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| | issue date = 12/15/1998 | | | issue date = 12/15/1998 |
| | title = LER 98-007-00:on 981116,unplanned ESF Following Loss of 4kV Unit Board 3B Occurred.Caused by Temporary Energization of Lockout Relay on 4kV Unit Board 3B When Resistor on Relay Monitoring Lamp Circuit Shorted.Replaced Resistor | | | title = LER 98-007-00:on 981116,unplanned ESF Following Loss of 4kV Unit Board 3B Occurred.Caused by Temporary Energization of Lockout Relay on 4kV Unit Board 3B When Resistor on Relay Monitoring Lamp Circuit Shorted.Replaced Resistor |
| | author name = MORRISON G M | | | author name = Morrison G |
| | author affiliation = TENNESSEE VALLEY AUTHORITY | | | author affiliation = TENNESSEE VALLEY AUTHORITY |
| | addressee name = | | | addressee name = |
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| {{#Wiki_filter:NRC FORM 366 (6-1996)U.S.NUCLEAR REGULATORY COMMISSION LICENSEE EVENT.REPORT (LER)(See reverse for required number of digits/characters for each block)APPROVED BY OMB NO.3150.0104 ExPIREsoersor2oot Esbmated burden per response to comply with this mandatory hformstion cosection request: 50 hrs.Reported lessons learned are incorporated into the licensing process end fed back to industry.Forward comments regarding burden estimate to the Records Management Branch (T<F33), V.S, Nuc(ear Regulatory Commission, Washington, DC 2055$0001, and to the Paperwork Reduction Project (3(500104), Office of Management and Budget, Washington, OC 20503.If an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person Is not required to respond to, the information co(lect(oIL FACIUTY NAME (I)Browns Ferry Nuclear Plant TITLE (4)Unplanned ESF Following the Loss of 4kV Unit Board 3B DOCKET NUMBER (2)05000296 PAGE (3)10f 6 EVENT DATE (5)LER NUMBER (6I REPORT DATE (7)OTHER FACILITIES INVOLVED (8)MONTH OAY YEAR 16 1998 YEAR SEQUENTIAL REVISION NUMBER NUMBER 1998-007-000 MONTH 12 DAY 15 1998 FACIUTY NAME NA DOCKET NUMBER 05000 OOCKETNUMBER 05000 OPERATING MODE (9)POWER LEVEL (10)100 20.2201(b) 20.2203(a)(1) 20.2203(a) | | {{#Wiki_filter:NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150.0104 ExPIREsoersor2oot (6-1996) Esbmated burden per response to comply with this mandatory hformstion cosection request: 50 hrs. Reported lessons learned are incorporated into the licensing process end fed back to industry. Forward comments regarding LICENSEE EVENT. REPORT (LER) burden estimate to the Records Management Branch (T< F33), V.S, Nuc(ear Regulatory Commission, Washington, DC 2055$ 0001, and to the Paperwork Reduction Project (3(500104), Office of Management and (See reverse for required number of Budget, Washington, OC 20503. If an information collection does not digits/characters for each block) display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person Is not required to respond to, the information co(lect(oIL FACIUTY NAME (I) DOCKET NUMBER (2) PAGE (3) |
| (2)(i)20.2203(a)(2)(ii) 20.2203(a)(2)(iii) 20.2203(a)(2)(v)20.2203(a) | | Browns Ferry Nuclear Plant 05000296 10f 6 TITLE (4) |
| (3)(i)20.2203(a) | | Unplanned ESF Following the Loss of 4kV Unit Board 3B EVENT DATE (5) LER NUMBER (6I REPORT DATE (7) OTHER FACILITIES INVOLVED (8) |
| (3)(ii)20.2203(a) | | MONTH OAY YEAR YEAR SEQUENTIAL REVISION MONTH DAY FACIUTY NAME DOCKET NUMBER NUMBER NUMBER NA 05000 OOCKETNUMBER 16 1998 1998 007 000 12 15 1998 05000 OPERATING THIS REPORT IS SUBMITTED PURSUA NT To THE REQUIREMENTS OF 10 CFR rn (Check one or more) (11) |
| (4)50.36(c)(1) 50.73(a)(2)(i) 50.73(a)(2)(ii)50.73(a)(2)(iii)50.73(a)(2)(iv)50.73(a)(2)(v) 50.73(a)(2)(viii)50.73 (a)(2)(x)73.71 OTHER Specify in Abstract below or In NRC Form 366A NT To THE REQUIREMENTS OF 10 CFR rn (Check one or more)(11)THIS REPORT IS SUBMITTED PURSUA 20.2203(a) | | MODE (9) 20.2201(b) 20. 2203(a) (2)(v) 50.73(a)(2)(i) 50.73(a)(2) (viii) |
| (2)(iv)50.36(c)(2)LICENSEE CONTACT FOR THIS LER (12)50.73(a)(2)(vii) | | POWER 20.2203(a)(1) 20.2203(a) (3)(i) 50.73(a) (2) (ii) 50.73 (a) (2) (x) |
| NAME G.M.Morrison, Senior Licensing Project Manger TELEPHONE NUMBER (Include Ares Code)256.729.7534 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)CAUSE SYSTEM EA COMPONENT IL MANUFACTURER G080 REPORTABLE TO NPRDS))I.:+X%M CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE TO NPROS SUPPLEMENTAL REPORT EXPECTED (14)YES (If yes, complete EXPECTED SUBMISSION DATE).X NO EXPECTED SUBMISSION DATE (15)'MONTH OAY YEAR ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)(16)At 1435 CST on November 16, 1998, the supply to 4kV Unit Board 3B deenergized due to a fault protection lockout.4kV Unit Board 3B supplies power to the Division II 4kV Shutdown Boards 3EC and 3ED.The loss of voltage caused the 3C and 3D Diesel Generators to start and tie to their respective shutdown boards.The transient loss of the shutdown boards caused Reactor.Protection System (RPS)Bus B to deenergize resulting in a half scram and Primary Containment Isolation System actuations. | | LEVEL (10) 100 20.2203(a) (2) (i) 20.2203(a) (3)(ii) 50.73(a) (2) (iii) 73.71 20.2203(a)(2)(ii) 20.2203(a) (4) 50.73(a) (2) (iv) OTHER 20.2203(a)(2)(iii) 50.36(c)(1) 50.73(a)(2)(v) Specify in Abstract below or In NRC Form 366A 20.2203(a) (2) (iv) 50.36(c) (2) 50.73(a)(2)(vii) |
| The Standby Gas Treatment and Control Room Emergency Ventilation systems initiated as expected due to the RPS power loss.The deenergization of 4kV Unit Board 3B resulted in the loss of its associated loads, the 3B Condensate Booster Pump, 3B Condensate Pump and the 3B Condenser Circulating Water Pump.As expected, the loss of condensate resulted in a Reactor Feed Pump Turbine 3A trip on loss of pump suction pressure.The Reactor Feed Pump Turbine 3A trip along with the resulting low water level initiated a recirculation system runback to 75%full power.The immediate cause of this event was the temporary energization of the lockout relay on 4KV Unit Board 3B when the resistor on the relay monitoring lamp circuit shorted, allowing sufficient current to energize the lockout relay coil.The most probable root cause of this event was physical damage sustained by the relay monitoring lamp circuit voltage dropping resistor during or prior to its last replacement. | | LICENSEE CONTACT FOR THIS LER (12) |
| Corrective actions include personnel briefings and inclusion of this event in the operations and electrical maintenance department training programs.This report is submitted pursuant to 10 CFR 50.73(a)(2)(iv) as an event that resulted in a manual or automatic actuation of engineered safety features.98i22302i2 98i2%5 PDR ADOCK 050002'))6 8 PDR v | | NAME TELEPHONE NUMBER (Include Ares Code) |
| NRC FORM 366A I6-1998)LICENSEE EVENT REPORT (LER)TEXT CONTINUATION U.S.NUCLEAR REGULATORY COMMISSION FACILITY NAME 1 Browne Ferry Nuclear Fiant.-Unit 3 TEXT (If more spece is required, use eddi rionel copies of NRC Form 366A/{17)DOCKET 05000296 LER NUMBER 6 YEAR SEQUENTIAL REVISION NUMBER 1996-007-000 PAGE 3 2of6 I.PLANT CONDITION(S)
| | G.M. Morrison, Senior Licensing Project Manger 256.729.7534 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13) |
| At the time the event occurred, Units 2 and 3 were in Mode 1 at 100 percent power.Unit 1 was shutdown and defueled.II.DESCRIPTION OF EVENT A.Event: At 1435 CST on November'16, 1998, the supply to 4kV Unit Board 3B[EA]deenergized due to a fault protection lockout.4kV,Unit Board 3B supplies power to the Division II 4kV Shutdown Boards 3EC and 3ED[EB].The loss of voltage caused the 3C and 3D Diesel Generators (DG)[EK]to start and tie to their respective shutdown boards.The transient loss of the shutdown boards caused the Reactor Protection System (RPS)[JC]Division II to deenergize resulting in a half scram and Primary Containment Isolation System[JM]actuations for group 2 (primary containment water lines), group 3 (Reactor Water Cleanup), group 6 (primary containment air lines and secondary containment), and group 8 (Traversing Incore Probe).The Standby Gas Treatment (SGT)[BH]and Control Room Emergency Ventilation (CREV)[Vl]systems initiated as expected due to the RPS power loss.The DG starts caused the standby Emergency Equipment Cooling Water[BI]pumps to start.The deenergization of 4kV Unit Board 3B resulted in the loss of its associated loads, the 3B Condensate Booster Pump[SD], 3B Condensate Pump[SD]and the 3B Condenser Circulating Water Pump[KE].As expected, the loss of condensate resulted in a Reactor Feed Pump Turbine (RFPT)3A[SJ]trip on loss of suction pressure.,The RFPT.3A trip along with the resulting low water level provided a 75%recirculation system runback initiation.
| | CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE TO CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE NPRDS TO NPROS EA IL G080 |
| Recovery from the event was completed at 1545 hours CST when Unit 3 reactor power was stabilized at approximately 67%full power.9 This report is submitted pursuant to 10 CFR 50.73(a)(2)(iv) as an event or condition that resulted in a manual or automatic actuation of any Engineered Safety Feature, including the Reactor Protection.
| | ))I.: +X% M SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED 'MONTH OAY YEAR YES X NO SUBMISSION DATE (15) |
| System.B.Ino erable Structures Com onents orS stemsthatContributedto the Event: None.NRC FORM 366 I6-1998) li" NRC FORM 366A I6-1998)LICENSEE EVENT REPORT (LER)TEXT CONTINUATION U;S.NUCLEAR REGULATORY COMMISSION FACILITY NAME 1 Browne Ferry Nuclear Plant-Unit 3 TEXT (Iimore spaceis required, use addirionai copies ofhfRC Form 366A/I17i DOCKET 05000296 LER NUMBER 6 YEAR SEQUENTIAL REVISiQN NUMBER 1998-007-000 PAGE 3 3 of 6 C.Dates and A roximate Times of Ma or Occurrences:
| | (If yes, complete EXPECTED SUBMISSION DATE). |
| November 16, 1998 1435 hours CST Loss of Unit Board 3B received in the main control room.Diesel generators 3C and 3D receive a start signal due to loss of voltage to Shutdown Boards 3EC and 3ED.November 16, 1998 1436 hours CST Recirculation system runback to 75%full power initiated.
| | ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16) |
| November 16, 1998 1545 hours CST Recovery from the event completed.
| | At 1435 CST on November 16, 1998, the supply to 4kV Unit Board 3B deenergized due to a fault protection lockout. 4kV Unit Board 3B supplies power to the Division II 4kV Shutdown Boards 3EC and 3ED. The loss of voltage caused the 3C and 3D Diesel Generators to start and tie to their respective shutdown boards. The transient loss of the shutdown boards caused Reactor. Protection System (RPS) Bus B to deenergize resulting in a half scram and Primary Containment Isolation System actuations. The Standby Gas Treatment and Control Room Emergency Ventilation systems initiated as expected due to the RPS power loss. The deenergization of 4kV Unit Board 3B resulted in the loss of its associated loads, the 3B Condensate Booster Pump, 3B Condensate Pump and the 3B Condenser Circulating Water Pump. As expected, the loss of condensate resulted in a Reactor Feed Pump Turbine 3A trip on loss of pump suction pressure. The Reactor Feed Pump Turbine 3A trip along with the resulting low water level initiated a recirculation system runback to 75% full power. |
| Unit 3 reactor power stabilized at-67%full power.November 16, 1998 1706 hours CST A four-hour non-emergency notification is made to the NRC via the Emergency Notification System pursuant to 10 CFR 50.72(b)(2)(ii).
| | The immediate cause of this event was the temporary energization of the lockout relay on 4KV Unit Board 3B when the resistor on the relay monitoring lamp circuit shorted, allowing sufficient current to energize the lockout relay coil. The most probable root cause of this event was physical damage sustained by the relay monitoring lamp circuit voltage dropping resistor during or prior to its last replacement. Corrective actions include personnel briefings and inclusion of this event in the operations and electrical maintenance department training programs. |
| D.Other S stems or Seconda Functions Affected None.E, Method of Discove The main control room operating crew received alarms associated with the deenergization of 4kV Unit Board 3B.F.0 erator Actions No operator actions contributed to this event.The operator actions in response to the event were proper and in accordance with plant instructions.
| | This report is submitted pursuant to 10 CFR 50.73(a)(2)(iv) as an event that resulted in a manual or automatic actuation of engineered safety features. |
| G.Safet S stem Res onses All safety systems responded as expected.NRC FORM 366 I6-199BI
| | 98i22302i2 98i2%5 PDR ADOCK 050002'))6 8 PDR |
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| NRC FORM 366A (6-I 998)LlCENSEE EVENT REPORT (LER)TEXT CONTINUATION U.S.NUCLEAR REGULATORY COMMISSION FACILITY NAME'Browne Ferry Nuclear Plant-Unit 3 TEXT flf more spece is required, use eddi rionel copies of fVRC Form 366AJ I 17)DQGKET 05000296 LER NUMBER 6 YEAR SEQUENTIAL REVISiON NUMBER 1998-007-000 PAGE 3 4of6 III.CAUSE OF THE EVENT A.Immediate Cause The immediate cause of this event was the temporary energization of the lockout relay on 4KV Unit Board 3B when the resistor in the relay monitoring lamp circuit shorted, allowing sufficient current flow to energize the lockout relay coil.B.Root Cause The most probable root cause of this event was physical damage sustained by the relay monitoring lamp circuit voltage dropping resistor during or prior to its last replacement.(Infrequent resistor failures necessitate replacement.) | | v NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION I6-1998) |
| The insulating material between the resistor anode and cathode is a glass composite.
| | LICENSEE EVENT REPORT (LER) |
| The resistor is installed in the lamp circuit via a push/twist receptacle. | | TEXT CONTINUATION FACILITY NAME 1 DOCKET LER NUMBER 6 PAGE 3 YEAR SEQUENTIAL REVISION NUMBER 2of6 Browne Ferry Nuclear Fiant.- Unit 3 05000296 1996 - 007 000 TEXT (If more spece is required, use eddi rionel copies of NRC Form 366A/ {17) |
| It was concluded that the most likely scenario is that the glass insulation was damaged from a pre-installation impact and continued to degrade from panel vibration and holder spring tension until the short occurred.The failed resistor is shown on Figure 1.C.Contributin Factors None.IV.ANALYSIS OF THE EVENT The event was uncomplicated operationally.
| | I. PLANT CONDITION(S) |
| The half-scram occurred due to the loss of power to RPS Bus 3B.A full-scram was not initiated because RPS Bus 3A remained energized throughout the event.The only impact of this event on Units 1 and 2 were Refuel Zone isolations and the autostart of the SGT and CREV systems which are expected responses to the loss of RPS Bus 3B.Operations personnel immediately recognized the cause of the ESF actuation and took appropriate actions in accordance with plant procedures.
| | At the time the event occurred, Units 2 and 3 were in Mode 1 at 100 percent power. Unit 1 was shutdown and defueled. |
| Proper communications and coordination took place between the Operations personnel in the Units 1, 2, and 3 control rooms.The initiations and actuations/isolations were consistent with the loss of RPS Bus 3B.V.ASSESSMENT OF THE SAFETY CONSEQUENCES There were no actual or potential safety consequences as a result of this event.The failed lamp circuit voltage dropping resistor which initiated this event does not perform a safety function.Plant safety systems performed as designed, operator actions were in accordance with plant procedures, and no other potential problems were created by this event.Therefore, this event did not adversely affect the safety of plant personnel or the public.NRC FORM 366{6-1998)
| | II. DESCRIPTION OF EVENT A. Event: |
| | At 1435 CST on November'16, 1998, the supply to 4kV Unit Board 3B [EA] deenergized due to a fault protection lockout. 4kV,Unit Board 3B supplies power to the Division II 4kV Shutdown Boards 3EC and 3ED [EB]. The loss of voltage caused the 3C and 3D Diesel Generators (DG) [EK] to start and tie to their respective shutdown boards. The transient loss of the shutdown boards caused the Reactor Protection System (RPS) [JC] Division II to deenergize resulting in a half scram and Primary Containment Isolation System [JM] actuations for group 2 (primary containment water lines), group 3 (Reactor Water Cleanup), group 6 (primary containment air lines and secondary containment), and group 8 (Traversing Incore Probe). The Standby Gas Treatment (SGT) [BH] and Control Room Emergency Ventilation (CREV) [Vl]systems initiated as expected due to the RPS power loss. The DG starts caused the standby Emergency Equipment Cooling Water [BI] pumps to start. |
| | The deenergization of 4kV Unit Board 3B resulted in the loss of its associated loads, the 3B Condensate Booster Pump [SD], 3B Condensate Pump [SD] and the 3B Condenser Circulating Water Pump [KE]. As expected, the loss of condensate resulted in a Reactor Feed Pump Turbine (RFPT) 3A [SJ] trip on loss of suction pressure.,The RFPT. 3A trip along with the resulting low water level provided a 75% |
| | recirculation system runback initiation. Recovery from the event was completed at 1545 hours CST when Unit 3 reactor power was stabilized at approximately 67% full power. |
| | 9 This report is submitted pursuant to 10 CFR 50.73(a)(2)(iv) as an event or condition that resulted in a manual or automatic actuation of any Engineered Safety Feature, including the Reactor Protection. |
| | System. |
| | B. Ino erable Structures Com onents orS stemsthatContributedto the Event: |
| | None. |
| | NRC FORM 366 I6-1998) |
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| NRC FORM 366A IS-1998I LICENSEE EVENT REPORT (LER)TEXT CONTINUATION U.S.NUCLEAR REGULATORY COMMiSSiON FACILITY NAME 1 Browne Ferry Nuclear Plant-Unit 3 TEXT llf more space is required, use,addirional copies of ftfRC Form 366Al i17)DOCKET 05000296 LER NUMBER 6 YEAR SEQUENTIAL REVISION NUMBER 1 998-007-000 PAGE 3 5 or 6 VI.CORRECTIVE ACTIONS A.Immediate Corrective Actions Electrical troubleshooting was performed which identified the damaged resistor in the in the 4kV Unit Board 3B lockout relay monitoring lamp circuit: After replacement of the resistor and testing of the relay, 4kV Unit Board 3B was reenergized. | | li" NRC FORM 366A U;S. NUCLEAR REGULATORY COMMISSION I6-1998) |
| B.Corrective Actions to Prevent Recurrence Engineering, Operations, and Maintenance personnel will be briefed on this event'.This event will be added to the lesson plans for Operations Department electrical training'. | | LICENSEE EVENT REPORT (LER) |
| | TEXT CONTINUATION FACILITY NAME 1 DOCKET LER NUMBER 6 PAGE 3 YEAR SEQUENTIAL REVISiQN NUMBER 3 of 6 Browne Ferry Nuclear Plant - Unit 3 05000296 1998 007 000 TEXT (Iimore spaceis required, use addirionai copies ofhfRC Form 366A/ I17i C. Dates and A roximate Times of Ma or Occurrences: |
| | November 16, 1998 1435 hours CST Loss of Unit Board 3B received in the main control room. Diesel generators 3C and 3D receive a start signal due to loss of voltage to Shutdown Boards 3EC and 3ED. |
| | November 16, 1998 1436 hours CST Recirculation system runback to 75% full power initiated. |
| | November 16, 1998 1545 hours CST Recovery from the event completed. Unit 3 reactor power stabilized at -67% full power. |
| | November 16, 1998 1706 hours CST A four-hour non-emergency notification is made to the NRC via the Emergency Notification System pursuant to 10 CFR 50.72(b)(2)(ii). |
| | D. Other S stems or Seconda Functions Affected None. |
| | E, Method of Discove The main control room operating crew received alarms associated with the deenergization of 4kV Unit Board 3B. |
| | F. 0 erator Actions No operator actions contributed to this event. The operator actions in response to the event were proper and in accordance with plant instructions. |
| | G. Safet S stem Res onses All safety systems responded as expected. |
| | NRC FORM 366 I6-199BI |
| | |
| | NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (6- I 998) |
| | LlCENSEE EVENT REPORT (LER) |
| | TEXT CONTINUATION FACILITY NAME' DQGKET LER NUMBER 6 PAGE 3 YEAR SEQUENTIAL REVISiON NUMBER 4of6 Browne Ferry Nuclear Plant - Unit 3 05000296 1998 - 007 - 000 TEXT flfmore spece is required, use eddi rionel copies of fVRC Form 366AJ I 17) |
| | III. CAUSE OF THE EVENT A. Immediate Cause The immediate cause of this event was the temporary energization of the lockout relay on 4KV Unit Board 3B when the resistor in the relay monitoring lamp circuit shorted, allowing sufficient current flow to energize the lockout relay coil. |
| | B. Root Cause The most probable root cause of this event was physical damage sustained by the relay monitoring lamp circuit voltage dropping resistor during or prior to its last replacement. (Infrequent resistor failures necessitate replacement.) The insulating material between the resistor anode and cathode is a glass composite. The resistor is installed in the lamp circuit via a push/twist receptacle. It was concluded that the most likely scenario is that the glass insulation was damaged from a pre-installation impact and continued to degrade from panel vibration and holder spring tension until the short occurred. The failed resistor is shown on Figure 1. |
| | C. Contributin Factors None. |
| | IV. ANALYSIS OF THE EVENT The event was uncomplicated operationally. The half-scram occurred due to the loss of power to RPS Bus 3B. A full-scram was not initiated because RPS Bus 3A remained energized throughout the event. The only impact of this event on Units 1 and 2 were Refuel Zone isolations and the autostart of the SGT and CREV systems which are expected responses to the loss of RPS Bus 3B. Operations personnel immediately recognized the cause of the ESF actuation and took appropriate actions in accordance with plant procedures. |
| | Proper communications and coordination took place between the Operations personnel in the Units 1, 2, and 3 control rooms. The initiations and actuations/isolations were consistent with the loss of RPS Bus 3B. |
| | V. ASSESSMENT OF THE SAFETY CONSEQUENCES There were no actual or potential safety consequences as a result of this event. The failed lamp circuit voltage dropping resistor which initiated this event does not perform a safety function. Plant safety systems performed as designed, operator actions were in accordance with plant procedures, and no other potential problems were created by this event. Therefore, this event did not adversely affect the safety of plant personnel or the public. |
| | NRC FORM 366 {6-1998) |
| | |
| | NRC FORM 366A U.S. NUCLEAR REGULATORY COMMiSSiON IS-1998I LICENSEE EVENT REPORT (LER) |
| | TEXT CONTINUATION FACILITY NAME 1 DOCKET LER NUMBER 6 PAGE 3 YEAR SEQUENTIAL REVISION NUMBER 5 or 6 Browne Ferry Nuclear Plant - Unit 3 05000296 1 998 007 000 TEXT llfmore space is required, use,addirional copies of ftfRC Form 366Al i17) |
| | VI. CORRECTIVE ACTIONS A. Immediate Corrective Actions Electrical troubleshooting was performed which identified the damaged resistor in the in the 4kV Unit Board 3B lockout relay monitoring lamp circuit: After replacement of the resistor and testing of the relay, 4kV Unit Board 3B was reenergized. |
| | B. Corrective Actions to Prevent Recurrence Engineering, Operations, and Maintenance personnel will be briefed on this event'. |
| | This event will be added to the lesson plans for Operations Department electrical training'. |
| This event will be added to the lesson plans for Electrical Maintenance continuing training'. | | This event will be added to the lesson plans for Electrical Maintenance continuing training'. |
| Vi).ADDITIONAL INFORMATION A.Failed Com onents Troubleshooting into the cause of this event revealed a shorted 5100 ohm dropping resistor, General Electric part number 0165A7844P004, in the 4kV Unit Board 3B lockout relay monitoring lamp circuit.The dropping resistor had apparently sustained impact damage during or prior to its last replacement. | | Vi). ADDITIONALINFORMATION A. Failed Com onents Troubleshooting into the cause of this event revealed a shorted 5100 ohm dropping resistor, General Electric part number 0165A7844P004, in the 4kV Unit Board 3B lockout relay monitoring lamp circuit. |
| B.Previous LERs on Similar Events No previous LERs have resulted from relay monitoring lamp circuit voltage dropping resistor failures at Browns Ferry..Vill.COMMITMENTS None.'VA does not consider these corrective actions regulatory commitments. | | The dropping resistor had apparently sustained impact damage during or prior to its last replacement. |
| The, completion of these items will be tracked in TVA's Corrective Action Pro ram.NRc FQRM 366 l6-1998) | | B. Previous LERs on Similar Events No previous LERs have resulted from relay monitoring lamp circuit voltage dropping resistor failures at Browns Ferry.. |
| C~L NRC FORM 366A (6-1998I LICENSEE EVENT REPORT (LER)TEXT CONTINUATION U.S.NUCLEAR REGULATORY COMMISSION FACILITY NAME 1I Browne Ferry NUclear Plant-Unit 3 TEXT (If more space'is required, use additional copies of lVRC Form 366A/(17I DOCKET 05000296 LER NUMBER 6 YEAR SEQUENTIAL REVISION NUMBER 1998-007-000 PAGE 3 6 of 6 Figure 1 Photograph of Failed Relay Monitoring Lamp Circuit Resistor Multiple Indentations On The Anode, Caused From The Varying Angles Of Impact From The Holder Socket Anod Glass Insulation:: | | Vill. COMMITMENTS None. |
| .::s Cath Ode Damage To The Cathode nsulatio rnlsslrl de short Glass i some is the ano cathode n is damaged and g.This resulted in.,'P.':.,'".!''!:.:.":.p':".,'ng to the.'.igQg~r,Ar~ | | 'VAdoes not consider these corrective actions regulatory commitments. The, completion of these items will be tracked in TVA's Corrective Action Pro ram. |
| NRC FORM 366 I6-1999) 0 0 I I}} | | NRc FQRM 366 l6-1998) |
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| | NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (6-1998I LICENSEE EVENT REPORT (LER) |
| | TEXT CONTINUATION FACILITY NAME 1I DOCKET LER NUMBER 6 PAGE 3 YEAR SEQUENTIAL REVISION NUMBER 6 of 6 Browne Ferry NUclear Plant - Unit 3 05000296 1998 007 000 TEXT (If more space'is required, use additional copies of lVRC Form 366A/ (17I Figure 1 Photograph of Failed Relay Monitoring Lamp Circuit Resistor Multiple Indentations On The Anode, Caused From The Varying Angles Of Impact From The Holder Socket Glass Insulation:: .::s Anod Damage To The Cathode Cath Ode Glass i nsulatio n is damaged and some is rnlsslrl g. This resulted in .,'P.':.,'".!''!:.:.":.p':".,'ng the ano de short to the .'. igQg~r,Ar~ |
| | cathode NRC FORM 366 I6-1999) |
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| | 0 0 I I}} |
LER 98-007-00:on 981116,unplanned ESF Following Loss of 4kV Unit Board 3B Occurred.Caused by Temporary Energization of Lockout Relay on 4kV Unit Board 3B When Resistor on Relay Monitoring Lamp Circuit Shorted.Replaced Resistor| ML18039A647 |
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| Site: |
Browns Ferry  |
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| Issue date: |
12/15/1998 |
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| From: |
Morrison G
TENNESSEE VALLEY AUTHORITY |
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| To: |
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| Shared Package |
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| ML18039A646 |
List: |
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| References |
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| LER-98-007, LER-98-7, NUDOCS 9812230212 |
| Download: ML18039A647 (12) |
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Category:LICENSEE EVENT REPORT (SEE ALSO AO
MONTHYEARML18039A9041999-10-15015 October 1999
LER 99-010-00:on 990917,automatic Reactor Scram on Turbine Stop Valve Closure Occurred.Caused by High Water Level in Main Steam Moisture Separator 2C2.Unit 2C2 Reservoir Level Transmitter & Relays Were Replaced & Tested Satisfactorily
ML18039A8981999-10-14014 October 1999
LER 99-009-00:on 990915,manual Reactor Scram Was Noted Due to EHC Leak.Caused by Failure of Stainles Steel Tubing Connection.Removed Damaged Tubing & Connection Plug
ML18039A8951999-10-0808 October 1999
LER 99-008-00:on 990905,HPCI Was Inoperable Due to Failed Flow Controller.Caused by Premature Failure of Capacitor 2C3.Replaced Controller & HPCI Sys Was Run IAW Sys Operating Instructions
ML18039A8751999-09-30030 September 1999
LER 99-005-00:on 990901,SR for Standby Liquid Control Sampling Was Not Met.Caused by Deficient Procedure for Chemical Addition to Standby Liquid Control.Revised Procedure.With 990930 Ltr
ML18039A8201999-07-26026 July 1999
LER 99-004-00:on 990625,facility Core Spray Divisions I & II Inoperable at Same Time Due to Personnel Error.Electrical Supply Breaker to Core Spray Division II Pump 3B Returned to Normal Racked in Position
ML18039A8171999-07-20020 July 1999
LER 99-007-00:on 990623,discovered That SR for Monitoring of Primary Containment Oxygen Concentration Had Not Been Met. Caused by Failure of Operators to Adequately Communicate. Required Surveillances Were Performed.With 990720 Ltr
ML18039A8161999-07-19019 July 1999
LER 99-006-00:on 990618,noted That Main Steam SRV Exceeded TS Setpoint Tolerance.Caused by Pilot Vlve disc-seat Bonding.Util Replaced All 13 SRV Pilot Cartridges with Cartridges Certified to Be Witin +/-1%.With 990719 Ltr
ML18039A8121999-07-12012 July 1999
LER 99-005-00:on 990617,ESF Actuation & HPCI Declared Inoperable.Caused by Personnel Error.Reset HPCI & Returned Sys to Operable Status with 25 Minutes.With 990712 Ltr
ML18039A8101999-06-28028 June 1999
LER 99-004-00:on 990530,safety Features Sys Actuations Occurred Due to RPS Trip.Caused by Failure of MG Set AC Drive Motor Starter Contractor Coil.Licensee Placed 2B RPS Bus on Alternate Feed & Half Scram Was Reset
ML18039A8011999-06-14014 June 1999
LER 99-001-00:on 990515,automatic Reactor Scram Occurred Due to Tt.Caused by Failure of Mechanical Trip Cylinder to Latch When Hydraulically Reset.Operations Crew Stabilized Reactor Following Scram.With 990614 Ltr
ML18039A8021999-06-14014 June 1999
LER 99-002-00:on 990501,SRs for Single CR Withdrawal During Cold SD Were Not Adequately Implemented.Caused by Procedural Inadequacy.Revised Applicable Plant Surveillances.With 990614 Ltr
ML18039A8071999-06-14014 June 1999
LER 99-003-00:on 990515,automatic Reactor Scram Due to Turbine Trip Was Noted.Caused by Failure of Mechanical Trip Cylinder to Latch When Hydraulically Reset.Operations Crew Stabilized Reactor Following Scram
ML18039A7791999-05-0606 May 1999
LER 99-003-00:on 990408,declared Plant HPCI Sys Inoperable Due to Loose Wire.Caused by Failure to Properly Tighten Screw at Some Time in Past.Loose Wire Was Tightened
ML18039A7461999-04-0707 April 1999
LER 99-001-00:on 990308,determined That Two Trains of Standby Gas Treatment (SGT) Were Inoperable.Caused by Trip C SGT Blower Motor Breaker.Initiated Shutdown of Plant,Reset C SGT Blower Motor Breaker & Declared Train Operable
ML18039A6951999-02-19019 February 1999
LER 99-002-00:on 990122,LCO Was Not Entered During Calibration Testing of 3D 480 Volt Rmov Board.Caused by Personnel Error.Tva Has Briefed Operations Personnel to Preclude Recurrence of Event.With 990219 Ltr
ML18039A6871999-02-12012 February 1999
LER 99-001-00:on 990114,Unit 3 HPCI Was Noted Inoperable. Caused by Oil Leak on Stop Valve.Corrective Maint Was Performed to Repair Oil Leak.With 990212 Ltr
ML18039A6671998-12-31031 December 1998
LER 98-004-00:on 981202,SR Intent Was Not Adequately Implemented.Caused by Procedural Inadequacy.Revised Procedures to Provide Proper SR Implementation.With 981231 Ltr
ML18039A6471998-12-15015 December 1998
LER 98-007-00:on 981116,unplanned ESF Following Loss of 4kV Unit Board 3B Occurred.Caused by Temporary Energization of Lockout Relay on 4kV Unit Board 3B When Resistor on Relay Monitoring Lamp Circuit Shorted.Replaced Resistor
ML18039A6371998-12-0707 December 1998
LER 98-006-00:on 981116,MSSR Valves Exceeded TS Setpoint Tolerance.Caused by Pilot Valve Disc/Seat Bonding. Installed SRV Pressure Switches During Unit 3,cycle 8 Outage.With 981207 Ltr
ML18039A6071998-11-12012 November 1998
LER 98-005-00:on 981014,mode Changes Not Allowed by TS 3.0.4 Were Made During Reactor Startup.Caused by TS LCO 3.0.4 Not Being Properly Applied.Training Info Memo Re Proper Application for TS LCO 3.0.4 Was Prepared.With 981112 Ltr
ML18039A6031998-11-0404 November 1998
LER 98-004-00:on 981007,primary Containment Allowable Leak Rate Was Exceeded.Caused by Failure of Check Valve to Fully Seat Following Shutdown of Rbbccw Sys for Llrt.Valve Was Retested During Next Refueling Outage.With 981104 Ltr
ML18039A5971998-10-28028 October 1998
LER 98-003-00:on 981001,Unit 2 Received Full Automatic Scram from 100% Reactor Power.Caused by Failure of Normally Open Isolation Valve Which Blocked Flow of Stator Cooling Water Through Associated Heat Exchangers.Replaced Failed Valve
ML18039A5171998-09-15015 September 1998
LER 98-002-00:on 980816,personnel Observed Both Channels of Rod Block Monitor Sys Bypassed for Cr.Caused by Failure of Gene to Properly Document & Specify Adjustments.Will Implement Necessary Procedure Controls
ML18039A3311998-05-0404 May 1998
LER 98-003-00:on 980407,reactor Manually Scrammed to Prevent thermal-hydraulic Instability After Recirculation Pump Runback.Caused by Human Error.Strengthened Controls Associated W/Walkdowns in NEDP-11
ML18039A3141998-04-0909 April 1998
LER 98-002-00:on 980310,ESF Actuation Occurred Due to Failure of Alternate Feeder Breaker Position Switch.Will Continue Testing & Visual Insps on Addl Breaker Position Switches & Will Revise Applicable Maint Instructions
ML18039A3101998-04-0707 April 1998
LER 98-001-00:on 980308,ESF Actuations Occurred When 2B RPS Bus Was Transferred to de-energized Source.Caused by Failure of Preparing Clearance to Exercise Proper Attention. 2B RPS Bus Restored to Transformer Source
ML18039A3051998-04-0101 April 1998
LER 96-001-00:on 980121,determined That Temp Sensors for Certain HELB May Not Detect All Possible Break Locations. Caused by Differences in Computer Codes Rather than Actual Response.Computer Code Correctly Utilized
ML18039A2041997-12-0303 December 1997
LER 97-008-00:on 971104,main Steam Safety/Relief Valves Exceeded TS Setpoint Limit.Caused by Pilot Valve Disc/Seat Bonding.Replaced All 13 Unit 2 Main Steam SRV Pilot Cartridges
ML18038B9961997-11-25025 November 1997
LER 97-007-00:on 971028,Unit 2 Automatically Scrammed.Caused by Momentary Pressure Drop in electro-hydraulic Control Sys at Turbine Control Valves.Scram Contactor Replaced
ML18038B9931997-11-18018 November 1997
LER 97-006-00:on 971019,declared Unit 2 Hpcis Inoperable. Caused by High Condensate Level in HPCI Turbine Inlet Steam Line Drain Pot.Work Request Initiated
ML18038B9861997-11-10010 November 1997
LER 97-005-00:on 971012,ESF Components Were Actuated.Caused by Inadequate Procedure.Cs Pumps Were Secured & Injection Valves Were Closed & Refueling Floor Activities Were Stopped
ML18038B9701997-10-0909 October 1997
LER 97-004-00:on 970909,TS Surveillances Were Not Performed During Refueling Outage Timeframe.Caused by Personnel Error. Incorporated Missed Snubber & Vacuum Breaker Surveillances Into Refueling Outage Schedule
ML18038B9661997-10-0303 October 1997
LER 97-005-00:on 970824,LCO Was Not Entered When Valve Was Malfunctioning.Caused by Lack of Questioning Attitude by Operations Crew.Involved SROs Were Counseled & Problem Evaluation Rept Will Be Discussed
ML18038B9321997-08-0707 August 1997
LER 97-003-00:on 970711,determined That HPCI Turbine Speed Lower than Indicated.Caused by Improper Evaluation of Valve Leak.Work Orders to Troubleshoot HPCI Initiated
ML18038B9231997-07-25025 July 1997
LER 97-002-00:on 970626,discovered That Four Surveillance Instructions (Sis) Did Not Fully Test All Relay Logic Combinations.Caused by Personnel Error.Verified Relay Contacts Operable & Revised Applicable SIs.W/970725 Ltr
ML18038B8811997-05-14014 May 1997
LER 97-004-00:on 970414,unplanned Manual Start of EDG During Scheduled Redundant Start Test Occurred.Caused by Personnel Error.Edg 3D Shutdown & Returned to pre-event Configuration. W/970514 Ltr
ML18038B8801997-05-0808 May 1997
LER 97-002-00:on 970410,HPCI Declared Inoperable.Caused by Personnel Error.Operations Personnel Stopped Instrument Mechanics Testing & Returned HPCI to Standby Readiness. W/970508 Ltr
ML18038B8701997-04-29029 April 1997
LER 96-004-02:on 960717,loss of ECCS Division I & Division II Instrumentation Renders ECCS Equipment Inoperable.Caused by Loss of Inverter Output.Failed Components Replaced in Atu Inverter Circuitry & Instrumentation Logic Restored
ML18038B8521997-04-0909 April 1997
LER 97-003-00:on 970314,Unit 3 Main Steam SRVs Pilot Cartridges Failed Setpoint Tolerance Bench Tests.Caused by Corrosion Bonding of SRV Pilot Disc/Seat Interface Resulting in Drifting.Main Steam SRV Pilot replaced.W/970409 Ltr
ML18038B8511997-04-0909 April 1997
LER 95-003-02:on 950301,Unit 2 Main Steam SRVs Failed Setpoint Acceptance Tests.Caused by Corrosion Bonding of SRV Pilot Disc/Seat Interface Resulting in Upward Setpoint Drift.Valves Currently Being Retested & Recertified
ML18038B8481997-04-0909 April 1997
LER 96-004-01:on 960425,Unit 2 SRV Pilot Cartridges Failed Setpoint Acceptance Tests.Caused by SRV Pilot Disc/Seat Bonding Resulting in SRV Setpoints Deviating.Valves Currently Being Retested & Recertified
ML18038B8451997-04-0909 April 1997
LER 96-008-01:on 961101,Unit 2 Main Steam SRV Pilot Cartridges Failed Setpoint Tolerence Bench Tests.Caused by SRV Pilot Disc/Seat Bonding Resulting in SRV Setpoints.Srv Pilot Cartridges replaced.W/970409 Ltr
ML18038B8551997-04-0404 April 1997
LER 97-001-00:on 970305,loss of Offsite Power on Unit 3 During Refueling Outage Resulted from Shorted Component. Replaced Relays Involved in Event W/Less Sensitive Relays
ML18038B8441997-03-26026 March 1997
LER 95-001-02:on 950123,DG Turbocharger Failure Resulted in Noncompliance W/Ts Lco.Instituted Vibration Monitoring Program for EDG Turbochargers
ML18038B8071997-01-15015 January 1997
LER 96-008-00:on 961217,loss of ECCS Division II Instrumentation Caused ECCS Equipment to Be Inoperable. Replaced Cleared Fuse & Shorted SCR
ML18038B8041997-01-13013 January 1997
LER 96-007-00 on 961213,engineered Safety Feature Actuations Resulting from Inadequate Planning of step-text Work Order Occurred.Tripped Breaker Reset & LCO Condition Exited
ML18038B7931996-12-0404 December 1996
LER 96-006-00:on 961106,loss of ECCS Div 1 Instrumentation Rendered ECCS Equipment Inoperable.Caused by Cleared Fuse in ECCS Div.Fuse Replaced & Addl Testing to Challenge Replacement Fuse performed.W/961204 Ltr
ML18038B7921996-11-27027 November 1996
LER 96-008-00:on 961101,MS SR Valves Exceeded TS Required Setpoint Limit as Result of Disc/Seat Bonding.Caused by Corrosion Bonding of SRV Pilot Interface.Replaced All Thirteen Ms SR Valve Pilot cartridges.W/961127 Ltr
ML18038B7911996-11-27027 November 1996
LER 96-007-00:on 961029,Unit 2 Scram on Turbine Control Valve Fast Closure Occurred Due to Loss of Excitation to Main Generator.Exciter Brushes Inspected & Replaced & Procedures Revised
ML18038B7741996-10-15015 October 1996
LER 96-005-03:on 960915,reactor Scrammed as Required by TSs Due to Trip of Reactor Recirculation Motor Generator Set 3A. Caused by Bus Bar in Generator Armature Circuit Failing. Collector Rings Were replaced.W/961015 Ltr
1999-09-30
[Table view]
Category:RO)
MONTHYEARML18039A9041999-10-15015 October 1999
LER 99-010-00:on 990917,automatic Reactor Scram on Turbine Stop Valve Closure Occurred.Caused by High Water Level in Main Steam Moisture Separator 2C2.Unit 2C2 Reservoir Level Transmitter & Relays Were Replaced & Tested Satisfactorily
ML18039A8981999-10-14014 October 1999
LER 99-009-00:on 990915,manual Reactor Scram Was Noted Due to EHC Leak.Caused by Failure of Stainles Steel Tubing Connection.Removed Damaged Tubing & Connection Plug
ML18039A8951999-10-0808 October 1999
LER 99-008-00:on 990905,HPCI Was Inoperable Due to Failed Flow Controller.Caused by Premature Failure of Capacitor 2C3.Replaced Controller & HPCI Sys Was Run IAW Sys Operating Instructions
ML18039A8751999-09-30030 September 1999
LER 99-005-00:on 990901,SR for Standby Liquid Control Sampling Was Not Met.Caused by Deficient Procedure for Chemical Addition to Standby Liquid Control.Revised Procedure.With 990930 Ltr
ML18039A8201999-07-26026 July 1999
LER 99-004-00:on 990625,facility Core Spray Divisions I & II Inoperable at Same Time Due to Personnel Error.Electrical Supply Breaker to Core Spray Division II Pump 3B Returned to Normal Racked in Position
ML18039A8171999-07-20020 July 1999
LER 99-007-00:on 990623,discovered That SR for Monitoring of Primary Containment Oxygen Concentration Had Not Been Met. Caused by Failure of Operators to Adequately Communicate. Required Surveillances Were Performed.With 990720 Ltr
ML18039A8161999-07-19019 July 1999
LER 99-006-00:on 990618,noted That Main Steam SRV Exceeded TS Setpoint Tolerance.Caused by Pilot Vlve disc-seat Bonding.Util Replaced All 13 SRV Pilot Cartridges with Cartridges Certified to Be Witin +/-1%.With 990719 Ltr
ML18039A8121999-07-12012 July 1999
LER 99-005-00:on 990617,ESF Actuation & HPCI Declared Inoperable.Caused by Personnel Error.Reset HPCI & Returned Sys to Operable Status with 25 Minutes.With 990712 Ltr
ML18039A8101999-06-28028 June 1999
LER 99-004-00:on 990530,safety Features Sys Actuations Occurred Due to RPS Trip.Caused by Failure of MG Set AC Drive Motor Starter Contractor Coil.Licensee Placed 2B RPS Bus on Alternate Feed & Half Scram Was Reset
ML18039A8011999-06-14014 June 1999
LER 99-001-00:on 990515,automatic Reactor Scram Occurred Due to Tt.Caused by Failure of Mechanical Trip Cylinder to Latch When Hydraulically Reset.Operations Crew Stabilized Reactor Following Scram.With 990614 Ltr
ML18039A8021999-06-14014 June 1999
LER 99-002-00:on 990501,SRs for Single CR Withdrawal During Cold SD Were Not Adequately Implemented.Caused by Procedural Inadequacy.Revised Applicable Plant Surveillances.With 990614 Ltr
ML18039A8071999-06-14014 June 1999
LER 99-003-00:on 990515,automatic Reactor Scram Due to Turbine Trip Was Noted.Caused by Failure of Mechanical Trip Cylinder to Latch When Hydraulically Reset.Operations Crew Stabilized Reactor Following Scram
ML18039A7791999-05-0606 May 1999
LER 99-003-00:on 990408,declared Plant HPCI Sys Inoperable Due to Loose Wire.Caused by Failure to Properly Tighten Screw at Some Time in Past.Loose Wire Was Tightened
ML18039A7461999-04-0707 April 1999
LER 99-001-00:on 990308,determined That Two Trains of Standby Gas Treatment (SGT) Were Inoperable.Caused by Trip C SGT Blower Motor Breaker.Initiated Shutdown of Plant,Reset C SGT Blower Motor Breaker & Declared Train Operable
ML18039A6951999-02-19019 February 1999
LER 99-002-00:on 990122,LCO Was Not Entered During Calibration Testing of 3D 480 Volt Rmov Board.Caused by Personnel Error.Tva Has Briefed Operations Personnel to Preclude Recurrence of Event.With 990219 Ltr
ML18039A6871999-02-12012 February 1999
LER 99-001-00:on 990114,Unit 3 HPCI Was Noted Inoperable. Caused by Oil Leak on Stop Valve.Corrective Maint Was Performed to Repair Oil Leak.With 990212 Ltr
ML18039A6671998-12-31031 December 1998
LER 98-004-00:on 981202,SR Intent Was Not Adequately Implemented.Caused by Procedural Inadequacy.Revised Procedures to Provide Proper SR Implementation.With 981231 Ltr
ML18039A6471998-12-15015 December 1998
LER 98-007-00:on 981116,unplanned ESF Following Loss of 4kV Unit Board 3B Occurred.Caused by Temporary Energization of Lockout Relay on 4kV Unit Board 3B When Resistor on Relay Monitoring Lamp Circuit Shorted.Replaced Resistor
ML18039A6371998-12-0707 December 1998
LER 98-006-00:on 981116,MSSR Valves Exceeded TS Setpoint Tolerance.Caused by Pilot Valve Disc/Seat Bonding. Installed SRV Pressure Switches During Unit 3,cycle 8 Outage.With 981207 Ltr
ML18039A6071998-11-12012 November 1998
LER 98-005-00:on 981014,mode Changes Not Allowed by TS 3.0.4 Were Made During Reactor Startup.Caused by TS LCO 3.0.4 Not Being Properly Applied.Training Info Memo Re Proper Application for TS LCO 3.0.4 Was Prepared.With 981112 Ltr
ML18039A6031998-11-0404 November 1998
LER 98-004-00:on 981007,primary Containment Allowable Leak Rate Was Exceeded.Caused by Failure of Check Valve to Fully Seat Following Shutdown of Rbbccw Sys for Llrt.Valve Was Retested During Next Refueling Outage.With 981104 Ltr
ML18039A5971998-10-28028 October 1998
LER 98-003-00:on 981001,Unit 2 Received Full Automatic Scram from 100% Reactor Power.Caused by Failure of Normally Open Isolation Valve Which Blocked Flow of Stator Cooling Water Through Associated Heat Exchangers.Replaced Failed Valve
ML18039A5171998-09-15015 September 1998
LER 98-002-00:on 980816,personnel Observed Both Channels of Rod Block Monitor Sys Bypassed for Cr.Caused by Failure of Gene to Properly Document & Specify Adjustments.Will Implement Necessary Procedure Controls
ML18039A3311998-05-0404 May 1998
LER 98-003-00:on 980407,reactor Manually Scrammed to Prevent thermal-hydraulic Instability After Recirculation Pump Runback.Caused by Human Error.Strengthened Controls Associated W/Walkdowns in NEDP-11
ML18039A3141998-04-0909 April 1998
LER 98-002-00:on 980310,ESF Actuation Occurred Due to Failure of Alternate Feeder Breaker Position Switch.Will Continue Testing & Visual Insps on Addl Breaker Position Switches & Will Revise Applicable Maint Instructions
ML18039A3101998-04-0707 April 1998
LER 98-001-00:on 980308,ESF Actuations Occurred When 2B RPS Bus Was Transferred to de-energized Source.Caused by Failure of Preparing Clearance to Exercise Proper Attention. 2B RPS Bus Restored to Transformer Source
ML18039A3051998-04-0101 April 1998
LER 96-001-00:on 980121,determined That Temp Sensors for Certain HELB May Not Detect All Possible Break Locations. Caused by Differences in Computer Codes Rather than Actual Response.Computer Code Correctly Utilized
ML18039A2041997-12-0303 December 1997
LER 97-008-00:on 971104,main Steam Safety/Relief Valves Exceeded TS Setpoint Limit.Caused by Pilot Valve Disc/Seat Bonding.Replaced All 13 Unit 2 Main Steam SRV Pilot Cartridges
ML18038B9961997-11-25025 November 1997
LER 97-007-00:on 971028,Unit 2 Automatically Scrammed.Caused by Momentary Pressure Drop in electro-hydraulic Control Sys at Turbine Control Valves.Scram Contactor Replaced
ML18038B9931997-11-18018 November 1997
LER 97-006-00:on 971019,declared Unit 2 Hpcis Inoperable. Caused by High Condensate Level in HPCI Turbine Inlet Steam Line Drain Pot.Work Request Initiated
ML18038B9861997-11-10010 November 1997
LER 97-005-00:on 971012,ESF Components Were Actuated.Caused by Inadequate Procedure.Cs Pumps Were Secured & Injection Valves Were Closed & Refueling Floor Activities Were Stopped
ML18038B9701997-10-0909 October 1997
LER 97-004-00:on 970909,TS Surveillances Were Not Performed During Refueling Outage Timeframe.Caused by Personnel Error. Incorporated Missed Snubber & Vacuum Breaker Surveillances Into Refueling Outage Schedule
ML18038B9661997-10-0303 October 1997
LER 97-005-00:on 970824,LCO Was Not Entered When Valve Was Malfunctioning.Caused by Lack of Questioning Attitude by Operations Crew.Involved SROs Were Counseled & Problem Evaluation Rept Will Be Discussed
ML18038B9321997-08-0707 August 1997
LER 97-003-00:on 970711,determined That HPCI Turbine Speed Lower than Indicated.Caused by Improper Evaluation of Valve Leak.Work Orders to Troubleshoot HPCI Initiated
ML18038B9231997-07-25025 July 1997
LER 97-002-00:on 970626,discovered That Four Surveillance Instructions (Sis) Did Not Fully Test All Relay Logic Combinations.Caused by Personnel Error.Verified Relay Contacts Operable & Revised Applicable SIs.W/970725 Ltr
ML18038B8811997-05-14014 May 1997
LER 97-004-00:on 970414,unplanned Manual Start of EDG During Scheduled Redundant Start Test Occurred.Caused by Personnel Error.Edg 3D Shutdown & Returned to pre-event Configuration. W/970514 Ltr
ML18038B8801997-05-0808 May 1997
LER 97-002-00:on 970410,HPCI Declared Inoperable.Caused by Personnel Error.Operations Personnel Stopped Instrument Mechanics Testing & Returned HPCI to Standby Readiness. W/970508 Ltr
ML18038B8701997-04-29029 April 1997
LER 96-004-02:on 960717,loss of ECCS Division I & Division II Instrumentation Renders ECCS Equipment Inoperable.Caused by Loss of Inverter Output.Failed Components Replaced in Atu Inverter Circuitry & Instrumentation Logic Restored
ML18038B8521997-04-0909 April 1997
LER 97-003-00:on 970314,Unit 3 Main Steam SRVs Pilot Cartridges Failed Setpoint Tolerance Bench Tests.Caused by Corrosion Bonding of SRV Pilot Disc/Seat Interface Resulting in Drifting.Main Steam SRV Pilot replaced.W/970409 Ltr
ML18038B8511997-04-0909 April 1997
LER 95-003-02:on 950301,Unit 2 Main Steam SRVs Failed Setpoint Acceptance Tests.Caused by Corrosion Bonding of SRV Pilot Disc/Seat Interface Resulting in Upward Setpoint Drift.Valves Currently Being Retested & Recertified
ML18038B8481997-04-0909 April 1997
LER 96-004-01:on 960425,Unit 2 SRV Pilot Cartridges Failed Setpoint Acceptance Tests.Caused by SRV Pilot Disc/Seat Bonding Resulting in SRV Setpoints Deviating.Valves Currently Being Retested & Recertified
ML18038B8451997-04-0909 April 1997
LER 96-008-01:on 961101,Unit 2 Main Steam SRV Pilot Cartridges Failed Setpoint Tolerence Bench Tests.Caused by SRV Pilot Disc/Seat Bonding Resulting in SRV Setpoints.Srv Pilot Cartridges replaced.W/970409 Ltr
ML18038B8551997-04-0404 April 1997
LER 97-001-00:on 970305,loss of Offsite Power on Unit 3 During Refueling Outage Resulted from Shorted Component. Replaced Relays Involved in Event W/Less Sensitive Relays
ML18038B8441997-03-26026 March 1997
LER 95-001-02:on 950123,DG Turbocharger Failure Resulted in Noncompliance W/Ts Lco.Instituted Vibration Monitoring Program for EDG Turbochargers
ML18038B8071997-01-15015 January 1997
LER 96-008-00:on 961217,loss of ECCS Division II Instrumentation Caused ECCS Equipment to Be Inoperable. Replaced Cleared Fuse & Shorted SCR
ML18038B8041997-01-13013 January 1997
LER 96-007-00 on 961213,engineered Safety Feature Actuations Resulting from Inadequate Planning of step-text Work Order Occurred.Tripped Breaker Reset & LCO Condition Exited
ML18038B7931996-12-0404 December 1996
LER 96-006-00:on 961106,loss of ECCS Div 1 Instrumentation Rendered ECCS Equipment Inoperable.Caused by Cleared Fuse in ECCS Div.Fuse Replaced & Addl Testing to Challenge Replacement Fuse performed.W/961204 Ltr
ML18038B7921996-11-27027 November 1996
LER 96-008-00:on 961101,MS SR Valves Exceeded TS Required Setpoint Limit as Result of Disc/Seat Bonding.Caused by Corrosion Bonding of SRV Pilot Interface.Replaced All Thirteen Ms SR Valve Pilot cartridges.W/961127 Ltr
ML18038B7911996-11-27027 November 1996
LER 96-007-00:on 961029,Unit 2 Scram on Turbine Control Valve Fast Closure Occurred Due to Loss of Excitation to Main Generator.Exciter Brushes Inspected & Replaced & Procedures Revised
ML18038B7741996-10-15015 October 1996
LER 96-005-03:on 960915,reactor Scrammed as Required by TSs Due to Trip of Reactor Recirculation Motor Generator Set 3A. Caused by Bus Bar in Generator Armature Circuit Failing. Collector Rings Were replaced.W/961015 Ltr
1999-09-30
[Table view]
Category:TEXT-SAFETY REPORT
MONTHYEARML18039A9041999-10-15015 October 1999
LER 99-010-00:on 990917,automatic Reactor Scram on Turbine Stop Valve Closure Occurred.Caused by High Water Level in Main Steam Moisture Separator 2C2.Unit 2C2 Reservoir Level Transmitter & Relays Were Replaced & Tested Satisfactorily
ML18039A8981999-10-14014 October 1999
LER 99-009-00:on 990915,manual Reactor Scram Was Noted Due to EHC Leak.Caused by Failure of Stainles Steel Tubing Connection.Removed Damaged Tubing & Connection Plug
ML18039A8951999-10-0808 October 1999
LER 99-008-00:on 990905,HPCI Was Inoperable Due to Failed Flow Controller.Caused by Premature Failure of Capacitor 2C3.Replaced Controller & HPCI Sys Was Run IAW Sys Operating Instructions
ML18039A8751999-09-30030 September 1999
LER 99-005-00:on 990901,SR for Standby Liquid Control Sampling Was Not Met.Caused by Deficient Procedure for Chemical Addition to Standby Liquid Control.Revised Procedure.With 990930 Ltr
ML20217F9671999-09-30030 September 1999
Monthly Operating Repts for Sept 1999 for Browns Ferry Nuclear Plant,Units 1,2 & 3.With
ML20212E6341999-09-23023 September 1999
Suppl to SE Resolving Error in Original 990802 Se,Clarifying Fact That Licensee Has Not Committed to Retain Those Specific Compensatory Measures That Were Applied to one-time Extension
ML20212D3831999-09-20020 September 1999
Safety Evaluation Supporting Proposed Rev to Withdrawal Schedule for First & Third Surveillance Capsules for BFN-3 RPV
ML20212B8561999-08-31031 August 1999
Monthly Operating Repts for Aug 1999 for Browns Ferry Nuclear Plant.With
ML18039A8821999-08-31031 August 1999
Increased MSIV Leakage Tech Spec Change Submittal - Seismic Evaluation Rept.
ML18039A8391999-08-0606 August 1999
BFN Unit 2 Cycle 10 ASME Section XI NIS-1 & NIS-2 Data Repts.
ML20210N1221999-08-0202 August 1999
Safety Evaluation Accepting Licensee Request for Relief from ASME B&PV Code,Section XI Requirements.Request 3-ISI-7, Pertains to Second 10-year Interval ISI for Plant,Unit 3
ML20210R0931999-07-31031 July 1999
Monthly Operating Repts for July 1999 for Browns Ferry Nuclear Plant,Units 1,2 & 3.With
ML18039A8201999-07-26026 July 1999
LER 99-004-00:on 990625,facility Core Spray Divisions I & II Inoperable at Same Time Due to Personnel Error.Electrical Supply Breaker to Core Spray Division II Pump 3B Returned to Normal Racked in Position
ML18039A8171999-07-20020 July 1999
LER 99-007-00:on 990623,discovered That SR for Monitoring of Primary Containment Oxygen Concentration Had Not Been Met. Caused by Failure of Operators to Adequately Communicate. Required Surveillances Were Performed.With 990720 Ltr
ML18039A8161999-07-19019 July 1999
LER 99-006-00:on 990618,noted That Main Steam SRV Exceeded TS Setpoint Tolerance.Caused by Pilot Vlve disc-seat Bonding.Util Replaced All 13 SRV Pilot Cartridges with Cartridges Certified to Be Witin +/-1%.With 990719 Ltr
ML20209J0771999-07-16016 July 1999
Safety Evaluation Concluding That Licensee Provided Adequate Information to Resolve ampacity-related Points of Concern Raised in GL 92-08 for BFN & That No Outstanding Issues Re GL 92-08 Ampacity Issues for Browns Ferry NPP Exist
ML18039A8121999-07-12012 July 1999
LER 99-005-00:on 990617,ESF Actuation & HPCI Declared Inoperable.Caused by Personnel Error.Reset HPCI & Returned Sys to Operable Status with 25 Minutes.With 990712 Ltr
ML20209H4381999-06-30030 June 1999
Monthly Operating Repts for June 1999 for Browns Ferry Nuclear Plant,Units 1,2 & 3.With
ML18039A8101999-06-28028 June 1999
LER 99-004-00:on 990530,safety Features Sys Actuations Occurred Due to RPS Trip.Caused by Failure of MG Set AC Drive Motor Starter Contractor Coil.Licensee Placed 2B RPS Bus on Alternate Feed & Half Scram Was Reset
ML20196F8811999-06-23023 June 1999
Safety Evaluation Accepting GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power Operated Gate Valves
ML18039A8071999-06-14014 June 1999
LER 99-003-00:on 990515,automatic Reactor Scram Due to Turbine Trip Was Noted.Caused by Failure of Mechanical Trip Cylinder to Latch When Hydraulically Reset.Operations Crew Stabilized Reactor Following Scram
ML18039A8021999-06-14014 June 1999
LER 99-002-00:on 990501,SRs for Single CR Withdrawal During Cold SD Were Not Adequately Implemented.Caused by Procedural Inadequacy.Revised Applicable Plant Surveillances.With 990614 Ltr
ML18039A8011999-06-14014 June 1999
LER 99-001-00:on 990515,automatic Reactor Scram Occurred Due to Tt.Caused by Failure of Mechanical Trip Cylinder to Latch When Hydraulically Reset.Operations Crew Stabilized Reactor Following Scram.With 990614 Ltr
ML20196B8051999-05-31031 May 1999
Monthly Operating Repts for May 1999 for Browns Ferry Nuclear Plant,Units 1,2 & 3.With
ML18039A7791999-05-0606 May 1999
LER 99-003-00:on 990408,declared Plant HPCI Sys Inoperable Due to Loose Wire.Caused by Failure to Properly Tighten Screw at Some Time in Past.Loose Wire Was Tightened
ML18039A7761999-04-30030 April 1999
Revised Surveillance Specimen Program Evaluation for TVA Browns Ferry Unit 3.
ML20206R0731999-04-30030 April 1999
Monthly Operating Repts for Apr 1999 for Bfnp.With
ML18039A7561999-04-23023 April 1999
Bfnp Risk-Informed Inservice Insp (RI-ISI) Program Submittal.
ML18039A7671999-04-0808 April 1999
Rev 0 to TVA-COLR-BF2C11, Browns Ferry Nuclear Plant Unit 2 Cycle 11 Colr.
ML18039A7461999-04-0707 April 1999
LER 99-001-00:on 990308,determined That Two Trains of Standby Gas Treatment (SGT) Were Inoperable.Caused by Trip C SGT Blower Motor Breaker.Initiated Shutdown of Plant,Reset C SGT Blower Motor Breaker & Declared Train Operable
ML20205N8341999-04-0101 April 1999
Part 21 Rept Re Automatic Switch Co Nuclear Grade Series X206380 & X206832 Solenoid Valves Ordered Without Lubricants That Were Shipped with Std Lubrication to PECO & Tva.Affected Plants Were Notified
ML20205F9341999-04-0101 April 1999
Safety Evaluation Authorizing Licensee 990108 Relief Request PV-38,from Requirements of ASME BPV Code Section XI IST Testing,Valve Program for Plant,Units 1,2 & 3
ML20205T5441999-03-31031 March 1999
Monthly Operating Repts for Mar 1999 for Bfnp.With
ML20205S0601999-03-31031 March 1999
Rept on Status of Public Petitions Under 10CFR2.206 with Status Change from Previous Update,990331
ML20205S0661999-03-31031 March 1999
Rept on Status of Public Petitions Under 10CFR2.206 with No Status Change from Previous Update,990331, Atlas Corp
ML18039A7361999-03-11011 March 1999
Rev 4 to TVA-COLR-BF2C10, Bfnp,Unit 2,Cycle 10 Colr.
ML20204C7891999-02-28028 February 1999
Monthly Operating Repts for Feb 1999 for Browns Ferry Nuclear Plant,Units 1,2 & 3.With
ML18039A6951999-02-19019 February 1999
LER 99-002-00:on 990122,LCO Was Not Entered During Calibration Testing of 3D 480 Volt Rmov Board.Caused by Personnel Error.Tva Has Briefed Operations Personnel to Preclude Recurrence of Event.With 990219 Ltr
ML18039A6871999-02-12012 February 1999
LER 99-001-00:on 990114,Unit 3 HPCI Was Noted Inoperable. Caused by Oil Leak on Stop Valve.Corrective Maint Was Performed to Repair Oil Leak.With 990212 Ltr
ML18039A6931999-02-0303 February 1999
Rev 3 to TVA-COLR-BF2C10, Bfnp Unit 2 Cycle 10 Colr.
ML18039A6941999-02-0303 February 1999
Rev 1 to TVA-COLR-BF3C9, Bfnp Unit 3 Cycle 9 Colr.
ML18039A6671998-12-31031 December 1998
LER 98-004-00:on 981202,SR Intent Was Not Adequately Implemented.Caused by Procedural Inadequacy.Revised Procedures to Provide Proper SR Implementation.With 981231 Ltr
ML18039A6661998-12-31031 December 1998
Ro:On 981215,HRPCRM 2-RM-90-273C Was Declared Inoperable. Caused by Downscale Indication.Containment RM Will Be Utilized as Planned Alternate Method of Monitoring Until Hrpcrm 2-RM-90-273C Can Be Returned to Operable Status
ML20199K8951998-12-31031 December 1998
Monthly Operating Repts for Dec 1998 for Browns Ferry Nuclear Plant.With
ML20199F2721998-12-31031 December 1998
ISI Summary Rept (NIS-1), for BFN Unit 3,Cycle 8 Operation
ML18039A6471998-12-15015 December 1998
LER 98-007-00:on 981116,unplanned ESF Following Loss of 4kV Unit Board 3B Occurred.Caused by Temporary Energization of Lockout Relay on 4kV Unit Board 3B When Resistor on Relay Monitoring Lamp Circuit Shorted.Replaced Resistor
ML18039A6371998-12-0707 December 1998
LER 98-006-00:on 981116,MSSR Valves Exceeded TS Setpoint Tolerance.Caused by Pilot Valve Disc/Seat Bonding. Installed SRV Pressure Switches During Unit 3,cycle 8 Outage.With 981207 Ltr
ML20199F2791998-12-0303 December 1998
Bfnp Unit 3 Cycle 8 ASME Section XI NIS-2 Data Rept
ML20198D9621998-11-30030 November 1998
Monthly Operating Repts for Nov 1998 for Bfn,Units 1,2 & 3. with
ML18039A6071998-11-12012 November 1998
LER 98-005-00:on 981014,mode Changes Not Allowed by TS 3.0.4 Were Made During Reactor Startup.Caused by TS LCO 3.0.4 Not Being Properly Applied.Training Info Memo Re Proper Application for TS LCO 3.0.4 Was Prepared.With 981112 Ltr
1999-09-30
[Table view] |
Text
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150.0104 ExPIREsoersor2oot (6-1996) Esbmated burden per response to comply with this mandatory hformstion cosection request: 50 hrs. Reported lessons learned are incorporated into the licensing process end fed back to industry. Forward comments regarding LICENSEE EVENT. REPORT (LER) burden estimate to the Records Management Branch (T< F33), V.S, Nuc(ear Regulatory Commission, Washington, DC 2055$ 0001, and to the Paperwork Reduction Project (3(500104), Office of Management and (See reverse for required number of Budget, Washington, OC 20503. If an information collection does not digits/characters for each block) display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person Is not required to respond to, the information co(lect(oIL FACIUTY NAME (I) DOCKET NUMBER (2) PAGE (3)
Browns Ferry Nuclear Plant 05000296 10f 6 TITLE (4)
Unplanned ESF Following the Loss of 4kV Unit Board 3B EVENT DATE (5) LER NUMBER (6I REPORT DATE (7) OTHER FACILITIES INVOLVED (8)
MONTH OAY YEAR YEAR SEQUENTIAL REVISION MONTH DAY FACIUTY NAME DOCKET NUMBER NUMBER NUMBER NA 05000 OOCKETNUMBER 16 1998 1998 007 000 12 15 1998 05000 OPERATING THIS REPORT IS SUBMITTED PURSUA NT To THE REQUIREMENTS OF 10 CFR rn (Check one or more) (11)
MODE (9) 20.2201(b) 20. 2203(a) (2)(v) 50.73(a)(2)(i) 50.73(a)(2) (viii)
POWER 20.2203(a)(1) 20.2203(a) (3)(i) 50.73(a) (2) (ii) 50.73 (a) (2) (x)
LEVEL (10) 100 20.2203(a) (2) (i) 20.2203(a) (3)(ii) 50.73(a) (2) (iii) 73.71 20.2203(a)(2)(ii) 20.2203(a) (4) 50.73(a) (2) (iv) OTHER 20.2203(a)(2)(iii) 50.36(c)(1) 50.73(a)(2)(v) Specify in Abstract below or In NRC Form 366A 20.2203(a) (2) (iv) 50.36(c) (2) 50.73(a)(2)(vii)
LICENSEE CONTACT FOR THIS LER (12)
NAME TELEPHONE NUMBER (Include Ares Code)
G.M. Morrison, Senior Licensing Project Manger 256.729.7534 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)
CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE TO CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE NPRDS TO NPROS EA IL G080
))I.: +X% M SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED 'MONTH OAY YEAR YES X NO SUBMISSION DATE (15)
(If yes, complete EXPECTED SUBMISSION DATE).
ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)
At 1435 CST on November 16, 1998, the supply to 4kV Unit Board 3B deenergized due to a fault protection lockout. 4kV Unit Board 3B supplies power to the Division II 4kV Shutdown Boards 3EC and 3ED. The loss of voltage caused the 3C and 3D Diesel Generators to start and tie to their respective shutdown boards. The transient loss of the shutdown boards caused Reactor. Protection System (RPS) Bus B to deenergize resulting in a half scram and Primary Containment Isolation System actuations. The Standby Gas Treatment and Control Room Emergency Ventilation systems initiated as expected due to the RPS power loss. The deenergization of 4kV Unit Board 3B resulted in the loss of its associated loads, the 3B Condensate Booster Pump, 3B Condensate Pump and the 3B Condenser Circulating Water Pump. As expected, the loss of condensate resulted in a Reactor Feed Pump Turbine 3A trip on loss of pump suction pressure. The Reactor Feed Pump Turbine 3A trip along with the resulting low water level initiated a recirculation system runback to 75% full power.
The immediate cause of this event was the temporary energization of the lockout relay on 4KV Unit Board 3B when the resistor on the relay monitoring lamp circuit shorted, allowing sufficient current to energize the lockout relay coil. The most probable root cause of this event was physical damage sustained by the relay monitoring lamp circuit voltage dropping resistor during or prior to its last replacement. Corrective actions include personnel briefings and inclusion of this event in the operations and electrical maintenance department training programs.
This report is submitted pursuant to 10 CFR 50.73(a)(2)(iv) as an event that resulted in a manual or automatic actuation of engineered safety features.
98i22302i2 98i2%5 PDR ADOCK 050002'))6 8 PDR
v NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION I6-1998)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME 1 DOCKET LER NUMBER 6 PAGE 3 YEAR SEQUENTIAL REVISION NUMBER 2of6 Browne Ferry Nuclear Fiant.- Unit 3 05000296 1996 - 007 000 TEXT (If more spece is required, use eddi rionel copies of NRC Form 366A/ {17)
I. PLANT CONDITION(S)
At the time the event occurred, Units 2 and 3 were in Mode 1 at 100 percent power. Unit 1 was shutdown and defueled.
II. DESCRIPTION OF EVENT A. Event:
At 1435 CST on November'16, 1998, the supply to 4kV Unit Board 3B [EA] deenergized due to a fault protection lockout. 4kV,Unit Board 3B supplies power to the Division II 4kV Shutdown Boards 3EC and 3ED [EB]. The loss of voltage caused the 3C and 3D Diesel Generators (DG) [EK] to start and tie to their respective shutdown boards. The transient loss of the shutdown boards caused the Reactor Protection System (RPS) [JC] Division II to deenergize resulting in a half scram and Primary Containment Isolation System [JM] actuations for group 2 (primary containment water lines), group 3 (Reactor Water Cleanup), group 6 (primary containment air lines and secondary containment), and group 8 (Traversing Incore Probe). The Standby Gas Treatment (SGT) [BH] and Control Room Emergency Ventilation (CREV) [Vl]systems initiated as expected due to the RPS power loss. The DG starts caused the standby Emergency Equipment Cooling Water [BI] pumps to start.
The deenergization of 4kV Unit Board 3B resulted in the loss of its associated loads, the 3B Condensate Booster Pump [SD], 3B Condensate Pump [SD] and the 3B Condenser Circulating Water Pump [KE]. As expected, the loss of condensate resulted in a Reactor Feed Pump Turbine (RFPT) 3A [SJ] trip on loss of suction pressure.,The RFPT. 3A trip along with the resulting low water level provided a 75%
recirculation system runback initiation. Recovery from the event was completed at 1545 hours0.0179 days <br />0.429 hours <br />0.00255 weeks <br />5.878725e-4 months <br /> CST when Unit 3 reactor power was stabilized at approximately 67% full power.
9 This report is submitted pursuant to 10 CFR 50.73(a)(2)(iv) as an event or condition that resulted in a manual or automatic actuation of any Engineered Safety Feature, including the Reactor Protection.
System.
B. Ino erable Structures Com onents orS stemsthatContributedto the Event:
None.
NRC FORM 366 I6-1998)
li" NRC FORM 366A U;S. NUCLEAR REGULATORY COMMISSION I6-1998)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME 1 DOCKET LER NUMBER 6 PAGE 3 YEAR SEQUENTIAL REVISiQN NUMBER 3 of 6 Browne Ferry Nuclear Plant - Unit 3 05000296 1998 007 000 TEXT (Iimore spaceis required, use addirionai copies ofhfRC Form 366A/ I17i C. Dates and A roximate Times of Ma or Occurrences:
November 16, 1998 1435 hours0.0166 days <br />0.399 hours <br />0.00237 weeks <br />5.460175e-4 months <br /> CST Loss of Unit Board 3B received in the main control room. Diesel generators 3C and 3D receive a start signal due to loss of voltage to Shutdown Boards 3EC and 3ED.
November 16, 1998 1436 hours0.0166 days <br />0.399 hours <br />0.00237 weeks <br />5.46398e-4 months <br /> CST Recirculation system runback to 75% full power initiated.
November 16, 1998 1545 hours0.0179 days <br />0.429 hours <br />0.00255 weeks <br />5.878725e-4 months <br /> CST Recovery from the event completed. Unit 3 reactor power stabilized at -67% full power.
November 16, 1998 1706 hours0.0197 days <br />0.474 hours <br />0.00282 weeks <br />6.49133e-4 months <br /> CST A four-hour non-emergency notification is made to the NRC via the Emergency Notification System pursuant to 10 CFR 50.72(b)(2)(ii).
D. Other S stems or Seconda Functions Affected None.
E, Method of Discove The main control room operating crew received alarms associated with the deenergization of 4kV Unit Board 3B.
F. 0 erator Actions No operator actions contributed to this event. The operator actions in response to the event were proper and in accordance with plant instructions.
G. Safet S stem Res onses All safety systems responded as expected.
NRC FORM 366 I6-199BI
NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (6- I 998)
LlCENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME' DQGKET LER NUMBER 6 PAGE 3 YEAR SEQUENTIAL REVISiON NUMBER 4of6 Browne Ferry Nuclear Plant - Unit 3 05000296 1998 - 007 - 000 TEXT flfmore spece is required, use eddi rionel copies of fVRC Form 366AJ I 17)
III. CAUSE OF THE EVENT A. Immediate Cause The immediate cause of this event was the temporary energization of the lockout relay on 4KV Unit Board 3B when the resistor in the relay monitoring lamp circuit shorted, allowing sufficient current flow to energize the lockout relay coil.
B. Root Cause The most probable root cause of this event was physical damage sustained by the relay monitoring lamp circuit voltage dropping resistor during or prior to its last replacement. (Infrequent resistor failures necessitate replacement.) The insulating material between the resistor anode and cathode is a glass composite. The resistor is installed in the lamp circuit via a push/twist receptacle. It was concluded that the most likely scenario is that the glass insulation was damaged from a pre-installation impact and continued to degrade from panel vibration and holder spring tension until the short occurred. The failed resistor is shown on Figure 1.
C. Contributin Factors None.
IV. ANALYSIS OF THE EVENT The event was uncomplicated operationally. The half-scram occurred due to the loss of power to RPS Bus 3B. A full-scram was not initiated because RPS Bus 3A remained energized throughout the event. The only impact of this event on Units 1 and 2 were Refuel Zone isolations and the autostart of the SGT and CREV systems which are expected responses to the loss of RPS Bus 3B. Operations personnel immediately recognized the cause of the ESF actuation and took appropriate actions in accordance with plant procedures.
Proper communications and coordination took place between the Operations personnel in the Units 1, 2, and 3 control rooms. The initiations and actuations/isolations were consistent with the loss of RPS Bus 3B.
V. ASSESSMENT OF THE SAFETY CONSEQUENCES There were no actual or potential safety consequences as a result of this event. The failed lamp circuit voltage dropping resistor which initiated this event does not perform a safety function. Plant safety systems performed as designed, operator actions were in accordance with plant procedures, and no other potential problems were created by this event. Therefore, this event did not adversely affect the safety of plant personnel or the public.
NRC FORM 366 {6-1998)
NRC FORM 366A U.S. NUCLEAR REGULATORY COMMiSSiON IS-1998I LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME 1 DOCKET LER NUMBER 6 PAGE 3 YEAR SEQUENTIAL REVISION NUMBER 5 or 6 Browne Ferry Nuclear Plant - Unit 3 05000296 1 998 007 000 TEXT llfmore space is required, use,addirional copies of ftfRC Form 366Al i17)
VI. CORRECTIVE ACTIONS A. Immediate Corrective Actions Electrical troubleshooting was performed which identified the damaged resistor in the in the 4kV Unit Board 3B lockout relay monitoring lamp circuit: After replacement of the resistor and testing of the relay, 4kV Unit Board 3B was reenergized.
B. Corrective Actions to Prevent Recurrence Engineering, Operations, and Maintenance personnel will be briefed on this event'.
This event will be added to the lesson plans for Operations Department electrical training'.
This event will be added to the lesson plans for Electrical Maintenance continuing training'.
Vi). ADDITIONALINFORMATION A. Failed Com onents Troubleshooting into the cause of this event revealed a shorted 5100 ohm dropping resistor, General Electric part number 0165A7844P004, in the 4kV Unit Board 3B lockout relay monitoring lamp circuit.
The dropping resistor had apparently sustained impact damage during or prior to its last replacement.
B. Previous LERs on Similar Events No previous LERs have resulted from relay monitoring lamp circuit voltage dropping resistor failures at Browns Ferry..
Vill. COMMITMENTS None.
'VAdoes not consider these corrective actions regulatory commitments. The, completion of these items will be tracked in TVA's Corrective Action Pro ram.
NRc FQRM 366 l6-1998)
C~
L
NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (6-1998I LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME 1I DOCKET LER NUMBER 6 PAGE 3 YEAR SEQUENTIAL REVISION NUMBER 6 of 6 Browne Ferry NUclear Plant - Unit 3 05000296 1998 007 000 TEXT (If more space'is required, use additional copies of lVRC Form 366A/ (17I Figure 1 Photograph of Failed Relay Monitoring Lamp Circuit Resistor Multiple Indentations On The Anode, Caused From The Varying Angles Of Impact From The Holder Socket Glass Insulation:: .::s Anod Damage To The Cathode Cath Ode Glass i nsulatio n is damaged and some is rnlsslrl g. This resulted in .,'P.':.,'".!!:.:.":.p':".,'ng the ano de short to the .'. igQg~r,Ar~
cathode NRC FORM 366 I6-1999)
0 0 I I