08-02-2017 | On June 5, 2017, at 0930 Eastern Daylight Time (EDT), Unit 1 was in Mode 1 at 100 percent power, and Unit 2 was in Mode 1 at 87 percent power and was increasing power after a preplanned control rod improvement evolution. Maintenance personnel were inspecting dampers in the Control Room Air Conditioning ( AC) system and Control Room Emergency Ventilation (CREV) system and disconnected an air supply to a damper. This resulted in the CREV system being inoperable due to interruption of the pneumatic supply. The CREV system was restored to operable status by 1009 EDT. At 1352 EDT, a second damper was inspected, and its pneumatic supply was disconnected. During the second occurrence, the Control Room AC system also tripped and was made inoperable. Affected systems were restored by 1407 EDT.
The event is reportable as a loss of safety function per 10 CFR 50.73(a)(2)(v)(D). The event resulted from inadequate use of human performance tools and inadequate work instructions. Corrective actions for this event include restoring the affected pneumatic supply, revising work orders, and taking steps to emphasize proper use of human performance tools. |
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Category:Letter
MONTHYEARIR 05000324/20230112023-12-26026 December 2023 NRC Fire Protection Team Inspection - FPTI Report 05000324/2023011 and 05000325/2023011 IR 05000324/20234022023-12-14014 December 2023 Security Baseline Inspection Report 05000324-2023402 and 05000325-2023402 ML23297A0262023-11-27027 November 2023 Proposed Alternatives to ASME Code Section XI Subsection IWE Requirements for Torus Metallic Liner Inspections ML23317A3462023-11-14014 November 2023 Duke Fleet - Correction Letter to License Amendment Nos. 312 & 340 Issuance of Amendments Regarding the Adoption of Technical Specifications Task Force Traveler TSTF-554, Revision 1 IR 05000324/20230032023-11-0101 November 2023 Integrated Inspection Report 05000324/2023003 and 05000325/2023003 IR 05000324/20230102023-10-17017 October 2023 Biennial Problem Identification and Resolution Inspection Report 05000324/2023010 and 05000325/2023010 IR 05000325/20234012023-10-16016 October 2023 Security Baseline Inspection Report 05000324 and 05000325 2023401 ML23346A1322023-10-0606 October 2023 Communication from C-10 Research & Education Foundation Regarding NextEra Common Emergency Fleet Plan License Amendment Request and Related Documents Subsequently Published ML23256A0882023-09-25025 September 2023 Issuance of Alternative to Steam Generator Welds ML23195A0782023-08-29029 August 2023 Issuance of Amendments Regarding the Adoption of Technical Specifications Task Force Traveler TSTF-554, Revision 1 IR 05000324/20230052023-08-23023 August 2023 Updated Inspection Plan for Brunswick Steam Electric Plant, Units 1 and 2 (Report 05000324/2023005 and 05000325/2023005) IR 05000324/20230022023-08-0404 August 2023 Integrated Inspection Report 05000324/2023002 and 05000325/2023002 ML23201A2042023-07-28028 July 2023 Summary of Regulatory Audit in Support of Alternative Request RA-22-0308 for Inservice Inspection of the Torus Metallic Liner ML23212B2682023-07-25025 July 2023 Notification of Licensed Operator Initial Examination 05000325/2024301 and 05000324/2024301 IR 05000324/20243012023-07-25025 July 2023 Notification of Licensed Operator Initial Examination 05000325/2024301 and 05000324/2024301 ML23146A0012023-05-24024 May 2023 EN 56538 - Engine Systems Inc and Brunswick ML23212A9502023-05-24024 May 2023 Engine Systems, Inc., Part 21 Report Re Woodward EGB-35P Governor/Actuator with Foreign Material ML23130A3902023-05-12012 May 2023 Regulatory Audit Plan in Support of Alternative Request RA 22-0308 for Inservice Inspection of the Torus Metallic Liner IR 05000324/20230012023-05-10010 May 2023 Integrated Inspection Report 05000324 2023001 and 05000325 2023001 ML23118A0762023-05-0101 May 2023 Approval for Use of Specific Provision of a Later Edition of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section XI IR 05000324/20220042023-04-0404 April 2023 Reissue - Brunswick Steam Electric Plant - Integrated Inspection Report 05000324/2022004 and 05000325/022004 ML22332A4932023-03-10010 March 2023 William States Lee III 1 and 2 - Issuance of Amendments Regarding the Relocation of the Emergency Operations Facility IR 05000324/20220062023-03-0101 March 2023 Annual Assessment Letter for Brunswick Steam Electric Plant, Units 1 and 2 NRC Inspection Reports 05000324/2022006 and 05000325/2022006 ML23033A5252023-02-0808 February 2023 Integrated Inspection Report 05000324/2022004 and 05000325/2022004 IR 05000324/20223012023-02-0303 February 2023 NRC Operator License Examination Report 05000325/2022301 and 05000324/2022301 ML22332A0132022-11-23023 November 2022 Operator Licensing Written Examination Approval 05000325/2022301 and 05000324/2022301 IR 05000324/20224022022-11-23023 November 2022 Security Baseline Inspection Report 05000324 2022402 and 05000325 2022402 ML22096A0032022-11-18018 November 2022 McGuire Nuclear Station and Shearon Harris Nuclear Power Plant Authorization of RA-19-0352 Regarding Use of Alternative for RPV Head Closure Stud Examinations ML22256A2532022-11-14014 November 2022 Issuance of Amendments Regarding the Adoption of Technical Specifications Task Force Traveler TSTF-541, Rev. 2 IR 05000324/20224032022-11-10010 November 2022 Cyber Security Inspection Report 05000324/2022403 and 05000325/2022403 ML22307A1762022-11-0707 November 2022 Notification of an NRC Fire Protection Team Inspection (FPTI) IR 05000324/20220032022-11-0707 November 2022 Integrated Inspection Report 05000324/2022003 and 05000325/2022003 ML22258A0302022-09-15015 September 2022 Evacuation Time Estimate Reports IR 05000324/20220052022-08-24024 August 2022 Updated Inspection Plan for Brunswick Steam Electric Plant (Report 05000324/2022005 and 05000325/2022005) ML22230D0692022-08-22022 August 2022 Documentation of the Completion of Required Actions Taken in Response to the Lessons Learned from the Fukushima Dai-ichi Accident IR 05000324/20220022022-08-0505 August 2022 Integrated Inspection Report 05000324/2022002 and 05000325/2022002 IR 05000324/20220102022-06-27027 June 2022 Design Basis Assurance Inspection (Teams) Inspection Report 05000324 2022010 and 05000325 2022010 ML22028A1742022-05-12012 May 2022 Issuance of Amendment Nos. 309 and 337 Regarding the Adoption of Technical Specifications Task Force Traveler TSTF-580, Revision 1 IR 05000324/20220012022-05-10010 May 2022 Integrated Inspection Report 05000324/2022001 and 05000325/2022001 ML22119A1352022-05-0909 May 2022 Information Request for the Cyber-Security Baseline Security Inspection, Notification to Perform Inspection 05000325/2022403; 05000324/2022403 ML22082A2682022-05-0202 May 2022 Issuance of Amendment Nos. 308 and 336 Regarding the Adoption of Technical Specifications Task Force Traveler TSTF-505, Revision 2 ML22102A0502022-04-11011 April 2022 301 Corporate Notification Letter IR 05000324/20224012022-03-16016 March 2022 Security Baseline Inspection Report 05000324/2022401 and 05000325/2022401 ML22054A2152022-03-0808 March 2022 Correction to Amendments to Revise Standby Liquid Control System Boron Solution Storage Tank Volume Technical Specifications IR 05000324/20210062022-03-0202 March 2022 Annual Assessment Letter for Brunswick Steam Electric Plant, Units 1 and 2 (Reports No. 05000324/2021006 and 05000325/2021006) IR 05000324/20210042022-02-14014 February 2022 Integrated Inspection Report 05000324/2021004 and 05000325/2021004 ML22035A1262022-02-0909 February 2022 Withdrawal of Exemption Request from the Requirements of 10 CFR Part 50, Appendix E, Section IV.F.2.d (EPID L-2021-LLE-0055 (COVID-19)) ML21354A5032022-01-24024 January 2022 Requested Exemption from 10 CFR 50, Appendix E, Section IV.F.2.D Not Required (EPID L-2021-LLE-0055 (COVID-19)) ML22018A1842022-01-18018 January 2022 Notification of Brunswick Steam Electric Plant, Units 1 & 2 - Design Bases Assurance Inspection - U.S. Nuclear Regulatory Inspection Report 05000324/2022010 and 05000325/2022010 ML21348A7192021-12-21021 December 2021 Regulatory Audit Summary Regarding License Amendment Request to Revise Technical Specifications to Adopt Risk-Informed Completion Times 2023-09-25
[Table view] Category:Licensee Event Report (LER)
MONTHYEAR05000324/LER-2017-0032017-08-0303 August 2017 1 OF 4, LER 17-003-00 for Brunswick, Unit 2, Regarding Setpoint Drift in Main Steam Line Safety/Relief Valves Results in Three Valves Inoperable, 05000325/LER-2017-0032017-08-0202 August 2017 Control Room Air Conditioning and Emergency Ventilation Systems Rendered Inoperable, LER 17-003-00 for Brunswick, Unit 1, Regarding Control Room Air Conditioning and Emergency Ventilation Systems Rendered Inoperable 05000324/LER-2017-0022017-06-12012 June 2017 Plant Mode Change with Primary Containment Inoperable, LER 17-002-00 for Brunswick, Unit 1, Regarding Foreign Material in Switch Results in Unplanned Automatic Start of Emergency Diesel Generators 05000324/LER-2017-0012017-05-18018 May 2017 Implementation of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3, LER 17-001-00 for Brunswick, Unit 2, Regarding Implementation of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3 05000324/LER-2016-0012016-08-0808 August 2016 Mispositioned Valves Result in Residual Heat Removal Service Water System Inoperability, LER 16-001-00 for Brunswick Steam Electric Plant, Unit 2, Regarding Mispositioned Valves Result in Residual Heat Removal Service Water System lnoperability 05000325/LER-2016-0032016-05-0202 May 2016 Implementation of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3, LER 16-003-00 for Brunswick Steam Electric Plant, Unit 1 Regarding Implementation of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3 05000324/LER-2016-0022016-05-0202 May 2016 High Pressure Coolant Injection System Inoperable due to Failed Relay Coil, LER 16-002-00 for Brunswick Steam Electric Plant (BSEP), Units 1 and 2, Regarding Emergency Diesel Generator 3 Inoperable Due to Failure to Auto-Start 05000325/LER-2016-0012016-04-0606 April 2016 Electriqal Bus Fault Results in Lockout of Startup Auxiliary Transformer and Loss of Offsite Power, LER 16-001-00 for Brunswick, Unit 1, Regarding Electrical Bus Fault Results in Lockout of Startup Auxiliary Transformer and Loss of Offsite Power BSEP 15-0088, Special Report, Technical Specification 5.6.6, Post Accident Monitoring (PAM) Instrumentation Report2015-10-22022 October 2015 Special Report, Technical Specification 5.6.6, Post Accident Monitoring (PAM) Instrumentation Report ML1019404522008-06-0303 June 2008 10CFR50.75g File: AR00237296 Overflowed CST ML1019404542008-05-13013 May 2008 10CFR50.75g File: AR00272173 Thru Wall Leak in Cw Intake Pipe Was Found to Contain Tritium in the Groundwater Leaking Into the Pipe ML1019404562008-04-28028 April 2008 10CFR50.75g File: AR00242461 Routine Environmental Soil/Water Sampling Has Identified Low Levels of Tritium . BSEP 03-0023, LER 2002-02-00 from Brunswick, Unit 2 Regarding Remote Shutdown Panel Power Supply Inventer Design Deficiency2003-02-14014 February 2003 LER 2002-02-00 from Brunswick, Unit 2 Regarding Remote Shutdown Panel Power Supply Inventer Design Deficiency 2017-08-03
[Table view] |
When initial efforts to open the damper manually were unsuccessful, craftsmen contacted the system engineer for guidance on opening the damper. The system engineer suggested the mechanics disconnect the normal instrument airline for the damper and reconnect a separate air source that would redirect air flow to allow the damper to cycle open. Therefore, the craftsmen removed the pneumatic supply from the damper port and connected a portable air tank to a port that channeled airflow to open the damper. The damper seals and the damper blade were then inspected and found to be satisfactory. The normal pneumatic supply was reconnected and restored to the original configuration by 1009 EDT.
On June 5, 2017, at 0930 Eastern Daylight Time (EDT), Unit 1 was in Mode 1 at 100 percent power, and Unit 2 was in Mode 1 at 87 percent power and was increasing reactor power after a preplanned control rod improvement evolution. No inoperable equipment contributed to this event other than as specified in the event description below.
In this event, the Control Room Air Conditioning (AC) system [NA] and the Control Room Emergency Ventilation (CREV) system [VI] were temporarily rendered incapable of performing their safety functions due to interruption of pneumatic pressure. Therefore, it is reportable per 10 CFR 50.73(a)(2)(v)(D) as a loss of safety function. The event was also reportable per 10 CFR 50.72(b)(3)(v)(D) for loss of safety function. This reporting requirement was fulfilled per Event Number 52788 on June 5, 2017, at 1940 EDT.
On June 5, 2017, at 0930 EDT, Maintenance personnel were performing an inspection of damper seals in the Control Room AC and CREV systems. In the as-found condition, certain dampers were closed, which restricted the inspection to one side only. Thus, a complete inspection could not be performed.
Craftsmen concluded that the particular damper being inspected needed to be stroked open so the inaccessible side could be viewed. They asked Operations personnel to open the damper. However, it was stated that due to the electrical logic configuration of these dampers, this single damper could not be actuated from the Control Room. Operations permission was given to the mechanics in the field to stroke the damper open locally.
On the same day at 1352 EDT, the steps described above were repeated for a second damper. In this instance, the configuration of the system resulted in air porting from the pneumatic system, depressurizing it. Within about three minutes, pneumatic pressure decreased to the point where the two operating Control Room AC systems tripped, and the third was unable to start because of low pneumatic supply pressure. In Energy Industry Identification System (EllS) codes are identified in the text as [XX].
Background
Initial Conditions Reportability Criteria
Event Description
(See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
CONTINUATION SHEET
APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 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.
2017 - 003
3. LER NUMBER
- 000 this condition, CREV dampers would have been unable to reposition as required due to lack of pneumatic pressure. Control Room personnel then contacted the craft personnel; the pneumatic line was promptly reconnected, and pneumatic pressure was restored, returning the CREV system and the Control Room AC system to operable status by 1407 EDT.
Upon reviewing the second event, personnel realized that similar steps had been used for the inspection of the first damper. The first event was not self-revealing because it did not result in tripping the Control Room AC. Only then was it understood that CREV had been made inoperable during the first event from 0930 EDT until 1009 EDT, and both CREV and Control Room AC were inoperable from 1352 EDT until 1407 EDT.
Three 50 percent capacity Control Room AC units provide temperature and humidity control for the Control Room during normal and accident conditions. Two units are normally required to maintain the designed environmental conditions. The CREV system provides a protected environment from which occupants can control the unit following an uncontrolled release of radioactivity, hazardous chemicals, or smoke. The safety related function of the CREV system is the radiation protection portion of the radiation/smoke protection mode and includes two redundant high efficiency air filtration subsystems for emergency treatment of recirculated air or outside supply air and a control room envelope (CRE) boundary that limits the inleakage of unfiltered air. The CREV system is a standby system that is common to both Unit 1 and Unit 2, parts of which also operate during normal unit operations to maintain the CRE environment.
Upon receipt of initiation signal(s) indicative of conditions that could result in radiation exposure to CRE occupants, the CREV system automatically switches to the radiation/smoke protection mode of operation to minimize infiltration of contaminated air into the CRE. A system of dampers isolates the CRE, and a part of the recirculated air is routed through either of the two filter subsystems. Outside air is taken in at the normal ventilation intake and is mixed with the recirculated air before being passed through one of the CREV subsystems for removal of airborne radioactive particles.
In this event, the Control Room AC and CREV system dampers described above were temporarily disabled by an interruption of their pneumatic supply. With the CREV recirculation dampers unable to respond as required, the CREV system was rendered inoperable and its safety function was lost. The combined duration of inoperability for CREV was 54 minutes. The Control Room AC was inoperable only during the second occurrence because it tripped and could not be restarted Therefore, its safety function was lost.
This event occurred because of inadequate use of human performance tools and an inadequate work order. The work order did not contain sufficient information to facilitate performance of the task.
Maintenance personnel did not stop to ensure that the work order was revised to provide instructions that would allow performance of steps to execute the damper seal inspections.
Safety Assessment Event Cause (See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
CONTINUATION SHEET
APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 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.
2017 - 003
3. LER NUMBER
- 000 Any changes to the corrective actions and schedules noted below will be made in accordance with the site's corrective action program.
The duration of this condition was 15 minutes. During that time, Control Room temperature, humidity, and radiation experienced no significant change, and there was no challenge to the habitability of the Control Room. Therefore, it is concluded that this event had no adverse impact on nuclear safety.
One event has been reported in the past three years in which the Control Room AC system was inoperable. That event was reported in Licensee Event Report 50-325/2016-006, dated February 13, 2017. That event resulted from corrosion which affected the seismic qualifications of supports for the air conditioning condensers. The corrective actions which addressed the failure were unrelated to the cause of the event described in this report.
This report contains no new regulatory commitments.
Corrective Actions
Corrective actions for this event include restoring the affected pneumatic supply to CREV and Control Room AC, revising work orders, taking steps to emphasize proper use of human performance tools, and performing a Maintenance cultural assessment. These actions are completed.
Planned corrective actions include performing a review of top latent organizational weaknesses and implementing a pilot for a fleet proficiency model. These actions are scheduled for completion by September 6, 2017.
Commitments
Previous Similar Events
(See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
CONTINUATION SHEET
APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 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.
2017 - 003
3. LER NUMBER
- 000
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05000325/LER-2017-001 | Speed and Frequency Oscillations Result in Inoperable Emergency Diesel Generator | 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 | 05000324/LER-2017-001 | Implementation of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3 LER 17-001-00 for Brunswick, Unit 2, Regarding Implementation of Enforcement Guidance Memorandum (EGM) 11-003, Revision 3 | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000325/LER-2017-002 | Foreign Material in Switch Results in Unplanned Automatic Start of Emergency Diesel Generators | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000324/LER-2017-002 | Plant Mode Change with Primary Containment Inoperable LER 17-002-00 for Brunswick, Unit 1, Regarding Foreign Material in Switch Results in Unplanned Automatic Start of Emergency Diesel Generators | 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 | 05000325/LER-2017-003 | Control Room Air Conditioning and Emergency Ventilation Systems Rendered Inoperable LER 17-003-00 for Brunswick, Unit 1, Regarding Control Room Air Conditioning and Emergency Ventilation Systems Rendered Inoperable | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000324/LER-2017-003 | 1 OF 4 LER 17-003-00 for Brunswick, Unit 2, Regarding Setpoint Drift in Main Steam Line Safety/Relief Valves Results in Three Valves Inoperable, | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
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