01-04-2018 | On November 5, 2017, at approximately 1240 CDT, the Main Control Room ( MCR) received numerous annunciators that indicated a trip of the Emergency Reserve Auxiliary Transformer ( ERAT) Static VAR Compensator ( SVC) caused by a voltage transient on the 138 kV offsite supply. Technical Specification (TS) Limiting Condition for Operation (LCO) 3.8.1, AC Sources-Operating, Required Action A.1 and A.2 were entered. As a result of the voltage transient, the Division 1 Fuel Building ventilation ( VF) system isolation dampers closed causing a trip of VF supply and exhaust fans. With no operating VF fans, Secondary Containment (SC) vacuum rose to slightly greater than 0 inches water gauge (WG) at 1241 CDT which exceeded the TS requirement of greater than 0.25 inches vacuum WG. The MCR entered Emergency Operating Procedure ( EOP)-8, Secondary Containment Control and TS LCO 3.6.4.1, Secondary Containment, Required Action A.1. The cause of the SC differential pressure becoming positive is that the circuit design of VF is not adequately robust to withstand loss of the 138 kV feed. At the time, the Division 1 safety bus was being fed from the ERAT.
Secondary Containment vacuum was restored within TS requirements at 1242 CDT by starting the Standby Gas Treatment System. A modification will be installed to prevent tripping VF during a momentary loss of power. Installation of a 138 kV Ring Bus is scheduled that is intended to improve the reliability of the radial feed of the 138 kV line. This event is being reported as a condition that could have prevented fulfillment of a safety function under 10 CFR 50.73(a)(2)(v)(C). |
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LER-2017-009, Trip of Emergency Reserve Auxiliary Transformer Static VAR Compensator Causes Positive Secondary Containment Pressure Following Voltage Transient on 138 kV Offsite Source.Clinton Power Station, Unit 1 . |
Event date: |
11-05-2017 |
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Report date: |
01-04-2018 |
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Reporting criterion: |
10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material |
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4612017009R00 - NRC Website |
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Category:Letter
MONTHYEARML24222A6772024-08-0909 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 05000461/20240022024-08-0909 August 2024 Integrated Inspection Report 05000461/2024002 ML24220A2772024-08-0707 August 2024 Request for Information for the NRC Quadrennial Comprehensive Engineering Team Inspection: Inspection Report 05000461/2025010 ML24212A2212024-08-0202 August 2024 License Renewal Regulatory Audit Regarding the Environmental Review of the License Renewal Application (EPID Number: L-2024-LNE-0000) (Docket Number: 50-461) ML24157A3242024-07-11011 July 2024 Issuance of Amendment No. 254 Revision of Reactor Water Cleanup Isolation Valve Timing ML24158A0772024-07-0303 July 2024 Notice of Consideration of Approval of Partial Site Release, Public Meeting, and Request for Comments (EPID L-2023-LLA-0088) - Letter ML24163A3252024-06-28028 June 2024 Aging Management Regulatory Audit Plan ML24163A3242024-06-28028 June 2024 LRA - Portal Letter ML24179A3112024-06-27027 June 2024 05000461; Notification of an NRC Biennial Licensed Operator Requalification Program Inspection and Request for Information ML24176A0272024-06-25025 June 2024 Confirmation of Initial License Examination, July 2025 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 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 IR 05000461/20240122024-05-20020 May 2024 Biennial Problem Identification and Resolution Inspection Report Report 05000461/2024012 RS-24-055, 2023 Corporate Regulatory Commitment Change Summary Report2024-05-17017 May 2024 2023 Corporate Regulatory Commitment Change Summary Report RS-24-050, Additional Information Supporting Request for License Amendment to Revise Technical Specifications Related to Reactor Water Cleanup Isolation Instrumentation2024-05-0909 May 2024 Additional Information Supporting Request for License Amendment to Revise Technical Specifications Related to Reactor Water Cleanup Isolation Instrumentation IR 05000461/20240012024-05-0707 May 2024 Integrated Inspection Report 05000461/2024001 ML24103A1032024-05-0101 May 2024 Shpo Consultation Letter for Clinton License Renewal ML24103A0992024-04-30030 April 2024 Achp Scoping Letter for Clinton License Renewal ML24103A1152024-04-30030 April 2024 Ltr. to Geoffrey Standing Bear, Principal Chief, the Osage Nation; Re., CPS Section 106 Consultation ML24120A3432024-04-30030 April 2024 Ltr. to Darwin Kaskaske, Chairman, Kickapoo Tribe of Oklahoma; Re., CPS Section 106 Consultation ML24120A3452024-04-30030 April 2024 Ltr. to Lester Randell, Chairman, Kickapoo Tribe of Indians of the Kickapoo Reservation in Kansas; Re., CPS Section 106 Consultation ML24120A3462024-04-30030 April 2024 Ltr. to Douglas Lankford, Chief, Miami Tribe of Oklahoma; Re., CPS Section 106 Consultation ML24120A3442024-04-30030 April 2024 Ltr. to Gena Kakkak, Chairman, Menominee Indian Tribe of Wisconsin; Re., CPS Section 106 Consultation 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 ML24107B0312024-04-29029 April 2024 Notice of Intent to Prepare an Environmental Impact Statement and Conduct Scoping Process 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 ML24089A2222024-04-11011 April 2024 LRA - Acceptance and Opportunity for Hearing - Letter 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 RS-24-031, Updated Safety Analysis Report (Usar), Revision 232024-04-0101 April 2024 Updated Safety Analysis Report (Usar), Revision 23 ML24092A3552024-04-0101 April 2024 Request for Information for NRC License Renewal Inspection: Inspection Report 05000461/2024010 RS-24-023, Report on Status of Decommissioning Funding.2024-03-22022 March 2024 Report on Status of Decommissioning Funding. ML24045A1422024-02-29029 February 2024 License Renewal Application Receipt and Availability - Letter IR 05000461/20230062024-02-28028 February 2024 Annual Assessment Letter for Clinton Power Station (Report 05000461/2023006) ML24054A7112024-02-23023 February 2024 Request for Information for NRC Commercial Grade Dedication Inspection: Inspection Report 05000461/2024011 ML24045A0242024-02-14014 February 2024 Application for Renewed Operating License RS-24-005, Additional Information Supporting Request for Partial Site Release2024-02-0808 February 2024 Additional Information Supporting Request for Partial Site Release IR 05000461/20230042024-02-0202 February 2024 Integrated Inspection Report 05000461/2023004 ML23361A1572024-01-24024 January 2024 Audit Plan in Support of Review of License Amendment Request Regarding Revision of Technical Specifications Related to Reactor Water Cleanup Isolation ML24004A0792024-01-18018 January 2024 Exemption from Select Requirements of 10 CFR Part 73 (EPID L-2023-LLE-0041 (Security Notifications, Reports, and Recordkeeping and Suspicious Activity Reporting)) IR 05000461/20234022023-12-27027 December 2023 Security Baseline Inspection Report 05000461/2023402 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 IR 05000461/20235012023-12-0505 December 2023 Emergency Preparedness Biennial Exercise Inspection Report 05000461/2023501 ML23284A2512023-11-22022 November 2023 Amendment No. 250 to Adopt TSTF-332 ML23317A1192023-11-10010 November 2023 Constellation Energy Generation, LLC - 2023 Annual Report - Guarantees of Payment of Deferred Premiums IR 05000461/20230032023-11-0808 November 2023 Integrated Inspection Report 05000461/2023003 ML22300A2212023-11-0202 November 2023 Preliminary Decommissioning Cost Estimate and Fuel Management Plan RS-23-097, Constellation Energy Generation, LLC, Advisement of Leadership Changes and Submittal of Updated Standard Practice Procedures Plans2023-10-12012 October 2023 Constellation Energy Generation, LLC, Advisement of Leadership Changes and Submittal of Updated Standard Practice Procedures Plans IR 05000461/20233012023-09-12012 September 2023 NRC Initial License Examination Report 05000461/2023301 RS-23-090, Annual Report of Emergency Core Cooling System Evaluation Model Changes and Errors for Clinton Power Station2023-09-0707 September 2023 Annual Report of Emergency Core Cooling System Evaluation Model Changes and Errors for Clinton Power Station 2024-08-09
[Table view] Category:Licensee Event Report (LER)
MONTHYEAR05000461/LER-2017-0102018-02-0505 February 2018 Division 1 Transformer Failure Leads to Instrument Air Isolation to Containment Requiring a Manual Reactor Scram, LER 17-010-00 for Clinton Power Station, Unit 1 Regarding Division 1 Transformer Failure Leads to Instrument Air Isolation to Containment Requiring a Manual Reactor Scram 05000461/LER-2017-0092018-01-0404 January 2018 Trip of Emergency Reserve Auxiliary Transformer Static VAR Compensator Causes Positive Secondary Containment Pressure Following Voltage Transient on 138 kV Offsite Source., LER 17-009-00 for Clinton, Unit 1, Regarding Trip of Emergency Reserve Auxiliary Transformer Static VAR Compensator Causes Positive Secondary Containment Pressure Following Voltage Transient on 138 kV Offsite Source 05000461/LER-2017-0052017-09-28028 September 2017 Automatic Reactor Scram During the Performance of Scram Time Testing As a Result of an Invalid Oscillation Power Range Monitor Growth Rate Trip, LER 17-005-01 for Clinton, Unit 1 Regarding Automatic Reactor Scram During the Performance of Scram Time Testing As a Result of an Invalid Oscillation Power Range Monitor Growth Rate Trip 05000461/LER-2017-0082017-08-11011 August 2017 Division 3 Shutdown Service Water Pump Start Failure, LER 17-008-00 for Clinton, Unit 1 re Division 3 Shutdown Service Water Pump Start Failure 05000461/LER-2017-0072017-08-0909 August 2017 Manual Reactor SCRAM due to Loss of Feedwater Heating, LER 17-007-00 for Clinton, Unit 1 re Manual Reactor SCRAM due to Loss of Feedwater Heating 05000461/LER-2017-0062017-08-0101 August 2017 1 OF 3, LER 17-006-00 for Clinton, Unit 1 re Secondary Containment Inoperable During Mode Change Due to Doors Propped Open 05000461/LER-2017-0042017-07-10010 July 2017 Main Steam Isolation Valve Local Leak Rate Test Limit Exceeded During Refueling Outage, LER 17-004-00 For Clinton Power Station, Unit 1 Re: Main Steam Isolation Valve Local Leak Rate Test Limit Exceeded During Refueling Outage 05000461/LER-2017-0022017-07-0505 July 2017 Failure of the Division 1 Diesel Generator Ventilation Fan Load Sequence Relay Circuit During Concurrent Maintenance of RHR Division 2 Results in an Unanalyzed Condition, LER 17-002-01 for Clinton, Unit 1, Regarding Failure of the Division 1 Diesel Generator Ventilation Fan Load Sequence Relay Circuit During Concurrent Maintenance of RHR Division 2 Results in an Unanalyzed Condition U-604357, Special Report: Inoperable Drywall High Range Gamma Radiation Monitor2017-07-0505 July 2017 Special Report: Inoperable Drywall High Range Gamma Radiation Monitor 05000461/LER-2017-0032017-07-0303 July 2017 Implementation of Enforcement Guidance Memorandum (EGM) 11 - 003, Revision 3, LER 17-003-00 for Clinton Power Station, Unit 1 Regarding Implementation of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3 05000461/LER-2017-0012017-04-21021 April 2017 Failure of the 138 kV Offsite Power Source Results in a Loss of Secondary Containment Vacuum, LER 17-001-00 for Clinton, Unit 1, Regarding Failure of the 138 kV Offsite Power Source Results in a Loss of Secondary Containment Vacuum 05000461/LER-2016-0102017-03-0606 March 2017 1 OF 3, LER 16-010-01 for Clinton Power Station, Unit 1 RE: Failure to Complete Technical Specification Required Actions within the Completion Time Resulted in a Condition Prohibited by Technical Specifications 05000461/LER-2016-0092016-08-22022 August 2016 Trip of Fuel Building Fans Due to Damper Failure Results in Loss of Secondary Containment, LER 16-009-00 for Clinton Power Station, Unit 1 Regarding Trip of Fuel Building Fans Due to Damper Failure Results in Loss of Secondary Containment 05000461/LER-2016-0072016-07-15015 July 2016 Main Steam Line Flexible Hose Intergranular Stress Corrosion Cracking Identified During Refueling Outage, LER 16-007-00 for Clinton Power Station, Unit 1, Regarding Main Steam Line Flexible Hose lntergranular Stress Corrosion Cracking Identified During Refueling Outage 05000461/LER-2016-0082016-07-15015 July 2016 Implementation of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3, LER 16-008-00 for Clinton Power Station, Unit 1, Regarding Implementation of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3 05000461/LER-2016-0062016-06-10010 June 2016 Missed Surveillance Results in a Condition Prohibited by Technical Specifications, LER 16-006-00 for Clinton Power Station Unit 1 RE: Missed Surveillance Results in a Condition Prohibited by Technical Specifications 05000461/LER-2016-0052016-05-31031 May 2016 Insulator Failure On the Reserve Auxiliary Transformer Results In A Loss of Secondary Containment Vacuum, LER 16-005-00 for Clinton Power Station, Unit 1, Regarding Insulator Failure on the Reserve Auxiliary Transformer Results in a Loss of Secondary Containment Vacuum 05000461/LER-2016-0042016-05-26026 May 2016 Trip of Emergency Reserve Auxiliary Transformer Static VAR Compensator Causes Positive Secondary Containment Pressure Following Lightning Strike on 138 kV Offsite Source, LER 16-004-00 for Clinton, Unit 1, Regarding Trip of Emergency Reserve Auxiliary Transformer Static VAR Compensator Causes Positive Secondary Containment Pressure Following Lightning Strike on 138 kV Offsite Source 05000461/LER-2016-0032016-05-23023 May 2016 Bypassing Both Divisions of Reactor Water Cleanup Leak Detection System is a Reportable Loss of Safety Function, LER 16-003-00 for Clinton Power Station, Unit 1 Regarding Bypassing Both Divisions of Reactor Water Cleanup Leak Detection System is a Reportable Loss of Safety Function 05000461/LER-2016-0022016-04-13013 April 2016 Trip of Fuel Building Ventilation Exhaust Fan Due to Moisture Formation Resulting In the Loss of Secondary Containment Vacuum, LER 16-002-00 for Clinton, Unit 1, Regarding Trip of Fuel Building Ventilation Exhaust Fan Due to Moisture Formation Resulting In the Loss of Secondary Containment Vacuum 2018-02-05
[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 Int ocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, 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
2017 - 00 009
PLANT AND SYSTEM IDENTIFICATION
General Electric -- Boiling Water Reactor, 3473 Megawatts Thermal Rated Core Power Energy Industry Identification System (EIIS) codes are identified in text as [XX].
EVENT IDENTIFICATION
Trip of Emergency Reserve Auxiliary Transformer Static VAR Compensator Causes Positive Secondary Containment Pressure Following Voltage Transient on 138 kV Offsite Source.
A. Plant Operating Conditions before the Event Unit: 1 Event Date: 11/05/17 Mode: 1 Mode Name: Power Operation Event Time: 1240 CDT Reactor Power: 98 percent
B. Description of Event
On November 5, 2017, at approximately 1240 hours0.0144 days <br />0.344 hours <br />0.00205 weeks <br />4.7182e-4 months <br /> CDT the Emergency Reserve Auxiliary Transformer (ERAT)[XFMR] Static VAR Compensator (SVC)[COMP] tripped due to a voltage transient on the 138 kV line owned and maintained by Ameren Illinois. The Main Control Room (MCR) entered Technical Specification (TS) Limiting Condition for Operation (LCO) 3.8.1, AC Sources-Operating, Required Actions A.1 and A.2. As a result of the voltage transient, the Division 1 Fuel Building Ventilation (VF) system isolation dampers closed causing a trip of the VF supply and exhaust fans. Ameren stated that the voltage transient was possibly due to weather. The effect of this condition was that Secondary Containment (SC) vacuum rose to slightly greater than 0 inches water gauge (WG) and exceeded the TS limit of -0.25 inch WG. Operations personnel entered Emergency Operating Procedure (EOP) -8, Secondary Containment Control, and TS LCO 3.6.4.1, Secondary Containment, Required Action A.1. As a result of the momentary loss of power, the following additional system actuations occurred:
- Division 1 MCR Ventilation Chiller tripped,
- Division 1 Diesel Generator Room Exhaust Fan 1VDO2CA tripped,
- Fission Product Monitoring (FPM) skid isolation valves shut,
- Division 1 Hydrogen Monitoring system isolation valves shut,
- Containment Service Air System Outboard Isolation valve 1SA029 shut,
- Nuclear Systems Protection System (NSPS) Inverter Trouble alarms (due to loss of synchronization) 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
2017 - 00 009 The Standby Gas Treatment System (VG) was manually started and SC vacuum was restored within TS limits at approximately 1242 hours0.0144 days <br />0.345 hours <br />0.00205 weeks <br />4.72581e-4 months <br />. The system actuations were addressed and plant equipment was restored to service in accordance with plant procedures. The momentary loss of power did not adversely affect the safe operation of the plant or the restoration of SC. During the investigation, Ameren reported that the Clinton feeder breaker that supplied the 138 kV line had tripped and reclosed probably due to weather. In addition, during inspection of the offsite power lines, two disconnects were found not fully seated. These disconnects were reseated and the ERAT SVC was returned to service and declared OPERABLE at 1702 hours0.0197 days <br />0.473 hours <br />0.00281 weeks <br />6.47611e-4 months <br />.
C. Cause of the Event
The cause of the SC differential pressure becoming positive is that the circuit design of VF is not adequately robust to withstand the loss of the 138 kV feed.
D. Safety Consequences This event is reportable in accordance with 10CFR50 50.73(a)(2)(v)(C) as a condition that could have prevented fulfillment of a safety function to control the release of radioactive material because the SC was declared inoperable.
The VG system was fully operable at the time of the event and capable of performing its required safety function. Operations entered EOP-8 for SC vacuum less than -0.25 inch WG and entered TS LCO 3.6.4.1 Required Action A.1. The SC vacuum was restored to within TS limits within the completion time requirement. The SC vacuum normally is kept slightly negative relative to atmospheric pressure to prevent leakage to the atmosphere. The VF system is a non-safety ventilation system which is normally in service to maintain SC vacuum. The VG system is the safety-related system which is relied upon to perform this function following an accident. During the event, the VG system was placed in service and restored SC to operability consistent with its safety function. Therefore, the ability of the station to maintain SC vacuum in the event of an accident was never jeopardized or challenged by the VF system trip. Engineering analysis has determined that this event is not considered a safety system functional failure.
E. Corrective Actions
A modification will be installed to prevent tripping VF during a momentary loss of power. Installation of a 138 kV Ring Bus is scheduled that is intended to improve the reliability of the radial feed of the 138 kV line.
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
2017 - 00 009 In addition, a License Amendment Request (LAR) was submitted to the NRC on November 8, 2017 to adopt Technical Specifications Task Force (TSTF)-551, Revise Secondary Containment Surveillance Requirements, to adopt a change to the CPS TS that would eliminate the requirement to declare SC inoperable under similar transient conditions. Adoption of this LAR would have prevented this event from being reportable.
F. Previous Similar Occurrences Licensee Event Report 2015-004-00: Trip of Emergency Reserve Auxiliary Transformer Static VAR Compensator Causes Positive Secondary Containment Pressure Following Lightning Strike on 138 kV Offsite Source.
On June 25, 2015 at 0301 CDT, the Main Control Room received numerous annunciators that indicated a trip of the ERAT Static VAR Compensator caused by a voltage transient on the 138 kV offsite source due to thunderstorms in the area. The Division 1 safety bus was manually aligned from the reserve source to its normal source.
As a result of the voltage transient, the Division 1 VF system isolation dampers closed causing a trip of VF supply and exhaust fans. Secondary Containment vacuum increased to greater than 0 inch WG which exceeded the TS requirement. Secondary Containment vacuum was restored within TS requirements by reopening the VF isolation dampers and restarting the VF supply and exhaust fans. The ERAT SVC was returned to service at 0457 CDT.
Licensee Event Report 2016-004-00: Trip of Emergency Reserve Auxiliary Transformer Static VAR Compensator Causes Positive Secondary Containment Pressure Following Lightning Strike on 138 kV Offsite Source On March 30, 2016, at approximately 1545 CDT, the Main Control Room received numerous annunciators that indicated a trip of the Emergency Reserve Auxiliary Transformer Static VAR Compensator caused by a voltage transient on the 138 kV supply. Technical Specification Limiting Condition for Operation 3.8.1, AC Sources-Operating, Required Action A.1 and A.2 were entered. As a result of the voltage transient, the Division 1 Fuel Building ventilation system isolation dampers closed causing a trip of VF supply and exhaust fans. With no operating VF fans, Secondary Containment vacuum rose to slightly greater than 0 inches water gauge which exceeded the TS requirement of greater than 0.25 inches vacuum WG.
Secondary Containment vacuum was restored within TS requirements at 1550 CDT by starting the Standby Gas Treatment System.
G. Component Failure Data
There were no component failures associated with this event.