07-14-2017 | During the February 2017 Unit 2 refueling outage, two main steam safety relief valves ( SRV) did not pass Technical Specification (TS) Surveillance Requirement 3.4.4.1 and Inservice Testing (1ST) Program lift pressure requirements. Both SRVs ( 2B21-F013C and 2B21-F013L) lifted below their expected lift pressures. On February 16, 2017, SRV 2B21-F013C was required to lift within plus or minus three percent of 1175 psi (i.e., 1175 psi plus or minus 35.2 psi), but actually lifted at 1131 psi. On February 17, 2017 SRV 2B21-F013L was required to lift within plus or minus three percent of 1195 psi (i.e., 1195 psi plus or minus 35.8 psi), but actually lifted at 1130 psi.
Multiple test failures are reportable under 10 CFR 50.73(a)(2)(i)(B) as an operation or condition prohibited by the plants Technical Specifications. Both SRVs lifted prior to their expected lift pressures, which is conservative in regards to maintaining reactor pressure vessel over-pressure limits. Both SRVs were replaced during the outage. A failure analysis was conducted; however, it did not identify a cause for the valves lifting below their expected lift set-points. |
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Category:Letter
MONTHYEARRS-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 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 ML24024A1332024-01-24024 January 2024 Confirmation of Initial License Examination IR 05000373/20230042024-01-24024 January 2024 County Station - Integrated Inspection Report 05000373/2023004 and 05000374/2023004 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)) ML23360A6082023-12-27027 December 2023 County Station Request for Information for NRC Commercial Grade Dedication Inspection: Inspection Report 05000373/2024010 and 05000374/2024010 ML23278A1292023-12-14014 December 2023 Units 1 & 2; Limerick, Units 1 & 2; Nine Mile Point, Units 1 & 2; and Peach Bottom, Units 2 & 3 -Revision to Approved Alternatives to Use Boiling Water Reactor Vessel and Internals Project Guidelines ML23305A1402023-12-13013 December 2023 Units 1 & 2; Nine Mile Point, Unit 2; Peach Bottom, Units 2 & 3; and Quad Cities, Units 1 and 2 - Issuance of Amendments to Adopt Traveler TSTF-580 ML23317A1192023-11-10010 November 2023 Constellation Energy Generation, LLC - 2023 Annual Report - Guarantees of Payment of Deferred Premiums RS-23-120, Supplemental Information Letter for Part 73 Exemption Request - Responses to Request for Confirmatory Information2023-11-10010 November 2023 Supplemental Information Letter for Part 73 Exemption Request - Responses to Request for Confirmatory Information IR 05000373/20230032023-11-0909 November 2023 County Station Integrated Inspection Report 05000373/2023003, 05000374/2023003, and 07200070/2023001 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 RA23-067, Turbine Stop Valve Limit Switch Failure Due to Lubricant Degradation2023-12-0404 December 2023 Turbine Stop Valve Limit Switch Failure Due to Lubricant Degradation 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] |
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 2. DOCKET NUMBER - 01 004
PLANT AND SYSTEM IDENTIFICATION
LaSalle County Station Unit 2 is a General Electric Boiling Water Reactor with 3546 Megawatts Thermal Rated Core Power.
The main steam safety relief valves (SRVs) are designed to prevent over-pressurization of the reactor pressure vessel (RPV) during transients and abnormal conditions, which protects against a failure of the reactor coolant pressure boundary (RCPB).
There are thirteen SRVs installed on the four main steam lines, which discharge near the bottom of the suppression pool to condense the steam through SRV tailpipes that exhaust beneath the suppression pool surface.
CONDITION PRIOR TO EVENT
2017
DESCRIPTION OF EVENT
During the February 2017 Unit 2 refueling outage L2R16, two main steam SRVs did not pass the lift pressure requirements of the Inservice Testing (1ST) Program and Technical Specification (TS) Surveillance Requirement 3.4.4.1. Both SRVs lifted outside their tolerance and below their expected lift pressures. On February 16, 2017, SRV 2821-F013C was removed and set- pressure tested. SRV 2B21-F013C was required to lift within plus or minus three percent of 1175 psi (i.e., 1175 psi plus or minus 35.2 psi), but actually lifted at 1131 psi. On February 17, 2017 SRV 2B21-F013L was removed and set-pressure tested.
SRV 2B21-F013L was required to lift within plus or minus three percent of 1195 psi (i.e., 1195 psi plus or minus 35.8 psi), but actually lifted at 1130 psi.
CAUSE OF EVENT
Disassembly and inspection of valves 2B21-F013C and 2B21-F013L were performed at NWS Technologies to determine the cause for the failures. The vendor reported that for both valves all the spring tolerances were within the acceptance limits. There were no other signs of degradation or any other issue that would affect the set-points. Second lift tests for both valves were satisfactory and were within the plus or minus three percent tolerance of the set pressures.
The cause for 2621-F013C and 2B21-F013L to fail their SRV set pressure tests was found to be indeterminate.
REPORTABILITY AND SAFETY ANALYSIS
This condition was discovered while Unit 2 was outside the mode of applicability for TS 3.4.4, Safety/Relief Valves (Modes 1, 2 and 3); however, multiple test failures are reportable under 10 CFR 50.73(a)(2)(i)(B) as an operation or condition prohibited by the plant's Technical Specifications.
The safety significance of this condition was minimal. The out-of-tolerance lift pressures were discovered while the plant was in Mode 5 during a refueling outage and the SRVs were not required to be operable. Both SRVs lifted prior to their expected lift pressures, which is conservative in regards to maintaining reactor pressure vessel overpressure limits.
CORRECTIVE ACTIONS
Both SRVs 2B21-F013C and 21321-F013L were replaced during the outage. Vendor lab testing was performed that did not identify a cause of the failures.
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 2. DOCKET NUMBER - 01
PREVIOUS OCCURRENCES
A review of past events for both units identified a previous occurrence in 2015 on Unit 2 for multiple SRV test failures as follows.
During the February 2015 Unit 2 refueling outage L2R15, two main steam safety relief valves (SRV) did not pass TS Surveillance Requirement 3.4.4.1 and Inservice Testing Program lift pressure requirements. Both SRVs lifted below their expected lift pressures. SRV 2621-F013S was required to lift within plus or minus three percent of 1150 psi (i.e., 1150 psi plus or minus 34.5 psi) and actually lifted at 1099 psi. SRV 2B21-F013M was required to lift within plus or minus three percent of 1195 psi (i.e., 1195 psi plus or minus 35.8 psi) and actually lifted at 1145 psi. A failure analysis was conducted by a vendor testing laboratory, but the cause for the valves lifting below their set-point was indeterminate.
COMPONENT FAILURE DATA
Manufacturer: Crosby Device: Main Steam Safety Relief Valves, ASME Section III, Class 1 Component ID: Style HB-65-BP, Size 6R10 2017 004