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Category:Letter
MONTHYEARML24319A2552024-11-14014 November 2024 Notification of NRC Baseline Inspection and Request for Information Inspection Report 05000373/2025001 and 05000374/2025001 IR 05000373/20240032024-11-0606 November 2024 County Station - Integrated Inspection Report 05000373/2024003 and 05000374/2024003 ML24317A1432024-11-0404 November 2024 Constellation Energy Generation, LLC, 2024 Annual Report - Guarantees of Payment of Deferred Premiums IR 05000373/20243012024-10-31031 October 2024 Initial License Examination Report 05000373/2024301 05000374/2024301 IR 05000373/20244042024-10-23023 October 2024 County Station – Security Baseline Inspection Report 05000373/2024404 and 05000374/2024404 RS-24-093, Response to Request for Additional Information - Alternative Request to Utilize Code Case OMN-32, Alternative Requirements for Range and Accuracy of Pressure, Flow, and Differential Pressure Instruments Used in Pump Tests2024-10-10010 October 2024 Response to Request for Additional Information - Alternative Request to Utilize Code Case OMN-32, Alternative Requirements for Range and Accuracy of Pressure, Flow, and Differential Pressure Instruments Used in Pump Tests 05000373/LER-2023-001-01, Air Circuit Breaker (Acb) Mechanically Operated Contacts (MOC) Switch Failed to Actuate2024-10-0909 October 2024 Air Circuit Breaker (Acb) Mechanically Operated Contacts (MOC) Switch Failed to Actuate ML24275A2442024-10-0303 October 2024 Reassignment of the U.S. Nuclear Regulatory Commission Branch Chief, Division of Operating Reactor Licensing IR 05000373/20244012024-09-27027 September 2024 County Station – Security Baseline Inspection Report 05000373/2024401 and 05000374/2024401 RS-24-094, Request to Recategorize an Indeterminate Exercise2024-09-20020 September 2024 Request to Recategorize an Indeterminate Exercise ML24263A2062024-09-19019 September 2024 Request for Exemption from Certain Requirements of 10 CFR 72.212 and 10 CFR 72.214 for LaSalle County Station - Holtec MPC-68MCBS ML24260A0492024-09-16016 September 2024 Operator Licensing Examination Approval - Lasalle County Station, Unit 1 and 2, September 2024 RS-24-090, Response to Request for Additional Information - Relief Request Concerning Extension of Permanent Relief from Ultrasonic Examination of Reactor Pressure Vessel Circumferential Shell Welds2024-09-12012 September 2024 Response to Request for Additional Information - Relief Request Concerning Extension of Permanent Relief from Ultrasonic Examination of Reactor Pressure Vessel Circumferential Shell Welds ML24255A8642024-09-0606 September 2024 Rscc Wire & Cable LLC Dba Marmon Industrial Energy & Infrastructure - Part 21 Retraction of Final Notification ML24249A1362024-09-0404 September 2024 EN 57304 - Westinghouse Electric Company, LLC, Final Report - No Embedded Files. Notification of the Potential Existence of Defects Pursuant to 10 CFR Part 21 IR 05000373/20240052024-08-29029 August 2024 Updated Inspection Plan and Assessment Follow-Up Letter for Lasalle County Station (Report 05000373/2024005; 05000374/2024005) IR 05000373/20244022024-08-28028 August 2024 County Station - Cyber Security Inspection Report 05000373/2024402 and 05000374/2024402 ML24239A3972024-08-23023 August 2024 Rssc Wire & Cable LLC Dba Marmon - Part 21 Final Notification - 57243-EN 57243 05000373/LER-2024-004-01, Emergency Diesel Generator Auto-Start and Load Due to Loss of System Auxiliary Transformer2024-08-22022 August 2024 Emergency Diesel Generator Auto-Start and Load Due to Loss of System Auxiliary Transformer IR 05000373/20240022024-08-13013 August 2024 County Station - Integrated Inspection Report 05000373/2024002 and 05000374/2024002 ML24222A6772024-08-0909 August 2024 Response to Request for Additional Information for Application to Revise Technical Specifications to Adopt TSTF-591-A, Revise Risk Informed Completion Time (RICT) Program Revision 0 and Revise 10 CFR 50.69 License Condition IR 05000373/20244202024-08-0505 August 2024 County Station - Security Baseline Inspection Report 05000373 2024420 and 05000374 2024420 05000373/LER-2024-003-01, Supplement to Technical Specification (TS) Limiting Condition for Operation (LCO) 3.6.1.3 Completion Time Exceeded2024-07-31031 July 2024 Supplement to Technical Specification (TS) Limiting Condition for Operation (LCO) 3.6.1.3 Completion Time Exceeded ML24208A0962024-07-25025 July 2024 57243-EN 57243 - Rssc Wire & Cable LLC, Dba Marmon - Part 21 Notification RS-24-064, Nuclear Radiological Emergency Plan Document Revisions2024-06-28028 June 2024 Nuclear Radiological Emergency Plan Document Revisions ML24178A2522024-06-27027 June 2024 County Station – Acknowledgement of Response to NRC Inspection Report 05000373/2024001 and 05000374/2024001 and Disputed Non-Cited Violation 05000373/LER-2024-004, Emergency Diesel Generator Auto-Start and Load Due to Loss of Station Auxiliary Transformer2024-06-19019 June 2024 Emergency Diesel Generator Auto-Start and Load Due to Loss of Station Auxiliary Transformer RS-24-061, Constellation Energy Generation, LLC, Response to NRC Regulatory Issue Summary 2024-01, Preparation and Scheduling of Operator Licensing Examinations2024-06-14014 June 2024 Constellation Energy Generation, LLC, Response to NRC Regulatory Issue Summary 2024-01, Preparation and Scheduling of Operator Licensing Examinations 05000373/LER-2024-003, Technical Specification (TS) Limiting Condition for Operation (LCO) 3.6.1.3 Completion Time Exceeded2024-06-0606 June 2024 Technical Specification (TS) Limiting Condition for Operation (LCO) 3.6.1.3 Completion Time Exceeded IR 05000373/20240102024-05-29029 May 2024 County Station - Commercial Grade Dedication Inspection Report 05000373/2024010 and 05000374/2024010 ML24079A0762024-05-23023 May 2024 Issuance of Amendments to Adopt TSTF 264 ML24142A3352024-05-21021 May 2024 Quad Cities—Information Request to Support the NRC Annual Baseline Emergency Action Level and Emergency Plan Changes RS-24-055, 2023 Corporate Regulatory Commitment Change Summary Report2024-05-17017 May 2024 2023 Corporate Regulatory Commitment Change Summary Report 05000373/LER-2024-002, Reactor Protection System Half Scram Due to Motor Generator Set Electric Power Monitoring Assembly Output Breaker Trip2024-05-17017 May 2024 Reactor Protection System Half Scram Due to Motor Generator Set Electric Power Monitoring Assembly Output Breaker Trip ML24131A1512024-05-13013 May 2024 County Station - Integrated Report 05000373/2024001 and 05000374/2024001 IR 05000373/20240012024-05-13013 May 2024 County Station - Integrated Report 05000373/2024001 and 05000374/2024001 RS-24-038, Relief Request Concerning Extension of Permanent Relief from Ultrasonic Examination of Reactor Pressure Vessel Circumferential Shell Welds2024-05-0202 May 2024 Relief Request Concerning Extension of Permanent Relief from Ultrasonic Examination of Reactor Pressure Vessel Circumferential Shell Welds RS-24-041, Alternative Request to Utilize Code Case OMN-32, Alternative Requirements for Range and Accuracy of Pressure, Flow, and Differential Pressure Instruments Used in Pump Tests2024-04-30030 April 2024 Alternative Request to Utilize Code Case OMN-32, Alternative Requirements for Range and Accuracy of Pressure, Flow, and Differential Pressure Instruments Used in Pump Tests 05000373/LER-2024-001, Core Operating Limits Report Thermal Limits Exceeded2024-04-26026 April 2024 Core Operating Limits Report Thermal Limits Exceeded ML24108A1562024-04-15015 April 2024 Updated Final Safety Analysis Report (Ufsar), Revision 26 and Fire Protection Report (Fpr), Revision 11 ML24103A2042024-04-12012 April 2024 Constellation Energy Generation, LLC, Application to Revise Technical Specifications to Adopt TSTF-591-A, Revise Risk Informed Completion Time (RICT) Program Revision 0 and Revise 10 CFR 50.69 License Condition RS-24-002, Constellation Energy Generation, LLC - Annual Property Insurance Status Report2024-04-0101 April 2024 Constellation Energy Generation, LLC - Annual Property Insurance Status Report ML24071A2122024-03-12012 March 2024 County Station - Information Request for the Cyber-Security Baseline Inspection, Notification to Perform Inspection IR 05000373/20230062024-02-28028 February 2024 Annual Assessment Letter for Lasalle County Station, Units 1 and 2 (Report 05000373/2023006; 05000374/2023006) RS-24-014, Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors2024-02-22022 February 2024 Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors ML24018A0682024-02-0909 February 2024 Issuance of Amendment Nos. 262 and 247 Revised Design Bases of Lower Downcomer Braces IR 05000373/20230042024-01-24024 January 2024 County Station - Integrated Inspection Report 05000373/2023004 and 05000374/2023004 ML24024A1332024-01-24024 January 2024 Confirmation of Initial License Examination IR 05000373/20230122024-01-18018 January 2024 County Station - Biennial Problem Identification and Resolution Inspection Report 05000373/2023012 and 05000374/2023012 ML23354A2902024-01-0505 January 2024 Exemption from Select Requirements of 10 CFR Part 73 (EPID L-2023-LLE-0028 (Security Notifications, Reports, and Recordkeeping and Suspicious Activity Reporting)) 2024-09-06
[Table view] Category:Licensee Event Report (LER)
MONTHYEAR05000373/LER-2023-001-01, Air Circuit Breaker (Acb) Mechanically Operated Contacts (MOC) Switch Failed to Actuate2024-10-0909 October 2024 Air Circuit Breaker (Acb) Mechanically Operated Contacts (MOC) Switch Failed to Actuate 05000373/LER-2024-004-01, Emergency Diesel Generator Auto-Start and Load Due to Loss of System Auxiliary Transformer2024-08-22022 August 2024 Emergency Diesel Generator Auto-Start and Load Due to Loss of System Auxiliary Transformer 05000373/LER-2024-003-01, Supplement to Technical Specification (TS) Limiting Condition for Operation (LCO) 3.6.1.3 Completion Time Exceeded2024-07-31031 July 2024 Supplement to Technical Specification (TS) Limiting Condition for Operation (LCO) 3.6.1.3 Completion Time Exceeded 05000373/LER-2024-004, Emergency Diesel Generator Auto-Start and Load Due to Loss of Station Auxiliary Transformer2024-06-19019 June 2024 Emergency Diesel Generator Auto-Start and Load Due to Loss of Station Auxiliary Transformer 05000373/LER-2024-003, Technical Specification (TS) Limiting Condition for Operation (LCO) 3.6.1.3 Completion Time Exceeded2024-06-0606 June 2024 Technical Specification (TS) Limiting Condition for Operation (LCO) 3.6.1.3 Completion Time Exceeded 05000373/LER-2024-002, Reactor Protection System Half Scram Due to Motor Generator Set Electric Power Monitoring Assembly Output Breaker Trip2024-05-17017 May 2024 Reactor Protection System Half Scram Due to Motor Generator Set Electric Power Monitoring Assembly Output Breaker Trip 05000373/LER-2024-001, Core Operating Limits Report Thermal Limits Exceeded2024-04-26026 April 2024 Core Operating Limits Report Thermal Limits Exceeded 05000374/LER-2022-003-02, Manual Scram Due to Lsophase Bus Duct Fire Followed by 2A RPS Normal Power Supply Trip2023-06-16016 June 2023 Manual Scram Due to Lsophase Bus Duct Fire Followed by 2A RPS Normal Power Supply Trip 05000373/LER-2023-001, Low Pressure Core Spray Inoperable Due to Minimum Flow Valve Flow Pressure Switch Failure2023-06-16016 June 2023 Low Pressure Core Spray Inoperable Due to Minimum Flow Valve Flow Pressure Switch Failure 05000374/LER-2021-002-02, Supplement to Reactor Protection System Half Scram Due to Motor Generator Set Output Breaker Trip2023-05-25025 May 2023 Supplement to Reactor Protection System Half Scram Due to Motor Generator Set Output Breaker Trip 05000374/LER-2023-003, Automatic Actuation of Reactor Protection System (RPS) During Restoration from Hydrostatic Test Conditions I2023-05-0202 May 2023 Automatic Actuation of Reactor Protection System (RPS) During Restoration from Hydrostatic Test Conditions I 05000373/LER-2023-002, Air Circuit Breaker (Acb) Mechanically Operated Contacts (MOC) Switch Failed to Actuate2023-04-25025 April 2023 Air Circuit Breaker (Acb) Mechanically Operated Contacts (MOC) Switch Failed to Actuate 05000374/LER-2023-001, Standby Liquid Control Valve Inoperable Due to Failed Motor Starter Contactor2023-04-17017 April 2023 Standby Liquid Control Valve Inoperable Due to Failed Motor Starter Contactor 05000374/LER-1922-003-01, Manual Scram Due to Lsophase Bus Duct Fire Followed by 2A RPS Normal Power Supply Trip2023-02-0909 February 2023 Manual Scram Due to Lsophase Bus Duct Fire Followed by 2A RPS Normal Power Supply Trip 05000373/LER-2022-004, Both Trains of Main Control Room and Auxiliary Electric Room HVAC Declared Inoperable Due to Compressor Trips2022-12-28028 December 2022 Both Trains of Main Control Room and Auxiliary Electric Room HVAC Declared Inoperable Due to Compressor Trips 05000373/LER-2022-003-02, Supplement to Main Control Room and Auxiliary Electric Room HVAC Declared Inoperable Due to Multiple Component Failures2022-12-28028 December 2022 Supplement to Main Control Room and Auxiliary Electric Room HVAC Declared Inoperable Due to Multiple Component Failures 05000374/LER-2022-003, Manual Scram Due to Lsophase Bus Duct Fire and 2A RPS Normal Power Supply Trip2022-11-15015 November 2022 Manual Scram Due to Lsophase Bus Duct Fire and 2A RPS Normal Power Supply Trip 05000373/LER-2022-003-01, Main Control Room and Auxiliary Electric Room HVAC Declared Inoperable Due to Multiple Component Failures2022-09-23023 September 2022 Main Control Room and Auxiliary Electric Room HVAC Declared Inoperable Due to Multiple Component Failures 05000373/LER-2022-003, Main Control Room and Auxiliary Electric Room HVAC Declared Inoperable Due to Multiple Component Failures2022-07-18018 July 2022 Main Control Room and Auxiliary Electric Room HVAC Declared Inoperable Due to Multiple Component Failures 05000373/LER-2022-001, Turbine Stop Valve Limit Switch Failure Due to Lubricant Degradation2022-05-27027 May 2022 Turbine Stop Valve Limit Switch Failure Due to Lubricant Degradation 05000374/LER-2022-002, Turbine Stop Valve Limit Switch Failure Due to Lubricant Degradation2022-05-27027 May 2022 Turbine Stop Valve Limit Switch Failure Due to Lubricant Degradation 05000374/LER-2021-002-01, Reactor Protection System Half Scram Due to Motor Generator Set Output Breaker Trip2021-09-23023 September 2021 Reactor Protection System Half Scram Due to Motor Generator Set Output Breaker Trip 05000374/LER-2021-002, Reactor Protection System Half Scram Due to Motor Generator Set Output Breaker Trip2021-07-29029 July 2021 Reactor Protection System Half Scram Due to Motor Generator Set Output Breaker Trip 05000374/LER-2021-001, High Pressure Core Spray Inoperable Due to Water Leg Pump Breaker Cubicle Motor Contactor2021-02-18018 February 2021 High Pressure Core Spray Inoperable Due to Water Leg Pump Breaker Cubicle Motor Contactor 05000373/LER-2017-0072017-08-18018 August 2017 Low Pressure Core Spray System Inoperable due to Loss of Cooling, LER 17-007-00 for LaSalle County Station, Unit 1, Regarding Low Pressure Core Spray System Inoperable due to Loss of Cooling 05000374/LER-2017-0032017-08-0909 August 2017 High Pressure Core Spray System Inoperable due to Injection Valve Stem-Disc Separation, LER 17-003-01 for LaSalle County Station, Unit 2 Regarding High Pressure Core Spray System Inoperable due to Injection Valve Stem-Disc Separation 05000373/LER-2017-0062017-07-14014 July 2017 Low Pressure Core Spray Inoperable due to Minimum Flow Valve Failure in Closed Position, LER 17-006-00 for LaSalle, Unit 1, Regarding Low Pressure Core Spray Inoperable due to Minimum Flow Valve Failure in Closed Position 05000374/LER-2017-0042017-07-14014 July 2017 Two Main Steam Safety Relief Valves Failed Inservice Lift Inspection Pressure Test, LER 17-004-01 for LaSalle, Unit 2, Regarding Two Main Steam Safety Relief Valves Failed Inservice Lift Inspection Pressure Test 05000373/LER-2017-0052017-04-18018 April 2017 Manual Reactor Scram Resulting From Feedwater Regulating Valve Failure Causing High Reactor Water Level, LER 17-005-00 for LaSalle County, Unit 1, Regarding Manual Reactor Scram Resulting From Feedwater Regulating Valve Failure Causing High Reactor Water Level 05000373/LER-2017-0042017-04-17017 April 2017 Secondary Containment Inoperable Due to Interlock Doors Open, LER 17-004-00 for LaSalle County, Unit 1, Regarding Secondary Containment Inoperable Due to Interlock Doors Open 05000373/LER-2017-0032017-04-14014 April 2017 Automatic Reactor Scram due to Main Generator Trip on Differential Current During Back-Feed Operations, LER 17-003-00 for LaSalle County Station, Unit 1, Regarding Automatic Reactor Scram due to Main Generator Trip on Differential Current During Back-Feed Operations 05000374/LER-2017-0022017-03-30030 March 2017 High Pressure Core Spray System Declared Inoperable due to Cooling Water Strainer Backwash Valve Stem-Disc Separation, LER 17-002-00 for LaSalle, Unit 2, Regarding High Pressure Core Spray System Declared Inoperable due to Cooling Water Strainer Backwash Valve Stem-Disc Separation 05000374/LER-2017-0012017-03-24024 March 2017 Manual Reactor Scram due to Turbine-Generator Run-Back Caused by Stem-Disc Separation in Stator Water Cooling Heat Exchanger Inlet Valve, LER 17-001-00 for LaSalle County, Unit 2 Regarding Manual Reactor Scram due to Turbine-Generator Run-Back Caused by Stem-Disc Separation in Stator Water Cooling Heat Exchanger Inlet Valve 05000373/LER-2017-0012017-02-0808 February 2017 Reactor Core Isolation Cooling System Inoperable Longer than Allowed by the Technical Specifications due to Low Suction Pressure Trips, LER 17-001-00 for LaSalle County, Unit 1, Regarding Reactor Core Isolation Cooling System Inoperable Longer than Allowed by the Technical Specifications due to Low Suction Pressure Trips 05000374/LER-2016-0012016-04-18018 April 2016 Secondary Containment Inoperable Due to Interlock Doors Open, LER 16-001-00 for LaSalle County, Unit 2, Regarding Secondary Containment Inoperable Due to Door Interlock Doors Open 05000373/LER-2016-0012016-04-11011 April 2016 Secondary Containment Inoperable due to Reactor Building Ventilation Damper Failure, LER 16-001-00 for LaSalle County, Unit 1 & 2, Regarding Secondary Containment Inoperable Due to Reactor Building Ventilation Damper Failure 2024-08-22
[Table view] |
LER-2023-001, Air Circuit Breaker (Acb) Mechanically Operated Contacts (MOC) Switch Failed to Actuate |
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text
Constellation.
RA24-043 October 9, 2024 U.S. Nuclear Regulatory Commission A TIN: Document Control Desk Washington, DC 20555-0001 LaSalle County Station, Units 1 and 2 Renewed Facility Operating License Nos. NPF-11 and NPF-18 NRC Docket No. 50-373 and 50-37 4 LaSalle County Station 2601 North 21 " Road Marseilles, IL 61341 815-415-2000 Telephone 10 CFR 50.73 Subject:
Licensee Event Report 2023-002-01, Supplement to Air Circuit Breaker (ACB)
Mechanically Operated Contacts (MOC) switch failed to actuate In accordance with 10 CFR 50.73(a)(2)(i)(B), Constellation Energy Generation, LLC (CEG) is submitting LER Number 2023-002-01 for LaSalle County Station, Units 1 and 2. The changes are administrative in nature and do not affect the reported information on the event.
There are no regulatory commitments contained in this letter.
Should you have any questions concerning this report, please contact Ms. Laura Ekern, Regulatory Assurance Manager, at (815) 415-2800.
Respectfully, tt2-~
Plant Manager LaSalle County Station Enclosure: Licensee Event Report 2023-002-01 cc:
Regional Administrator - NRC Region Ill NRC Senior Resident Inspector - LaSalle County Station
Abstract
During operability surveillance testing of the Unit 2, Division 2 Unit Cross Tie Air Circuit Breaker (ACB 2424), the Unit 1, Division 2 Cross Tie (ACB 1424) failed to close. It was found that the contact from the Mechanically Operated Contacts (MOC) switch of ACB 1422 was not made up as is required for closing in ACB 1424. Troubleshooting identified a misaligned linkage to the ACB 1422 MOC switch, resulting in contacts not closing as required. This established firm evidence that a past inoperability condition existed since the breaker was last racked out of service during the Unit 1 refueling outage in 2022.
Failure of ACB 1422 MOC switch contacts results in inoperability of one of the two offsite power sources for Unit 2 Division 2 required by LCO 3.8.1 (AC Sources - Operating) and degraded voltage protection required by LCO 3.3.8.1 (Loss of Power Instrumentation). At the failure time of discovery, Unit 2 was in Mode 5, and LCO 3.8.1 was not in the mode of applicability and the unit cross-tie power source was not required for LCO 3.8.2 (AC sources -Shutdown). There were no reportability thresholds applicable to this issue at the time of the event, and there was no loss of safety function. The condition is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) for operation or condition prohibited by Technical Specifications.
The MOC switch linkage was adjusted and ACB 1422 was restored to operable.
Plant and System Identification
- 2. DOCKET NUMBER YEAR 00374 2023 -
- 3. LER NUMBER SEQUENTIAL NUMBER 002 REV NO.
01 LaSalle County Station Unit 2 is a General Electric Boiling Water Reactor with 3546 Megawatts Thermal Rated Core Power. The affected system was the AC Power system. The affected component is ACB 1422, Unit 1 System Auxiliary Transformer Main Feed to Unit 1 Division 2 AC power, 142Y.
Condition Prior to Event Unit(s): 1/2 Date: February 24, 2023 Time: 14:25 CST Reactor Mode(s): 1/5 Mode(s) Name: Power Operation/Refuel Power Level: 100 percent/0 percent Description On 2/24/2023, during performance of the operability surveillance testing of the Unit 2, Division 2 Air Circuit Breaker (ACB) 2424, the Unit 1, Division 2 Cross Tie ACB 1424 failed to close. It was identified that that contacts on the Unit 1 System Auxiliary Transformer (SAT) feed to Division 2, ACB 1422, MOC switch remained in the open position when they should have been closed. This resulted in the ACB 1422 closing permissive not being actuated and preventing closure of ACB 1424. Troubleshooting identified a misaligned linkage on the ACB 1422 MOC switch. This linkage misalignment occurred during the last time the breaker was racked out of service during the Unit 1 refueling outage in 2022. This established firm evidence that a past inoperability condition existed.
Cause Troubleshooting identified a misaligned linkage for the ACB 1422 MOC switch which resulted in the MOC switch contacts remaining open when they should have been closed.
Reportability and Safety Analysis ACB 1422 MOC switch linkage misalignment occurred during the last time the breaker was racked out of service during the Unit 1 refueling outage in 2022. This established firm evidence that a past inoperability condition existed. There were no reportability thresholds met for this issue at the time of the event, and there was no loss of safety function. The condition is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) for operation or condition prohibited by Technical Specifications.
Failure of ACB 1424 to close resulted in inoperability of one of the two offsite power sources for Unit 2 Division 2 required by LCO 3.8.1 (AC Sources - Operating). At the time of discovery Unit 2 was in Mode 5, and LCO 3.8.1 was not in the mode of applicability. Additionally, the unit cross-tie power source was not required for LCO 3.8.2 (AC sources -
Shutdown). The required offsite power source for Unit 1 was not impacted by this failure. The contacts on ACB 1422 MOC switch also provide the permissive to enable degraded voltage protection for Unit 1 Division 2 emergency AC Power, 142Y. This function is required per LCO 3.3.8.1, (Loss of Power (LOP) Instrumentation).
LCO 3.8.1 requires two qualified circuits between the offsite transmission network and the onsite Class 1 E AC Electric Power Distribution System in modes 1, 2 and 3. Condition A is entered when one required offsite circuit is inoperable. The 1422 MOC switch contact remaining open prevents the closure of ACB 1424, Unit 1 SAT feed to Unit 2 Division 2 Emergency AC bus 242Y. As such one of the qualified offsite sources for bus 242Y was inoperable. The applicable Required Actions (RA) are RA A.1 perform SR 3.8.1.1 for operable required offsite circuit and A.3 restore the required offsite circuit to operable status in 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. If this action is not met Condition H is entered and requires the unit to be in Mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
- 2. DOCKET NUMBER
- 3. LER NUMBER YEAR SEQUENTIAL REV NUMBER NO.
00374 2023 -
002 01 LCO 3.8.1 condition E is entered when one required offsite circuit AND one required Division 1, 2 or 3 Diesel Generator (DG) is inoperable. Required actions E.1 and E.2 include restore the required offsite circuit to operable OR restore the required DG to operable within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> or in accordance with the Risk Informed Completion Time Program. If this action is not met condition H is entered and requires the unit to be in Mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Examples of concurrent inoperability were identified where the required actions were not taken.
LCO 3.3.8.1 requires the Division 1, 2 and opposite Unit Division 2 - 4.16 kV Emergency Bus Undervoltage, Degraded Voltage - 4.16kV Basis function to be operable (Function 1.c). If this function is inoperable LCO 3.3.8.1 condition A is entered and RA A.1 requires the channel to be placed in trip within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> or in accordance with the Risk Informed Completion Time Program. If this action is not met, condition B.1 is entered and requires the associated DG to be declared inoperable immediately. The ACB 1422 linkage misalignment resulted in the Unit 1 Division 2 degraded voltage function to be inoperable when the Emergency Bus 142Y is fed from the System Auxiliary Transformer (SAT) and non-Emergency bus, 142X, is fed from the Unit Auxiliary Transformer (UAT). This lineup was entered during the period of inoperability with required actions not taken.
Corrective Actions The linkage was adjusted and surveillance testing was completed to restore operability.
I Previous Occurrences No previous occurrences identified.
Component Failure Data Manufacturer: ITE Device: Air Circuit Breaker, 4160V Component ID: 1AP06E-1, Air Circuit Breaker, System Auxiliary Transformer Main Feed to bus 142Y Page_3_ of _3_