On June 19, 2017, during performance of surveillance 6.PC.207, "Torus to Drywell Vacuum Breaker Operation," the control switch for vacuum breaker PC-AOV-NRV21 was cycled open, then closed. When the control switch was taken to close, the vacuum breaker failed to indicate closed. As such, Operations declared primary containment and PC-AOV-NRV21 inoperable and entered Technical Specification (TS) Limiting Condition for Operation (LCO) 3.6.1.1 Condition A and LCO 3.6.1.8 Condition B at 21:15 hours. In addition, TS LCO 3.6.1.1 Condition B was entered at 22:15 hours due to PC-AOV-NRV21 still indicating intermediate.
The control switch for PC-AOV-NRV21 was cycled open, and then closed a second time. At this time, PC-A0V- NRV21 indicated closed. Operations declared primary containment and PC-A0V-NRV21 operable at 23:11 hours and exited TS LCO 3.6.1.1, Condition A and Condition B, and TS LCO 3.6.1.8, Condition B.
The cause is currently under investigation. Cooper Nuclear Station will provide a supplement to this Licensee Event Report after inspection of the vacuum breakers can be performed (i.e., during Refueling Outage 30).
There were no safety consequences associated with this condition. |
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Category:Letter
MONTHYEARML23334A2012024-01-0303 January 2024 Issuance of Amendment No. 274 Revision to Technical Specifications to Adopt TSTF-551, Revision 3, Revise Secondary Containment Surveillance Requirements ML23311A1122023-11-0909 November 2023 Project Manager Assignment ML23311A2082023-11-0909 November 2023 Reassignment of U.S. Nuclear Regulatory Commission Branch Chief in the Division of Operating Reactor Licensing for Plant Licensing Branch IV IR 05000298/20230032023-11-0202 November 2023 Integrated Inspection Report 05000298/2023003 IR 05000298/20234012023-11-0101 November 2023 Cyber Security Report 05000298/2023401 Public ML23264A8052023-10-11011 October 2023 Issuance of Amendment No. 273 Revision to Technical Specifications to Adopt TSTF-580, Revision 1, Provide Exception from Entering Mode 4 with No Operable RHR Shutdown Cooling ML23233A1882023-09-0505 September 2023 Regulatory Audit Plan in Support of Relief Request RC3-02 Regarding Drywell Head Bolting IR 05000298/20243012023-09-0101 September 2023 Notification of NRC Initial Operator Licensing Examination 05000298/2024301 IR 05000298/20230052023-08-21021 August 2023 Updated Inspection Plan for Cooper Nuclear Station (Report 05000298/2023005)- Mid Cycle Letter IR 05000298/20230022023-08-0808 August 2023 Integrated Inspection Report 05000298/2023002 IR 05000298/20234022023-08-0303 August 2023 NRC Security Inspection Report 05000298/2023402 ML23214A2742023-08-0303 August 2023 Nuclear Station - Notification of Inspection (NRC Inspection Report 05000298/2023004) and Request for Information IR 05000298/20234202023-08-0101 August 2023 Security Baseline Inspection Report 05000298/2023420 ML23173A0862023-06-26026 June 2023 Information Request for the Cybersecurity Baseline Inspection, Notification to Perform Inspection 05000298/2023401 IR 05000298/20230102023-05-17017 May 2023 Biennial Problem Identification and Resolution Inspection Report 05000298/2023010 IR 05000298/20234032023-05-0404 May 2023 Security Baseline Inspection Report 05000298/2023403 ML23129A2822023-04-20020 April 2023 Submittal of Revision 31 to Updated Safety Analysis Report ML23102A0282023-04-19019 April 2023 U.S. Nuclear Regulatory Commission Presentation at the May 8, 2023, Brownville Village Meeting IR 05000298/20230012023-04-17017 April 2023 Integrated Inspection Report 05000298/2023001 ML23060A1582023-03-0808 March 2023 Design Basis Assurance Inspection (Programs) Inspection Report 05000298/2023001 IR 05000298/20220062023-03-0101 March 2023 Annual Assessment Letter for Cooper Nuclear Station Report 05000298/2022006 ML23041A1622023-02-10010 February 2023 Licensed Operator Positive Fitness-for-Duty Test Request for Additional Information IR 05000298/20220042023-01-30030 January 2023 Integrated Inspection Report 05000298/2022004 IR 05000298/20220112022-12-23023 December 2022 License Renewal Phase 4 Inspection Report 05000298/2022011 ML22286A2072022-11-30030 November 2022 Issuance of Amendment No. 272 Revision to Technical Specifications to Adopt TSTF-554, Revision 1, Revise Reactor Coolant Leakage Requirements IR 05000298/20220032022-10-27027 October 2022 Integrated Inspection Report 05000298/2022003 ML22304A0052022-10-26026 October 2022 Surveillance Capsule Location (Re-insertion Into the Reactor Vessel) IR 05000298/20223022022-10-20020 October 2022 NRC Initial Operator Licensing Examination Approval 05000298/2022302 ML22276A1562022-10-0505 October 2022 Notification of Commercial Grade Dedication Inspection 05000298/2023011 and Request for Information IR 05000298/20224022022-09-29029 September 2022 NRC Security Inspection Report 05000298/2022402 (Full Report) IR 05000298/20220052022-08-18018 August 2022 Updated Inspection Plan for Cooper Nuclear Station (Report 05000298 2022005) IR 05000298/20223012022-08-10010 August 2022 NRC Examination Report 05000298/2022301 IR 05000298/20220022022-07-28028 July 2022 Integrated Inspection Report 05000298/2022002 ML22200A2772022-07-21021 July 2022 Correction to Proposed Inservice Testing Alternative RS-01, Revision of Error in Safety Evaluation ML22152A1232022-07-18018 July 2022 Issuance of Amendment No. 271 Request for Exception from Certain Primary Containment Leak Rate Testing Requirements IR 05000298/20224012022-06-29029 June 2022 Security Baseline Inspection Report 05000298/2022401 IR 05000298/20224032022-06-28028 June 2022 Security Baseline Inspection Report 05000298/2022403 IR 05000298/20220102022-06-16016 June 2022 Triennial Fire Protection Inspection Report 05000298/2022010 ML22140A1612022-06-0808 June 2022 Proposed Inservice Inspection Alternative RR5-01 Revision 1 ML22147A1122022-06-0101 June 2022 NRC Initial Operator Licensing Examination Approval 05000298/2022301 ML22111A1382022-05-13013 May 2022 Proposed Inservice Testing Alternative RS-01, Revision 0 IR 05000298/20220012022-04-28028 April 2022 Integrated Inspection Report 05000298/2022001 IR 05000298/20224042022-04-13013 April 2022 Material Control and Accounting Program Inspection Report 05000298/2022404 - (Public) ML22084A6032022-04-0404 April 2022 Notification of NRC Evaluations of Changes, Tests and Experiments Inspection 05000298/2022002 and Request for Information ML22090A2892022-04-0101 April 2022 John Larson'S Invitation to Participate in the 8th Nuclear Regulatory Commission'S Workshop on Vendor Oversight ML22045A0012022-03-31031 March 2022 Proposed Inservice Inspection Alternative RI5- 02 Revision 3 IR 05000298/20210062022-03-0202 March 2022 Annual Assessment Letter for Cooper Nuclear Station (Report 05000298/2021006) IR 05000298/20210042022-01-24024 January 2022 Integrated Inspection Report 05000298/2021004 ML21350A0582021-12-21021 December 2021 Withdrawal of an Amendment Request ML21340A2362021-12-20020 December 2021 Issuance of Amendment No. 270 Adoption of Technical Specifications Task Force Traveler TSTF-582, Revision 0, RPV WIC Enhancements 2024-01-03
[Table view] Category:Licensee Event Report (LER)
MONTHYEAR05000298/LER-2016-0012017-09-27027 September 2017 De-Energized High Pressure Coolant Injection Auxiliary Lube Oil Pump Caused by Relay Failure Results in Loss of Safety Function and a Condition Prohibited by Technical Specifications, LER 16-001-01 for Cooper Nuclear Station Regarding De-Energized High Pressure Coolant Injection Auxiliary Lube Oil Pump Caused by Relay Failure Results in Loss of Safety Function, a Condition Prohibited by Tech Specs, and a 10 CFR Part 21 Report 05000298/LER-2017-0042017-08-17017 August 2017 Torus to Drywell Vacuum Breaker Failure to Indicate Full Closed Causes Loss of Safety Function, LER 17-004-00 for Cooper Nuclear Station Regarding Torus to Drywall Vacuum Breaker Failure to Indicate Full Closed Causes Loss of Safety Function 05000298/LER-2017-0052017-08-17017 August 2017 Traversing In-core Probe In-shield Limit Switch Mounting Failure Results in Common Cause Inoperability of Independent Trains or Channels and Condition Prohibited by Technical Specifications, LER 17-005-00 for Cooper Nuclear Station Regarding Traversing In-core Probe In-shield Limit Switch Mounting Failure Results in Common Cause lnoperability of Independent Trains or Channels and Condition Prohibited by Technical Specifications 05000298/LER-2017-0032017-07-24024 July 2017 Mispositioned Control Room Emergency Filter System Supply Fan Damper Causes Loss of Safety Function, LER 17-003-00 for Cooper Nuclear Station re Mispositioned Control Room Emergency Filter System Supply Fan Damper Causes Loss of Safety Function 05000298/LER-2017-0022017-04-27027 April 2017 Valve Test Failures Result in Condition Prohibited by Technical Specifications and a Loss of Safety Function, LER 17-002-00 for Cooper Nuclear Station Regarding Valve Test Failures Result in Condition Prohibited by Technical Specifications and a Loss of Safety Function 05000298/LER-2017-0012017-04-0505 April 2017 Residual Heat Removal Minimum Flow Valves OUt of Position Results in Loss of Safety Function and Condition Prohibited by Technical Specifications, LER 17-001-00 for Cooper Regarding Residual Heat Removal Minimum Flow Valves Out of Position Results in Loss of Safety Function and Condition Prohibited by Technical Specifications 05000298/LER-2016-0082017-01-0505 January 2017 Purchase and Installation of Incorrect Actuator Results in a Condition Prohibited by Technical Specifications, LER 16-008-00 for Cooper Nuclear Station Regarding Purchase and Installation of Incorrect Actuator Results in a Condition Prohibited by Technical Specifications 05000298/LER-2016-0072016-12-19019 December 2016 Isolation of Shutdown Cooling due to Relay Maintenance Results in a Loss of Safety Function, LER 16-007-00 for Cooper Nuclear Station Regarding Isolation of Shutdown Cooling due to Relay Maintenance Results in a Loss of Safety Function 05000298/LER-2016-0062016-12-19019 December 2016 High Vibration on Control Room Emergency Filter System Fan Results in Inoperability and Loss of Safety Function, LER-16-006-00 for Cooper Nuclear Station Regarding High Vibration on Control Room Emergency Filter System Fan Results in Inoperability and Loss of Safety Function 05000298/LER-2016-0042016-11-22022 November 2016 Closure of Multiple Main Steam Isolation Valves due to High Flow Signal, LER 16-004-00 for Cooper Nuclear Station Regarding Closure of Multiple Main Steam Isolation Valves due to High Flow Signal 05000298/LER-2016-0032016-11-0909 November 2016 Scaffold Construction Places Plant in a Condition Prohibited by Technical Specifications, LER 16-003-00 for Cooper Nuclear Station RE: Scaffold Construction Places Plant in a Condition Prohibited by Technical Specifications 05000298/LER-2016-0022016-06-27027 June 2016 De-Energized High Pressure Coolant Injection Auxiliary Lube Oil Pump Caused By Light Bulb Failure Results in Loss of Safety Function, LER 16-002-00 for Cooper Regarding De-Energized High Pressure Coolant Injection Auxiliary Lube Oil Pump Caused By Light Bulb Failure Results in Loss of Safety Function NLS2015063, Retraction of Licensee Event Report 2014-005-00, Lube Oil Leak Results in a Potential Condition Prohibited by Technical Specifications and a Potential Loss of Safety Function.2015-06-0909 June 2015 Retraction of Licensee Event Report 2014-005-00, Lube Oil Leak Results in a Potential Condition Prohibited by Technical Specifications and a Potential Loss of Safety Function. ML13149A1722013-05-26026 May 2013 E-mail from Micheal Mulligan to R.Guzman, Pilgrim Evacuation Plan Broken During Blizzard Nemo and Unenforced by the Nrc. NLS2013015, Special Report, Offgas Treatment System Charcoal Adsorbers Out of Service2013-01-29029 January 2013 Special Report, Offgas Treatment System Charcoal Adsorbers Out of Service NLS2008058, LER 08-S01-00 for Cooper Regarding Temporary Suspension of Security Measures Due to Tornado Warning2008-08-0505 August 2008 LER 08-S01-00 for Cooper Regarding Temporary Suspension of Security Measures Due to Tornado Warning 2017-09-27
[Table view] |
Reported lessons learned are incorporated into the licensing process and fed back to industry. Send comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S.
Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means 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.
V:ICY-4) Cooper Nuclear Station 05000- 298 NUMBER NO.
2017 -04 - 00
PLANT STATUS
Cooper Nuclear Station (CNS) was in Mode 1, Power Operations, 100 percent power, at the time of discovery; i.e., June 19, 2017.
BACKGROUND
The function of the Torus to Drywell Vacuum Breaker [EIIS:VACB] is to relieve vacuum in the drywell.
There are 12 internal vacuum breakers which allow air and steam flow from the suppression chamber (torus) to the drywell when the drywell is at a negative pressure. Torus to Drywell Vacuum breakers prevent an excessive negative differential pressure across the drywell boundary. Each vacuum breaker is a self-actuating valve [EllS:V], similar to a check valve, which can be remotely operated for testing purposes.
A negative differential pressure across the drywell wall is caused by rapid depressurization of the drywell.
Design Bases Accident (DBA) analyses assume the vacuum breakers to be closed initially and to remain closed and leak tight, until the suppression pool is at a positive pressure relative to the drywell. The requirement that the vacuum breakers be closed ensures that there is no excessive bypass leakage should a Loss of Coolant Accident (LOCA) occur.
The function of the primary containment [EIIS:NH] is to isolate and contain fission products released from the Reactor Primary System following a design basis LOCA and to confine the postulated release of radioactive material. The safety design basis for the primary containment is that it must withstand the pressures and temperatures of the limiting DBA without exceeding the design leakage rate. The leakage from the drywell to the suppression chamber must be limited to ensure the pressure suppression function is accomplished and the suppression chamber pressure does not exceed design limits.
The vacuum breaker has a safety function in the closed position to limit the amount of bypass flow to ensure proper containment response on a postulated LOCA event and an open safety function post LOCA to limit negative differential pressure between the drywell and the suppression chamber. With the valve partially open, the LOCA containment response cannot be assured.
EVENT DESCRIPTION
On June 19, 2017, during performance of surveillance 6.PC.207, "Torus to Drywell Vacuum Breaker Operation," the control switch for vacuum breaker PC-AOV-NRV21 was cycled open, then closed. When the control switch was taken to close, the vacuum breaker failed to indicate closed. As such, Operations declared primary containment and PC-AOV-NRV21 inoperable and entered Technical Specification (TS) Limiting Condition for Operation (LCO) 3.6.1.1 Condition A and LCO 3.6.1.8 Condition B at 21:15 hours.
In addition, TS LCO 3.6.1.1 Condition B was entered at 22:15 hours due to PC-AOV-NRV21 still indicating intermediate.
control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
Cooper Nuclear Station 05000- 298 NUMBER NO.
The control switch for PC-AOV-NRV21 was cycled open, then closed a second time. At this time, PC- AOV-NRV21 indicated closed. Operations declared primary containment operable at 23:11 hours and exited TS LCO 3.6.1.1, Condition A and Condition B, and TS LCO 3.6.1.8 Condition B.
The event is currently under investigation. CNS will provide additional event details, the safety significance, cause, corrective actions, and previous events in a supplement to this Licensee Event Report.
BASIS FOR REPORT
CNS is reporting this event under 10 CFR 50.73(a)(2)(v)(D) as a condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.
CNS also reported this event to the Nuclear Regulatory Commission Operations Center per Event Notification 52813.
CNS subsequently performed an engineering evaluation which concluded that PC-AOV-NRV21 would have completed its closure under forces resulting from reactor blowdown. As such, this event is not considered a Safety System Functional Failure.
Other criteria, if determined to be applicable, will be provided in the supplemental report.