On May 2, 2017, at 1945 Eastern Daylight Time (EDT) and on May 4, 2017 at 1710 EDT, Watts Bar Nuclear ( WBN) Plant Unit 1 reactor was manually tripped due to a failure of the Reactor Coolant Pump ( RCP) Board 1C normal feeder breaker to close during the planned power transfer to unit power following plant startup. Concurrent with each reactor trip, the Auxiliary Feedwater system actuated as designed. All control and shutdown rods fully inserted. All safety systems responded as designed for both events.
For the first event. the cause was incorrectly attributed to a high resistance contact resulting in the normal feeder breaker failing to close. In the investigation following the second event, a relay associated with the RCP Board 1C control circuit was found incorrectly configured due to a human performance issue, which resulted in a standing trip signal on the RCP normal feeder breaker. To prevent recurrence, procedures will be revised to address material control of pretested components. |
|
---|
Category:Letter
MONTHYEARML23319A2452024-01-29029 January 2024 Issuance of Amendment Nos. 366 and 360; 164 and 71 Regarding the Adoption of TSTF-567, Revision 1, Add Containment Sump TS to Address GSI-191 Issues ML24008A2462024-01-18018 January 2024 Revision to the Reactor Vessel Material Surveillance Capsule Withdrawal Schedule CNL-24-017, Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure and Emergency Preparedness Department Procedure Revisions2024-01-17017 January 2024 Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure and Emergency Preparedness Department Procedure Revisions CNL-24-016, Supplement to Application to Modify the Technical Specification Surveillance Requirement 3.9.5.1 (WBN-TS-21-14)2024-01-10010 January 2024 Supplement to Application to Modify the Technical Specification Surveillance Requirement 3.9.5.1 (WBN-TS-21-14) CNL-23-052, Application to Adopt TSTF-427-A, Revision 2, Allowance for Non-Technical Specification Barrier Degradation on Supported System Operability2024-01-0909 January 2024 Application to Adopt TSTF-427-A, Revision 2, Allowance for Non-Technical Specification Barrier Degradation on Supported System Operability CNL-23-062, Application to Revise the Technical Specifications Section 3.8.2, AC Sources-Shutdown, to Remove Reference to the C-S Diesel Generator (WBN-TS-23-018)2024-01-0808 January 2024 Application to Revise the Technical Specifications Section 3.8.2, AC Sources-Shutdown, to Remove Reference to the C-S Diesel Generator (WBN-TS-23-018) ML23346A1382024-01-0303 January 2024 Regulatory Audit Summary Related to Request to Increase the Number of Tritium Producing Burnable Absorber Rods CNL-23-069, Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation2023-12-21021 December 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation IR 05000390/20234412023-12-21021 December 2023 Plantfinal Significance Determination for a Security-Related Greater than Green Finding, Nov, and Assessment Follow-up, 05000390-2023441 and 05000391-2023441-Public CNL-23-036, Application to Revise Function 5 of Technical Specification Table 3.3.2-1, Engineered Safety Feature Actuation System Instrumentation, for the Sequoyah Nuclear Plant and Watts Bar Nuclear Plant (SQN-TS-23-02 and WBN-TS-23-08)2023-12-18018 December 2023 Application to Revise Function 5 of Technical Specification Table 3.3.2-1, Engineered Safety Feature Actuation System Instrumentation, for the Sequoyah Nuclear Plant and Watts Bar Nuclear Plant (SQN-TS-23-02 and WBN-TS-23-08) IR 05000390/20234042023-12-14014 December 2023 Security Baseline Inspection Report 05000390/2023404 and 05000391/2023404 CNL-23-001, Rebaseline of Sections 3.1 and 3.2 of the Technical Specifications (WBN-TS-23-01)2023-12-13013 December 2023 Rebaseline of Sections 3.1 and 3.2 of the Technical Specifications (WBN-TS-23-01) ML23293A0572023-12-0606 December 2023 Issuance of Amendment Nos. 163 and 70 Regarding Adoption of TSTF-501-A, Revision 1, Relocate Stored Fuel Oil and Lube Oil Volume Values to Licensee Control IR 05000390/20230102023-11-30030 November 2023 RE-Issue Watts Bar Nuclear Plant - Biennial Problem Identification and Resolution Inspection Report 050000390/2023010 and 05000391/2023010 and Apparent Violation CNL-23-067, Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2023-11-27027 November 2023 Central Emergency Control Center Emergency Plan Implementing Procedure Revisions IR 05000390/20230032023-11-13013 November 2023 Integrated Inspection Report 05000390/2023003 and 05000391/2023003 and Apparent Violation ML23312A1432023-11-0808 November 2023 Submittal of Dual Unit Updated Final Safety Analysis Report (UFSAR) Amendment 5 CNL-23-059, Supplement to Sequoyah Nuclear Plant, Units 1 and 2, and Watts Bar Nuclear Plant, Units 1 and 2, Application to Revise Technical Specifications to Adopt TSTF-567-A, Revision 1, Add Containment Sump TS to Address GSI-191 Issues (SQN-TS-23-2023-09-20020 September 2023 Supplement to Sequoyah Nuclear Plant, Units 1 and 2, and Watts Bar Nuclear Plant, Units 1 and 2, Application to Revise Technical Specifications to Adopt TSTF-567-A, Revision 1, Add Containment Sump TS to Address GSI-191 Issues (SQN-TS-23-03 CNL-23-061, Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure Revision2023-09-20020 September 2023 Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure Revision ML23251A2002023-09-11011 September 2023 Request for Withholding Information from Public Disclosure for Watts Bar Nuclear Plant, Units 1 and 2 CNL-23-057, Central Emergency Control Center Emergency Plan Implementing Procedure Revisions. Includes CECC-EPIP-1, Revision 76 and CECC-EPIP-9, Revision 642023-09-0505 September 2023 Central Emergency Control Center Emergency Plan Implementing Procedure Revisions. Includes CECC-EPIP-1, Revision 76 and CECC-EPIP-9, Revision 64 IR 05000390/20230052023-08-30030 August 2023 Updated Inspection Plan for Watts Bar Nuclear Plant, Units 1 and 2 - Report 05000390/2023005 and 05000391/2023005 ML23233A0042023-08-28028 August 2023 Proposed Alternative to the Requirements of the ASME Boiler and Pressure Vessel Code for Upper Head Injection Dissimilar Metal Butt Welds IR 05000390/20230022023-08-16016 August 2023 Reissue - Watts Bar Nuclear Plant - Integrated Inspection Report 05000390/2023002 and 05000391/2023002 ML23220A1582023-08-0909 August 2023 Integrated Inspection Report 05000390/2023002 and 05000391/2023002 CNL-23-045, License Amendment Request to Revise Technical Specification Table 1.1-1 Regarding the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Bolts (WBN-TS-23-010)2023-08-0707 August 2023 License Amendment Request to Revise Technical Specification Table 1.1-1 Regarding the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Bolts (WBN-TS-23-010) CNL-23-028, Application to Revise Technical Specifications to Adopt TSTF-567-A, Revision 1, Add Containment Sump TS to Address GSI-191 Issues (SQN-TS-23-03 and WBN-TS-23-06)2023-08-0202 August 2023 Application to Revise Technical Specifications to Adopt TSTF-567-A, Revision 1, Add Containment Sump TS to Address GSI-191 Issues (SQN-TS-23-03 and WBN-TS-23-06) ML23192A4472023-07-31031 July 2023 Staff Assessment of Updated Seismic Hazards at TVA Sites Following the NRC Process for the Ongoing Assessment of Natural Hazards Information CNL-23-055, Tennessee Valley Authority - Emergency Preparedness Department Procedure Revision. Includes EPDP-3, Revision 3, Emergency Plan Exercises and Preparedness Drills2023-07-25025 July 2023 Tennessee Valley Authority - Emergency Preparedness Department Procedure Revision. Includes EPDP-3, Revision 3, Emergency Plan Exercises and Preparedness Drills IR 05000390/20230112023-07-24024 July 2023 Quadrennial Focused Engineering Inspection (FEI) Commercial Grade Dedication Report 05000390 2023011 and 05000391 2023011 CNL-23-053, Tennessee Valley Authority - Radiological Emergency Plan Revisions2023-07-18018 July 2023 Tennessee Valley Authority - Radiological Emergency Plan Revisions CNL-23-020, Application to Revise Technical Specifications to Adopt TSTF-501-A, Revision 1, Relocate Stored Fuel Oil and Lube Oil Volume Values to Licensee Control (WBN-TS-22-06)2023-06-28028 June 2023 Application to Revise Technical Specifications to Adopt TSTF-501-A, Revision 1, Relocate Stored Fuel Oil and Lube Oil Volume Values to Licensee Control (WBN-TS-22-06) CNL-23-049, Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan .2023-06-26026 June 2023 Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan . ML23122A2322023-06-0707 June 2023 Issuance of Amendment Nos. 162 and 69 Regarding Change to Date in Footnotes for Technical Specification 3.7.11, Control Room Emergency Air Temperature Control System (Creatcs) CNL-23-044, Transmittal of Revision 3 to WCAP-18774-P and WCAP-18774-NP, Addendum to the Rotterdam Dockyard Company Final Stress Report for 173 P.W.R. Vessels TVA III & IV (Report No. 30749-B-030, Rev. 3) - Evaluation of One Closure Stud Out2023-06-0101 June 2023 Transmittal of Revision 3 to WCAP-18774-P and WCAP-18774-NP, Addendum to the Rotterdam Dockyard Company Final Stress Report for 173 P.W.R. Vessels TVA III & IV (Report No. 30749-B-030, Rev. 3) - Evaluation of One Closure Stud Out IR 05000390/20234032023-05-30030 May 2023 Cyber Security Inspection Report 05000390/2023403 and 05000391/2023403 ML23131A1812023-05-23023 May 2023 Correction to Amendment No. 161 to Facility Operating License No. NPF-90 CNL-23-042, Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2023-05-16016 May 2023 Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions IR 05000390/20220032023-05-0909 May 2023 Reissue Watts Bar Nuclear Plant - Integrated Inspection Report 05000390/2022003 and 05000391/2022003 ML23125A2202023-05-0505 May 2023 Issuance of Amendment No. 161 Regarding a Change to Footnotes for Technical Specification Table 1.1-1 Modes (Emergency Circumstances) IR 05000390/20230012023-05-0404 May 2023 Integrated Inspection Report 05000390/2023001 and 05000391/2023001 CNL-23-043, Emergency License Amendment Request to Relax the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Studs in Technical Specification Table 1.1-1, Modes (WBN-TS-23-09)2023-05-0404 May 2023 Emergency License Amendment Request to Relax the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Studs in Technical Specification Table 1.1-1, Modes (WBN-TS-23-09) CNL-23-032, Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Unit 1 and 2, Nuclear Quality Assurance Plan, TVA-NQA-PLN89-A, Revision 412023-04-27027 April 2023 Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Unit 1 and 2, Nuclear Quality Assurance Plan, TVA-NQA-PLN89-A, Revision 41 CNL-23-030, Tennessee Valley Authority - Hydrologic Engineering Center River Analysis System Project Milestone Status Update2023-04-27027 April 2023 Tennessee Valley Authority - Hydrologic Engineering Center River Analysis System Project Milestone Status Update CNL-23-033, Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revision2023-04-24024 April 2023 Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revision CNL-23-029, Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2023-04-11011 April 2023 Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions ML23072A0652023-04-0505 April 2023 Units 1 and 2 Issuance of Amendment Nos. 364 and 358; 160 and 68 Regarding a Revision to Technical Specification 3.4.12 ML23073A2762023-04-0303 April 2023 Individual Notice of Consideration of Issuance of Amendments to Facility Operating Licenses, Proposed No Significant Hazards Consideration Determination, and Opportunity for a Hearing (EPID L-2023-LLA-0029) (Letter) CNL-23-023, Annual Insurance Status Report2023-03-30030 March 2023 Annual Insurance Status Report CNL-23-024, TVA Guarantee of Payment of Deferred Premiums - 2022 Annual Report2023-03-29029 March 2023 TVA Guarantee of Payment of Deferred Premiums - 2022 Annual Report 2024-01-09
[Table view] Category:Licensee Event Report (LER)
MONTHYEAR05000391/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 2018-01-08
[Table view] |
comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to used to impose 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 collection.
3. LER NUMBER
2017 - 01 004
I. PLANT OPERATING CONDITIONS BEFORE THE EVENT
Watts Bar Nuclear Plant (WBN) Unit 1 was at approximately 26 percent rated thermal power (RTP) for the first trip and at approximately 28 percent for the second trip.
II. DESCRIPTION OF EVENT
A. Event Summary On May 2, 2017, at 1945 Eastern Daylight Time (EDT) and on May 4, 2017 at 1710 EDT, Watts Bar Nuclear (WBN) Plant Unit 1 reactor was manually tripped due to a failure of the Reactor Coolant Pump (RCP) {EIIS:P} Board 1C normal feeder breaker {EIIS:BKR} to close during the planned power transfer to unit power {EIIS:EA} during plant startup following a refueling outage.
Concurrent with the manual reactor trip, the Auxiliary Feedwater (AFW) {EIIS:BA} system actuated as designed. All control and shutdown rods fully inserted. All safety systems responded as designed for both events.
These events are being reported to the Nuclear Regulatory Commission (NRC) under 10 CFR 50.73(a)(2)(iv)(A) for initiation of a manual reactor trip and automatic actuation of the AFW system.
B. Inoperable Structures, Components, or Systems that Contributed to the Event Control relay WBN-1-RLY-245-0152-Z2, associated with the RCP Board 1C power transfer logic, was configured incorrectly.
C. Dates and Approximate Times of Occurrences Date Time Event (EDT) 4/06/2017 Work Order (WO) 117754323 steps performed to set-up replacement relay WBN-1-RLY-245-0152-Z2. Work steps include verification of contact configuration and an energized test. Craft took relay to Fix-It Now (FIN) shop upon completion of bench test.
4/08/2017 Craft gave relay to foreman for storage.
4/13/2017 WO 117543323 work resumed, relay is installed in the Main Relay board. An independent verification of wire lifts and lands for the replacement relay is performed.
5/02/2017 1945 Unit 1 is manually tripped when RCP 1C failed to transfer to its normal source. Enter 1-E-0, Reactor Trip or Safety Injection.
5/02/2017 1948 Transition to 1-ES-0.1, Reactor Trip Response.
5/02/2017 2012 Transition to 1-GO-5, Unit Shutdown from 30 percent Reactor Power to Hot Standby.
5/03/2017 Troubleshooting incorrectly concludes that high resistance on a breaker limit switch is the cause of the breaker for the RCP Board 1C normal feeder failing to close.
comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to used to impose 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 collection.
Date Time Event (EDT) 5/04/2017 1710 Unit 1 is manually tripped when the RCP Board 1C failed to transfer to its normal source. Enter 1-E-0.
5/04/2017 1716 Transition to 1-ES-0.1, Reactor Trip Response.
5/04/2017 1743 Transition to 1-GO-5, Unit Shutdown from 30 Percent Reactor Power to Hot Standby.
5/07/2017 Troubleshooting concludes that failure to transfer is associated with misconfigured relay contacts.
5/09/2017 0355 RCP Board 1C successfully transferred from alternate to normal power during plant startup.
D. Manufacturer and Model Number of Components that Failed During the Event The relay that failed was an MG-6 multi-contact Auxiliary Relay with six configurable contacts, Part number 2896359A21, manufactured by Westinghouse Electric Corporation.
E. Other Systems or Secondary Functions Affected
All safety systems and secondary functions operated as designed.
F. Method of discovery of each Component or System Failure or Procedural Error Inspection of relay WBN-1-RLY-245-0152-Z2 found that the contacts were not properly configured.
G. Failure Mode and Effect of Each Failed Component With the relay misconfigured, RCP 1C could not be loaded onto the plant unit board.
H. Operator Actions
For both events, when RCP Board 1C failed to transfer to its normal operating power source, plant operators manually tripped the reactor. An automatic trip is not expected for the plant conditions and the manual reactor trip was briefed prior to the commencement of the transfer evolution. Plant operators promptly stabilized the plant and transitioned from the emergency operating procedures to the normal shutdown procedure.
I. Automatically and Manually Initiated Safety System Responses The plant operators initiated a manual reactor trip when RCP 1C failed to transfer to its operating power source. AFW automatically actuated and all automatic systems operated as designed.
III. CAUSE OF THE EVENT
A. The cause of each component or system failure or personnel error, if known.
After the first event, the cause was incorrectly attributed to a high resistance contact resulting in comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects.Resource@nrc.gov. and to the Desk Officer, Office of Information and Regulatory Affairs, used to impose 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 collection.
3. LER NUMBER
the normal feeder breaker failing to close. In the investigation following the second event, a relay associated with the RCP Board 1C control circuit was found incorrectly configured as a result of a loss of material control that occurred following bench testing but prior to installation.
1-RLY-245-152-Z2 had been replaced during the Unit 1 refueling outage. The replacement relay was installed with a misconfigured contact pair which provided a standing trip signal on the RCP Board Normal Feeder Breaker. This event was the result of material controls not being clearly defined and enforced by maintenance personnel to ensure the integrity of pre-tested materials is maintained between testing and installation.
B. The cause(s) and circumstances for each human performance related root cause.
Following initial setup and testing of the relay during the refueling outage, the relay was staged in the FIN shop from April 6 to April 8, 2017. This inappropriate storage resulted in a loss of material control.
IV. ANALYSIS OF THE EVENT
During a normal start up at WBN, after the main generator has been synchronized to the grid, the power source for the RCPs is transferred from the Common Station Service Transformers (CSSTs, offsite power) to the Unit Station Service Transformers (USSTs) which are powered by the main generator. With relay WBN-1-RLY-245-0152-Z2 misconfigured, the RCP normal feeder breaker to the USSTs would not close.
Prior to performing this power transfer, operations personnel had briefed on actions to perform in the event the power transfer failed, which included manually tripping the reactor. Operations personnel were able to promptly stabilize the plant following these trips.
V. ASSESSMENT OF SAFETY CONSEQUENCES
These events are bounded by a partial loss of forced reactor coolant flow, which is an anticipated operational occurrence described in the Final Safety Analysis Report (FSAR).
A. Availability of systems or components that could have performed the same function as the components and systems that failed during the event All safety systems operated as designed during this event.
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 heat, control the release of radioactive material, or mitigate the consequences of an accident Not applicable.
C. For failure that rendered a train of a safety system inoperable, an estimate of the elapsed time from the discovery of the failure until the train was returned to service All safety systems operated as designed during this event.
comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to used to impose 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 collection.
VI. CORRECTIVE ACTIONS
These events were entered into the Tennessee Valley Authority (TVA) Corrective Action Program and are being tracked under Condition Reports (CRs) 1291140 and 1292231.
A. Immediate Corrective Actions
Following the second event, the misconfigured relay was replaced and properly tested.
B. Corrective Actions to Prevent Recurrence or to Reduce Probability of Similar Events Occurring in the Future Procedures related to control of materials will be revised to ensure requirements are established to appropriately label materials to identify pretesting has been satisfactorily completed.
VII. PREVIOUS SIMILAR EVENTS AT THE SAME SITE
A manual reactor trip was reported to the NRC in LER 391/2017-002 dated May 12, 2017. This event was attributed to craft personnel inadvertently tripping a secondary pump, which led to a secondary plant transient requiring operations personnel to manually trip the plant when steam generator levels could not be adequately maintained. While the event described in this LER also involves human performance, the prior event involved contractor control.
VIII. ADDITIONAL INFORMATION
None.
IX. COMMITMENTS
None.
|
---|
|
|
| | Reporting criterion |
---|
05000390/LER-2017-010 | 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 | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000390/LER-2017-011 | 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 | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000390/LER-2017-001 | Failure of Emergency Raw Cooling Water Pump Reverse Rotation Keys Represents Potential Common Cause Inoperability Watts Bar, Units 1 and 2 - Cancellation of Licensee Event Report 390/2017-001 Related to Essential Raw Cooling Water Pump Reverse Rotation Keys Representing a Potential Common Cause lnoperability | 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability | 05000391/LER-2017-001 | 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 | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material | 05000391/LER-2017-002 | 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 | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000390/LER-2017-012 | 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 | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000390/LER-2017-002 | 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 | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000391/LER-2017-003 | 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 | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000390/LER-2017-013 | 1 OF 5 LER 17-013-01 for Watts Bar Nuclear Plant, Units 1 and 2 Regarding Incorrectly Adjusted Auxiliary Building Gas Treatment System Damper Leads to a Condition Prohibited by Technical Specifications | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000390/LER-2017-003 | 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 | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000390/LER-2017-014 | 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 | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000391/LER-2017-004 | 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 | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000390/LER-2017-004 | 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 | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000391/LER-2017-005 | 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 | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000390/LER-2017-005 | 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 | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000390/LER-2017-015 | 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 | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000390/LER-2017-006 | 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 | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000391/LER-2017-006 | Manual Reactor Trip in Response to Indication of Multiple Dropped Control Rods | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000390/LER-2017-007 | 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 | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.73(a)(2)(v), Loss of Safety Function | 05000390/LER-2017-008 | 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 | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.73(a)(2)(v), Loss of Safety Function | 05000390/LER-2017-009 | Unanalyzed Condition Related to Dual Unit Operation of the Essential Raw Cooling Water System During a Design Basis Accident | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.73(a)(2)(ii) |
|