On April 25, 2016, while performing a walkdown of Control Room panels, it was noticed that the green indication light for High Pressure Coolant Injection ( HPCI) auxiliary lube oil pump (ALOP) was not illuminated.
A non-licensed operator was dispatched to the HPCI ALOP starter and reported that the local indication lights were not illuminated. HPCI was declared inoperable at 2117 Central Daylight Time (CDT) resulting in entry into Technical Specifications (TS) Limiting Condition of Operation 3.5.1, Condition C, HPCI System Inoperable.
Investigation determined that the coil in the electrical relay for the ALOP, which had recently been replaced during a preventive maintenance window, had failed after 133 hours0.00154 days <br />0.0369 hours <br />2.199074e-4 weeks <br />5.06065e-5 months <br /> of service. The cause of the failure was determined to be the prior pre-installation checks performed by NuTherm on the relay were inadequate to prevent the type of infant mortality failure that occurred in this case. HPCI was declared operable at 1314 CDT on April 26, 2016, after the coil was replaced.
This event is being reported as a loss of safety function due to HPCI being a single-train safety system and as a condition prohibited by TS.
The potential safety consequences of this event were minimal due to both the limited duration the condition existed and the redundant/diverse core cooling systems which remained operable. |
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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 FOR, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e- mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory 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.
3. LER NUMBER
2016
PLANT STATUS
Cooper Nuclear Station (CNS) was in Mode 1, Power Operation, at 100 percent steady state power at the time the condition was identified. Service Water Pump "B" and Service Water Booster Pump "B" were inoperable when High Pressure Coolant Injection (HPCI) was inoperable. No other emergency core cooling systems were inoperable during the event.
BACKGROUND
The HPCI System (EIIS:BJ) provides protection to the core for the case of a small break in the reactor coolant pressure boundary which does not result in rapid depressurization of the reactor vessel (EIIS:RPV). The HPCI System permits the nuclear plant to be shutdown while maintaining sufficient
- reactor vessel water inventory until the reactor vessel is depressurized. The HPCI System continues to operate until reactor vessel pressure is below the pressure at which Low Pressure Coolant Injection (EIIS:BO) operation or Core Spray System (El IS:BM) operation can be used to maintain core cooling.
HPCI consists of a steam turbine assembly (EIIS:TRB) driving a multi-stage booster and main pump assembly (EIIS:P) and system piping, valves, controls and instrumentation. The HPCI turbine is driven by steam from the reactor which is generated by decay and residual heat.
A control governor (EIIS:65) receives a HPCI flow signal and adjusts the turbine steam control valve (EIIS:SCV) so that HPCI design pump discharge flow rate is obtained. The flow signal used for automatic control of the HPCI turbine is derived from a differential pressure measurement across a flow element (EIIS:FE) in the HPCI pump discharge pipeline. The governor controls the pressure applied to the hydraulic operator of the turbine control valve, which, in turn, controls the steam flow to the HPCI turbine.
Upon receipt of the actuation signal, the auxiliary oil pump starts, providing hydraulic pressure for the turbine stop valve and turbine control valve hydraulic operator. The flow signal will ramp the control governor until rated flow is achieved. As hydraulic oil pressure is developed, the turbine stop valve and the turbine control valve open simultaneously and the turbine accelerates toward the speed setting of the control governor. As HPCI flow increases, the flow signal adjusts the control governor setting so that design flow is maintained.
EVENT DESCRIPTION
On April 25, 2016, while performing a walkdown of Control Room panels, a licensed operator noticed that the green indication light for the HPCI auxiliary lube oil pump (ALOP) was not illuminated. The bulb in the Control Room panel was replaced, but did not illuminate. A non-licensed station operator was subsequently sent to the HPCI ALOP starter to verify local indications and found the local indication lights were not illuminated on the starter rack, indicating that the ALOP starter had lost power. The ALOP is required to start in order to open the steam admission valves for the HPCI turbine. An attempt was made in the Control Room to start the ALOP, but it did not start.
Cooper Nuclear Station 05000- 298 - 001 -00 Reported lessons learned are incorporated, into the licensing process and fed back to industry. Send 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 Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory 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.
3. LER NUMBER
2016 Operations then declared HPCI inoperable at 2117 Central Daylight Time (CDT), resulting in entry into Technical Specifications Limiting Condition of Operation 3.5.1, Condition C, HPCI System Inoperable.
Investigation revealed that the electrical relay (27) [Allen Bradley 700DC Type P relay] for the ALOP had been replaced on April 19, 2016, during the recent three-year required preventive maintenance window.
After various checks were made, it was discovered that the coil within the relay had failed after 133 hours0.00154 days <br />0.0369 hours <br />2.199074e-4 weeks <br />5.06065e-5 months <br /> of service. The relay is expected to provide three years of reliable service between replacements.
As such, it was concluded that the coil had sustained an infant mortality type failure.
The dedication process used by the vendor of the relay, NuTherm, at the time the relay was purchased by CNS, consisted of verifying the pickup and dropout voltages, and verifying contact resistances. After purchase of the relay, but prior to installation, NuTherm revised their dedication process to require additionally cycling the relay 30 times in addition to the previous voltage and resistance checks:
The relay that failed was replaced with a new relay that was purchased in September 2013 from a different lot than the failed relay purchased in March 2011. After satisfactory completion of post work testing of the ALOP, HPCI was declared operable at 1314 CDT on April 26, 2016.
BASIS FOR REPORT
The HPCI System is a single train safety system. This condition is reportable in accordance with 10 CFR 50.73(a)(2)(v) as "any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to...(D) Mitigate the consequences of an accident." The condition is also reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by TS since, due to HPCI inoperability, the verification of the Reactor Core Isolation Cooling system operability exceeded the 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> required completion time plus the 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> completion time to be in Mode 3 if this verification is not completed. The event was reported as Event Notification Number 51882.
SAFETY SIGNIFICANCE
This is a Safety System Functional Failure. There were no actual safety consequences associated with this event. The potential safety consequences of this event were minimal due to the limited duration the condition existed and the redundant/diverse core cooling systems which remained operable throughout the event. The HPCI system is an emergency core cooling system designed to inject water into the reactor vessel to provide core cooling. The total duration of inoperability, including the time prior to discovery of the condition was less than the 14 day Technical Specification Completion Time. During the time period of inoperability, other core cooling systems (Automatic Depressurization System, Core Spray, and Low Pressure Coolant Injection) were operable and would have adequately responded to a design basis event. The Reactor Core Isolation Cooling system was also operable during this event.
Cooper Nuclear Station 05000- 298 - 001 - 00 Reported lessons learned are incorporated into the licensing process and fed back to industry. Send 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 Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory 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.
CAUSE
The root cause of the event was determined to be that the prior pre-installation checks performed by NuTherm on the relay were inadequate to prevent the infant mortality failure that occurred in this case.
CORRECTIVE ACTIONS
NuTherm revised their dedication process such that this type of failure will be detected. In addition, there are no relays from this lot in storage at CNS; however a check of maintenance records found that some of the relays from this lot are installed in the plant. These installed relays are well beyond the infant mortality period and have performed as expected.
PREVIOUS EVENTS
- There have been no events reported in the last three years related to the HPCI ALOp.
Cooper Nuclear Station 05000- 298 - 001 -00
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05000298/LER-2016-001 | 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 | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000298/LER-2016-002 | 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 | 10 CFR 50.73(a)(2)(v), Loss of Safety Function | 05000298/LER-2016-003 | 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 | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000298/LER-2016-004 | 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 | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000298/LER-2016-005 | Implementation of Enforcement Guidance Memorandum 11-003, Revision 3, Causes Conditions Prohibited by Technical Specifications | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000298/LER-2016-006 | 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 | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000298/LER-2016-007 | 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 | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000298/LER-2016-008 | 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 | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
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