07-10-2017 | On May 10, 2017, at 0907 Eastern Daylight Time (EDT), Watts Bar Nuclear Plant ( WBN) Unit 1 operations personnel discovered the 1B-B Safety Injection pump discharge isolation valve (1-ISV-63-527) closed. Technical Specification (TS) 3.5.2, ECCS - Operating, Condition A was immediately entered for one or more trains of the Emergency Core Cooling System ( ECCS) inoperable. TS 3.5.2 Condition A was exited at 0913 EDT when 1-ISV-63-527 was opened.
Investigation determined that the 1 B-B SI pump discharge isolation valve had been closed prior to Unit 1 entering Mode 3 on April 26, 2017, representing a condition prohibited by TS. During this time period, the 1A-A SI pump was inoperable for 21 minutes, representing a condition that could have prevented fulfillment of a safety function.
The cause of the mispositioned valve was the result of an individual failing to follow procedure use and adherence requirements during the performance of Emergency Diesel Generator ( EDG) Blackout testing. The safety injection pump discharge valve was closed to support the test but was not reopened following the testing. Corrective actions for this event include personal accountability actions, revision of the EDG blackout procedures to ensure the SI pump discharge valves are reopened, and additional station focus on procedure use, particularly use of Not Applicable (N/A) in performing procedures. |
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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.
I. PLANT OPERATING CONDITIONS BEFORE THE EVENT
Watts Bar Nuclear Plant (WBN) Unit 1 was at 46 percent rated thermal power (RTP) .
II. DESCRIPTION OF EVENT
A. Event Summary operations personnel discovered the 1B-B Safety Injection (SI) {EllS:BQ} pump discharge isolation valve {EIIS:V}(1-ISV-63-527) closed. Technical Specification (TS) 3.5.2, ECCS - Operating, Condition A was immediately entered for one or more trains of the Emergency Core Cooling System (ECCS) inoperable. TS 3.5.2 Condition A was exited at 0913 EDT when 1-ISV-63-527 was opened. Investigation determined that the 1B-B SI pump discharge isolation valve had been closed since prior to Unit 1 entering Mode 3 on April 26, 2017, representing a condition prohibited by TS. During this time period, the 1A-A SI pump was inoperable for 21 minutes, representing a loss of safety function.
This event is being reported to the Nuclear Regulatory Commission (NRC) under 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by TS and under 10 CFR 50.73(a)(2)(v)(D) as an event or condition that could have prevented fulfillment of a safety function.
B. Inoperable Structures, Components, or Systems that Contributed to the Event No inoperable equipment contributed to this event.
C. Dates and Approximate Times of Occurrences Date Time Event (EDT) 4/11/2017 Preparations occur to perform 0-SI-82-4, 1B EDG Blackout Test, with Unit 1 in Mode 6. To prevent injection of water into the reactor coolant system, the SI pump discharge isolation valve was closed.
4/26/2017 1624 Unit 1 enters Mode 3 5/9/2017 1240 1A-A Emergency Diesel Generator (EDG) declared inoperable to check water in cylinders.
5/9/2017 1301 1A-A EDG declared operable.
5/10/2017 0907 1 B-B SI pump discharge isolation valve found closed, pump declared inoperable.
5/10/2017 0913 1B-B SI pump discharge isolation valve opened, pump declared operable.
D. Manufacturer and Model Number of Components that Failed During the Event Not applicable.
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 - 00 005
E. Other Systems or Secondary Functions Affected
No other systems or secondary functions were affected .
F. Method of discovery of each Component or System Failure or Procedural Error This valve misposition was discovered by an operator performing routine operator rounds.
G. Failure Mode and Effect of Each Failed Component Not applicable.
H. Operator Actions
Upon discovering valve 1-ISV-63-527 isolated, the operator promptly opened the valve.
I. Automatically and Manually Initiated Safety System Responses Not applicable.
III. CAUSE OF THE EVENT
A. The cause of each component or system failure or personnel error, if known.
The test director for the EDG Blackout Test failed to follow procedure use and adherence requirements related to the application of Not Applicable (N/A), and did not obtain Section Manager concurrence for the use of N/A.
B. The cause(s) and circumstances for each human performance related root cause.
The test director for the EDG Blackout Test failed to follow procedure use and adherence requirements related to the application of Not Applicable (N/A), and did not obtain Section Manager concurrence for the use of N/A.
IV. ANALYSIS OF THE EVENT
On April 11, 2017, WBN Unit 1 was in Mode 6 during the Unit 1 fourteenth refueling outage (U1R14). The station was making preparations to perform 0-S1-82-4, 1B EDG Blackout Test. Blackout testing is normally conducted with the unit in Mode 5, however, due to a delay in the U1R14 schedule, the decision was made to conduct the testing in Mode 6. O-S1-82-4 Appendix B aligns the SI System for the blackout testing to ensure that water is not inadvertently injected into the core. Section 3.1 of Appendix B accomplishes this task by ensuring that the Cold Overpressure Mitigation System (COMS) clearance is in place. Normally, a COMS clearance places a hold order on the breakers and hand switches of the system pumps with the capability to inject high pressure water into the core. Appendix B, Section 3.1, Step [2] assumes this clearance for COMS is in place. Appendix B, Section 3.1, Step [3] takes the additional step of ensuring that the 1B-B SI Pump discharge valve (1-ISV-63-527-B) is closed and tagged. This is accomplished by 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 - 00 005 verifying that the COMS clearance in Step [2] already holds 1-ISV-63-527-B closed and tagged or that the clearance is modified to include this valve.
0-S1-82-4 is written with the assumption that the unit will be in Mode 5 during the performance of the surveillance. An appendix to the procedure restores system alignment following conduct of the testing.
That appendix does not contain restoration steps for 1-ISV-63-527-B because the procedure assumes configuration control for this valve is maintained under the COMS clearance. The surveillance essentially transfers responsibility for configuration control to the COMS clearance, which was not required in this case due to the test being performed in Mode 6. This lack of configuration control in 0-S1-82-4 was a latent error introduced in the procedure in 2004.
The test director recognized that the unit was in Mode 6 and that the COMS clearance was neither required nor hanging at the time of the test. 0-S1-82-4 Appendix B, Section 3.1, Step [2] and [3] were marked N/A during the preparation. Step [2] is marked with a note that states "COMS not required in Mode 6". Step [3] is marked with a note that states "Valve verified closed but not tagged. Mode 6 does not require valve to be tagged for COMS". The test director failed to follow procedure use and adherence requirements. Specifically, the Section Manager concurrence was not obtained prior to moving to the next step in the procedure. Additionally, the test director did not consider the effect of N/A on these steps with regard to configuration control. The system restoration appendix was not reviewed to ensure adequate restoration steps were in place to restore 1-ISV-63-527-B to its required open position for normal operation.
Contributing to the event, while not required, performance of an 18 month locked valve verification and a system alignment verification were waived during the outage.
V. ASSESSMENT OF SAFETY CONSEQUENCES
Both trains of SI were required to be in service to comply with TS 3.5.2 following re-entry into Mode 3 on April 26, 2017. During the time until the valve misposition was identified on May 10, 2017, the 1A-A SI was operable except for a 21 minute period when its associated EDG was inoperable while it was checked to confirm water was not present in the engine cylinders. Therefore, during this 21 minute period, both SI trains were considered inoperable. An evaluation concluded the change in core damage probability from the 1 B-B SI pump being isolated for 14 days considering the brief period where the 1A-A SI pump was also unavailable, was less than 1E-7 during this time period, and the risk significance of this event was very small.
A. Availability of systems or components that could have performed the same function as the components and systems that failed during the event The 1A-A SI pump was operable during the period in question except for a 21 minute period.
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.
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.
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 The isolated 1B-B SI pump was returned to service seven minutes after discovery. The 1B-B SI pump was out of service from April 26, 2017 until May 10, 2017, or just over fourteen days.
VI. CORRECTIVE ACTIONS
This event was entered into the Tennessee Valley Authority (TVA) Corrective Action Program and is being tracked under Condition Report (CR) 1294133.
A. Immediate Corrective Actions
Upon discovering the 1B-B SI pump discharge isolation valve closed, the valve was immediately opened.
B. Corrective Actions to Prevent Recurrence or to Reduce Probability of Similar Events Occurring in the Future The EDG blackout procedures will be revised to ensure the SI pump discharge valves are reopened at the completion of testing. Additional management focus has been applied since this event related to procedure use and adherence, particularly in the application of N/A associated with procedure use.
VII. PREVIOUS SIMILAR EVENTS AT THE SAME SITE
clearance was placed on the wrong fuses for a containment purge valve. This led to the purge valve not having power removed to its actuator while leak testing was being performed. While this configuration control issue was also associated with human performance (failure to identify the proper fuse location), it was not associated with procedural compliance.
containment penetration was not isolated within four hours. The event described in this LER is different in that the correct actions to comply with the TS were understood, but a human performance error resulted in the correct actions not being performed.
Concerns with procedural use and adherence are a station focus area and are described in Section VI.B of this LER.
VIII. ADDITIONAL INFORMATION
None.
IX. COMMITMENTS
None.
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