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| {{#Wiki_filter:Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381August 4, 2016ATTN: Document Control DeskU.S. Nuclear Regulatory CommissionWashington, D.C 20555-0001 | | {{#Wiki_filter:Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381August 4, 2016ATTN: Document Control DeskU.S. Nuclear Regulatory Commission Washington, D.C 20555-0001 |
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| 10 cFR 50 73Watts Bar Nuclear Plant, Unit 2Facility Operating License No. NPF-96NRC Docket No.50-391Licensee Event Report 391/2016-004-00, Reactor Trip and Safety lnjectionActuation Caused by Turbine Governor Valve FailureThis submittal provides Licensee Event Report (LER) 39112016-004-00. This LERprovides details concerning a recent reactor trip with safety injection as a result of a turbinegovernor valve failure. This report is being submitted in accordance with1 0 cFR 50.73(a)(2)(ivXA).Please direct any questions concerning this matter to Gordon Arent, WBN LicensingDirector, at (423) 365-2004.Paul SimmonsSite Vice PresidentWatts Bar Nuclear PlantEnclosurecc: See Pag e 2Respectfully, U.S. Nuclear Regulatory CommissionPage 2August 4, 2016cc (Enclosure):NRC Regional Administrator - Region llNRC Senior Resident lnspector - Watts Bar Nuclear Plant NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION{11-2015)$tto*"t'o"iw;e-:Y.c LTcENSEE EVENT REPoRT (LER)-r a*rlAPPROVED BY OMB: NO. 3150-0104 EXPIRES: t0/31/2018Estimated burden per response to comply with this mandatory collection request: 80 hours,Reported lessons learned are incorporated into the licensing process and fed back to industry,Send comments regarding burden estimate to the FOIA, Privacy and lnformation CollectionsBranch (T-5 F53), U,S, Nuclear Regulatory Commission, Washington, DC 20555-0001, or byinternet e-mail to lnfocollects.Resource@nrc,gov, and to the Desk Officer, Office of lnformation andRegulatory Affairs, NE0B-10202, (3150-0104), ffice of Management and Budget, Washington,DC 20503 lf a means used to impose an information collection does not display a currently validOMB control number, the NRC may not conduct or sponsor, and a person is not required torespond to, the information collection,1. FACILITY NAMEWatts Bar Nuclear Plant, Unit 22, DOCKET NUMBER0500039 13. PAGE10F54. TITLEReactor Trip and Safety lnjection Actuation Caused by Turbine Governor Valve Failure5. EVENT DATE6. LER NUMBER7. REPORT DATE8. OTHER FACILITIES INVOLVEDMONTHI DAY I YEARYEAR I 'i,Hrut$REVNO,MONTH I DAYYEARFACTLTTY NAME I DOCKET NUMBERN/A lN/A0605 I 20162016 -004 -0008a42016FACILITY NAME I DOCKET NUMBERN/A IN/A9. OPERATING MODEIT.THISREPORTISSUBMITTEDPURSUANTTOTHEREQUlREMENTSOFl0CFR$: (Checkallthatapply)1n zo.z2o1(b)tr zo.2zo3(aX3Xi)tl 50 73(aX2Xii)(A)tr 50 73(a)(2Xv.iiXA)n 20 2zo1(d)n 2o.2zo3(aX3Xii)n so 73(aX2XiiXB)n 50 73(aX2XviiiXB)n 2o.z2o3(a)(1)n 20.2203(aX4)n 50.73(a)(2)(iii)tr 50 73(ax2X.x)(A)n 2o.22os(aX2)(i)tl 50,36(cxl xixA)X 50.73(ax2xivxA)n 50.73(ax2)(x)10, POWER LEVEL12.5t] 20.z2o3(aX2Xii)n 50,36(c)(1Xii)(A)tl 50.73(a)(2xv)(A)tl nl1 (aX4)n 20.2203(aX2Xii.)n 50 36(cX2)n 50.73(aX2XvXB)tl rc r1(aX5)n zo.22o3(aX2Xiv)n 50 46(ax3xii)n 50.73(aX2XvXc)n rc.tr(a'lr)n 2o.2zo3(aX2Xv)n 50.73(aX2)(i)(A)n 50.73(a)(2XvXD)tl ft Tl(ax2)(i)n zo.2zas(aX2Xvi)n 50.73(aX2XiXB)n 50.73(aX2xvii)n ft.77(a)(2)(ii)n 50 73(ax2)(i)(c)t] OTHER Specify in Abstract betow or in NRC Form 366A12, LIEENSEE CONTACT FOR THIS LERTICENSEE CONTACTDean Baker, Licensing EngineerTELEPHONE NUMBER (lnclude Area Code)423-452-4589t3. COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORTcAUSE I svsrerta lconrnoNENrlro.ruRERREPORTABLETO EPIXCAUSESYSTEM I COMPONENTMANU- I REPORTABLEFAcTuRER I ro EPrxB I SB I LVDT ISIEMENSNNO14. SUPPLEMENTAL REPORTfJ ves (f yes, comptete 15.EXPECTEDEXPECTED SUBMISS/Oru DATE)x15. EXPECTEDSUBMISSIONDATEMONTHI DAY I YEARABSTMCT (Limit to 1 4 00 spaces, i.e., approximately 1 5 single-spaced Upewfitten lines)On June 5,2016 at 1227 Eastern Daylight Time (EDT), Watts Bar Nuclear Plant Unit 2 was in MODE 1 atapproximately 12.5 percent power when a safety injection (Sl) actuation occurred, followed by an automatic reactorprotection system (RPS) trip. No primary safety barriers (Reactor Coolant System, containment and fuel clad) werechallenged and no primary or secondary safety or relief valves actuated during the event. The Unit 2 plant trip wasconsidered a complicated trip due to Sl actuation. Safety equipment operated as expected and Sl was promptlyterminated.The reactor trip and Sl were caused by a turbine governor valve failing open, causing a steam header pressure rate ofdecrease Sl actuation signal.NRC FORM 366 (1 1-201s) | | 10 cFR 50 73Watts Bar Nuclear Plant, Unit 2Facility Operating License No. NPF-96NRC Docket No.50-391 Licensee Event Report 391/2016-004-00, Reactor Trip and Safety lnjection Actuation Caused by Turbine Governor Valve FailureThis submittal provides Licensee Event Report (LER) 39112016-004-00. |
| Page 2 of 5NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION(11-2015)LICENSEE EVENT REPORT (LER)CONTINUATION SHEETAPPROVED BY OMB: NO.3150-0104 EXPIRES: 1013112018Estimated burden per response to comply with this mandatory collection request: B0 hours, Reportedlessons learned are incorporated into the licensing process and fed back to industry, Sendcomments regarding burden estimate to the FOIA, Privacy and lnformation Collections Branch (T-5F53), U.S Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail tolnfocollects,Resource@nrc.gov, and to the Desk 0fficer, Office of lnformation and Regulatory Affairs,NEOB-10202, (3150-0104), Ofiice of Management and Budget, Washington, DC 20503 lf a meansused to impose an information collection does not display a currently valid OMB control number, theNRC may nol conduct or sponsor, and a person is not required to respond to, the informationcollection.1. FACILITY NAMEWatts Bar Nuclear Plant, Unit 22. DOCKET NUMBER0500039 13. LER NUMBERYEAR2016SEQUENTIALNUMBER- 004REVNO.-00NARRATIVEI PLANT OPERATING CONDITIONS BEFORE THE EVENTWatts Bar Nuclear Plant (WBN) Unit 2 was in Mode 1 at 12.5 percent rated thermal power (RTP)II. DESCRIPTION OF EVENTA. EventOn June 5, 2016 at1227 Eastern Daylight Time (EDT), Watts Bar Nuclear Plant (WBN) Unit 2 wasin MODE 1 at approximately 12.5 percent powerwhen a safety injection (Sl) actuation occurred,followed by an automatic reactor protection system (RPS) trip. The cause of the trip with Sl was afailure of the No.1 high pressure turbine governor valve {EIIS:XCV} in the open position causing asteam header pressure rate of decrease Sl actuation signal. At1245, Operations personnelsecured safety injection and Unit 2 was stabilized in MODE 3 at normal operating pressure andtemperature. No primary safety barriers (reactor coolant system, containment and fuel clad) werechallenged and no primary or secondary safety or relief valves actuated during the event. The Unit2 plant trip was considered a complicated trip due to Sl actuation. Safety equipment operated asexpected and Sl was promptly terminated.This event was reported to the Nuclear Regulatory Commission (NRC) on June 5, 2016 via EventNotification 51982 pursuant to 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(bX3XivXA).B. lnoperable Structures, Components, or Systems that Contributed to the EventA bracket for the No.'! turbine governor valve linear variable differential transmifter (LVDT) faileddue to vibration induced fatigue.C. Dates and Approximate Times of OccurrencesDate Time (EDT) Event613116 2038 Power level increases from 0 percent power. Governor valve vibrationlevels estimated between2.4 and 4 inches per second (ips). Vibrationinformation obtained during Unit 2 start-up subsequent to this event.614116 1658 Power level reached 127 Megawatt Electric (MWe). Valve positionapproximately 9.3 percent open, vibration estimated between2.5 and 4 ips.615116 1122 Unit 2 generator synchronized with governor valve 1 between 4 and 5percent open. Expected vibration 4 ips.615116 1204 Governor valve 1 7.5 to 8 percent open615116 1227 Unit 2 trips with Sl actuation. Operations enters procedure 2-E-0,Reactor Trip or Safety lnjection615116 1236 Transition to procedure 2-ES-1.1, Sl Termination615116 1245 Slsecured.615116 1320 Plant transitions to 2-GO-5, Unit Shutdown from 30 percent ReactorPower to Hot StandbyNRC FORM 366A (1 1-2015) ae5()NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION(11-2015).":::* *'n":?,^* \l:=.. :4.iffi} LTcENSEE EVENr REPoRT (LER)"";-::S*.*NO CONTINUATION SHEET't*r*rAPPROVED BY OMB: NO.3150-0104 EXPIRES: 101312A18Estimated burden per response to comply with this mandatory collection requestr 80 houm. Reportedlessons learned are incorporated into the licensing process and fed back to industry, SendcommenB regarding burden estimate to the FOIA, Privacy and lnformation Collections Branch (T-5F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail tolnfocollects,Resource@nrc,gov, and to the Desk Officer, 0ffice of lnformation and Regulatory Affairs,NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. lf a meansused to impose an information collection does not display a currently valid OMB control number, theNRC may not conduct or sponsor, and a person is not required to respond to, the informationcollection.1. FACILITY NAMEWatts Bar Nuclear Plant, Unit 22. DOCKET NUMBER0500039 13. LER NUMBERYEAR2016SEQUENTIALNUMBER- 004REVNO.00NARRATIVED. Manufacturer and Model Number of Components that FailedA bracket that mounted the LVDT to the No. 1 governor valve failed due to vibration relatedfatigue.E. Other Systems or Secondary Functions AffectedDuring the event, anomalies were noted with the 2B Motor Driven Auxiliary Feedwater Pump(MDAFWP) and the Turbine Driven Auxiliary Feedwater Pump (TDAFWP). The 28 MDAFWP wasshutdown due to smoke coming from the pump packing. After discussion with the vendor, this wasdetermined to be an expected condition for this type of new packing with minimal break-in timeand the pump was restarted. During operation of the TDAFWP, no oil was noted in one of thebearing sight glasses and the pump was manually secured. This was determined to be an issuewith the sight glass providing inaccurate indication and not a lack of oil. The pump wassubsequently returned to service.F. Method of discovery of each Component or System Failure or Procedural ErrorThe failure became apparent after the plant trip.G. Failure Mode and Effect of Each Failed ComponentThe No. 1 governor valve mounting bracket failed from vibration related fatigue.H. Operator ActionsThis reactor trip was complicated by a concurrent Sl. Operations personnel were able to promptlyterminate Sl in accordance with plant procedures and restore the plant to a normal shutdownalignment.L Automatically and Manually lnitiated Safety System ResponsesAll automatic and manualsafety systems responded as expected.III. CAUSE OF THE EVENTA. The cause of each component or system failure or personnel error, if known.The Unit 2 No. 1 governor valve LVDT bracket experienced failure due to short term cyclic fatigueduring extended start-up conditions.B. The cause(s) and circumstances for each human performance related root cause.There were no apparent human performance related root cause.NRC FORM 3664 (11-2015)Paqe 3 of 5 Page 4 of 5NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION(1 1-201s).":':* "ou:hi ffii LTcENSEE EVENr REPoRT (LER)-f+^.<ffi>.C;T- CONTINUATION SHEET, t11*tAPPROVED BY OMB: NO.3150-0104 EXPIRES: 10/31/2018Estimated burden per response to comply with this mandatory collection request: B0 hours, Reportedlessons learned are incorporated into the licensing process and fed back to industry, Sendcommenb regarding burden estimate to the FOIA, Privrcy and lnformation Collections Branch (T-5F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail tolnfocollects,Resource@nrc,gov, and to the Desk Officer, Office of lnformation and Regulatory Affaim,NE0B-10242, (3150-0104), Office of Management and Budget, Washington, DC 20503 lf a meansused to impose an information collection does not display a currently valid OMB control number, theNRC may not conduct or sponsor, and a person is not required to respond to, the informationcollection,1. FACILITY NAMEWatts Bar Nuclear Plant, Unit 22. DOCKET NUMBER0500039 13. LER NUMBERYEAR2416SEQUENTIALNUMBER- 004REVNO.-00NARRATIVEIV. ANALYSIS OF THE EVENTThe turbine governor valves experience high vibration when operated at low steam flow. This flow inducedvibration is inherent to the turbine governor valve design when its position is less than 20 percent open.Vibration is highest with the valve less than 12 percent open. While operating WBN Unit 2 at low power foran extended period, a bracket supporting a position transducer failed, causing an associated failure on theLVDT position rod. During operation, the broken LVDT core rod "walked off'the actuator arm, giving afalse low position of the governor valve. The control system, based on the false indication, provided anopen demand signal to the No.1 governor valve, which lead to a steam header pressure rate of decreasesafety injection actuation signal and an automatic reactor trip.V. ASSESSMENT OF SAFETY CONSEQUENCESWBN Unit 2 experienced a safety injection with an automatic reactor trip. All safety equipment respondedas expected and operations personnel promptly terminated safe$ injection. The plant was stabilized inMode 3 without any additional complications. The risk associated this event was determined to be lessthan 1E-6.A. Availability of systems or components that could have performed the same function as thecomponents and systems that failed during the eventThe failure that occurred was on a non-safety related turbine component. No safety systems wereimpacted as a result of this failure .B. For events that occurred when the reactor was shut down, availability of systems or componentsneeded to shutdown the reactor and maintain safe shutdown conditions, remove residual heatcontrol the release of radioactive material, or mitigate the consequences of an accidentNot applicable.C. For failure that rendered a train of a safety system inoperable, an estimate of the elapsed timefrom the discovery of the failure until the train was returned to serviceNot applicable.VI. CORRECTIVE ACTIONSThis event was entered into the Tennessee Valley Authority (TVA) Corrective Action Program and is beingtracked under condition report 1178855.A. lmmediate Corrective ActionsThe plant was placed in a safe condition. The failed turbine governor components were replaced.NRC FORM 366A (11-2015) | | This LERprovides details concerning a recent reactor trip with safety injection as a result of a turbinegovernor valve failure. |
| Page 5 of 5NRC FORM 366A U.S. NUCLEAR REGULATORY COM]I'IISSION(1 1-201s)LICENSEE EVENT REPORT (LER)CONTINUATION SHEETAPPROVED BY OMB: NO.3150-0104 EXPIRES: 1013112018Estimated burden per response to comply with this mandatory collection request: 80 hours, Reportedlessons learned are incorporated into the licensing process and fed back to industry, Sendcomments regarding burden estimate to the FOIA, Privacy and lnformation Collections Branch (T-5F53), U S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail tolnfocollects,Resource@nrc.gov, and to the Desk Officer, 0ffice of lnformation and Regulatory Afiains,NE0B-10202, (3150-0104),Office of Management and Budget, Washington, DC 20503 lf a meansused to impose an information collection does not display a currently valid OMB control number, theNRC may not conduct or sponsor, and a person is not required to respond to, the informationcollection.1. FACILITY NAMEWatts Bar Nuclear Plant, Unit 22. DOCKET NUMBER0500039 13. LER NUMBERYEAR2016SEQUENTIALNUMBER- 004REVNO.00NARRATIVEB. Corrective Actions to Prevent RecurrencePlant operating procedures will be revised to minimize governor valve operation when the valveposition is less than 12 percent open. TVA will work with the turbine vendor to determine if workcan be performed within the existing valve design requirements to reduce flow induced vibration.VII. ADDITIONAL INFORMATIONA. Previous similar events at the same plantNo similar events have been identified at the Watts Bar plant .B. Additional lnformationNone.C. Safety System Functional Failure ConsiderationThis condition did not result in a safety system functionalfailure.D. Scrams with Complications ConsiderationThere was an Sl associated with this plant trip. Operations personnel were able to promptlyterminate Sl in accordance with plant procedures and restore the plant to a normal shutdownalignment.VIII. COMMITMENTSNone.NRC FORM 366A (1 1-2015)}} | | This report is being submitted in accordance with1 0 cFR 50.73(a)(2)(ivXA). |
| | Please direct any questions concerning this matter to Gordon Arent, WBN Licensing |
| | : Director, at (423) 365-2004. |
| | Paul SimmonsSite Vice President Watts Bar Nuclear PlantEnclosure cc: See Pag e 2Respectfully, U.S. Nuclear Regulatory Commission Page 2August 4, 2016cc (Enclosure): |
| | NRC Regional Administrator |
| | - Region llNRC Senior Resident lnspector |
| | - Watts Bar Nuclear Plant NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION |
| | {11-2015) |
| | $tto*"t'o" iw;e-:Y.c LTcENSEE EVENT REPoRT (LER)-r a*rlAPPROVED BY OMB: NO. 3150-0104 EXPIRES: |
| | t0/31/2018 Estimated burden per response to comply with this mandatory collection request: |
| | 80 hours,Reported lessons learned are incorporated into the licensing process and fed back to industry, Send comments regarding burden estimate to the FOIA, Privacy and lnformation Collections Branch (T-5 F53), U,S, Nuclear Regulatory Commission, Washington, DC 20555-0001, or byinternet e-mail to lnfocollects.Resource@nrc,gov, and to the Desk Officer, Office of lnformation andRegulatory |
| | : Affairs, NE0B-10202, (3150-0104), |
| | ffice of Management and Budget, Washington, DC 20503 lf a means used to impose an information collection does not display a currently validOMB control number, the NRC may not conduct or sponsor, and a person is not required torespond to, the information collection, |
| | : 1. FACILITY NAMEWatts Bar Nuclear Plant, Unit 22, DOCKET NUMBER0500039 13. PAGE10F54. TITLEReactor Trip and Safety lnjection Actuation Caused by Turbine Governor Valve Failure5. EVENT DATE6. LER NUMBER7. REPORT DATE8. OTHER FACILITIES INVOLVEDMONTHI DAY I YEARYEAR I 'i,Hrut$REVNO,MONTH I DAYYEARFACTLTTY NAME I DOCKET NUMBERN/A lN/A0605 I 20162016 -004 -0008a42016FACILITY NAME I DOCKET NUMBERN/A IN/A9. OPERATING MODEIT.THISREPORTISSUBMITTEDPURSUANTTOTHEREQUlREMENTSOFl0CFR$: |
| | (Checkallthatapply) 1n zo.z2o1(b) tr zo.2zo3(aX3Xi) tl 50 73(aX2Xii)(A) tr 50 73(a)(2Xv.iiXA) n 20 2zo1(d)n 2o.2zo3(aX3Xii) n so 73(aX2XiiXB) n 50 73(aX2XviiiXB) n 2o.z2o3(a)(1) n 20.2203(aX4) n 50.73(a)(2)(iii) tr 50 73(ax2X.x)(A) n 2o.22os(aX2)(i) tl 50,36(cxl xixA)X 50.73(ax2xivxA) n 50.73(ax2)(x) 10, POWER LEVEL12.5t] 20.z2o3(aX2Xii) n 50,36(c)(1Xii)(A) tl 50.73(a)(2xv)(A) tl nl1 (aX4)n 20.2203(aX2Xii.) |
| | n 50 36(cX2)n 50.73(aX2XvXB) tl rc r1(aX5)n zo.22o3(aX2Xiv) n 50 46(ax3xii) n 50.73(aX2XvXc) n rc.tr(a'lr) n 2o.2zo3(aX2Xv) n 50.73(aX2)(i)(A) n 50.73(a)(2XvXD) tl ft Tl(ax2)(i) n zo.2zas(aX2Xvi) n 50.73(aX2XiXB) n 50.73(aX2xvii) n ft.77(a)(2)(ii) n 50 73(ax2)(i)(c) t] OTHER Specify in Abstract betow or in NRC Form 366A12, LIEENSEE CONTACT FOR THIS LERTICENSEE CONTACTDean Baker, Licensing EngineerTELEPHONE NUMBER (lnclude Area Code)423-452-4589 t3. COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORTcAUSE I svsrerta lconrnoNENrlro.ruRER REPORTABLE TO EPIXCAUSESYSTEM I COMPONENT MANU- I REPORTABLE FAcTuRER I ro EPrxB I SB I LVDT ISIEMENSNNO14. SUPPLEMENTAL REPORTfJ ves (f yes, comptete 15.EXPECTEDEXPECTED SUBMISS/Oru DATE)x15. EXPECTEDSUBMISSION DATEMONTHI DAY I YEARABSTMCT (Limit to 1 4 00 spaces, i.e., approximately 1 5 single-spaced Upewfitten lines)On June 5,2016 at 1227 Eastern Daylight Time (EDT), Watts Bar Nuclear Plant Unit 2 was in MODE 1 atapproximately 12.5 percent power when a safety injection (Sl) actuation |
| | : occurred, followed by an automatic reactorprotection system (RPS) trip. No primary safety barriers (Reactor Coolant System, containment and fuel clad) werechallenged and no primary or secondary safety or relief valves actuated during the event. The Unit 2 plant trip wasconsidered a complicated trip due to Sl actuation. |
| | Safety equipment operated as expected and Sl was promptlyterminated. |
| | The reactor trip and Sl were caused by a turbine governor valve failing open, causing a steam header pressure rate ofdecrease Sl actuation signal.NRC FORM 366 (1 1-201s) |
| | Page 2 of 5NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (11-2015) |
| | LICENSEE EVENT REPORT (LER)CONTINUATION SHEETAPPROVED BY OMB: NO.3150-0104 EXPIRES: |
| | 1013112018 Estimated burden per response to comply with this mandatory collection request: |
| | B0 hours, Reportedlessons learned are incorporated into the licensing process and fed back to industry, Sendcomments regarding burden estimate to the FOIA, Privacy and lnformation Collections Branch (T-5F53), U.S Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail tolnfocollects,Resource@nrc.gov, and to the Desk 0fficer, Office of lnformation and Regulatory Affairs,NEOB-10202, (3150-0104), |
| | Ofiice of Management and Budget, Washington, DC 20503 lf a meansused to impose an information collection does not display a currently valid OMB control number, theNRC may nol conduct or sponsor, and a person is not required to respond to, the information collection. |
| | : 1. FACILITY NAMEWatts Bar Nuclear Plant, Unit 22. DOCKET NUMBER0500039 13. LER NUMBERYEAR2016SEQUENTIAL NUMBER- 004REVNO.-00NARRATIVE I PLANT OPERATING CONDITIONS BEFORE THE EVENTWatts Bar Nuclear Plant (WBN) Unit 2 was in Mode 1 at 12.5 percent rated thermal power (RTP)II. DESCRIPTION OF EVENTA. EventOn June 5, 2016 at1227 Eastern Daylight Time (EDT), Watts Bar Nuclear Plant (WBN) Unit 2 wasin MODE 1 at approximately 12.5 percent powerwhen a safety injection (Sl) actuation |
| | : occurred, followed by an automatic reactor protection system (RPS) trip. The cause of the trip with Sl was afailure of the No.1 high pressure turbine governor valve {EIIS:XCV} |
| | in the open position causing asteam header pressure rate of decrease Sl actuation signal. At1245, Operations personnel secured safety injection and Unit 2 was stabilized in MODE 3 at normal operating pressure andtemperature. |
| | No primary safety barriers (reactor coolant system, containment and fuel clad) werechallenged and no primary or secondary safety or relief valves actuated during the event. The Unit2 plant trip was considered a complicated trip due to Sl actuation. |
| | Safety equipment operated asexpected and Sl was promptly terminated. |
| | This event was reported to the Nuclear Regulatory Commission (NRC) on June 5, 2016 via EventNotification 51982 pursuant to 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(bX3XivXA). |
| | B. lnoperable Structures, Components, or Systems that Contributed to the EventA bracket for the No.'! turbine governor valve linear variable differential transmifter (LVDT) faileddue to vibration induced fatigue.C. Dates and Approximate Times of Occurrences Date Time (EDT) Event613116 2038 Power level increases from 0 percent power. Governor valve vibration levels estimated between2.4 and 4 inches per second (ips). Vibration information obtained during Unit 2 start-up subsequent to this event.614116 1658 Power level reached 127 Megawatt Electric (MWe). Valve positionapproximately 9.3 percent open, vibration estimated between2.5 and 4 ips.615116 1122 Unit 2 generator synchronized with governor valve 1 between 4 and 5percent open. Expected vibration 4 ips.615116 1204 Governor valve 1 7.5 to 8 percent open615116 1227 Unit 2 trips with Sl actuation. |
| | Operations enters procedure 2-E-0,Reactor Trip or Safety lnjection 615116 1236 Transition to procedure 2-ES-1.1, Sl Termination 615116 1245 Slsecured. |
| | 615116 1320 Plant transitions to 2-GO-5, Unit Shutdown from 30 percent ReactorPower to Hot StandbyNRC FORM 366A (1 1-2015) ae5()NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (11-2015) |
| | .":::* *'n":?,^* \l:=.. :4.iffi} LTcENSEE EVENr REPoRT (LER)"";-::S*.*NO CONTINUATION SHEET't*r*rAPPROVED BY OMB: NO.3150-0104 EXPIRES: |
| | 101312A18 Estimated burden per response to comply with this mandatory collection requestr 80 houm. Reportedlessons learned are incorporated into the licensing process and fed back to industry, SendcommenB regarding burden estimate to the FOIA, Privacy and lnformation Collections Branch (T-5F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail tolnfocollects,Resource@nrc,gov, and to the Desk Officer, 0ffice of lnformation and Regulatory Affairs,NEOB-10202, (3150-0104), |
| | Office of Management and Budget, Washington, DC 20503. lf a meansused to impose an information collection does not display a currently valid OMB control number, theNRC may not conduct or sponsor, and a person is not required to respond to, the information collection. |
| | : 1. FACILITY NAMEWatts Bar Nuclear Plant, Unit 22. DOCKET NUMBER0500039 13. LER NUMBERYEAR2016SEQUENTIAL NUMBER- 004REVNO.00NARRATIVE D. Manufacturer and Model Number of Components that FailedA bracket that mounted the LVDT to the No. 1 governor valve failed due to vibration relatedfatigue.E. Other Systems or Secondary Functions AffectedDuring the event, anomalies were noted with the 2B Motor Driven Auxiliary Feedwater Pump(MDAFWP) and the Turbine Driven Auxiliary Feedwater Pump (TDAFWP). |
| | The 28 MDAFWP wasshutdown due to smoke coming from the pump packing. |
| | After discussion with the vendor, this wasdetermined to be an expected condition for this type of new packing with minimal break-in timeand the pump was restarted. |
| | During operation of the TDAFWP, no oil was noted in one of thebearing sight glasses and the pump was manually secured. |
| | This was determined to be an issuewith the sight glass providing inaccurate indication and not a lack of oil. The pump wassubsequently returned to service.F. Method of discovery of each Component or System Failure or Procedural ErrorThe failure became apparent after the plant trip.G. Failure Mode and Effect of Each Failed Component The No. 1 governor valve mounting bracket failed from vibration related fatigue.H. Operator ActionsThis reactor trip was complicated by a concurrent Sl. Operations personnel were able to promptlyterminate Sl in accordance with plant procedures and restore the plant to a normal shutdownalignment. |
| | L Automatically and Manually lnitiated Safety System Responses All automatic and manualsafety systems responded as expected. |
| | III. CAUSE OF THE EVENTA. The cause of each component or system failure or personnel error, if known.The Unit 2 No. 1 governor valve LVDT bracket experienced failure due to short term cyclic fatigueduring extended start-up conditions. |
| | B. The cause(s) and circumstances for each human performance related root cause.There were no apparent human performance related root cause.NRC FORM 3664 (11-2015) |
| | Paqe 3 of 5 Page 4 of 5NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (1 1-201s).":':* "ou:hi ffii LTcENSEE EVENr REPoRT (LER)-f+^.<ffi>.C;T-CONTINUATION SHEET, t11*tAPPROVED BY OMB: NO.3150-0104 EXPIRES: |
| | 10/31/2018 Estimated burden per response to comply with this mandatory collection request: |
| | B0 hours, Reportedlessons learned are incorporated into the licensing process and fed back to industry, Sendcommenb regarding burden estimate to the FOIA, Privrcy and lnformation Collections Branch (T-5F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail tolnfocollects,Resource@nrc,gov, and to the Desk Officer, Office of lnformation and Regulatory Affaim,NE0B-10242, (3150-0104), |
| | Office of Management and Budget, Washington, DC 20503 lf a meansused to impose an information collection does not display a currently valid OMB control number, theNRC may not conduct or sponsor, and a person is not required to respond to, the information collection, |
| | : 1. FACILITY NAMEWatts Bar Nuclear Plant, Unit 22. DOCKET NUMBER0500039 13. LER NUMBERYEAR2416SEQUENTIAL NUMBER- 004REVNO.-00NARRATIVE IV. ANALYSIS OF THE EVENTThe turbine governor valves experience high vibration when operated at low steam flow. This flow inducedvibration is inherent to the turbine governor valve design when its position is less than 20 percent open.Vibration is highest with the valve less than 12 percent open. While operating WBN Unit 2 at low power foran extended period, a bracket supporting a position transducer failed, causing an associated failure on theLVDT position rod. During operation, the broken LVDT core rod "walked off'the actuator arm, giving afalse low position of the governor valve. The control system, based on the false indication, provided anopen demand signal to the No.1 governor valve, which lead to a steam header pressure rate of decreasesafety injection actuation signal and an automatic reactor trip.V. ASSESSMENT OF SAFETY CONSEQUENCES WBN Unit 2 experienced a safety injection with an automatic reactor trip. All safety equipment responded as expected and operations personnel promptly terminated safe$ injection. |
| | The plant was stabilized inMode 3 without any additional complications. |
| | The risk associated this event was determined to be lessthan 1E-6.A. Availability of systems or components that could have performed the same function as thecomponents and systems that failed during the eventThe failure that occurred was on a non-safety related turbine component. |
| | No safety systems wereimpacted as a result of this failure .B. For events that occurred when the reactor was shut down, availability of systems or components needed to shutdown the reactor and maintain safe shutdown conditions, remove residual heatcontrol the release of radioactive |
| | : material, or mitigate the consequences of an accidentNot applicable. |
| | C. For failure that rendered a train of a safety system inoperable, an estimate of the elapsed timefrom the discovery of the failure until the train was returned to serviceNot applicable. |
| | VI. CORRECTIVE ACTIONSThis event was entered into the Tennessee Valley Authority (TVA) Corrective Action Program and is beingtracked under condition report 1178855.A. lmmediate Corrective ActionsThe plant was placed in a safe condition. |
| | The failed turbine governor components were replaced. |
| | NRC FORM 366A (11-2015) |
| | Page 5 of 5NRC FORM 366A U.S. NUCLEAR REGULATORY COM]I'IISSION (1 1-201s)LICENSEE EVENT REPORT (LER)CONTINUATION SHEETAPPROVED BY OMB: NO.3150-0104 EXPIRES: |
| | 1013112018 Estimated burden per response to comply with this mandatory collection request: |
| | 80 hours, Reportedlessons learned are incorporated into the licensing process and fed back to industry, Sendcomments regarding burden estimate to the FOIA, Privacy and lnformation Collections Branch (T-5F53), U S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail tolnfocollects,Resource@nrc.gov, and to the Desk Officer, 0ffice of lnformation and Regulatory Afiains,NE0B-10202, (3150-0104),Office of Management and Budget, Washington, DC 20503 lf a meansused to impose an information collection does not display a currently valid OMB control number, theNRC may not conduct or sponsor, and a person is not required to respond to, the information collection. |
| | : 1. FACILITY NAMEWatts Bar Nuclear Plant, Unit 22. DOCKET NUMBER0500039 13. LER NUMBERYEAR2016SEQUENTIAL NUMBER- 004REVNO.00NARRATIVE B. Corrective Actions to Prevent Recurrence Plant operating procedures will be revised to minimize governor valve operation when the valveposition is less than 12 percent open. TVA will work with the turbine vendor to determine if workcan be performed within the existing valve design requirements to reduce flow induced vibration. |
| | VII. ADDITIONAL INFORMATION A. Previous similar events at the same plantNo similar events have been identified at the Watts Bar plant .B. Additional lnformation None.C. Safety System Functional Failure Consideration This condition did not result in a safety system functionalfailure. |
| | D. Scrams with Complications Consideration There was an Sl associated with this plant trip. Operations personnel were able to promptlyterminate Sl in accordance with plant procedures and restore the plant to a normal shutdownalignment. |
| | VIII. COMMITMENTS None.NRC FORM 366A (1 1-2015)}} |
|
|---|
Category:Letter
MONTHYEARIR 05000390/20250102024-11-0404 November 2024
Notification of an NRC (FPTI) (NRC Inspection Report 05000390/2025010 0500039/ 2025010) (RFI)
CNL-24-074, Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2024-10-23023 October 2024
Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure Revisions
IR 05000390/20243012024-10-17017 October 2024
Operator Licensing Examination Approval 05000390/2024301 and 05000391/2024301
ML24282B0412024-10-15015 October 2024
Request for Withholding Information from Public Disclosure for Sequoyah Nuclear Plant, Units 1 and 2 and Watts Bar Nuclear Plant, Units 1 and 2
ML24260A1682024-10-0404 October 2024
Regulatory Audit Summary Related to Request to Add and Revise Notes Related to Technical Specification Table 3.3.2-1, Function 5
ML24261C0062024-10-0404 October 2024
Correction to Amendment No. 134 to Facility Operating License No. NPF-90 and Amendment No. 38 to Facility Operating License No. NPF-96
ML24284A1072024-09-26026 September 2024
Affidavit for Request for Withholding Information from Public Disclosure for Sequoyah Nuclear Plant, Units 1 and 2, and Watts Bar Nuclear Plant, Units 1 and 2
CNL-24-047, Decommitment of Flood Mode Mitigation Improvement Systems2024-09-24024 September 2024
Decommitment of Flood Mode Mitigation Improvement Systems
CNL-24-060, Supplement to Request for Approval of the Tennessee Valley Authority Nuclear Quality Assurance Program Description2024-09-24024 September 2024
Supplement to Request for Approval of the Tennessee Valley Authority Nuclear Quality Assurance Program Description
ML24262A0602024-09-23023 September 2024
Summary of August 19, 2024, Meeting with Tennessee Valley Authority Regarding a Proposed Supplement to the Tennessee Valley Authority Nuclear Quality Assurance Plan
CNL-24-065, Tennessee Valley Authority – Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2024-09-18018 September 2024
Tennessee Valley Authority – Central Emergency Control Center Emergency Plan Implementing Procedure Revisions
05000390/LER-2024-002, Automatic Reactor Trip Due to Main Generator Protection Relay Actuation2024-09-0505 September 2024
Automatic Reactor Trip Due to Main Generator Protection Relay Actuation
IR 05000390/20240052024-08-28028 August 2024
Updated Inspection Plan and Assessment Follow-Up Letter for Watts Bar Nuclear Plant, Units 1 and 2 - Report 05000390-2024005 and 05000391-2024005
ML24218A1442024-08-27027 August 2024
Issuance of Amendment Nos. 169 and 75 Regarding Technical Specification Surveillance Requirement 3.9.5.1 to Reduce the Residual Heat Removal Flow Rate
IR 05000390/20244022024-08-20020 August 2024
– Security Baseline Inspection Report 05000390-2024402 and 05000391/2024402 - Public
CNL-24-061, Supplement to Application to Revise Function 5 of Technical Specification Table 3.3.2-1, ‘Engineered Safety Feature Actuation System Instrumentation,’ for the Sequoyah and Watts Bar (SQN-TS-23-02 and WBN-TS-23-08),2024-08-19019 August 2024
Supplement to Application to Revise Function 5 of Technical Specification Table 3.3.2-1, ‘Engineered Safety Feature Actuation System Instrumentation,’ for the Sequoyah and Watts Bar (SQN-TS-23-02 and WBN-TS-23-08),
ML24219A0262024-08-12012 August 2024
Request for Withholding Information from Public Disclosure
IR 05000390/20240022024-08-0707 August 2024
Integrated Inspection Report 05000390/2024002 and 05000391/2024002 Rev
ML24204A2652024-07-25025 July 2024
Regulatory Audit Summary Related to Request to Revise Technical Specification Surveillance Requirement 3.9.5.1 to Reduce the Residual Heat Removal Flow Rate
ML24199A0012024-07-22022 July 2024
Clarification and Correction to Exemption from Requirement of 10 CFR 37.11(c)(2)
ML24170A8002024-07-15015 July 2024
Issuance of Amendment Nos. 168 and 74 Regarding Revision to Technical Specification Table 1.1-1 for Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Bolts
ML24172A1342024-07-15015 July 2024
Exemptions from 10 CFR 37.11(C)(2) (EPID L-2023-LLE-0024) - Letter
IR 05000390/20244402024-07-12012 July 2024
95001 Supplemental Inspection Supplemental Report 05000390-2024440 and 05000391-2024440 and Follow-Up Assessment Letter
05000391/LER-2024-003, Inoperability of Both Trains of Unit 2 Low Head Safety Injection2024-07-11011 July 2024
Inoperability of Both Trains of Unit 2 Low Head Safety Injection
ML24131A0012024-07-0202 July 2024
Issuance of Amendment Nos. 167 and 73 Regarding Adoption of Technical Specification Task Force Traveler TSTF-427-A, Revision 2
CNL-24-052, Response to Request for Additional Information Regarding Application to Modify the Technical Specification Surveillance Requirement 3.9.5.1 (WBN-TS-21-14)2024-06-27027 June 2024
Response to Request for Additional Information Regarding Application to Modify the Technical Specification Surveillance Requirement 3.9.5.1 (WBN-TS-21-14)
CNL-24-018, License Amendment Request for Adoption of Technical Specification Task Force Traveler TSTF-276-A, Revision 2, Regarding TS 3.8.1 AC Sources – Operating to Clarify Requirements for Diesel Generator Testing (WBN-TS2024-06-25025 June 2024
License Amendment Request for Adoption of Technical Specification Task Force Traveler TSTF-276-A, Revision 2, Regarding TS 3.8.1 AC Sources – Operating to Clarify Requirements for Diesel Generator Testing (WBN-TS
ML24089A1152024-06-21021 June 2024
Transmittal Letter, Environmental Assessments and Findings of No Significant Impact Related to Exemption Requests from 10 CFR 37.11(c)(2)
ML24141A0482024-05-17017 May 2024
EN 56958_1 Ametek Solidstate Controls, Inc
ML24100A7642024-05-16016 May 2024
Issuance of Amendment No. 166 Regarding Revision to Technical Specification 3.8.2, AC Sources-Shutdown, to Remove Reference to C-S Diesel Generator (CNL-23-062)
IR 05000390/20240012024-05-14014 May 2024
Integrated Inspection Report 05000390/2024001 and 05000391/2024001
CNL-24-040, Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2024-05-0808 May 2024
Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure Revisions
05000391/LER-2024-002, Re Automatic Reactor Trip Due to Steam Generator 3 Level LO-LO2024-05-0606 May 2024
Re Automatic Reactor Trip Due to Steam Generator 3 Level LO-LO
IR 05000391/20240072024-04-30030 April 2024
Assessment Follow-up Letter for Watts Bar Nuclear Plant, Unit 2 – Report 05000391/2024007
ML24120A1182024-04-29029 April 2024
– Notification of NRC Supplemental Inspection (95001) and Request for Information
CNL-24-037, Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Unit 1 and 2, Nuclear Quality Assurance Plan, TVA-NQA-PLN89-A, Revision 422024-04-22022 April 2024
Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Unit 1 and 2, Nuclear Quality Assurance Plan, TVA-NQA-PLN89-A, Revision 42
ML24087A1912024-04-18018 April 2024
Exemption from Select Requirements of 10 CFR Part 73, Security Notifications, Reports, and Recordkeeping and Suspicious Activity Reporting
CNL-24-024, Hydrologic Engineering Center River Analysis System Project Milestone Status Update2024-04-17017 April 2024
Hydrologic Engineering Center River Analysis System Project Milestone Status Update
CNL-24-010, License Amendment Request to Recapture Low-Power Testing Time (WBN-TS-23-19)2024-04-17017 April 2024
License Amendment Request to Recapture Low-Power Testing Time (WBN-TS-23-19)
CNL-24-033, Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2024-04-17017 April 2024
Central Emergency Control Center Emergency Plan Implementing Procedure Revisions
ML24072A0052024-04-15015 April 2024
Issuance of Amendment Nos. 165 and 72 Regarding Increase in the Maximum Number of Tritium Producing Burnable Absorber Rods and Supporting Changes, and Revision to the Updated Final Safety Analysis Report
CNL-24-004, Application to Modify the Watts Bar Nuclear Plant, Unit 1 and Unit 2 Technical Specifications for Main Control Room Chiller Completion Time Extension (WBN-TS-23-13)2024-04-0404 April 2024
Application to Modify the Watts Bar Nuclear Plant, Unit 1 and Unit 2 Technical Specifications for Main Control Room Chiller Completion Time Extension (WBN-TS-23-13)
IR 05000390/20244012024-04-0202 April 2024
– Security Baseline Inspection Report 05000390/2024401 and 05000391/2024401 - (Public)
CNL-24-020, Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Units 1 and 2, Request for Approval of Quality Assurance Program Description and Application to Revise the Technical Specifications Associated with QAPD Requirements2024-04-0101 April 2024
Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Units 1 and 2, Request for Approval of Quality Assurance Program Description and Application to Revise the Technical Specifications Associated with QAPD Requirements
CNL-24-008, Guarantee of Payment of Deferred Premiums - 2023 Annual Report2024-03-27027 March 2024
Guarantee of Payment of Deferred Premiums - 2023 Annual Report
05000391/LER-2024-001, Automatic Reactor Trip Due to Main Generator Protection Relay Actuation2024-03-27027 March 2024
Automatic Reactor Trip Due to Main Generator Protection Relay Actuation
CNL-24-007, Annual Insurance Status Report2024-03-27027 March 2024
Annual Insurance Status Report
CNL-24-025, Notice of Intent to Pursue License Renewal for Watts Bar Nuclear Plant, Unit 1 - Submittal Schedule2024-03-25025 March 2024
Notice of Intent to Pursue License Renewal for Watts Bar Nuclear Plant, Unit 1 - Submittal Schedule
ML24081A0262024-03-21021 March 2024
Emergency Plan Implementing Procedure Revisions
ML24079A0312024-03-19019 March 2024
Wb 2024-301, Corporate Notification Letter (210-day Ltr)
2024-09-05
[Table view]
Category:Licensee Event Report (LER)
MONTHYEAR05000390/LER-2024-002, Automatic Reactor Trip Due to Main Generator Protection Relay Actuation2024-09-0505 September 2024
Automatic Reactor Trip Due to Main Generator Protection Relay Actuation
05000391/LER-2024-003, Inoperability of Both Trains of Unit 2 Low Head Safety Injection2024-07-11011 July 2024
Inoperability of Both Trains of Unit 2 Low Head Safety Injection
05000391/LER-2024-002, Re Automatic Reactor Trip Due to Steam Generator 3 Level LO-LO2024-05-0606 May 2024
Re Automatic Reactor Trip Due to Steam Generator 3 Level LO-LO
05000391/LER-2024-001, Automatic Reactor Trip Due to Main Generator Protection Relay Actuation2024-03-27027 March 2024
Automatic Reactor Trip Due to Main Generator Protection Relay Actuation
05000391/LER-2023-003-01, Automatic Reactor Trip Due to Loss of Main Feedwater Regulating Valve Control2024-02-29029 February 2024
Automatic Reactor Trip Due to Loss of Main Feedwater Regulating Valve Control
05000391/LER-2023-003, Automatic Reactor Trip Due to Loss of Main Feedwater Regulating Valve Control2023-10-0303 October 2023
Automatic Reactor Trip Due to Loss of Main Feedwater Regulating Valve Control
05000390/LER-2023-001-01, Inadequate 10 CFR 50.59 Results in Failure to Obtain Prior NRC Approval for Condition Prohibited by Technical Specifications2023-09-27027 September 2023
Inadequate 10 CFR 50.59 Results in Failure to Obtain Prior NRC Approval for Condition Prohibited by Technical Specifications
05000391/LER-2023-002, Automatic Reactor Trip Due to Main Generator Protection Relay Actuation2023-08-24024 August 2023
Automatic Reactor Trip Due to Main Generator Protection Relay Actuation
05000391/LER-2023-001, Unanalyzed Condition Related to Loss of the 2A Emergency Diesel Generator During a Postulated Appendix R Fire2023-07-20020 July 2023
Unanalyzed Condition Related to Loss of the 2A Emergency Diesel Generator During a Postulated Appendix R Fire
05000390/LER-2023-001, Interpretation of Technical Specification (TS) Table 1.1-1 Leads to a Condition Prohibited by TS2023-07-0303 July 2023
Interpretation of Technical Specification (TS) Table 1.1-1 Leads to a Condition Prohibited by TS
05000391/LER-2017-0052018-01-25025 January 2018
Unplanned Emergency Core Cooling System Injection into the Reactor Coolant System due to Personnel Error, LER 17-005-00 for Watts Bar, Unit 2, Regarding Unplanned Emergency Core Cooling System Injection into the Reactor Coolant System due to Personnel Error
05000390/LER-2017-0152018-01-0808 January 2018
Failure to Enter Limiting Condition of Operation Action Statement Results in a Condition Prohibited by Technical Specifications, LER 17-015-00 for Watts Bar, Units 1 and 2, Regarding Failure to Enter Limiting Condition of Operation Action Statement Results in a Condition Prohibited by Technical Specifications
05000390/LER-2017-0142017-12-20020 December 2017
Main Control Room Boundary Door Left Open Leading to a Loss of Safety Function, LER 17-014-00 for Watts Bar, Unit 1, Regarding Main Control Room Boundary Door Left Open Leading to a Loss of Safety Function
05000390/LER-2017-0122017-10-23023 October 2017
Error in Plant Emergency Procedures Leads to a Condition Prohibited by the Technical Specifications, LER 17-012-00 for Watts Bar, Unit 1, Regarding Error in Plant Emergency Procedures Leads to a Condition Prohibited by the Technical Specifications
05000390/LER-2017-0112017-10-23023 October 2017
Failure to Enter Technical Specification 3.6.3 for Containment Isolation Valve, LER 17-011-00 for Watts Bar, Unit 1, Regarding Failure to Enter Technical Specification 3.6.3 for Containment lsolation Valve
05000390/LER-2017-0102017-10-10010 October 2017
Actuation of Turbine Driven Auxiliary Feedwater Pump Due to Loss of 6.9kV Shutdown Board, LER 17-010-00 for Watts Bar Nuclear Plant, Unit 1 Regarding Actuation of Turbine Driven Auxiliary Feedwater Pump Due to Loss of 6.9kV Shutdown Board
05000391/LER-2017-0042017-09-25025 September 2017
Manual Reactor Trip Due to Inoperable Rod Position Indication, LER 17-004-00 for Watts Bar Nuclear Plant, Unit 2 Regarding Manual Reactor Trip Due to Inoperable Rod Position Indication
05000390/LER-2017-0042017-08-31031 August 2017
Manual Reactor Trips Due to Failed Reactor Coolant Pump Power Transfer During Plant Startup, LER 17-004-01 for Watts Bar, Unit 1, Regarding Manual Reactor Trips Due to Failed Reactor Coolant Pump Power Transfer During Plant Startup
05000390/LER-2017-0082017-08-14014 August 2017
Shield Building Inoperability and Potential Loss of Safety Function Resulting from Spurious Equipment Operation, LER 17-008-00 for Watts Bar, Unit 1, Regarding Shield Building Inoperability and Potential Loss of Safety Function Resulting from Spurious Equipment Operation
05000390/LER-2017-0072017-08-0808 August 2017
Multiple Unreported Potential Loss of Safety Function Events Associated with Inoperable Single Train Systems Due to Misinterpretation of Reporting Guidance, LER 17-007-00 for Watts Bar, Unit 1, Regarding Multiple Unreported Potential Loss of Safety Function Events Associated with Inoperable Single Train Systems Due to Misinterpretation of Reporting Guidance
05000390/LER-2017-0062017-07-31031 July 2017
Structural Degradation of 161 kV Line Pole Leads to a Condition Prohibited by Technical Specifications, LER 17-006-00 for Watts Bar, Unit 1, Regarding Structural Degradation of 161 kV Line Pole Leads to a Condition Prohibited by Technical Specifications
05000390/LER-2017-0052017-07-10010 July 2017
Isolation of the 1 B-B Safety Injection Pump Leads to Condition Prohibited by Technical Specifications, LER 17-005-00 for Watts Bar re Isolation of the 1B-B Safety Injection Pump Leads to a Condition Prohibited by Technical Specifications
05000391/LER-2017-0032017-05-22022 May 2017
Automatic Start of Auxiliary Feedwater System Due to Main Condenser Failure, LER 17-003-00 for Watts Bar, Unit 2, Regarding Automatic Start of Auxiliary Feedwater System Due to Main Condenser Failure
05000391/LER-2017-0022017-05-12012 May 2017
Manual Reactor Trip as a Result of a Secondary Plant Transient, LER 17-002-00 for Watts Bar, Unit 2, Regarding Manual Reactor Trip as a Result of a Secondary Plant Transient
05000391/LER-2017-0012017-05-0303 May 2017
Containment Airlock Function Lost Due to Equalizing Valve Not Closing, LER 17-001-00 for Watts Bar, Unit 2, Regarding Containment Airlock Function Lost Due to Equalizing Valve Not Closing
05000390/LER-2017-0032017-03-0303 March 2017
Inadequate Operability Determination Leads to a Condition Prohibited by the Technical Specifications, LER 17-003-00 for Watts Bar, Unit 1, Regarding Inadequate Operability Determination Leads to a Condition Prohibited by the Technical Specifications
05000390/LER-2017-0022017-02-22022 February 2017
Incorrectly Hung Clearance Leads to a Condition Prohibited by the Technical Specifications, LER 17-002-00 for Watts Bar Nuclear Plant, Unit 1, Regarding: Incorrectly Hung Clearance Leads to a Condition Prohibited by the Technical Specifications
05000390/LER-2016-0112016-12-0909 December 2016
Loss of Centrifugal Charging Pump Due to Repeat Failure of Associated Room Cooler, LER 16-011-01 for Watts Bar Nuclear Plant, Unit 1 Regarding Loss of Centrifugal Charging Pump Due to Repeat Failure of Associated Room Cooler
05000391/LER-2016-0082016-10-28028 October 2016
Reactor Trip Resulting from Failure of 2B Main Bank Transformer, LER 16-008-00 for Watts Bar, Unit 2, Regarding Reactor Trip Resulting from Failure of 2B Main Bank Transformer
05000391/LER-2016-0052016-08-19019 August 2016
Main Feedwater Pump Trip on Loss of Condenser Vacuum Leads to Turbine Trip and Reactor Trip, LER 16-005-00 for Watts Bar, Unit 2, Regarding Main Feedwater Pump Trip on Loss of Condenser Vacuum Leads to Turbine Trip and Reactor Trip
05000390/LER-2016-0102016-08-0808 August 2016
Emergency Diesel Generator Crankcase Pressure Switches Not Analyzed to Withstand the Effects of a Tornado, LER-16-010-00 for Watts Bar Nuclear Plant, Units 1 and 2 Regarding Emergency Diesel Generator Crankcase Pressure Switches Not Analyzed to Withstand the Effects of a Tornado
05000391/LER-2016-0042016-08-0404 August 2016
Reactor Trip and Safety Injection Actuation Caused by Turbine Governor Valve Failure, LER 16-004-00 for Watts Bar, Unit 2, Regarding Reactor Trip and Safety Injection Actuation Caused by Turbine Governor Valve Failure
05000391/LER-2016-0032016-07-27027 July 2016
Turbine Driven Auxiliary Feedwater Pump Inoperable for Longer than Allowable Outage Time due to Governor Valve Spring Over-Tensioning, LER 16-003-00 for Watts Bar, Unit 2, Regarding Turbine Driven Auxiliary Feedwater Pump lnoperable for Longer Than Allowable Outage Time Due to Governor Valve Spring Over-Tensioning
05000390/LER-2016-0082016-07-15015 July 2016
Emergency Diesel Generator Manual Start Due to Loss of Voltage on the 6.9kV Shutdown Board 1B-B, LER 16-008-00 for Watts Bar, Unit 1, Regarding Emergency Diesel Generator Manual Start Due to Loss of Voltage on the 6.9kV Shutdown Board 1B-B
05000390/LER-2016-0092016-07-15015 July 2016
Failure to Complete Surveillance Requirements Causes a Condition Prohibited by the Technical Specifications, LER 16-009-00 for Watts Bar, Unit 1, Regarding Failure to Complete Surveillance Requirements Causes Conditions Prohibited by the Technical Specifications
05000391/LER-2016-0022016-07-11011 July 2016
Turbine Driven Auxiliary Feedwater Pump Inoperable for Longer than Allowable Outage Time due to Turbine Speed Control Failure, LER 16-002-00 for Watts Bar, Unit 2, Regarding Turbine Driven Auxiliary Feedwater Pump Inoperable for Longer Than Allowable Outage Time Due to Turbine Speed Control Failure
05000390/LER-2016-0062016-06-30030 June 2016
Undersized Room Cooler Fan Shaft Results in Loss of Centrifugal Charging Pump, LER 16-006-00 for Watts Bar, Unit 1, Regarding Undersized Room Cooler Fan Shaft Results in Loss of Centrifugal Charging Pump
05000390/LER-2016-0072016-06-20020 June 2016
Technical Specification Action Not Met for Rod Position Indication, LER 16-007-00 for Watts Bar Nuclear Plant, Unit 1 Regarding Technical Specification Action Not Met for Rod Position Indication
05000391/LER-2016-0012016-06-13013 June 2016
Loss of Automatic Containment Isolation for the Steam Generator Blowdown Sampling Lines, LER 16-001-00 for Watts Bar, Unit 2, Regarding Loss of Automatic Containment Isolation for the Steam Generator Blowdown Sampling Lines
05000390/LER-2016-0042016-05-23023 May 2016
Automatic Reactor Trip Due to Actuation of Over Temperature Delta Temperature Bistables, LER 16-004-00 for Watts Bar, Unit 1, Regarding Automatic Reactor Trip Due to Actuation of Over Temperature Delta Temperature Bistables
05000390/LER-2016-0052016-05-13013 May 2016
Both Trains of Unit 1 Emergency Gas Treatment System Inoperable During Unit 2 Testing, LER 16-005-00 for Watts Bar, Unit 1, Regarding Both Trains of Unit 1, Emergency Gas Treatment System Inoperable During Unit 2, Testing
05000390/LER-2016-0032016-05-10010 May 2016
Technical Specification Surveillance Requirement Not Met During Emergency Core Cooling System Venting, LER 16-003-00 for Watts Bar, Unit 1, Regarding Technical Specification Surveillance Requirement Not Met During Emergency Core Cooling System Venting
05000390/LER-2016-0022016-05-0404 May 2016
Technical Specification Action Not Met for Inoperable Containment Isolation Valve, LER 16-002-00 for Watts Bar, Unit 1, Regarding Technical Specification Action Not Met for Inoperable Containment Isolation Valve
05000390/LER-2016-0012016-03-0909 March 2016
Channel Mode Switch in Incorrect Position Renders Lower Containment Atmosphere Particulate Radiation Monitor Inoperable, LER 16-001-00 for Watts Bar, Unit 1, Regarding Channel Mode Switch in Incorrect Position Renders Lower Containment Atmosphere Particulate Radiation Monitor Inoperable
ML1134703432011-12-13013 December 2011
Withdrawal of License Event Report 390/2011-003, Mode Change Without Meeting Limiting Condition for Operation (LCO) 3.7.5
2024-09-05
[Table view] |
Text
Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381August 4, 2016ATTN: Document Control DeskU.S. Nuclear Regulatory Commission Washington, D.C 20555-0001
Subject:
10 cFR 50 73Watts Bar Nuclear Plant, Unit 2Facility Operating License No. NPF-96NRC Docket No.50-391 Licensee Event Report 391/2016-004-00, Reactor Trip and Safety lnjection Actuation Caused by Turbine Governor Valve FailureThis submittal provides Licensee Event Report (LER) 39112016-004-00.
This LERprovides details concerning a recent reactor trip with safety injection as a result of a turbinegovernor valve failure.
This report is being submitted in accordance with1 0 cFR 50.73(a)(2)(ivXA).
Please direct any questions concerning this matter to Gordon Arent, WBN Licensing
- Director, at (423) 365-2004.
Paul SimmonsSite Vice President Watts Bar Nuclear PlantEnclosure cc: See Pag e 2Respectfully, U.S. Nuclear Regulatory Commission Page 2August 4, 2016cc (Enclosure):
NRC Regional Administrator
- Region llNRC Senior Resident lnspector
- Watts Bar Nuclear Plant NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION
{11-2015)
$tto*"t'o" iw;e-:Y.c LTcENSEE EVENT REPoRT (LER)-r a*rlAPPROVED BY OMB: NO. 3150-0104 EXPIRES:
t0/31/2018 Estimated burden per response to comply with this mandatory collection request:
80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />,Reported lessons learned are incorporated into the licensing process and fed back to industry, Send comments regarding burden estimate to the FOIA, Privacy and lnformation Collections Branch (T-5 F53), U,S, Nuclear Regulatory Commission, Washington, DC 20555-0001, or byinternet e-mail to lnfocollects.Resource@nrc,gov, and to the Desk Officer, Office of lnformation andRegulatory
- Affairs, NE0B-10202, (3150-0104),
ffice of Management and Budget, Washington, DC 20503 lf a means used to impose an information collection does not display a currently validOMB control number, the NRC may not conduct or sponsor, and a person is not required torespond to, the information collection,
- 1. FACILITY NAMEWatts Bar Nuclear Plant, Unit 22, DOCKET NUMBER0500039 13. PAGE10F54. TITLEReactor Trip and Safety lnjection Actuation Caused by Turbine Governor Valve Failure5. EVENT DATE6. LER NUMBER7. REPORT DATE8. OTHER FACILITIES INVOLVEDMONTHI DAY I YEARYEAR I 'i,Hrut$REVNO,MONTH I DAYYEARFACTLTTY NAME I DOCKET NUMBERN/A lN/A0605 I 20162016 -004 -0008a42016FACILITY NAME I DOCKET NUMBERN/A IN/A9. OPERATING MODEIT.THISREPORTISSUBMITTEDPURSUANTTOTHEREQUlREMENTSOFl0CFR$:
(Checkallthatapply) 1n zo.z2o1(b) tr zo.2zo3(aX3Xi) tl 50 73(aX2Xii)(A) tr 50 73(a)(2Xv.iiXA) n 20 2zo1(d)n 2o.2zo3(aX3Xii) n so 73(aX2XiiXB) n 50 73(aX2XviiiXB) n 2o.z2o3(a)(1) n 20.2203(aX4) n 50.73(a)(2)(iii) tr 50 73(ax2X.x)(A) n 2o.22os(aX2)(i) tl 50,36(cxl xixA)X 50.73(ax2xivxA) n 50.73(ax2)(x) 10, POWER LEVEL12.5t] 20.z2o3(aX2Xii) n 50,36(c)(1Xii)(A) tl 50.73(a)(2xv)(A) tl nl1 (aX4)n 20.2203(aX2Xii.)
n 50 36(cX2)n 50.73(aX2XvXB) tl rc r1(aX5)n zo.22o3(aX2Xiv) n 50 46(ax3xii) n 50.73(aX2XvXc) n rc.tr(a'lr) n 2o.2zo3(aX2Xv) n 50.73(aX2)(i)(A) n 50.73(a)(2XvXD) tl ft Tl(ax2)(i) n zo.2zas(aX2Xvi) n 50.73(aX2XiXB) n 50.73(aX2xvii) n ft.77(a)(2)(ii) n 50 73(ax2)(i)(c) t] OTHER Specify in Abstract betow or in NRC Form 366A12, LIEENSEE CONTACT FOR THIS LERTICENSEE CONTACTDean Baker, Licensing EngineerTELEPHONE NUMBER (lnclude Area Code)423-452-4589 t3. COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORTcAUSE I svsrerta lconrnoNENrlro.ruRER REPORTABLE TO EPIXCAUSESYSTEM I COMPONENT MANU- I REPORTABLE FAcTuRER I ro EPrxB I SB I LVDT ISIEMENSNNO14. SUPPLEMENTAL REPORTfJ ves (f yes, comptete 15.EXPECTEDEXPECTED SUBMISS/Oru DATE)x15. EXPECTEDSUBMISSION DATEMONTHI DAY I YEARABSTMCT (Limit to 1 4 00 spaces, i.e., approximately 1 5 single-spaced Upewfitten lines)On June 5,2016 at 1227 Eastern Daylight Time (EDT), Watts Bar Nuclear Plant Unit 2 was in MODE 1 atapproximately 12.5 percent power when a safety injection (Sl) actuation
- occurred, followed by an automatic reactorprotection system (RPS) trip. No primary safety barriers (Reactor Coolant System, containment and fuel clad) werechallenged and no primary or secondary safety or relief valves actuated during the event. The Unit 2 plant trip wasconsidered a complicated trip due to Sl actuation.
Safety equipment operated as expected and Sl was promptlyterminated.
The reactor trip and Sl were caused by a turbine governor valve failing open, causing a steam header pressure rate ofdecrease Sl actuation signal.NRC FORM 366 (1 1-201s)
Page 2 of 5NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (11-2015)
LICENSEE EVENT REPORT (LER)CONTINUATION SHEETAPPROVED BY OMB: NO.3150-0104 EXPIRES:
1013112018 Estimated burden per response to comply with this mandatory collection request:
B0 hours, Reportedlessons learned are incorporated into the licensing process and fed back to industry, Sendcomments regarding burden estimate to the FOIA, Privacy and lnformation Collections Branch (T-5F53), U.S Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail tolnfocollects,Resource@nrc.gov, and to the Desk 0fficer, Office of lnformation and Regulatory Affairs,NEOB-10202, (3150-0104),
Ofiice of Management and Budget, Washington, DC 20503 lf a meansused to impose an information collection does not display a currently valid OMB control number, theNRC may nol conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAMEWatts Bar Nuclear Plant, Unit 22. DOCKET NUMBER0500039 13. LER NUMBERYEAR2016SEQUENTIAL NUMBER- 004REVNO.-00NARRATIVE I PLANT OPERATING CONDITIONS BEFORE THE EVENTWatts Bar Nuclear Plant (WBN) Unit 2 was in Mode 1 at 12.5 percent rated thermal power (RTP)II. DESCRIPTION OF EVENTA. EventOn June 5, 2016 at1227 Eastern Daylight Time (EDT), Watts Bar Nuclear Plant (WBN) Unit 2 wasin MODE 1 at approximately 12.5 percent powerwhen a safety injection (Sl) actuation
- occurred, followed by an automatic reactor protection system (RPS) trip. The cause of the trip with Sl was afailure of the No.1 high pressure turbine governor valve {EIIS:XCV}
in the open position causing asteam header pressure rate of decrease Sl actuation signal. At1245, Operations personnel secured safety injection and Unit 2 was stabilized in MODE 3 at normal operating pressure andtemperature.
No primary safety barriers (reactor coolant system, containment and fuel clad) werechallenged and no primary or secondary safety or relief valves actuated during the event. The Unit2 plant trip was considered a complicated trip due to Sl actuation.
Safety equipment operated asexpected and Sl was promptly terminated.
This event was reported to the Nuclear Regulatory Commission (NRC) on June 5, 2016 via EventNotification 51982 pursuant to 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(bX3XivXA).
B. lnoperable Structures, Components, or Systems that Contributed to the EventA bracket for the No.'! turbine governor valve linear variable differential transmifter (LVDT) faileddue to vibration induced fatigue.C. Dates and Approximate Times of Occurrences Date Time (EDT) Event613116 2038 Power level increases from 0 percent power. Governor valve vibration levels estimated between2.4 and 4 inches per second (ips). Vibration information obtained during Unit 2 start-up subsequent to this event.614116 1658 Power level reached 127 Megawatt Electric (MWe). Valve positionapproximately 9.3 percent open, vibration estimated between2.5 and 4 ips.615116 1122 Unit 2 generator synchronized with governor valve 1 between 4 and 5percent open. Expected vibration 4 ips.615116 1204 Governor valve 1 7.5 to 8 percent open615116 1227 Unit 2 trips with Sl actuation.
Operations enters procedure 2-E-0,Reactor Trip or Safety lnjection 615116 1236 Transition to procedure 2-ES-1.1, Sl Termination 615116 1245 Slsecured.
615116 1320 Plant transitions to 2-GO-5, Unit Shutdown from 30 percent ReactorPower to Hot StandbyNRC FORM 366A (1 1-2015) ae5()NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (11-2015)
.":::* *'n":?,^* \l:=.. :4.iffi} LTcENSEE EVENr REPoRT (LER)"";-::S*.*NO CONTINUATION SHEET't*r*rAPPROVED BY OMB: NO.3150-0104 EXPIRES:
101312A18 Estimated burden per response to comply with this mandatory collection requestr 80 houm. Reportedlessons learned are incorporated into the licensing process and fed back to industry, SendcommenB regarding burden estimate to the FOIA, Privacy and lnformation Collections Branch (T-5F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail tolnfocollects,Resource@nrc,gov, and to the Desk Officer, 0ffice of lnformation and Regulatory Affairs,NEOB-10202, (3150-0104),
Office of Management and Budget, Washington, DC 20503. lf a meansused to impose an information collection does not display a currently valid OMB control number, theNRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAMEWatts Bar Nuclear Plant, Unit 22. DOCKET NUMBER0500039 13. LER NUMBERYEAR2016SEQUENTIAL NUMBER- 004REVNO.00NARRATIVE D. Manufacturer and Model Number of Components that FailedA bracket that mounted the LVDT to the No. 1 governor valve failed due to vibration relatedfatigue.E. Other Systems or Secondary Functions AffectedDuring the event, anomalies were noted with the 2B Motor Driven Auxiliary Feedwater Pump(MDAFWP) and the Turbine Driven Auxiliary Feedwater Pump (TDAFWP).
The 28 MDAFWP wasshutdown due to smoke coming from the pump packing.
After discussion with the vendor, this wasdetermined to be an expected condition for this type of new packing with minimal break-in timeand the pump was restarted.
During operation of the TDAFWP, no oil was noted in one of thebearing sight glasses and the pump was manually secured.
This was determined to be an issuewith the sight glass providing inaccurate indication and not a lack of oil. The pump wassubsequently returned to service.F. Method of discovery of each Component or System Failure or Procedural ErrorThe failure became apparent after the plant trip.G. Failure Mode and Effect of Each Failed Component The No. 1 governor valve mounting bracket failed from vibration related fatigue.H. Operator ActionsThis reactor trip was complicated by a concurrent Sl. Operations personnel were able to promptlyterminate Sl in accordance with plant procedures and restore the plant to a normal shutdownalignment.
L Automatically and Manually lnitiated Safety System Responses All automatic and manualsafety systems responded as expected.
III. CAUSE OF THE EVENTA. The cause of each component or system failure or personnel error, if known.The Unit 2 No. 1 governor valve LVDT bracket experienced failure due to short term cyclic fatigueduring extended start-up conditions.
B. The cause(s) and circumstances for each human performance related root cause.There were no apparent human performance related root cause.NRC FORM 3664 (11-2015)
Paqe 3 of 5 Page 4 of 5NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (1 1-201s).":':* "ou:hi ffii LTcENSEE EVENr REPoRT (LER)-f+^.<ffi>.C;T-CONTINUATION SHEET, t11*tAPPROVED BY OMB: NO.3150-0104 EXPIRES:
10/31/2018 Estimated burden per response to comply with this mandatory collection request:
B0 hours, Reportedlessons learned are incorporated into the licensing process and fed back to industry, Sendcommenb regarding burden estimate to the FOIA, Privrcy and lnformation Collections Branch (T-5F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail tolnfocollects,Resource@nrc,gov, and to the Desk Officer, Office of lnformation and Regulatory Affaim,NE0B-10242, (3150-0104),
Office of Management and Budget, Washington, DC 20503 lf a meansused to impose an information collection does not display a currently valid OMB control number, theNRC may not conduct or sponsor, and a person is not required to respond to, the information collection,
- 1. FACILITY NAMEWatts Bar Nuclear Plant, Unit 22. DOCKET NUMBER0500039 13. LER NUMBERYEAR2416SEQUENTIAL NUMBER- 004REVNO.-00NARRATIVE IV. ANALYSIS OF THE EVENTThe turbine governor valves experience high vibration when operated at low steam flow. This flow inducedvibration is inherent to the turbine governor valve design when its position is less than 20 percent open.Vibration is highest with the valve less than 12 percent open. While operating WBN Unit 2 at low power foran extended period, a bracket supporting a position transducer failed, causing an associated failure on theLVDT position rod. During operation, the broken LVDT core rod "walked off'the actuator arm, giving afalse low position of the governor valve. The control system, based on the false indication, provided anopen demand signal to the No.1 governor valve, which lead to a steam header pressure rate of decreasesafety injection actuation signal and an automatic reactor trip.V. ASSESSMENT OF SAFETY CONSEQUENCES WBN Unit 2 experienced a safety injection with an automatic reactor trip. All safety equipment responded as expected and operations personnel promptly terminated safe$ injection.
The plant was stabilized inMode 3 without any additional complications.
The risk associated this event was determined to be lessthan 1E-6.A. Availability of systems or components that could have performed the same function as thecomponents and systems that failed during the eventThe failure that occurred was on a non-safety related turbine component.
No safety systems wereimpacted as a result of this failure .B. For events that occurred when the reactor was shut down, availability of systems or components needed to shutdown the reactor and maintain safe shutdown conditions, remove residual heatcontrol the release of radioactive
- material, or mitigate the consequences of an accidentNot applicable.
C. For failure that rendered a train of a safety system inoperable, an estimate of the elapsed timefrom the discovery of the failure until the train was returned to serviceNot applicable.
VI. CORRECTIVE ACTIONSThis event was entered into the Tennessee Valley Authority (TVA) Corrective Action Program and is beingtracked under condition report 1178855.A. lmmediate Corrective ActionsThe plant was placed in a safe condition.
The failed turbine governor components were replaced.
NRC FORM 366A (11-2015)
Page 5 of 5NRC FORM 366A U.S. NUCLEAR REGULATORY COM]I'IISSION (1 1-201s)LICENSEE EVENT REPORT (LER)CONTINUATION SHEETAPPROVED BY OMB: NO.3150-0104 EXPIRES:
1013112018 Estimated burden per response to comply with this mandatory collection request:
80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />, Reportedlessons learned are incorporated into the licensing process and fed back to industry, Sendcomments regarding burden estimate to the FOIA, Privacy and lnformation Collections Branch (T-5F53), U S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail tolnfocollects,Resource@nrc.gov, and to the Desk Officer, 0ffice of lnformation and Regulatory Afiains,NE0B-10202, (3150-0104),Office of Management and Budget, Washington, DC 20503 lf a meansused to impose an information collection does not display a currently valid OMB control number, theNRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAMEWatts Bar Nuclear Plant, Unit 22. DOCKET NUMBER0500039 13. LER NUMBERYEAR2016SEQUENTIAL NUMBER- 004REVNO.00NARRATIVE B. Corrective Actions to Prevent Recurrence Plant operating procedures will be revised to minimize governor valve operation when the valveposition is less than 12 percent open. TVA will work with the turbine vendor to determine if workcan be performed within the existing valve design requirements to reduce flow induced vibration.
VII. ADDITIONAL INFORMATION A. Previous similar events at the same plantNo similar events have been identified at the Watts Bar plant .B. Additional lnformation None.C. Safety System Functional Failure Consideration This condition did not result in a safety system functionalfailure.
D. Scrams with Complications Consideration There was an Sl associated with this plant trip. Operations personnel were able to promptlyterminate Sl in accordance with plant procedures and restore the plant to a normal shutdownalignment.
VIII. COMMITMENTS None.NRC FORM 366A (1 1-2015)
