11-30-2017 | On October 3, 2017 at 0800 PDT, Secondary Containment (Reactor Building) became inoperable due to pressure increasing above the Technical Specification (TS) limit of -0.25 inches of water gauge (inwg). While the plant was at 100% power, a Reactor Building exhaust valve unexpectedly closed, resulting in a loss of Secondary Containment for approximately two minutes. Secondary Containment was declared inoperable and TS Action Statement 3.6.4.1.A was entered. The Control Room operators reopened the Reactor Building exhaust valve and pressure returned to within limits automatically. Secondary Containment was declared operable at 0810 PDT and TS Action Statement 3.6.4.1.A was exited. The event was reported under 10 CFR 50.72(b)(3)(v)(C) and 10 CFR 50.72 (b)(3)(v)(D) as Event Notification #52999.
The apparent cause of the event is a surface degradation on the lower stab of an electrical disconnect causing a momentary high resistance when the cubicle door is opened. This event occurred during performance of thermography in the cubicle. |
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Category:Letter
MONTHYEARGO2-24-004, License Amendment Request to Revise Emergency Plan2024-01-30030 January 2024 License Amendment Request to Revise Emergency Plan IR 05000397/20230042024-01-29029 January 2024 Integrated Inspection and Independent Spent Fuel Storage Installation Report 05000397/2023004 and 07200035/2023001 GO2-24-003, Relief Requests for the Columbia Generating Station Fifth Ten-Year Interval Inservice Testing2024-01-29029 January 2024 Relief Requests for the Columbia Generating Station Fifth Ten-Year Interval Inservice Testing ML24011A1522024-01-10010 January 2024 March 2024 Emergency Preparedness Exercise Inspection-Request for Information GO2-24-005, Docket No. 50-397 Supplement to Reply to a Notice of Violation; EA-21-1702024-01-0808 January 2024 Docket No. 50-397 Supplement to Reply to a Notice of Violation; EA-21-170 GO2-23-136, Guarantee of Payment of Deferred Premium2023-12-20020 December 2023 Guarantee of Payment of Deferred Premium GO2-23-135, Notice of Readiness for Supplemental Inspection2023-12-14014 December 2023 Notice of Readiness for Supplemental Inspection GO2-23-130, Reply to a Notice of Violation; EA-23-0542023-12-14014 December 2023 Reply to a Notice of Violation; EA-23-054 GO2-23-105, Licensing Basis Document Update and Biennial Commitment Change Report2023-12-12012 December 2023 Licensing Basis Document Update and Biennial Commitment Change Report ML23288A0002023-12-0707 December 2023 Issuance of Amendment No. 272 to Adopt TSTF-541, Revision 2, Add Exceptions to Surveillance Requirements for Valves and Dampers Locked in the Actuated Position GO2-23-107, Application to Revise Technical Specifications to Adopt TSTS-584, Eliminate Automatic RWCU System Isolation on SLC Initiation2023-12-0505 December 2023 Application to Revise Technical Specifications to Adopt TSTS-584, Eliminate Automatic RWCU System Isolation on SLC Initiation GO2-23-126, Docket No. 50-397 Voluntary Response to Regulatory Issue Summary 2023-012023-11-28028 November 2023 Docket No. 50-397 Voluntary Response to Regulatory Issue Summary 2023-01 GO2-23-121, Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation2023-11-27027 November 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation IR 05000397/20230122023-11-20020 November 2023 Commercial Grade Dedication Inspection Report 05000397/2023012 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 05000397/20230102023-11-0909 November 2023 Biennial Problem Identification and Resolution Inspection Report 05000397/2023010 IR 05000397/20230932023-11-0101 November 2023 Final Significance Determination of a White Finding, Notice of Violation and Follow-Up Assessment Letter; NRC Inspection Report 05000397/2023093 ML23299A2072023-10-26026 October 2023 Biennial Requalification Inspection Request for Information IR 05000397/20230032023-10-25025 October 2023 Integrated Inspection Report 05000397/2023003 IR 05000397/20230112023-10-0404 October 2023 License Renewal Phase 2 Report 05000397/2023011 IR 05000397/20234012023-09-11011 September 2023 Security Baseline Inspection Report 05000397/2023401 GO2-23-097, In-Service Inspection Summary Report for the Twenty-Sixth Refueling Outage (R26)2023-09-0606 September 2023 In-Service Inspection Summary Report for the Twenty-Sixth Refueling Outage (R26) ML24032A2182023-09-0101 September 2023 Information Request, Security IR 2024401 GO2-23-100, Technical Specification Section 5.6.4 Post Accident Monitoring Instrumentation 14-Day Report for Inoperable Suppression Pool Level Indication2023-08-31031 August 2023 Technical Specification Section 5.6.4 Post Accident Monitoring Instrumentation 14-Day Report for Inoperable Suppression Pool Level Indication GO2-23-056, Application to Revise Technical Specifications to Adopt TSTF-230, Add New Condition B to LCO 3.6.2.3, RHR Suppression Pool Cooling2023-08-29029 August 2023 Application to Revise Technical Specifications to Adopt TSTF-230, Add New Condition B to LCO 3.6.2.3, RHR Suppression Pool Cooling IR 05000397/20230052023-08-22022 August 2023 Updated Inspection Plan for Columbia Generating Station (Report 05000397/2023005) - Mid Year Letter IR 05000397/20230022023-08-0101 August 2023 Integrated Inspection Report 05000397/2023002 GO2-23-093, Supplement to Reply to a Notice of Violation: EA-21-1702023-07-27027 July 2023 Supplement to Reply to a Notice of Violation: EA-21-170 ML23206A2442023-07-25025 July 2023 Energy Northwest Columbia Generating Station, Response to Apparent Violation in NRC Inspection Report 05000397/2023092; EA-23-054 GO2-23-068, Notification of Completion of Commitments Required Prior to Entry Into the Period of Extended Operation2023-07-19019 July 2023 Notification of Completion of Commitments Required Prior to Entry Into the Period of Extended Operation GO2-23-090, Reply to a Notice of Violation2023-07-12012 July 2023 Reply to a Notice of Violation ML23143A1202023-06-27027 June 2023 Request Number 4ISI-11 to the American Society of Mechanical Engineers Boiler and Pressure Vessel Code Regarding Alternate Examination of Reactor Vessel Welds GO2-23-073, Notification of NPDES Permit Issuance2023-06-26026 June 2023 Notification of NPDES Permit Issuance ML23163A2502023-06-12012 June 2023 Summary of Changes and Analysis for Revision 41 of Plant Procedures Manual 13.8.1 Emergency Dose Projection System Operations GO2-23-072, Cycle 27 Core Operating Limits Report2023-06-0505 June 2023 Cycle 27 Core Operating Limits Report ML23157A2702023-06-0101 June 2023 4-2022-011 -022 Letter - OI Closure to Licensee IR 05000397/20230922023-06-0101 June 2023 NRC Inspection Report 05000397/2023092 and Preliminary White Finding IR 05000397/20230902023-06-0101 June 2023 Final Significance Determination of a White Finding, Notice of Violation and Follow-Up Assessment Letter; NRC Inspection Report 05000397/2023090 GO2-23-055, Independent Spent Fuel Storage Installation, 2022 Annual Radiological Environmental Operating Report2023-05-15015 May 2023 Independent Spent Fuel Storage Installation, 2022 Annual Radiological Environmental Operating Report IR 05000397/20230012023-05-0505 May 2023 Integrated Inspection Report 05000397/2023001 - April 26, 2023 GO2-23-006, License Amendment Request to Clean-Up Operating License and Appendix a Technical Specifications2023-05-0101 May 2023 License Amendment Request to Clean-Up Operating License and Appendix a Technical Specifications IR 05000397/20233012023-05-0101 May 2023 NRC Examination Report 05000397/2023301 GO2-23-053, 2022 Annual Environmental Operating Report2023-04-26026 April 2023 2022 Annual Environmental Operating Report GO2-23-057, 2022 Annual Radioactive Effluent Release Report2023-04-25025 April 2023 2022 Annual Radioactive Effluent Release Report ML23110A2642023-04-20020 April 2023 Request for Information License Renewal Phase 2 Inspection GO2-23-012, Application to Revise Technical Specifications to Adopt Tstf-541, Add Exceptions to Surveillance Requirements for Valves and Dampers Locked in the Actuated Position2023-03-27027 March 2023 Application to Revise Technical Specifications to Adopt Tstf-541, Add Exceptions to Surveillance Requirements for Valves and Dampers Locked in the Actuated Position GO2-23-041, Generation Station - Level of Financial Protection - Annual Reporting Requirement2023-03-15015 March 2023 Generation Station - Level of Financial Protection - Annual Reporting Requirement GO2-23-038, Plant Decommissioning Fund Status Report2023-03-15015 March 2023 Plant Decommissioning Fund Status Report ML23013A0812023-03-15015 March 2023 Issuance of Amendment No. 270 Revision to Technical Specifications to Adopt TSTF 505, Revision 2, Provide Risk-Informed Extended Completion Times-RITSTF Initiative 4B GO2-23-034, Report of Changes or Errors in Emergency Core Cooling System Loss of Coolant Accident Analysis Models Pursuant to 10 CFR 50.462023-03-13013 March 2023 Report of Changes or Errors in Emergency Core Cooling System Loss of Coolant Accident Analysis Models Pursuant to 10 CFR 50.46 2024-01-08
[Table view] Category:Licensee Event Report (LER)
MONTHYEAR05000397/LER-2017-0072017-11-30030 November 2017 Valve Closure Results in Momentary Increase in Secondary Containment Pressure, LER 17-007-00 for Columbia Generating Station Regarding Valve Closure Results in Momentary Increase in Secondary Containment Pressure 05000397/LER-2017-0062017-11-0909 November 2017 CONDITION PROHIBITED BY TECHNICAL SPECIFICATIONS DUE TO INCOMPLETE ACTION STATEMENT, LER 17-006-00 for Columbia Generating Station for Condition Prohibited by Technical Specifications Due to Incomplete Action Statement 05000397/LER-2017-0052017-11-0909 November 2017 Valve Closure Results in Momentary Increase in Secondary Containment Pressure, LER 17-005-00 for Columbia Generating Station Regarding Valve Closure Results in Momentary Increase in Secondary Containment Pressure 05000397/LER-2017-0042017-10-18018 October 2017 MANUAL REACTOR SCRAM DUE TO HIGH MAIN CONDENSER BACK PRESSURE, LER 17-004-00 for Columbia Generating Station Regarding Manual Reactor Scram Due to High Main Condenser Back Pressure 05000397/LER-2016-0022017-09-27027 September 2017 1 OF 3, LER 16-002-01 for Columbia Generating Station Regarding Valve Closure Results in Momentary Increase in Secondary Containment Pressure 05000397/LER-2016-0032017-08-29029 August 2017 Failure of Fan to Start Results in Momentary Increase in Secondary Containment Pressure, LER 16-003-01 for Columbia Regarding Failure of Fan to Start Results in Momentary Increase in Secondary Containment Pressure 05000397/LER-2017-0032017-08-24024 August 2017 Momentary loss of Secondary Containment due to Weather, LER 17-003-00 for Columbia Generating Station Regarding Momentary Loss of Secondary Containment due to Weather 05000397/LER-2017-0022017-07-10010 July 2017 Implementation of Enforcement Guidance Memorandum 11-003, Revision 3, LER 17-002-00 for Columbia Generating Station re Implementation of Enforcement Guidance Memorandum 11-003, Revision 3 05000397/LER-2016-0042017-06-0808 June 2017 1 OF 3, LER 16-004-01 for Columbia Generating Station Regarding Automatic Scram Due to Off-site Load Reject 05000397/LER-2017-0012017-03-20020 March 2017 Contactor Coil Failure Results in Tripping of HPCS Diesel Mixed Air Fan, LER 17-001-00 for Columbia Generating Station Regarding Contactor Coil Failure Results in Tripping of HPCS Diesel Mixed Air Fan 05000397/LER-2016-0052017-02-15015 February 2017 Leak in Minimum Flow Line Makes HPCS and Primary Containment Inoperable, LER 16-005-00 for Columbia Generating Station Regarding Leak in Minimum Flow Line Makes HPCS and Primary Containment Inoperable 05000397/LER-2016-0012016-05-24024 May 2016 MANUAL REACTOR SCRAM FOLLOWING LOSS OF REACTOR CLOSED COOLING, LER 16-001-00 for Columbia Regarding Manual Reactor Scram Following Loss of Reactor Closed Cooling 05000397/LER-2015-0072016-01-0707 January 2016 REACTOR BUILDING PRESSURE GREATER THAN TECHNICAL SPECIFICATIONS REQUIREMENT, LER 15-007-00 for Columbia Regarding Reactor Building Pressure Greater Than Technical Specifications Requirement 2017-09-27
[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 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 Columbia Generating Station 05000- 397 17 - 007 - 00
Plant Conditions
At the time of the event, the plant was operating in Mode 1 at 100% power. The division 1 emergency diesel generator [EK] [DG] (DG1) was out of service for maintenance but did not contribute to this event. There were no other structures, systems, or components that were inoperable at the start of the event that contributed to the event.
Event Description
On October 3, 2017 at 0800 PDT, Operations personnel received an annunciator alarm for high Secondary Containment [NH] differential pressure when the Reactor Building [NG] exhaust inboard isolation valve [V] failed shut. For a time period of approximately two minutes, Secondary Containment differential pressure increased above -0.25 inches of water gauge (inwg), resulting in Technical Specification (TS) 3.6.4.1 not being met. The pressure rise was due to unexpected isolation of the Reactor Building inboard exhaust isolation valve during electrical switchgear inspections.
This event is reportable as an event that could have prevented fulfillment of safety functions needed to control the release of radiation, and mitigate the consequences of an accident per 10 CFR 50.73(a)(2)(v)(C) and 10 CFR 50.73(a)(2)(v)(D).
This condition was reported under 10 CFR 50.72(b)(3)(v)(C) and 10 CFR 50.72(b)(3)(v)(D) via Event Notification #52999 for an event or condition that could have prevented fulfillment of a safety function needed to control the release of radioactive material and accident mitigation.
Immediate Corrective Actions
Control Room operators reopened the Reactor Building exhaust inboard isolation valve and pressure was restored within TS limits.
Assessment of Safety Consequences
This event resulted in an unplanned entry into TS 3.6.4.1.A, in which Secondary Containment pressure was greater than -0.25 inwg for approximately two minutes. The peak pressure during this event was +3.7 inwg. While the actual pressure was beyond the range allowed by Technical Specifications, the purpose of maintaining a slight negative pressure is to assist in drawdown of secondary containment to support accident response of the safety related SGT system. Existing engineering analysis demonstrates the drawdown credited in Columbia's accident analysis could have been attained using either of the two available trains of the SGT system. There was no actual safety consequence associated with this event since opening the Reactor Building exhaust inboard isolation valve restored Secondary Containment, and there was no loss of safety function or potential for radiological release.
Cause of Event
The apparent cause of the event is a surface degradation on the lower stab of an electrical disconnect causing a momentary high resistance when the cubicle door is opened. This event occurred during performance of thermography in the cubicle.
Further Corrective actions Cleaning and inspection of the disconnect switches including the stab to bus connection on the electrical disconnects and correction of any deficiency found will be performed in the next available outage. As an interim corrective action, thermography on the electrical panels associated with the degraded electrical disconnects will be discontinued until after the cleaning and inspection of the electrical disconnect is completed.
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.
Columbia Generating Station 05000- 397 17 - 007 - 00 Similar Events A loss of the ability to maintain Secondary Containment pressure greater than required by Technical Specifications has occurred at Columbia Generating Station six times in the past two years. One event was due to inclement weather, one event was due degraded lubrication on a circuit breaker [52] fan [FAN],one was a faulty control switch on a fan, one was due to human performance errors during rescheduled work, and two events were due to latent errors from initial construction of the plant.
Energy Industry Identification System (EllS) Information codes from IEEE Standards 805-1984 and 803-1983 are represented in brackets as [XX] and [XXX] throughout the body of the narrative.
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05000397/LER-2017-001 | Contactor Coil Failure Results in Tripping of HPCS Diesel Mixed Air Fan LER 17-001-00 for Columbia Generating Station Regarding Contactor Coil Failure Results in Tripping of HPCS Diesel Mixed Air Fan | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000397/LER-2017-002 | Implementation of Enforcement Guidance Memorandum 11-003, Revision 3 LER 17-002-00 for Columbia Generating Station re Implementation of Enforcement Guidance Memorandum 11-003, Revision 3 | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000397/LER-2017-003 | Momentary loss of Secondary Containment due to Weather LER 17-003-00 for Columbia Generating Station Regarding Momentary Loss of Secondary Containment due to Weather | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000397/LER-2017-004 | MANUAL REACTOR SCRAM DUE TO HIGH MAIN CONDENSER BACK PRESSURE LER 17-004-00 for Columbia Generating Station Regarding Manual Reactor Scram Due to High Main Condenser Back Pressure | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | 05000397/LER-2017-005 | Valve Closure Results in Momentary Increase in Secondary Containment Pressure LER 17-005-00 for Columbia Generating Station Regarding Valve Closure Results in Momentary Increase in Secondary Containment Pressure | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | 05000397/LER-2017-006 | CONDITION PROHIBITED BY TECHNICAL SPECIFICATIONS DUE TO INCOMPLETE ACTION STATEMENT LER 17-006-00 for Columbia Generating Station for Condition Prohibited by Technical Specifications Due to Incomplete Action Statement | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000397/LER-2017-007 | Valve Closure Results in Momentary Increase in Secondary Containment Pressure LER 17-007-00 for Columbia Generating Station Regarding Valve Closure Results in Momentary Increase in Secondary Containment Pressure | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident |
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