer PORV to lift seven times. The 6900V Switchgear 1TC is separated into two sides which are connected by normally open Tie Breaker ITC-7.

The tie breaker was closed because IT2A was out of service. The tie breaker tripped open on overcurrent because a ground overcurrent relay was installed in the time delay overcurrent relay location. The ground overcurrent relay was not designed for the inrush current caused by starting the NC Pump.

The Unit was in Moce 5, Cold Shutdown, when the incident occurred and had operated in all modes of operation. This incident is attributed to an inappropriate action.

It appears the relays were swapped during the initial installation during 1978.

Time delay and ground overcurrent relays were placed into the correct locations.

An inspection was performed to verify the correct relays were installed in all other similar applications.

1 Ngrer=ses o u s opo,es4+4suetns7se

U S NUCLEAR EECULATORY COMMISE804 7"

UCENSEE EVENT REPORT (LER) TEXT. CONTINUATION

• • ,aoveo ove so mom (RPIR($ g p g FACWTvhamEsu DocmET NUMBER 60 ggg gyuggg,gi

,,g,3,

" t' W."

'A%',W

's'a Catawba Nuc1 car Station, Unit 1 0 l5 l0 jo jo j4 l 1l3 8l9 0l0,1 0l2 0l2 0F 0 l5 TEXT ## more Ipsce e recusred, use amWermet NAC #cmr JMif,# (171 BACKGROUND The 6900V Normal Auxiliary Power [EIIS:EB] (EPB) System distributes power to auxiliary equipment required for normal plant operation. The EPB System also serves as the normal supply to the 4160V Essential Auxiliary Power System.

[EIIS:EB]. Each 6900V Switchgear [E!IS:SWGR], ITA, 1TB, 1TC, and ITD, normally receives power from two of four auxiliary transformers [EIIS:XFMR] per Unit:

1TIA, 1T2A, ITIB, and 1T2B. Normally, one auxiliary transformer is used to feed one side of a 6900V Switchgear assembly. However, each transformer is sized to carry the loads of ~one entire switchgear in the event that one of the normal

' sources is out of service (see Enclosure 6.1).

The bus tie breaker [EIIS:BRK] in the switchgear is normally open so that each side of the 6900V Switchgear is normally fed from a separate transformer. The bus tie breaker is rated for 2000 amps and is equipped with protective relaying [EIIS:RLY]. A time delay overcurrent relay (51ZYX) is provided to trip the breaker on current greater than 2000 amps for a predetermined amount of time.

The bus tie breaker is also equipped with a ground overcurrent relay to trip the breaker on ground fault. The two relays are very similar except for their time response curves. The time delay relay will allow for inrush current greater than the setpoint of the relay, which allows for starting large pump motors.

The ground overcurrent relay does not allow for inrush currents and would trip the tie breaker much faster than the time delay overcurrent relay.

The 6900V Switchgear ITC supplies power to various plant loads including the Reactor Coolant [EIIS:AB] (NC) Pump [EIIS:P] 1C and is the alternate supply to Essential Switchgear Train A (1 ETA), via shared Transformer SATA.

DESCRIPTION OF INCIDENT On January 7,1989, Unit 1 was in Mode 5, Cold Shutdown, during a refueling outage. Auxiliary Transformer ITIA was out of service for maintenance and Tie Breaker ITC-7 was closed allowing Auxiliary Transformer IT2B to supply power to the entire 6900V Switchgear ITC.

1 ETA, 4160V Essential Switchgear Train A, was j

being fed by Transformer SATA. Diesel Generator [E!IS:DG) 1A was out of service for overhaul and inspection. Component Cooling [EIIS:CC] (KC) Pumps 1A2 and IB1 were in service, Charging Pump 1B was in service, and Residual Heat Removal [EIIS:BP] (ND) Pump 1A was in service.

l At 0302:35 hours, on January 7, 1989, Operations personnel started NC Pump 1C per OP/1/A/6150/01, Filling and Venting the Reactor Coolant System. A Hi Amps on NC Pump 1C alarm due to motor start was immediately received as expected.

Approximately seven seconds after starting NC Pump 1C, 6900V Switchgear Tie Breaker, 1TC-7, tripped, deenergizing the short side of ITC, which resulted in a loss of power to 1 ETA. As expected, NC Pump 1C tripped, ND Pump 1A tripped, KC Pump 1A2 tripped, Fuel Pool Cooling Pump 1A tripped, INV294, NV Pumps A and B Flow Control valve, failed open, Containment Purge [EIIS:VA] (VP) isolated, Control Room Area Pressurized Filter Train 1 (PFTF-1) initiated, and Diesel l

i

.4,o M u..

hnC form ased.

U $ NUCLEAR REGutat03Y COMMI558CN P.'

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION maovio ove no no o,os expires 8/3185 7 ACILITY NAM 4 414 DOCKEY NUMSER (2) ggn quugg2 461 PAGg 13

)

.. =

.::.n 0l011 Cstawba Nuc1 car Station, Unit 1 o l5 l0 jo l0 l 4 j1 l 3 8l 9 0l 2 013 0F Ol 5 TEXT f# more seco e regunod, use swomonef ##C Form Wat (17)

Generator Load Sequencer Train A (DGLSA) Blackout Logic initiated. The Control Room Operator (CRO) responded by starting KC Pump 182 and entered

)

AP/1/A/5500/21, Loss of Component Cooling. The CR0s realized they had lost all

' Train A Essential Switchgear related equipment and depressed the OFF pushbutton i

for NC Pump IC Breaker to prevent the pump from restarting when power was restored. At this time, the Eight Second Undervoltage Time Delay was complete on IETA and DGLSA actuated, opening the IETA Alternate Incoming Feeder Breaker and initiating 1 ETA Lead Shed.

Twenty-seven seconds after losing power to ND Pump 1A, the CR0 attempted to establish ND flow to the core by starting ND Pump 1B. The pump started but no

- flow was provided to the Reactor. After further investigation, the CR0 discovered'1NI1788, ND Header IB to Cold Legs A and B, was closed. The CR0 opened the valve and ND flow was restored to the Reactor [EIIS:VSL] core 136 seconds into the incident.

During this period, the Operators used AP/1/A/5500/019, Loss of Residual Heat Removal.

At 0303:23 hours, NC pressure had risen to 361 psig.

Eight seconds later, INC34A Pressurizer PORV lifted which indicates NC System pressure reached approximately 400 psig. The Pressurizer PORV lifted a total of seven times within the next 116 seconds.

During this time, the CR0 diagnosed that INV294 had failed open.

Charging Pump 1B was then tripped by the CR0 and NC System pressure began to decrease.

Letdown was isolated approximately 13 minutes later to maintain 100 psig NC System pressure.

The CR0 then entered Loss of Normal Power Procedure AP/1/A/5500/07, Case II.

Operations investigated the problem and found Time Delay Overcurrent Relay 51Z.t.

tripped. The relay was reset and 1TC-7 was closed to reenergize switchgear ITC.

The CR0 next followed the Loss of Normal Power Procedure to reenergize IETA.

1 ETA was reenergized within 28 minutes and the VP System was realigned. One hour, five minutes after the incident, charging flow was reestablished and the NC System was returned to its initial condition.

At 0435 hours0.00503 days <br />0.121 hours <br />7.19246e-4 weeks <br />1.655175e-4 months <br />, Operations personnel initiated Priority 5F Work Request 29800 OPS. Transmissions personnel discovered that Time Delay Overcurrent Relay, 51ZYX, had the wrong time response curve.

Further investigation determined that the Ground Overcurrent Relay (51G) and the Time Delay Overcurrent Relay (51ZYX) were swapped. A new 51ZYX Relay was calibrated,and installed. The inservice 51G Relay was recalibrates and installed in its proper location.

Transmissions personnel verified proper protective relays were installed for all other 6900V Switchgear incoming and tie breakers.

CONCLUSION This incident is attributed to inappropriate action.

It appears the relays were swapped during the initial installation during 1978, possibly due to a lack of attention to detail. This could not be confirmed by a documentation review.

. 4,o M m.

' 6, [,,, y

~

u s Nucteaa nout Toav commiss.oh LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPaOV ED eM8 NO 3:50-0104

+82' f uPiat5 81115 DOCatT NuMsta (21 ggn wyuggn e6l PAGE (31 F AClui? NAME IU

• saa

-" t

• R.

"'#,W 010l1 01 2 0l4 oF 0 15 f

C tawba Nuclear Station, Unit 1 o l5 jo jo jo l4 l 1l3 81 9 Text w,...,.w...mammac w assa w im Prior to the initial installation, Transmissions personnel performed an acceptance test on these relays to verify the relay had the correct time current characteristics. A relay test was then performed to verify or adjust the correct setting of the relay. After the relay was set up, it was tagged and installed. When the relays were found swapped, it was discovered that they also I

were tagged incorrectly.

The tagging indicated that the ground overcurrent i

relay should have been installed in the time delay overcurrent location and the time delay overcurrent relay should have been installed in the ground overcurrent location. Since the tagging was performed during the initial installation, it appears the relays have been installed incorrectly since May 4, 1978. Transmissions performed a routine test on these relays every other refueling outags. However, their testing only verifies the setting of the relay and does not verify the correct time current characteristics.

This incident has not occurred previously because NC Pump 1C was not required to start while ITIA was out of service with ITC supo!ying IETA along with its normal loads.

One item of concern which was noted during this incident is the amount of noise in the Control Room caused by the increased air flow when PFTF-1 started. It was noted by the Operators that this disruption was great enough to cause communication to be very difficult at a time when it was most important.

An additional problem was the lack of information that was available.

During the Sutage, numerous chart recorders were tecured in the Control Room, making ev u nion of plant response difficult. Data obtained by the Transient M.Mtwing System was also not saved, following the incident.

In the previous twelve months, there have been no ESF actuations due to incorrect relay installations.

CORRECTIVE ACTION

IMMEDIATE (1) CR0 started Component Cooling Pump 1B2.

SUBSEQUENT (1) CR0 reestablished Residual Heat Removal by placing ND Train B in service 136. seconds into the incident.

(2) Under Work Request 29800 OPS, Transmissions found ITC-7 Protective Relays 51ZYX and SIG swapped. Transmissions calibrated and installed a new 512YX relay and recalibrates the SIG relay and installed it in the proper location.

g,o. m.--_

' bc perm ansa, U $ NuCLEA3 KEGubaTolv COMuitsioN M

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION anRoveo ous No mo_eio.

ExhRES 61186 DOCK 4Y NUmstm (26 LER NUMBER t66 pacg g3i FACluTV NAME til

" C'3

t'#0

"*a 010l1 01 2 01 S oF 0 l5 C:tawba Nuclear Station, Unit 1 ol6l0jolol4l1l3 8] 9 1

iEXT t# more space e regerest, use eseopauf NAC harm Jg8A'st tih (3) Also under Work Request 29800 OPS, Transmissions vedfied proper i

protective relay installation for all other 6900V Switchgear incoming l

breakers and tie breakers.

J (4) Design Engineering evaluated the failure mode of valves 1,2NV204 I

during a complete loss of Train A esssntial power.

PLANNED (1) Duke Power personnel will evaluate excessive noise caused by the pressure filter fan and practices concerning retention of plant data, as appropriate, (2) Design Engineering will be requested to evaluate the possibility of adding an additional backup power supply to 1,2NV294.

(3) This report will be revised based on the results of Design Engineering evaluating the possibility of adding an additional backup power supply to 1,2NV294.

SAFETY ANALYSIS

i At the time of the incident, Unit 1 was in Mode 5, Cold Shutdown, following refueling and Diesel Generator 1A was inoperable. Following the initiation of the Blackout, power was lost to ND Pump 1A and KC Pump 1A2.

KC Pump 1B2 was immediately started by the Operators and flow was also reestablished to the core using ND Pump 1B within 136 seconds. There was no significant increase in temperature noted in the NC System during this time. During this incident, 1NV294 failed open. The v*.lve failing open caused NC pressure to increase to approximately 400 psig which in turn lifted Pressurizer PORV INC34A seven times to control primary coolant system pressure. Control Room Operators secured Charging Pump 18 and stabilized Reactor Coolant System pressure.

In Mode 5, Reactor Coolant inventory and core cooling would normally be provided by the ND System. Although lifting the PORV was undesirable in this event, it was preferable, since ND was not reestablished for 136 seconds.

Design Engineering has evaluated the failure mode of valves 1,2NV294 during a complete loss of Train A Essential power. The ultimate failure position has been selected based on the most desirable safety function. Since the cause of.he Tie Breaker ITC-7 trip was located and corrected, it is unlikely that the same set of conditions will exist in future C Pump start sequences during Mode 5.

Although this is unlikely to recur, Desi9, Engineering will evaluate the possibility of adding an additional ockup power sapply to 1,2NV294 in all Modes of operation. The health and safety of the ptblic were unaffected by this incident. This incident is reportable pursuant to 10CFR 50.72, Section (b)(5)(ii) and 10CFR 50.73, Section (a)(2)(iv). The lifting of PORV 1NC-34 is reportable pursuant to Technical Specifications 3.4.9.3 and 6.9.2.

l 1

I S"?'?' _ _ ___- - _ __ ____ -____