06-09-2017 | On April 13, 2017, Unit 2 was in Mode 4 preparing to exit a refueling outage. The primary containment was being vented to ensure habitability of the Drywell. The valve alignment for Drywell ventilation makes the primary containment inoperable due to the Drywell and Suppression Chamber airspaces being in communication with each other. At 23:47 Eastern Daylight Time (EDT), the reactor mode was changed from Mode 4 to Mode 2 with ventilation still in progress. In Mode 2, the Primary Containment is required to be operable. Therefore, the plant entered a condition prohibited by the Technical Specifications, and the event is reportable per 10 CFR 50.73(a)(2)(i)(B). It is also reportable per 10 CFR 50.73(a)(2)(v)(D) because the primary containment safety function was lost. The condition was discovered 28 minutes later on April 14, 2017, at 00:15 EDT and was corrected by closing the ventilation flowpaths at 00:30 EDT on April 14, 2017.
This event resulted from Control Room personnel not initiating a tracking document while in Mode 4 with the primary containment inoperable. When preparing to change the plant mode from Mode 4 to Mode 2, the primary containment ventilation status was overlooked. Corrective actions for this event included closing the containment ventilation paths and remediating the Shift Manager and Control Room Supervisor. |
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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] |
This event is reportable per 10 CFR 50.73(a)(2)(v)(D) because the plant experienced a loss of the safety function of a system designed to mitigate the consequences of an accident. Since the containment was rendered inoperable by having the Drywell and Suppression Chamber airspaces in communication with each other, the safety function was lost.
On April 13, 2017, Unit 2 was in Mode 4 preparing to exit a refueling outage. At 20:48 EDT, Control Room personnel began ventilating the primary containment in preparation for a personnel entry into the Drywell to perform minor maintenance. The ventilation procedure requires valves be opened from the Suppression Chamber atmosphere and the Drywell atmosphere into a shared ventilation line. With both atmospheres communicating, the Primary Containment is not operable. However, Primary Containment is not required to be operable with the unit in Mode 4.
When the maintenance was completed in the Drywell, Control Room personnel resumed preparations for starting up the reactor. At 23:47 EDT, the reactor mode was changed from Mode 4 to Mode 2. In Mode 2, Energy Industry Identification System (EllS) codes are identified in the text as [XX].
Background
Initial Conditions This event is reportable per 10 CFR 50.73(a)(2)(i)(B) because the plant entered a condition which is prohibited by the plant's Technical Specifications (TS). Specifically, TS 3.6.1.1 requires the primary containment to be operable in Modes 1, 2, and 3. With the drywell and suppression chamber atmospheres communicating, the containment is inoperable. Additionally, TS Limiting Condition for Operation (LCO) 3.0.4 requires all LCOs to be met for the plant condition to be entered, prior to entry. Primary containment operability is required in Mode 2 (i.e., Startup). Therefore, at 23:47 EDT on April 13, 2017, when the plant changed modes from Mode 4 to Mode 2 without meeting the LCO for primary containment, this failed to meet TS LCO 3.0.4.
This event is also reportable per 10 CFR 50.72(b)(3)(v)(D) via an 8-hour telephone report. The telephone report was completed as Event Number 52679 at 07:37 EDT on April 14, 2017.
On April 13, 2017, at approximately 23:47 Eastern Daylight Time (EDT), Unit 2 was in Mode 4 (i.e. Cold Shutdown) in preparation for exiting a refueling outage. At that time, the ventilation valves for both the Drywell and Suppression Chamber were open to ensure the atmosphere in the containment was breathable for personnel performing maintenance in the Drywell.
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 - 002
3. LER NUMBER
- 000 the Primary Containment is required to be operable. Since it was still being ventilated as described above, it was not operable. Therefore, this mode change was not allowed per TS 3.0.4.
On April 14, 2017, at 00:15 EDT (i.e., 28 minutes later), a licensed operator was performing a routine survey of Control Room panels to verify expected plant condition and valve alignments during reactor startup. He observed the Drywell and Suppression Chamber atmospheres being simultaneously vented.
He immediately notified other shift personnel, and by 00:30 EDT on April 14, 2017, the ventilation paths were closed, terminating the event. The total time during which Primary Containment was inoperable while in Mode 2 was 43 minutes.
This event occurred because Control Room personnel did not issue an LCO for tracking (i.e., “tracking LCO”) primary containment inoperability in preparation for eventual plant mode change and startup.
Procedure 0OI-01.01, “BNP Conduct of Operations Supplement,” provides instructions for initiating a tracking LCO when a structure, system, or component (SSC) is removed from service while the plant is in a mode where that SSC is not required. In this instance, Unit 2 was in Mode 4 when the Drywell and Suppression Chamber were simultaneously vented, rendering the primary containment inoperable. Since the primary containment is not required in Mode 4, a tracking LCO should have been initiated to ensure it was restored to operable status before entering Mode 2. This step was not performed, so the condition was not identified during preparations for changing the plant mode.
The function of the primary containment is to isolate and contain fission products released from the Reactor Primary System following a design basis Loss of Coolant Accident (LOCA) and to confine the postulated release of radioactive material. The primary containment consists of two volumes, a Drywell and a Suppression Chamber. Steam and water piping for the nuclear process is located within the Drywell. A large volume of water is located in the Suppression Chamber for the rapid suppression of steam. The atmospheres of these two volumes are normally isolated from each other. In the event of a LOCA, steam released into the Drywell passes through downcomers into the Suppression Chamber below the water level where it is quenched. Should a LOCA occur while the Drywell and Suppression Chamber atmospheres are communicating, released steam could bypass the downcomers, potentially pressurizing both volumes of the containment. The containment would be susceptible to being pressurized beyond its capability, potentially causing containment to fail.
In this event, the two atmospheres of the primary containment were allowed to communicate via a shared ventilation line as described previously. During this time, the plant was emerging from a refueling outage, and the reactor coolant was still well below 212 degrees F as determined by the inlet temperature of the Residual Heat Removal [BO] heat exchanger and by the loop temperatures of the Reactor Recirculation [AD] system. If a LOCA had occurred during this time, the result would have been loss of cold water into the otherwise intact primary containment. No pressurization of the containment could have resulted. It 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 - 002
3. LER NUMBER
- 000 should be noted that the ventilation valve alignment was identified promptly by a routine inspection of Control Room panels and was corrected within 15 minutes of discovery (i.e., 43 minutes from changing from Mode 2 to Mode 4).
Corrective Actions
The primary containment was restored to operable status at 00:30 on April 14, 2017.
A remediation plan was developed and implemented to assess the Shift Manager and Control Room Supervisor for watchstanding and being reinstated as appropriate. This action is complete.
Previous Similar Events
No events were identified in the past three years in which the primary containment was made inoperable when it was required to be operable.
Commitments This report contains no new regulatory commitments.
This event did not result in any adverse impact on the health and safety of the public. This analysis applies to the plant condition that existed at the time with reactor coolant below 212 degrees F.
(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 - 002
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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