On April 1, 2016 at 20:24, Unit 2 entered Technical Specification 3.8.1 due to the A Diesel Generator ( DG) being inoperable due to misaligned contacts on a Mechanism-Operated Cell ( MOC) switch resulting in Fan 1V222A starting without a time delay. Based upon review of the history and cause, the condition likely existed since the supply breaker was replaced on July 19, 2010. The A DG was still able to perform its intended safety function; however, since the condition results in inability to meet Surveillance Requirement 3.8.1.18, the A DG must be considered inoperable during periods when 1V222A would have been available to start (without a time delay). As a result, this event is reportable as a condition prohibited by Technical Specifications, in accordance with 10CFR50.73(a)(2)(i)(B), since the inoperability is assumed to have existed for a period of time greater than allowed by the Technical Specifications. A review of historical information for the last three years identified instances in which one of the other DGs (B, C, or D) was inoperable.
Based on this information, this condition is also reportable as a condition that could have prevented fulfillment of a safety function in accordance with 10CFR50.73(a)(2)(v)(D).
The direct cause of the MOC switch contacts not aligning properly was mis-adjustment of the MOC switch linkage. The apparent cause of the MOC switch contacts not aligning properly is inadequate post maintenance testing (PMT) for the breaker swap because PMT did not check MOC switch contact alignment.
Procedures will be revised to include visual inspection to ensure the MOC switch contacts are properly aligned during post maintenance testing.
There were no actual consequences to the health and safety of the public as a result of this event. |
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Category:Letter
MONTHYEARIR 05000387/20230042024-02-0707 February 2024 Integrated Inspection Report 05000387/2023004 and 05000388/2023004 PLA-8096, Response to Request for Additional Information Regarding Proposed Relief Request for the Fifth 10-Year Inservice Test Program Interval2024-01-0404 January 2024 Response to Request for Additional Information Regarding Proposed Relief Request for the Fifth 10-Year Inservice Test Program Interval PLA-8077, Emergency Plan Revision 67 (PLA-8077)2023-12-27027 December 2023 Emergency Plan Revision 67 (PLA-8077) IR 05000387/20230102023-12-11011 December 2023 Fire Protection Team Inspection Report 05000387/2023010 and 05000388/2023010 PLA-8089, Submittal of Revision to Inservice Testing Program Plan2023-12-0505 December 2023 Submittal of Revision to Inservice Testing Program Plan PLA-8084, Application to Revise Technical Specifications to Adopt TSTF-568, Revise Applicability of BWR TS 3.6.2.5 and TS 3.6.3.22023-11-29029 November 2023 Application to Revise Technical Specifications to Adopt TSTF-568, Revise Applicability of BWR TS 3.6.2.5 and TS 3.6.3.2 ML23345A0682023-11-28028 November 2023 Technical Specification Bases, Manual PLA-8091, Response to Request for Additional Information Regarding Proposed Relief Request for the Fifth 10-Year Inseervice Inspection Interval (PLA-8091)2023-11-0808 November 2023 Response to Request for Additional Information Regarding Proposed Relief Request for the Fifth 10-Year Inseervice Inspection Interval (PLA-8091) IR 05000387/20230032023-11-0303 November 2023 Integrated Inspection Report 05000387/2023003 and 05000388/2023003 PLA-8082, Proposed Amendment to Licenses NPF-14 and NPF-22: Application to Revise Technical Specifications to Adopt TSTF-563, Revise Instrument Testing Definitions to Incorporate the Surveillance Frequency Control Program2023-11-0202 November 2023 Proposed Amendment to Licenses NPF-14 and NPF-22: Application to Revise Technical Specifications to Adopt TSTF-563, Revise Instrument Testing Definitions to Incorporate the Surveillance Frequency Control Program ML23291A1132023-10-12012 October 2023 Submittal of Revision 71 to Updated Final Safety Analysis Report and Revision 25 to Fire Protection Review Report ML23279A0612023-10-0505 October 2023 Paragon Energy Solutions LLC, Part 21 Final Report Re Potential Defect with Eaton Jd and Hjd Series Molded Case Circuit Breakers (Mccbs) ML23277A0412023-10-0505 October 2023 Notification of Commercial Grade Dedication Inspection (05000387/2024011 and 05000388/2024011) and Request for Information IR 05000387/20233012023-09-20020 September 2023 Initial Operator Licensing Examination Report 05000387/2023301 and 05000388/2023301 ML23254A0242023-09-0606 September 2023 Paragon Energy Solutions LLC, Potential Defect with Eaton Jd and Hjd Series Molded Case Circuit Breakers (Mccbs) IR 05000387/20230052023-08-31031 August 2023 Updated Inspection Plan for Susquehanna Steam Electric Station, Units 1 and 2 (Report 05000387/2023005 and 05000388/2023005) ML23228A1952023-08-21021 August 2023 Summary of August 10, 2023, Public Observation Meeting Re. Proposed Alternative PLA-8080, Proposed Relief for Valve 251130 (PLA-8080)2023-08-14014 August 2023 Proposed Relief for Valve 251130 (PLA-8080) PLA-8074, Proposed Relief Request for the Fifth 10-Year Inservice Test Program Interval2023-08-0303 August 2023 Proposed Relief Request for the Fifth 10-Year Inservice Test Program Interval IR 05000387/20230022023-08-0101 August 2023 Integrated Inspection Report 05000387/2023002 and 05000388/2023002 ML23195A1852023-07-27027 July 2023 Correction to Technical Specifications Page 3.3-73 in Amendment No. 265 PLA-8076, Unit 2 - 21st Refueling Outage Owner'S Activity Report (PLA-8076)2023-07-20020 July 2023 Unit 2 - 21st Refueling Outage Owner'S Activity Report (PLA-8076) ML23201A0152023-07-20020 July 2023 Operator Licensing Examination Approval ML23200A1012023-07-19019 July 2023 Notification of Conduct of a Fire Protection Team Inspection ML23193A0062023-07-12012 July 2023 Requalification Program Inspection PLA-8078, Submittal of Unit 2 Cycle 22 Core Operating Limits Report, Revision 1, PLA-80782023-07-0505 July 2023 Submittal of Unit 2 Cycle 22 Core Operating Limits Report, Revision 1, PLA-8078 ML23163A1012023-06-12012 June 2023 10 CFR 50.46 Annual Report (Pla 8065) PLA-8054, Proposed Amendment to Licenses NPF-14 and NPF-22: Remove Control Rod Operability Separation Criteria and Replace Reference to Banked Position Withdrawal Sequence with the Analyzed Rod Position Sequence2023-06-0808 June 2023 Proposed Amendment to Licenses NPF-14 and NPF-22: Remove Control Rod Operability Separation Criteria and Replace Reference to Banked Position Withdrawal Sequence with the Analyzed Rod Position Sequence IR 05000387/20234012023-06-0707 June 2023 Security Baseline Inspection Report 05000387/2023401 and 05000388/2023401 PLA-8073, Proposed Relief Request for the Fifth 10-Year Inservice Inspection Interval2023-06-0101 June 2023 Proposed Relief Request for the Fifth 10-Year Inservice Inspection Interval PLA-8064, Response to NRC Regulatory Issue Summary 2023-01 (PLA-8064)2023-05-17017 May 2023 Response to NRC Regulatory Issue Summary 2023-01 (PLA-8064) ML23132A3212023-05-17017 May 2023 Associated Independent Spent Fuel Storage Installation - Issuance of Amendment Nos. 285 and 269 Related to Order Approving Transfer of Licenses PLA-8067, Notification of Completion of Emergence from Bankruptcy (PLA-8067)2023-05-17017 May 2023 Notification of Completion of Emergence from Bankruptcy (PLA-8067) IR 05000387/20230012023-05-12012 May 2023 Integrated Inspection Report 05000387/2023001 and 05000388/2023001 PLA-8066, Notification of Planned Closing Date and Information Identified in March 30, 2023 Order, PLA-80662023-05-0808 May 2023 Notification of Planned Closing Date and Information Identified in March 30, 2023 Order, PLA-8066 PLA-8053, Radiation Exposure Information and Reporting System2023-04-27027 April 2023 Radiation Exposure Information and Reporting System PLA-8058, Annual Radiological Environmental Operating Report (PLA-8058)2023-04-26026 April 2023 Annual Radiological Environmental Operating Report (PLA-8058) PLA-8041, Radioactive Effluent Release Report and Offsite Dose Calculation Manual (PLA-8041)2023-04-25025 April 2023 Radioactive Effluent Release Report and Offsite Dose Calculation Manual (PLA-8041) PLA-8047, 2022 Annual Environmental Operating Report (Nonradiological), PLA-80472023-04-19019 April 2023 2022 Annual Environmental Operating Report (Nonradiological), PLA-8047 PLA-8062, Supplement to Relief Request 4RR-10 Relief from Code Seal Weld Requirement for Valve 252F007B, PLA-80622023-04-11011 April 2023 Supplement to Relief Request 4RR-10 Relief from Code Seal Weld Requirement for Valve 252F007B, PLA-8062 PLA-8061, Relief Request 4RR-10 Relief from Code Seal Weld Requirement for Valve 25F007B, PLA-80612023-04-10010 April 2023 Relief Request 4RR-10 Relief from Code Seal Weld Requirement for Valve 25F007B, PLA-8061 ML23090A2302023-03-31031 March 2023 NRC Decommissioning Funding Status Report PLA-8049 PLA-8060, Submittal of Unit 2 Cycle 22 Core Operating Limits Report (PLA-8060)2023-03-30030 March 2023 Submittal of Unit 2 Cycle 22 Core Operating Limits Report (PLA-8060) ML23095A0572023-03-29029 March 2023 NRC Decommissioning Funding Status Report December 31, 2022 PLA-8057, Application for Order Approving Indirect Transfer of Control of Licenses and Approving Conforming License Amendments- Supplemental Information, PLA-80572023-03-15015 March 2023 Application for Order Approving Indirect Transfer of Control of Licenses and Approving Conforming License Amendments- Supplemental Information, PLA-8057 ML23065A1962023-03-0202 March 2023 EN 56387 Paragon - Part 21 Report Re Defect Identified in Automatic Transfer Switch Pn: NLI-ATS480A400X1 IR 05000387/20220062023-03-0101 March 2023 Annual Assessment Letter for Susquehanna Steam Electric Station, Units 1 and 2 (Reports 05000387/2022006 and 05000388/2022006) PLA-8052, (Sses), Proof of Financial Protection and Guarantee of Payment of Deferred Premiums2023-02-13013 February 2023 (Sses), Proof of Financial Protection and Guarantee of Payment of Deferred Premiums IR 05000387/20220042023-02-0808 February 2023 Integrated Inspection Report 05000387/2022004 and 05000388/2022004 ML23010A0882023-01-15015 January 2023 Summary of Regulatory Audit in Support of License Amendment Request to Revise Control Rod Technical Specifications 2024-02-07
[Table view] Category:Licensee Event Report (LER)
MONTHYEAR05000388/LER-2017-0102018-02-0202 February 2018 Condition Prohibited by Technical Specifications Due to Drift of Reactor Pressure Switches, LER 17-010-00 for Susquehanna, Unit 2 Regarding Condition Prohibited by Technical Specifications Due to Drift of Reactor Pressure Switches 05000387/LER-2017-0072017-10-0909 October 2017 Secondary Containment Declared Inoperable Due to the opening of a plenum., LER 17-007-00 for Susquehanna Steam Electric Station Regarding Secondary Containment Declared Inoperable Due to Supply Air Flow 05000387/LER-2017-0052017-10-0404 October 2017 Automatic Reactor Protection System Trip on High Neutron Flux, LER 17-005-01 for Susquehanna, Unit 1 Regarding Automatic Reactor Protection System Trip on High Neutron Flux 05000388/LER-2017-0082017-09-18018 September 2017 1 OF 3, LER 17-008-00 for Susquehanna, Unit 2, Regarding Condition Prohibited by Technical Specifications Due to a Loose Terminal Block Associated with a Primary Containment Isolation Valve 05000387/LER-2017-0062017-09-0606 September 2017 Control Room Envelope In-leakage Exceeded the Technical Specification Limit, LER 17-006-00 for Susquehanna, Unit 2, Regarding Secondary Containment Declared Inoperable Due to Trip of Zone II Exhaust Fan 05000387/LER-2017-0042017-08-0404 August 2017 Secondary Containment Declared Inoperable Due to Failure of an Exhaust Fan Breaker., LER 17-004-00 for Susquehanna, Unit 1, Regarding Secondary Containment Declared Inoperable Due to Failure of an Exhaust Fan Breaker 05000388/LER-2017-0022017-05-0505 May 2017 Implementation of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3 during Unit 2 Refueling, LER 17-002-00 for Susquehanna, Unit 2, Regarding Implementation of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3 During Unit 2 Refueling 05000387/LER-2017-0032017-05-0505 May 2017 Susquehanna Steam Electric Station Unit 1 05000387, LER 17-003-00 for Susquehanna, Units 1 and 2, Regarding Loss of Secondary Containment Zone 3 Due to Fan Trip 05000387/LER-2017-0012017-05-0505 May 2017 Secondary Containment Breach Due to Simultaneous Opening of Airlock Doors, LER 17-001-00 for Susquehanna, Unit 2, Regarding Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to Sticking Door Latch 05000387/LER-2017-0022017-04-12012 April 2017 Secondary Containment Breach due to Simultaneous Opening of Airlock Doors, LER 17-002-00 for Susquehanna, Unit 1, Regarding Secondary Containment Breach due to Simultaneous Opening of Airlock Doors 05000388/LER-2016-0052016-07-12012 July 2016 Unit 2 HPCI Manually Overridden Prior to a Manual Scram During a Plant Transient, LER 16-005-00 for Susquehanna, Unit 2, Regarding HPCI Manually Overridden Prior to a Manual Scram During a Plant Transient 05000387/LER-2016-0152016-06-15015 June 2016 Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to a Human Performance Error, LER 16-015-00 for Susquehanna, Unit 1, Regarding Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to a Human Performance Error 05000387/LER-2016-0142016-06-0909 June 2016 Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to a Human Performance Error, LER 16-014-00 for Susquehanna, Unit 1, Regarding Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to a Human Performance Error 05000387/LER-2016-0132016-06-0909 June 2016 Secondary Containment Declared Inoperable Due to Simultaneous Opening of Double Airlock Doors, LER 16-013-00 for Susquehanna, Unit 1, Regarding Secondary Containment Declared Inoperable Due to Simultaneous Opening of Double Airlock Doors 05000387/LER-2016-0102016-05-31031 May 2016 Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to Medical Emergency, LER 16-010-00 for Susquehanna, Unit 1, Regarding Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to Medical Emergency 05000387/LER-2016-0092016-05-26026 May 2016 Valid Primary Containment Isolation Actuation during Local Leak Rate Testing due to Human Performance Error, LER 16-009-00 for Susquehanna, Unit 1, Regarding Valid Primary Containment Isolation Actuation During Local Leak Rate Testing Due to Human Performance Error 05000387/LER-2016-0082016-05-19019 May 2016 Inoperability of Diesel Generator Due to Misalignment of MOC Switch Contacts Due to Inadequate Post Maintenance Testing, LER 16-008-00 for Susquehanna, Unit 1, Regarding Inoperability of Diesel Generator Due to Misalignment of MOC Switch Contacts Due to Inadequate Post Maintenance Testing 05000387/LER-2016-0112016-05-16016 May 2016 Valve inoperability for a period longer than allowed by Technical Specifications, LER 16-011-00 for Susquehanna, Unit 1, Regarding Valve Inoperability for a Period Longer Than Allowed by Technical Specifications 05000387/LER-2016-0052016-05-16016 May 2016 Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to Human Performance Error, LER 16-005-00 for Susquehanna, Units 1 and 2, Regarding Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to Human Performance Error 05000387/LER-2016-0062016-05-10010 May 2016 Implementation of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3, LER 16-006-00 for Susquehanna, Unit 1, Regarding Implementation of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3 05000387/LER-2016-0042016-05-10010 May 2016 Momentary Loss of Secondary Containment due to Both Airlock Doors on Elevation 779 of the Unit 2 Reactor Building being Opened at the Same Time, LER 16-004-00 for Susquehanna, Unit 1, Regarding Momentary Loss of Secondary Containment Due to Both Airlock Doors on Elevation 779 of the Unit 2 Reactor Building Being Opened at the Same Time 05000387/LER-2016-0032016-05-0606 May 2016 Unit 2 Zone 3 HVAC unable to maintain Zone 3 differential pressure greater than 0.25 in wg, LER 16-003-00 for Susquehanna, Unit 1, Regarding Unit 2 Zone 3 HVAC Unable to Maintain Zone 3 Differential Pressure Greater Than 0.25 in wg 05000387/LER-2016-0072016-05-0303 May 2016 Inoperability of Swing Bus Transfer Switch Due to Deformed Bolt on Linkage, LER 16-007-00 for Susquehanna, Unit 1, Regarding Inoperability of Swing Bus Transfer Switch Due to Deformed Bolt on Linkage 05000387/LER-2016-0012016-04-18018 April 2016 Secondary Containment Declared Inoperable Due to an Airlock Doors Open Due to Random Occurrence, LER 16-001-00 for Susquehanna, Unit 1, Regarding Secondary Containment Declared Inoperable Due to an Airlock Doors Open Due to Random Occurrence 05000387/LER-2016-0022016-04-18018 April 2016 Secondary Containment Declared Inoperable Due to an Airlock Doors Open Due to Random Occurrence, LER 16-002-00 for Susquehanna, Unit 1, Regarding Secondary Containment Declared Inoperable Due to an Airlock Doors Open Due to Random Occurrence 05000387/LER-2015-0062016-03-30030 March 2016 Loss of Safety Function due to Inoperability of Both Trains of the Standby Gas Treatment System and a Loss of Safety Function of the Control Room Emergency Outside Air Supply System due to Air Flow Controller found in Manual, LER 15-006-01 for Susquehanna, Unit 1, Regarding Loss of Safety Function due to Inoperability of Both Trains of the Standby Gas Treatment System and a Loss of Safety Function of the Control Room Emergency Outside Air Supply System due to Air Flow... 05000387/LER-2015-0012016-02-10010 February 2016 Inoperability of the 'B' Emergency Diesel Generator due to Fuel Oil Leakage, LER 15-001-01 for Susquehanna, Unit 1, Regarding Condition Prohibited by Technical Specifications Due to Drift of Reactor Pressure Steam Dome - Low Switches 05000387/LER-2015-0032016-01-26026 January 2016 Secondary Containment Inoperability Due to Failure to Meet Technical Specification Surveillance Requirement 3.6.4.1.1, LER 15-003-01 for Susquehanna, Unit 1, Regarding Secondary Containment Inoperability Due to Failure to Meet Technical Specification Surveillance Requirement 3.6.4.1.1 05000387/LER-2015-0092016-01-11011 January 2016 Pressure Boundary Leakage From an Inadequate Weld Repair in Small Bore Pump Seal Vent Piping, LER 15-009-00 for Susquehanna, Unit 1, Regarding Pressure Boundary Leakage From an Inadequate Weld Repair in Small Bore Pump Seal Vent Piping 05000387/LER-2015-0072016-01-0808 January 2016 Unit 1 'B' Inboard Main Steam Isolation Valve, HV141F022B closed during surveillance test which caused a SCRAM on Unit 1, LER 15-007-00 for Susquehanna, Unit 1, Regarding 'B' Inboard Main Steam Isolation Valve, HV141 F022B Closed During Surveillance Test Which Caused a SCRAM PLA-7323, LER 015-001-00 for Susquehanna Regarding Inoperability of the B Emergency Diesel Generator Due to Fuel Oil Leakage2015-04-28028 April 2015 LER 015-001-00 for Susquehanna Regarding Inoperability of the B Emergency Diesel Generator Due to Fuel Oil Leakage 2018-02-02
[Table view] |
comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet 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.
CONDITIONS PRIOR TO EVENT
Unit 1 — Mode 5, 0 percent Rated Thermal Power Unit 2 — Mode 1, 100 percent Rated Thermal Power There were no structures, systems, or components that were inoperable at the start of the event that contributed to the event other than the failed component itself.
EVENT DESCRIPTION
On April 1, 2016 at 20:24, Unit 2 entered Technical Specification (TS) 3.8.1 due to the A Diesel generator (DG) [EIIS System/Component Identifier: EK/DG] being inoperable due to the misaligned contacts [EIIS Component Identifier: CNTR] on the Mechanism-Operated Cell (MOC) switch. Based upon review of the history and cause, the condition likely existed since the supply breaker [EIIS Component Identifier: BKR] was replaced on July 19, 2010. A detailed timeline is provided below:
On July 19, 2010, Supply Breaker 1A20104 for the A DG was replaced during routine preventive maintenance activities.
On May 12, 2012, the timer (62X1A20104) [EIIS Component Identifier: TMR] associated with the Emergency Switchgear and Load Center Cooling Supply Fan (1V222A) [EIIS Component Identifier: FAN] immediately went to run without a time delay during performance of the Unit 1 Division I LOCA/LOOP test.
The acceptance criterion for this timer is greater than or equal to 54 seconds. The timer was replaced.
Post maintenance testing (PMT) was an abbreviated test performed by simulating the LOOP logic via a jumper and confirming the fan started after an appropriate time delay.
On April 17, 2014, during performance of Unit 1 Division I LOCA/LOOP testing, 1V222A started without a time delay. The timer was replaced. PMT was an abbreviated test to ensure the timer's delay was correct.
On April 25, 2014, during re-performance of LOCA/LOOP testing, 1V222A failed to give proper indication during bus stripping and bus re-energization, but the timing acceptance criterion was met. Possible wiring issues were investigated but none were found.
On March 23, 2016 at 13:36, Timer 62X1A20104 failed acceptance criteria during LOCA/LOOP testing as a result of 1V222A starting without a time delay. In accordance with the TS Bases, operability of the associated AC sources can be restored by rendering the affected load inoperable; Fan 1V222A was shut down by taking the hand switch to STOP. Extensive troubleshooting was performed to determine the cause, and on April 1, 2016, it was determined that the contacts on MOC Switch S1 in Breaker 1A20104 were not properly aligned.
On April 1, 2016 at 20:24, Unit 2 entered TS 3.8.1 due to the A DG being inoperable due to the misaligned contacts on the MOC switch. Unit 1 was in a refuel outage (Mode 5) and did not require the A DG; therefore, TS 3.8.2 was not entered on Unit 1.
On April 2, 2016 at 19:37, the A DG was declared Operable and Unit 2 exited TS 3.8.1 after MOC switch linkage adjustments were made and the contacts were cleaned.
comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet 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.
Based upon review of the history and cause, there is firm evidence that the condition existed since the supply breaker was replaced on July 19, 2010. As noted in the safety significance section, the A DG was still able to perform its intended safety function; however, since the condition results in inability to meet Surveillance Requirement 3.8.1.18, the A DG must be considered inoperable during periods when 1V222A would have been available to start (without a time delay). As a result, this event is reportable as a condition prohibited by Technical Specifications, in accordance with 10CFR50.73(a)(2)(i)(B), since the inoperability is assumed to have existed for a period of time greater than allowed by the Technical Specifications. A review of historical information for the last three years identified instances in which one of the other DGs (B, C, or D) was inoperable. Based on this information, this condition is also reportable as a condition that could have prevented fulfillment of a safety function in accordance with 10CFR50.73(a)(2)(v)(D).
CAUSE OF EVENT
The direct cause of the MOC switch contacts not aligning properly was mis-adjustment of the MOC switch linkage. The apparent cause of the MOC switch contacts not aligning properly is inadequate post maintenance testing (PMT) for the breaker swap because PMT did not check MOC switch contact alignment.
ANALYSIS/SAFETY SIGNIFICANCE
Actual Consequences:
As a result of declaring the A DG inoperable, Unit 2 entered a 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> shutdown action in accordance with TS 3.8.1. This TS entry caused Unit 2 EOOS to be Yellow. Unit 1 was in Mode 5 and the A DG was not required for Unit 1; therefore TS 3.8.2 was not entered. Due to the minimal loading resulting from 1V222A, there was no impact on the ability of the A DG to perform its safety function. Other loads such as Core Spray and RHR were proven to have the correct time delay during the performance of Unit 1 Division I LOCA/LOOP testing on March 23, 2016.
Potential Consequences:
If the issue was not resolved within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, Unit 2 would have had to initiate shutdown activities.
CORRECTIVE ACTIONS
Key corrective actions will include the following:
1. Revising procedures to include visual inspection to ensure the MOC switch contacts are properly aligned during post maintenance testing.
COMPONENT FAILURE INFORMATION
Westinghouse Porcelain Metal Clad Switchgear Type DH-P Housing comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet 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.
PREVIOUS SIMILAR EVENTS
The following are Susquehanna MOC switch issues identified within the past 10 years:
CR-1071573 — On September 9, 2008, 13.8kV Bus 10 failed to transfer due to an open contact in the circuit, which was a MOC switch on the 13kV Breaker. Troubleshooting found that the MOC switches were preloaded and that the pantograph was not moving freely. The linkage was adjusted; pantograph was cleaned, adjusted and lubricated so that it would not bind and so that all contacts were making up properly.
CR-1308123 — On September 28, 2010, a minimum flow valve did not auto open due to MOC switch contacts not fully making up. The condition was corrected by adjusting the MOC switch operating rod in order to have the contacts make up.
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05000387/LER-2016-010 | Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to Medical Emergency LER 16-010-00 for Susquehanna, Unit 1, Regarding Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to Medical Emergency | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material | 05000387/LER-2016-001 | Secondary Containment Declared Inoperable Due to an Airlock Doors Open Due to Random Occurrence LER 16-001-00 for Susquehanna, Unit 1, Regarding Secondary Containment Declared Inoperable Due to an Airlock Doors Open Due to Random Occurrence | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material | 05000387/LER-2016-011 | Valve inoperability for a period longer than allowed by Technical Specifications LER 16-011-00 for Susquehanna, Unit 1, Regarding Valve Inoperability for a Period Longer Than Allowed by Technical Specifications | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000388/LER-2016-001 | Secondary Containment Breach due to Simultaneous Opening of Airlock Doors Due to Degraded Latch Mechanism | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material | 05000388/LER-2016-002 | Secondary Containment Breach due to Simultaneous Opening of Airlock Doors Due to Degraded Latch Mechanism | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material | 05000387/LER-2016-012 | Secondary Containment declared inoperable due to loss of differential pressure as a result of a solenoid failure. | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material | 05000387/LER-2016-002 | Secondary Containment Declared Inoperable Due to an Airlock Doors Open Due to Random Occurrence LER 16-002-00 for Susquehanna, Unit 1, Regarding Secondary Containment Declared Inoperable Due to an Airlock Doors Open Due to Random Occurrence | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material | 05000387/LER-2016-013 | Secondary Containment Declared Inoperable Due to Simultaneous Opening of Double Airlock Doors LER 16-013-00 for Susquehanna, Unit 1, Regarding Secondary Containment Declared Inoperable Due to Simultaneous Opening of Double Airlock Doors | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material | 05000388/LER-2016-003 | Secondary Containment Inoperability due to Failure to Meet Surveillance Requirement 3.6.4.1.1 | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material | 05000387/LER-2016-003 | Unit 2 Zone 3 HVAC unable to maintain Zone 3 differential pressure greater than 0.25 in wg LER 16-003-00 for Susquehanna, Unit 1, Regarding Unit 2 Zone 3 HVAC Unable to Maintain Zone 3 Differential Pressure Greater Than 0.25 in wg | 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 | 05000387/LER-2016-014 | Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to a Human Performance Error LER 16-014-00 for Susquehanna, Unit 1, Regarding Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to a Human Performance Error | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material | 05000388/LER-2016-004 | Unit 2 experienced an electrical transient resulting in a manual SCRAM | 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 | 05000387/LER-2016-004 | Momentary Loss of Secondary Containment due to Both Airlock Doors on Elevation 779 of the Unit 2 Reactor Building being Opened at the Same Time LER 16-004-00 for Susquehanna, Unit 1, Regarding Momentary Loss of Secondary Containment Due to Both Airlock Doors on Elevation 779 of the Unit 2 Reactor Building Being Opened at the Same Time | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material | 05000387/LER-2016-015 | Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to a Human Performance Error LER 16-015-00 for Susquehanna, Unit 1, Regarding Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to a Human Performance Error | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material | 05000387/LER-2016-005 | Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to Human Performance Error LER 16-005-00 for Susquehanna, Units 1 and 2, Regarding Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to Human Performance Error | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material | 05000388/LER-2016-005 | Unit 2 HPCI Manually Overridden Prior to a Manual Scram During a Plant Transient LER 16-005-00 for Susquehanna, Unit 2, Regarding HPCI Manually Overridden Prior to a Manual Scram During a Plant Transient | 10 CFR 50.73(a)(2)(v), Loss of Safety Function | 05000387/LER-2016-006 | Implementation of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3 LER 16-006-00 for Susquehanna, Unit 1, Regarding Implementation of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3 | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000387/LER-2016-007 | Inoperability of Swing Bus Transfer Switch Due to Deformed Bolt on Linkage LER 16-007-00 for Susquehanna, Unit 1, Regarding Inoperability of Swing Bus Transfer Switch Due to Deformed Bolt on Linkage | 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 | 05000387/LER-2016-008 | Inoperability of Diesel Generator Due to Misalignment of MOC Switch Contacts Due to Inadequate Post Maintenance Testing LER 16-008-00 for Susquehanna, Unit 1, Regarding Inoperability of Diesel Generator Due to Misalignment of MOC Switch Contacts Due to Inadequate Post Maintenance Testing | 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 | 05000387/LER-2016-009 | Valid Primary Containment Isolation Actuation during Local Leak Rate Testing due to Human Performance Error LER 16-009-00 for Susquehanna, Unit 1, Regarding Valid Primary Containment Isolation Actuation During Local Leak Rate Testing Due to Human Performance Error | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
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