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| issue date = 05/08/1990
| issue date = 05/08/1990
| title = LER 90-003-02:on 900409,reactor Protection Sys Actuation Occurred Due to Failure of Reactor Coolant Pump Underfrequency Relay Power Supply Capacitor.Caused by Open Supply Breakers.Relay replaced.W/900508 Ltr
| title = LER 90-003-02:on 900409,reactor Protection Sys Actuation Occurred Due to Failure of Reactor Coolant Pump Underfrequency Relay Power Supply Capacitor.Caused by Open Supply Breakers.Relay replaced.W/900508 Ltr
| author name = HARRIS K N, POWELL D R
| author name = Harris K, Powell D
| author affiliation = FLORIDA POWER & LIGHT CO.
| author affiliation = FLORIDA POWER & LIGHT CO.
| addressee name =  
| addressee name =  
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=Text=
=Text=
{{#Wiki_filter:ACCELERATED DHUBUTION DEMONSTIZION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)ACCESSION NBR:9005160071 DOC.DATE: 90/05/08 NOTARIZED:
{{#Wiki_filter:ACCELERATED DHUBUTION                             DEMONSTIZION             SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM           (RIDS)
NO DOCKET FACIL:50-251 Turkey Point Plant, Unit 4, Florida Power and Light C 05000251 AUTH.NAME AUTHOR AFFILIATION POWELL, D.R.Florida Power&Light Co.HARRIS,K.N.
ACCESSION NBR:9005160071               DOC.DATE:   90/05/08   NOTARIZED: NO           DOCKET FACIL:50-251 Turkey Point Plant, Unit 4, Florida Power and Light                   C 05000251 AUTH. NAME             AUTHOR AFFILIATION POWELL, D. R.         Florida   Power & Light Co.
Florida Power&Light Co.RECIP.NAME RECIPIENT AFFILIATION
HARRIS,K.N.           Florida   Power & Light Co.
RECIP.NAME             RECIPIENT AFFILIATION


==SUBJECT:==
==SUBJECT:==
LER 90-003-02:on 900409,unit trip due to under frequency relay failure.W/9 ltr.DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR
LER   90-003-02:on 900409,unit         trip due to under frequency relay failure.
!ENCL 1 SIZE: TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.NOTES: RECIPIENT ID CODE/NAME PD2-2 LA EDISON,G INTERNAL: ACNW AEOD/DSP/TPAB DEDRO NRR/DET/EMEB9H3 NRR/DLPQ/LPEB10 NRR/DREP/PRPB11 NRR/DST/SICB 7E NRR/DST/SRXB SE RES/DSIR/EIB EXTERNAL EG&G STUART I V A LPDR NSIC MAYS,G NUDOCS FULL TXT COPIES LTTR ENCL 1 1 1 1 2 2 1 1 1 1 1 1 1 1 2 2 1 1 1 1 1 1 4 4 1 1 1 1 1 1 RECIPIENT ID CODE/NAME PD2-2 PD AEOD/DOA AEOD/ROAB/DS P NRR/DET/ECMB 9H NRR/DLPQ/LHFB11 NRR/DOEA/OEAB11 NRR/DST/SELB SD NRR DST SPLBSD1 a RGN2 FILE 01 L ST LOBBY WARD NRC PDR NSIC MURPHY,G.A COPIES LTTR ENCL 1 1 1 1 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 NOTE TO ALL"RIDS" RECIPIEhHS:
W/9         ltr.
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 tF'.,!
DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR !                 ENCL 1   SIZE:
P..ox14000,Juno Beach,FL 33408 0420~AY Os tSBO L-90-143 10 CFR 50.73 U.,S.Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C.20555 Gentlemen:
TITLE: 50.73/50.9 Licensee Event Report (LER),               Incident Rpt, etc.
Re: Turkey Point Unit 4 Docket No~50-251 Reportable Event: 90-003 Date of Event: April 9, 1990 Unit Tri Due to Underfre uenc Rela Failure The attached Licensee Event Report is being provided pursuant to the requirements, of 10 CFR 50.73 for notification of the subject event.Very r ly yqurs, de%N.Harris Vic resident Tur y Point Plant Nuclear KNH/DRP/JEK/rat cc: Stewart D.Ebneter, Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, Turkey Point Plant>Q0516ppp~
NOTES:
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RECIPIENT              COPIES            RECIPIENT           COPIES ID  CODE/NAME          LTTR ENCL        ID CODE/NAME       LTTR ENCL PD2-2 LA                     1    1      PD2-2 PD                1    1 EDISON,G                     1    1 INTERNAL: ACNW                           2    2      AEOD/DOA                1    1 AEOD/DSP/TPAB                 1    1      AEOD/ROAB/DS P          2    2 DEDRO                         1    1      NRR/DET/ECMB 9H        1    1 NRR/DET/EMEB9H3               1    1      NRR/DLPQ/LHFB11        1    1 NRR/DLPQ/LPEB10               1    1      NRR/DOEA/OEAB11        1    1 NRR/DREP/PRPB11               2    2      NRR/DST/SELB SD        1    1 NRR/DST/SICB 7E               1    1      NRR DST SPLBSD1        1    1 NRR/DST/SRXB SE               1    1        a                    1    1 RES/DSIR/EIB                 1    1      RGN2    FILE  01      1    1 EXTERNAL   EG&G STUART I V A             4    4      L ST LOBBY  WARD      1     1 LPDR                          1     1     NRC PDR                1     1 NSIC MAYS,G                  1     1     NSIC MURPHY,G.A         1     1 NUDOCS FULL TXT              1     1 NOTE TO ALL "RIDS" RECIPIEhHS:
HIIC roi~<<O tr42t LICENSEE EVENT REPORT (LER)U.S.HUCLSAA 1EOULATOAY CooaotSSIOH A~<<AOYED OMI HO f X<<IXII I/2)t SACILITY HAMt Ill Turkey Point Unit 4 TITLE ISI Urt it Trip Due To Under Fre uenc Rela Failure DOCXIT HU>al 1 ITI 0 5 0 0 0 25 1>pF0 IVIHT OATI tll LtA NUMOEA III It<<OAT DATE ITI OTKIA<<AC>LIT>IS INVOLVED a>MONT tr OAV YfAA VEAA SSQVSHTIAL Hutrst 1~rttsrsth OAY YEAA<<ACILI'TY HAtrto OOCXET HUMSIAISI 0 5 0 0 0 0 4 099 09 0 0 0 3 0005 0 8 9 0 0 5 0 0 0 OOEIIATINO MOOS I~>Ootsl A LlvlL 1 0 THIS Al<<OAT IS SUaslTTED<<UASUANT To TKE AIOUIAIMEHTS Oo 10 C<<A f: IC<<oos oos or~oa ot ths/ottoa rrl)ill x a.rSN>u>IH) 20.OOSI sl aMIs>Ill a.ssl<<u>a.res)u)I)a.r SN)ul It>a.rsN)u)a>20.IOSI~I 20.Oa>s)I>
PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!
IIO 20.oaN)>l))l>
FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR               34   ENCL   34
20.O Stol>1)INI SO.OINls)(1)
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a.rt>o)u)W LICE>t I CONTACT OOA TK>S LEA Ill)TS.T I I~I TS.TI I~)OTKEA ISOOCtry ri O<<r<<OCC~rroe rot>ii Trit Hoc<<ones ASSAI HAMf David R.Powel 1, Licensin Su erintendent TELE<<>tOHE HUMSEA AAIA CODE 30 524 6-655 COMPLETE ONE I,INI OOA tACK COAMONENT SAILUAI DISCI>ISO IN TH>S At<<OAT 1121 CAUSE SYSTEM COMOOHEHT MANU>tAC TUAIA EOOATASLE To HOODS SYSTEM COMOONEHT MANU<<AC.TUN IA EOOATAIL TO AMOS.o'%O J+X A 8 C A P G080 SV<<<<LEMINTAL AE<<OAT EX<<ECTED l>A>Ytl Ilt yrr.rt<<i<<toto tX<<tCTto SIISAIISSIOht OATtl AIITAAcT IL<<rK to Iooo At<<ca.t A.sooiorrrtsaty he>orts o<<Nsoosco tyooovt tao hors)IIII MOHTtr OAY EX<<ECTED SUISSISSION DATE lll>YEA<<On April 9, 1990 at 1814 EDT, with Unit 4 in Mode 1 (Power Operation) at 100 percent power, a Reactor Protection System actuation occurred due to a failure of a Reactor Coolant Pump (RCP)underfrequency relay power supply capacitor.
The reactor trip occurred because one of three reactor coolant pump power supply breakers opened with the reactor at greater than 45 percent power.The faulty underfrequency re'lay was replaced and Unit 4 was returned to serv'ce.'he RCP power supply underfrequency relays on'both Unit 3 and Unit 4 have been replaced with new models.A review of the failure modes of the replacement relays will be performed and planned maintenance will be developed as appropriate.
On April 9, 1990, at 1914 EDT, a four hour report of the event was made to the NRC in accordance with 10 CFR 50.72.NAC Tore&1942>


NRC Form 3ddA<983 I LICENSEE NT REPORT (LER)TEXT CONTINUA N U.S.NUCLEAR REGULATORY COMMISSION APPROVEO OMB NO.3150&)04 EXPIAES.Bl31 85 FACILITY NAME 11)OOCKET NUMBEA 12I YEAR LER NUMBER ld)SEOVSNTIAL h~Mi;NVMSSR REVISION NVMSSR PAGE 13)TURKEY POINT UNIT 4 TEXT N more speciis reh)virid, use edChsiorhei HAC Form 38M's)l)T)I.EVENT DESCRIPTION o s o o o 0 0 3 0002 OF 0 4 On April 9, 1990 at 1814 Eastern Daylight Time (EDT), with Unit 4 in Mode 1 (Power Operations) at 100 percent power, a Reactor Protection System (EIIS:JC)actuation occurred causing a reactor trip.The trip was due to a failure of Reactor Coolant Pump underfrequency relay 4B2 (EIIS:AB Component:81).
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The underfrequency relay monitors the 4B 4160 volt bus (EIIS:EB Component:BU) for frequency and trips the 4B and 4C Reactor Coolant Pumps (EIIS:AB Component:P) when an underfrequency condition of 56.1 Hertz or less is sensed by one of two relays.Review of recorded frequency information indicated that no underfrequency condition existed at the time of the trip.The reactor trip occurred when of one of three reactor coolant pump breakers (EIIS:AB Component:BRK) opened with the reactor at greater than 45 percent power.After the trip, pressurizer level declined to a level resulting in letdown isolation.
Volume Control Tank (VCT)(EIIS:CB Component:TK) level declined to an indicated 5 percent level.As a result, the following occurred: Charging pump (EIIS:CB Component:P)"B" was started but tripped soon after starting.Charging pump suction did not switch automatically from the VCT to the Refueling Water Storage Tank (RWST)(EIIS:BP Component:TK)
.The transfer of charging pump suction from the VCT to the RWST was made manually.After a successful second attempt at starting the"B" charging pump, all three charging pumps were used to restore pressurizer level.Letdown was then restored.At 1845 EDT, with the unit stabilized in Mode 3 (Hot Shutdown), Control room personnel transferred from use of the Emergency Operating Procedures to General Operating Procedure 4-GOP-103,"Power Operation to Hot Standby." At 1914 EDT, a four hour report of the event was made to the NRC in accordance with 10 CFR 50.72.II.EVENT CAUSE The cause of the trip was the internal failure of an underfrequency relay.A capacitor (EIIS:AB Component:CAP) ih the relay's power supply failed causing the relay to change to the tripped position.This relay trip caused the trip of the supply breakers to the 4B and 4C Reactor Coolant Pumps which resulted in a Reactor Protection System trip of the reactor.NRC FORM SddA 19 83)


NAC form 366A I9431 LICENSEE ENT REPORT (LER)TEXT CONTINUA I ON U.S.NUCLEAR REGULATORY COMMISSION APPAOVEO OMB NO 3150mTICS EXPIRES;Bl31 85 FACILITY NAME 11)COCKET NUMBER 13)LER NUMBER l61 SEGVENTIAL NUMBER REVISION NVMBEA PAGE 131 TURKEY POINT UNIT 4 TEXT III moro spsseis rerrrrired, use eddin'encl HRC Form 3NA'sl lltl o s o o o 2 0 0 3 0 0 0 3 QF 0 4 III.EVENT SAFETY ANALYSIS Reactor Trip The failed underfrequency relay was part of a one out of two logic.If any of four underfrequency relays fail in a manner similar to that which occurred on April 9, the result is a reactor trip.A reactor trip from 100 percent power is a previously analyzed event.Since the reactor trip response occurred as designed, there was no impact on the'ealth or safety of plant personnel or the general public.2.Reduced Charging Flow.Loss of charging flow is a previously analyzed event that is covered by Emergency Operating Procedures.
P.. ox14000,Juno Beach,FL 33408 0420
In accordance with these procedures, the suction of the charging pumps was transferred from the VCT to the RWST.Charging was established and pressurizer program level was restored.Therefore there was no impact on the health or safety of plant personnel or the general public.This Licensee Event Report is submitted in accordance with 10 CFR 50.73 (a)(2)(iv).IV.CORRECTIVE ACTIONS Reactor Trip: The failed General Electric model 12SFF18C1A undervoltage relay has been replaced with a newer model 12SFF31D1A.
                                                  ~AY Os    tSBO L-90-143 10 CFR 50.73 U.,S. Nuclear Regulatory Commission Attn:  Document Control Desk Washington, D. C.                20555 Gentlemen:
The installed model is no longer available.
Re:    Turkey Point Unit              4 Docket No 50-251~
The new model is a direct replacement which can be installed into the original case.The 12SFF18C1A and 12SFF23C1A reactor coolant pump underfrequency relays have been replaced on both Unit 3 and 4 with new 12SFF31D1A models.Due to apparent end-of-life internal component failure an appropriate maintenance program will be developed by September 1, 1990 to reduce the probability of relay or capacitor failure.NAC FORM 366A (9 831 NRC Form SddA (S 4131 LICENSEE EVENT REPORT (LER)TEXT CONTINUATION U.S.NUCI.EAR REGULATORY COMMISSION APPAOVEO OMB NO.3(50M(04 EXPIRES.6/31'85 FACILITY NAME (11 TURKEY POINT UNZT 4 DOCKET NUMBER (21 osooo251 LER NUMBER (6)YEAR ggv SEGVSNTIAL S+>?REVISION NVMBSA'NVMSSA 9 0-0 0 3-0 0 I'AGE (31 4 OF 0 4 TEXT N'more spaceis required.use eddieorIe/NRC Farm SSSA'si (171 2.Reduced Charging Flow The effected VCT level transmitter (LT)was repaired and LT 112 and 115 were recalibrated to provide for the automatic transfer of charging pump suction from the VCT to the RWST based upon low VCT level.Calibration of the Unit 3 VCT level transmitters was accomplished during the 1990 spring refueling outage.The root cause of this failure is under investigation.
Reportable Event: 90-003 Date of Event: April 9, 1990 Unit Tri Due to Underfre uenc      Rela Failure The attached Licensee Event Report is being provided pursuant to the requirements, of 10 CFR 50.73 for notification of the subject event.
The evaluation will be complete and corrective action will be determined by July 15, 1990.V.ADDZTZONAL ZNFORMATZON Previous Events Similar trips due to the malfunction of underfrequency relays have occurred at Turkey Point in the past.Three trips occurred in late 1978;two on Unit 3 and one on Unit 4.In all three cases no relay failure mode was found.At that time the three relays were replaced with newer models.Until the failure of the capacitor on April 9 the new models have exhibited no malfunction tendencies.
Very    r ly yqurs, N.
2.Component Failures Underfrequency relay Manufactured by General Electric Model Number 12SFF18C1A NRC FORM Sdd*(9 831}}
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Harris Vic resident Tur y Point Plant Nuclear KNH/DRP/JEK/rat cc:    Stewart D. Ebneter, Regional Administrator, Region II,            USNRC Senior Resident Inspector, USNRC, Turkey Point Plant
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IVIHT OATI tll                        LtA NUMOEA III SSQVSHTIAL                                    OAY      YEAA                <<ACILI'TY HAtrto                    OOCXET HUMSIAISI MONT  tr  OAV        YfAA      VEAA            Hutrst 1            ~ rttsrsth 0    5    0      0    0 0 4      099 09                    0        0        0 3              0005              0 8      9 0
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HAMf                                                                                                                                                            TELE<<>tOHE HUMSEA AAIA CODE David R. Powel 1, Licensin                                    Su      erintendent                                30 524 6- 655 COMPLETE ONE        I,INI OOA tACK COAMONENT SAILUAI DISCI>ISO IN TH>S At<<OAT 1121 MANU>tAC              EOOATASLE                                              COMOONEHT MANU<<AC.            EOOATAIL CAUSE    SYSTEM        COMOOHEHT                                                                            SYSTEM                            TUN IA            TO AMOS            .o'%O TUAIA              To HOODS                                                                                                                J +
X    A      8        C    A P      G080 SV<<<<LEMINTAL AE<<OAT EX<<ECTED              l>A>                                                                        MOHTtr        OAY      YEA<<
EX<<ECTED SUISSISSION DATE  lll>
Ytl Ilt yrr. rt<<i<<toto tX<<tCTto SIISAIISSIOht OATtl AIITAAcTIL<<rK to Iooo At<<ca. t A. sooiorrrtsaty          he>orts o<<Nsoosco tyooovt tao hors)    IIII On      April            9, 1990                  at 1814 EDT, with Unit 4 in Mode 1 (Power Operation)                      at      100        percent power, a Reactor Protection System actuation occurred due to a failure of a Reactor Coolant Pump (RCP) underfrequency relay power supply capacitor.
The reactor trip occurred because one of three reactor coolant pump power supply breakers opened with the reactor at greater than 45 percent power. The faulty underfrequency                                                                        'he              re'lay was replaced                and          Unit            4    was        returned          to      serv'ce.                                RCP        power supply            underfrequency                                relays          on  'both        Unit        3    and        Unit          4      have been replaced                            with        new      models.              A  review          of        the      failure                modes of the replacement relays will be performed and planned maintenance will be developed as appropriate.
On April 9, 1990, at 1914 EDT, a four hour report of the event was made to the NRC in accordance with 10 CFR 50.72.
NAC Tore 1942>
 
NRC Form 3ddA                                                                                                    U.S. NUCLEAR REGULATORY COMMISSION
<983 I LICENSEE                 NT REPORT (LER) TEXT CONTINUA       N                APPROVEO OMB NO. 3150&)04 EXPIAES. Bl31 85 FACILITY NAME 11)                                                          OOCKET NUMBEA 12I            LER NUMBER ld)                  PAGE 13)
YEAR    SEOVSNTIAL  h~Mi; REVISION NVMSSR          NVMSSR TURKEY POINT UNIT 4                            o  s  o  o  o              0 0 3              0002          OF    0 4 TEXT N more speciis reh)virid, use edChsiorhei HAC Form 38M's) l)T)
I.            EVENT DESCRIPTION On      April          9, 1990 at 1814 Eastern Daylight Time (EDT), with Unit          4  in Mode 1 (Power Operations) at 100 percent power, a Reactor Protection System (EIIS:JC) actuation occurred causing a reactor trip. The trip was due to a failure of Reactor Coolant Pump underfrequency relay 4B2 (EIIS:AB Component:81).                          The underfrequency relay monitors the 4B 4160          volt      bus        (EIIS:EB Component:BU) for frequency and trips the        4B and 4C              Reactor Coolant Pumps (EIIS:AB Component:P) when an underfrequency condition of 56.1 Hertz or less is sensed by one of two relays. Review of recorded frequency information indicated that no underfrequency condition existed at the time of the trip. The reactor trip occurred when of one of three reactor coolant pump breakers (EIIS:AB Component:BRK) opened with the reactor at greater than 45 percent power.
After the trip, pressurizer level declined to a level resulting in letdown isolation. Volume Control Tank (VCT) (EIIS:CB Component:TK) level declined to an indicated 5 percent level. As a result, the following occurred:
Charging pump (EIIS:CB Component:P) "B" was started but tripped soon after starting. Charging pump suction did not switch automatically from the VCT to the Refueling Water Storage Tank (RWST) (EIIS:BP Component:TK) . The transfer of charging pump suction from the VCT to the RWST was made manually. After a successful second attempt at starting the "B" charging pump, all three charging pumps were used to restore pressurizer level. Letdown was then restored. At 1845 EDT, with the unit stabilized in Mode 3 (Hot Shutdown),
Control room personnel transferred from use of the Emergency Operating Procedures to General Operating Procedure 4-GOP-103, "Power Operation to Hot Standby."
At 1914 EDT, a four hour report of the event was made to the NRC in accordance with 10 CFR 50.72.
II.          EVENT CAUSE The cause                  of the trip was the internal failure of an underfrequency relay. A capacitor (EIIS:AB Component:CAP) ih the relay's power supply failed causing the relay to change to the tripped position. This relay trip caused the trip of the supply breakers to the Protection                    4B and 4C Reactor Coolant Pumps            which        resulted      in  a  Reactor                  System trip of the reactor.
NRC FORM SddA 19 83)
 
NAC form 366A                                                                                                      U.S. NUCLEAR REGULATORY COMMISSION I9431 LICENSEE              ENT REPORT (LER) TEXT CONTINUA I ON                      APPAOVEO OMB NO 3150mTICS EXPIRES; Bl31 85 FACILITY NAME 11)                                                           COCKET NUMBER 13)           LER NUMBER l61                     PAGE 131 SEGVENTIAL       REVISION NUMBER       NVMBEA TURKEY POINT UNIT 4                         o   s   o o   o 2           0 0 3           0 0         0 3   QF     0 4 TEXT IIImoro spsseis rerrrrired, use eddin'encl HRC Form 3NA'sl lltl III. EVENT                     SAFETY ANALYSIS Reactor Trip The     failed underfrequency relay was part of a one out of two logic. If any of four underfrequency relays fail in a manner similar to that which occurred on April 9, the result is a reactor trip. A reactor trip from 100 percent power is a previously analyzed event.
Since the reactor trip response occurred as designed, there was no impact on the'ealth or safety of plant personnel or the general public.
: 2.           Reduced Charging Flow.
Loss       of charging flow is a previously analyzed event that is covered by Emergency Operating Procedures.                                           In accordance with these procedures, the suction of the charging pumps was transferred from the VCT to the RWST.           Charging was established and pressurizer program level was restored. Therefore there was no impact on the health or safety of plant personnel or the general public.
This Licensee Event Report is submitted in accordance with 10 CFR 50.73 (a) (2) (iv) .
IV.           CORRECTIVE ACTIONS Reactor Trip:
The       failed       General   Electric       model 12SFF18C1A undervoltage relay has been replaced with a newer model 12SFF31D1A.             The installed model is no longer available. The new model is a direct replacement which can be installed into the original case.                             The 12SFF18C1A and 12SFF23C1A reactor coolant pump underfrequency relays have been replaced on both Unit 3 and 4 with new 12SFF31D1A models.                         Due to apparent end-of-life internal component failure an appropriate maintenance program will be developed by September 1, 1990 to reduce the probability of relay or capacitor failure.
NAC FORM 366A (9 831
 
NRC Form SddA                                                                                                   U.S. NUCI.EAR REGULATORY COMMISSION (S 4131 LICENSEE EVENT REPORT (LER) TEXT CONTINUATION                                     APPAOVEO OMB NO. 3(50M(04 EXPIRES. 6/31'85 FACILITY NAME (11                                                         DOCKET NUMBER (21           LER NUMBER (6)                     I'AGE (31 YEAR ggv SEGVSNTIAL NVMBSA    ' S+>?
REVISION NVMSSA TURKEY POINT UNZT 4                          osooo251              9 0   0     0 3       0       0       4 OF     0 4 TEXT N'more spaceis required. use eddieorIe/NRC Farm SSSA'si (171
: 2.           Reduced Charging Flow The     effected VCT level transmitter (LT) was repaired and LT 112 and 115 were                   recalibrated to provide for the automatic transfer of charging pump suction from the VCT to the RWST based upon low VCT level.                             Calibration of the Unit 3 VCT level transmitters was accomplished during the 1990 spring refueling outage. The root cause of this failure is under investigation.                                     The evaluation will be complete and corrective action will be determined by July 15, 1990.
V.           ADDZTZONAL ZNFORMATZON Previous Events Similar trips due to the malfunction of underfrequency relays have occurred at Turkey Point in the past.
Three trips occurred in late 1978; two on Unit 3 and one on Unit 4. In all three cases no relay failure mode was found. At that time the three relays were replaced with newer models. Until the failure of the capacitor on April 9 the new models have exhibited no malfunction tendencies.
: 2.           Component             Failures Underfrequency relay Manufactured by General                   Electric Model Number 12SFF18C1A NRC FORM Sdd*
(9 831}}

Latest revision as of 21:54, 3 February 2020

LER 90-003-02:on 900409,reactor Protection Sys Actuation Occurred Due to Failure of Reactor Coolant Pump Underfrequency Relay Power Supply Capacitor.Caused by Open Supply Breakers.Relay replaced.W/900508 Ltr
ML17348A239
Person / Time
Site: Turkey Point NextEra Energy icon.png
Issue date: 05/08/1990
From: Harris K, Dawn Powell
FLORIDA POWER & LIGHT CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-90-143, LER-90-003-02, LER-90-3-2, NUDOCS 9005160071
Download: ML17348A239 (10)
v • d • e


Text

ACCELERATED DHUBUTION DEMONSTIZION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9005160071 DOC.DATE: 90/05/08 NOTARIZED: NO DOCKET FACIL:50-251 Turkey Point Plant, Unit 4, Florida Power and Light C 05000251 AUTH. NAME AUTHOR AFFILIATION POWELL, D. R. Florida Power & Light Co.

HARRIS,K.N. Florida Power & Light Co.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 90-003-02:on 900409,unit trip due to under frequency relay failure.

W/9 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ! ENCL 1 SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-2 LA 1 1 PD2-2 PD 1 1 EDISON,G 1 1 INTERNAL: ACNW 2 2 AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DS P 2 2 DEDRO 1 1 NRR/DET/ECMB 9H 1 1 NRR/DET/EMEB9H3 1 1 NRR/DLPQ/LHFB11 1 1 NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB11 1 1 NRR/DREP/PRPB11 2 2 NRR/DST/SELB SD 1 1 NRR/DST/SICB 7E 1 1 NRR DST SPLBSD1 1 1 NRR/DST/SRXB SE 1 1 a 1 1 RES/DSIR/EIB 1 1 RGN2 FILE 01 1 1 EXTERNAL EG&G STUART I V A 4 4 L ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC MAYS,G 1 1 NSIC MURPHY,G.A 1 1 NUDOCS FULL TXT 1 1 NOTE TO ALL "RIDS" RECIPIEhHS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 34 ENCL 34

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P.. ox14000,Juno Beach,FL 33408 0420

~AY Os tSBO L-90-143 10 CFR 50.73 U.,S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Gentlemen:

Re: Turkey Point Unit 4 Docket No 50-251~

Reportable Event: 90-003 Date of Event: April 9, 1990 Unit Tri Due to Underfre uenc Rela Failure The attached Licensee Event Report is being provided pursuant to the requirements, of 10 CFR 50.73 for notification of the subject event.

Very r ly yqurs, N.

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Harris Vic resident Tur y Point Plant Nuclear KNH/DRP/JEK/rat cc: Stewart D. Ebneter, Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, Turkey Point Plant

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IVIHT OATI tll LtA NUMOEA III SSQVSHTIAL OAY YEAA <<ACILI'TY HAtrto OOCXET HUMSIAISI MONT tr OAV YfAA VEAA Hutrst 1 ~ rttsrsth 0 5 0 0 0 0 4 099 09 0 0 0 3 0005 0 8 9 0

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HAMf TELE<<>tOHE HUMSEA AAIA CODE David R. Powel 1, Licensin Su erintendent 30 524 6- 655 COMPLETE ONE I,INI OOA tACK COAMONENT SAILUAI DISCI>ISO IN TH>S At<<OAT 1121 MANU>tAC EOOATASLE COMOONEHT MANU<<AC. EOOATAIL CAUSE SYSTEM COMOOHEHT SYSTEM TUN IA TO AMOS .o'%O TUAIA To HOODS J +

X A 8 C A P G080 SV<<<<LEMINTAL AE<<OAT EX<<ECTED l>A> MOHTtr OAY YEA<<

EX<<ECTED SUISSISSION DATE lll>

Ytl Ilt yrr. rt<<i<<toto tX<<tCTto SIISAIISSIOht OATtl AIITAAcTIL<<rK to Iooo At<<ca. t A. sooiorrrtsaty he>orts o<<Nsoosco tyooovt tao hors) IIII On April 9, 1990 at 1814 EDT, with Unit 4 in Mode 1 (Power Operation) at 100 percent power, a Reactor Protection System actuation occurred due to a failure of a Reactor Coolant Pump (RCP) underfrequency relay power supply capacitor.

The reactor trip occurred because one of three reactor coolant pump power supply breakers opened with the reactor at greater than 45 percent power. The faulty underfrequency 'he re'lay was replaced and Unit 4 was returned to serv'ce. RCP power supply underfrequency relays on 'both Unit 3 and Unit 4 have been replaced with new models. A review of the failure modes of the replacement relays will be performed and planned maintenance will be developed as appropriate.

On April 9, 1990, at 1914 EDT, a four hour report of the event was made to the NRC in accordance with 10 CFR 50.72.

NAC Tore 1942>

NRC Form 3ddA U.S. NUCLEAR REGULATORY COMMISSION

<983 I LICENSEE NT REPORT (LER) TEXT CONTINUA N APPROVEO OMB NO. 3150&)04 EXPIAES. Bl31 85 FACILITY NAME 11) OOCKET NUMBEA 12I LER NUMBER ld) PAGE 13)

YEAR SEOVSNTIAL h~Mi; REVISION NVMSSR NVMSSR TURKEY POINT UNIT 4 o s o o o 0 0 3 0002 OF 0 4 TEXT N more speciis reh)virid, use edChsiorhei HAC Form 38M's) l)T)

I. EVENT DESCRIPTION On April 9, 1990 at 1814 Eastern Daylight Time (EDT), with Unit 4 in Mode 1 (Power Operations) at 100 percent power, a Reactor Protection System (EIIS:JC) actuation occurred causing a reactor trip. The trip was due to a failure of Reactor Coolant Pump underfrequency relay 4B2 (EIIS:AB Component:81). The underfrequency relay monitors the 4B 4160 volt bus (EIIS:EB Component:BU) for frequency and trips the 4B and 4C Reactor Coolant Pumps (EIIS:AB Component:P) when an underfrequency condition of 56.1 Hertz or less is sensed by one of two relays. Review of recorded frequency information indicated that no underfrequency condition existed at the time of the trip. The reactor trip occurred when of one of three reactor coolant pump breakers (EIIS:AB Component:BRK) opened with the reactor at greater than 45 percent power.

After the trip, pressurizer level declined to a level resulting in letdown isolation. Volume Control Tank (VCT) (EIIS:CB Component:TK) level declined to an indicated 5 percent level. As a result, the following occurred:

Charging pump (EIIS:CB Component:P) "B" was started but tripped soon after starting. Charging pump suction did not switch automatically from the VCT to the Refueling Water Storage Tank (RWST) (EIIS:BP Component:TK) . The transfer of charging pump suction from the VCT to the RWST was made manually. After a successful second attempt at starting the "B" charging pump, all three charging pumps were used to restore pressurizer level. Letdown was then restored. At 1845 EDT, with the unit stabilized in Mode 3 (Hot Shutdown),

Control room personnel transferred from use of the Emergency Operating Procedures to General Operating Procedure 4-GOP-103, "Power Operation to Hot Standby."

At 1914 EDT, a four hour report of the event was made to the NRC in accordance with 10 CFR 50.72.

II. EVENT CAUSE The cause of the trip was the internal failure of an underfrequency relay. A capacitor (EIIS:AB Component:CAP) ih the relay's power supply failed causing the relay to change to the tripped position. This relay trip caused the trip of the supply breakers to the Protection 4B and 4C Reactor Coolant Pumps which resulted in a Reactor System trip of the reactor.

NRC FORM SddA 19 83)

NAC form 366A U.S. NUCLEAR REGULATORY COMMISSION I9431 LICENSEE ENT REPORT (LER) TEXT CONTINUA I ON APPAOVEO OMB NO 3150mTICS EXPIRES; Bl31 85 FACILITY NAME 11) COCKET NUMBER 13) LER NUMBER l61 PAGE 131 SEGVENTIAL REVISION NUMBER NVMBEA TURKEY POINT UNIT 4 o s o o o 2 0 0 3 0 0 0 3 QF 0 4 TEXT IIImoro spsseis rerrrrired, use eddin'encl HRC Form 3NA'sl lltl III. EVENT SAFETY ANALYSIS Reactor Trip The failed underfrequency relay was part of a one out of two logic. If any of four underfrequency relays fail in a manner similar to that which occurred on April 9, the result is a reactor trip. A reactor trip from 100 percent power is a previously analyzed event.

Since the reactor trip response occurred as designed, there was no impact on the'ealth or safety of plant personnel or the general public.

2. Reduced Charging Flow.

Loss of charging flow is a previously analyzed event that is covered by Emergency Operating Procedures. In accordance with these procedures, the suction of the charging pumps was transferred from the VCT to the RWST. Charging was established and pressurizer program level was restored. Therefore there was no impact on the health or safety of plant personnel or the general public.

This Licensee Event Report is submitted in accordance with 10 CFR 50.73 (a) (2) (iv) .

IV. CORRECTIVE ACTIONS Reactor Trip:

The failed General Electric model 12SFF18C1A undervoltage relay has been replaced with a newer model 12SFF31D1A. The installed model is no longer available. The new model is a direct replacement which can be installed into the original case. The 12SFF18C1A and 12SFF23C1A reactor coolant pump underfrequency relays have been replaced on both Unit 3 and 4 with new 12SFF31D1A models. Due to apparent end-of-life internal component failure an appropriate maintenance program will be developed by September 1, 1990 to reduce the probability of relay or capacitor failure.

NAC FORM 366A (9 831

NRC Form SddA U.S. NUCI.EAR REGULATORY COMMISSION (S 4131 LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPAOVEO OMB NO. 3(50M(04 EXPIRES. 6/31'85 FACILITY NAME (11 DOCKET NUMBER (21 LER NUMBER (6) I'AGE (31 YEAR ggv SEGVSNTIAL NVMBSA ' S+>?

REVISION NVMSSA TURKEY POINT UNZT 4 osooo251 9 0 0 0 3 0 0 4 OF 0 4 TEXT N'more spaceis required. use eddieorIe/NRC Farm SSSA'si (171

2. Reduced Charging Flow The effected VCT level transmitter (LT) was repaired and LT 112 and 115 were recalibrated to provide for the automatic transfer of charging pump suction from the VCT to the RWST based upon low VCT level. Calibration of the Unit 3 VCT level transmitters was accomplished during the 1990 spring refueling outage. The root cause of this failure is under investigation. The evaluation will be complete and corrective action will be determined by July 15, 1990.

V. ADDZTZONAL ZNFORMATZON Previous Events Similar trips due to the malfunction of underfrequency relays have occurred at Turkey Point in the past.

Three trips occurred in late 1978; two on Unit 3 and one on Unit 4. In all three cases no relay failure mode was found. At that time the three relays were replaced with newer models. Until the failure of the capacitor on April 9 the new models have exhibited no malfunction tendencies.

2. Component Failures Underfrequency relay Manufactured by General Electric Model Number 12SFF18C1A NRC FORM Sdd*

(9 831

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