03-16-2016 | On January 23, 2016, at approximately 1703 hours0.0197 days <br />0.473 hours <br />0.00282 weeks <br />6.479915e-4 months <br />, with Units 1 and 2 operating at 100 .
percent power Mode 1, the North Anna 34.5kv Bus 3, offsite power feed to the "C" Reserve Station Service Transformer, was lost due to the opening of the L102 breaker. This resulted in the loss of power to the Unit 1H and Unit 2J emergency buses and the automatic start of the 1H and 2J emergency diesel generators (EDG). The Unit 1H
- emergency bus off-site power was restored and the 1H EDG was secured and returned to automatic. The 2J EDG continued to carry the 2J bus until repairs to L102 were completed
- and the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> limiting action for Unit 2 was exited at 1706 hours0.0197 days <br />0.474 hours <br />0.00282 weeks <br />6.49133e-4 months <br /> on 1/24/16. .The direct cause for-the opening of the L102 breaker was an internal switch contact failure.due to moisture. At 1948 hours0.0225 days <br />0.541 hours <br />0.00322 weeks <br />7.41214e-4 months <br /> on January 23, 2016, an 8-hour Non-Emergency Report was made to the NRC in accordance with 10 CFR 50.72(b)(3)(iv)(A) as a condition that resulted in valid actuation of Engineered Safety Features (ESF). Units 1 and 2 continued to operate safely during the event. The health and safety of the public were not affected by this event.
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LER-2016-001, 1 OF 3 |
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01-23-2016 |
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Category:Letter
MONTHYEARML24032A1112024-02-0101 February 2024 Owner'S Activity Report for North Anna, Unit 2, Refueling Outage N2R29 - First Period of the Fifth ISI Interval ML24032A4662024-01-16016 January 2024 Response to Comments on Draft Vpdes Permit No. VA0052451 ML24017A0802024-01-11011 January 2024 Notification of Licensed Operator Initial Examination 05000338/2024301 and 05000339/2024301 ML24003A8372024-01-0909 January 2024 Letter to Elizabeth Toombs, Thpo, Cherokee Nation, Notice of Availability of the Draft Site-Specific EIS for North Anna Power Station, Units 1 and 2, Subsequent License Renewal ML24003A8412024-01-0909 January 2024 Notice of Availability of the Draft Site-Specific Environmental Impact Statement for the North Anna Power Station, Units 1 and 2, Subsequent License Renewal ML24003A8502024-01-0909 January 2024 Letter to Wenonah Haire, Thpo, Catawba Indian Nation, Notice of Availability of the Draft Site-Specific EIS for North Anna Power Station, Units 1 and 2, Subsequent License Renewal ML23332A7272024-01-0909 January 2024 Notice of Availability of the Draft Site-Specific Environmental Impact Statement for the North Anna Power Station, Units 1 and 2, Subsequent License Renewal ML24003A8382024-01-0909 January 2024 Letter to G. Anne Richardson, Chief, Rappahannock Tribe, Inc., Notice of Availability of Draft Site-Specific Environmental Impact Statement for North Anna Power Station Units 1 and 2, Subsequent License Renewal ML24003A8482024-01-0909 January 2024 Notice of Availability of the Draft Site-Specific Environmental Impact Statement for the North Anna Power Station, Units 1 and 2, Subsequent License Renewal ML24003A8392024-01-0909 January 2024 Letter to Gerald Stewart, Chief, Chickahominy Indian Tribe, Eastern Division Re Re Notice of Availability of the Draft Site-Specific Environmental Impact Statement for North Anna Power Station Subsequent License Renewal ML24003A8472024-01-0909 January 2024 Letter to Tom Jonathan, Chief, Tuscarora Nation, Notice of Availability of the Draft Site-Specific EIS for North Anna Power Station, Units 1 and 2, Subsequent License Renewal ML24003A8492024-01-0909 January 2024 Letter to W. Frank Adams, Chief, Upper Mattaponi Tribe Re Re Notice of Availability of the Draft Site-Specific Environmental Impact Statement for North Anna Power Station Subsequent License Renewal ML24003A8462024-01-0909 January 2024 Notice of Availability of the Draft Site-Specific Environmental Impact Statement for the North Anna Power Station, Units 1 and 2, Subsequent License Renewal ML24003A8352024-01-0909 January 2024 Letter to Acee Watt, Thpo, United Keetoowah Band of Cherokee Indians in Oklahoma Re Notice of Availability of the Draft Site-Specific Environmental Impact Statement for North Anna Power Station Subsequent License Renewal ML24003A8422024-01-0909 January 2024 Letter to Paul Barton, Thpo, Eastern Shawnee Tribe of Oklahoma, Notice of Availability of Draft Site-Specific Environmental Impact Statement for North Anna Power Station Units 1 and 2, Subsequent License Renewal ML24003A8432024-01-0909 January 2024 Letter to Robert Gray, Chief, Pamunkey Indian Tribe, Notice of Availability of the Draft Site-Specific EIS for North Anna Power Station, Units 1 and 2, Subsequent License Renewal ML24003A8362024-01-0909 January 2024 Notice of Availability of the Draft Site-Specific Environmental Impact Statement for the North Anna Power Station, Units 1 and 2, Subsequent License Renewal ML24003A8442024-01-0909 January 2024 Letter to Russell Townsend, Thpo, Eastern Band of Cherokee Indians ML24003A8402024-01-0909 January 2024 Letter to Katelyn Lucas, Thpo, Delaware Nation, Oklahoma, Notice of Availability of Draft Site-Specific Environmental Impact Statement for North Anna Power Station Units 1 and 2, Subsequent License Renewal ML24003A8452024-01-0909 January 2024 Letter to Stephen Adkins, Chief, Chickahominy Indian Tribe, Notice of Availability of Draft Site-Specific Environmental Impact Statement for North Anna Power Station Units 1 and 2, Subsequent License Renewal ML23332A1852024-01-0404 January 2024 Notice of Availability of the Draft Site-Specific Environmental Impact Statement for the North Anna Power Station, Units 1 and 2, Subsequent License Renewal ML23332A0872024-01-0404 January 2024 Notice of Availability of the Draft Site-Specific Environmental Impact Statement for the North Anna Power Station, Units 1 and 2, Subsequent License Renewal ML23360A6352024-01-0404 January 2024 Letter to Dominion Availability for North Anna Units 1 and 2 Draft Site Specific Environmental Impact Statement ML23332A1472023-12-21021 December 2023 Issuance of Environmental Scoping Summary Report Associated with the Staff'S Review of the North Anna Power Station, Units 1 and 2, Subsequent License Renewal Application ML23283A3052023-12-20020 December 2023 Review of Appendix F to DOM-NAF2, Qualification of the Framatome ORFEO-GAIA and ORFEO-NMGRID CHF Correlations in the Dominion Energy VIPRE-D Computer Code (EPID L-2022-LLT-0003) (Nonproprietary) ML23346A0972023-12-11011 December 2023 License Amendment Request to Revise the Emergency Plan Relocation of the Technical Support Center - Response to NRC Request for Additional Information ML23346A1022023-12-11011 December 2023 2024 North Anna Power Station Brq Inspection Notification Letter ML24012A0942023-12-0707 December 2023 GL Report from Dominion Virginia Power Regarding Transfer of Devices ML24012A0892023-12-0707 December 2023 GL Registration from Dominion Virginia Power ML23334A2432023-11-30030 November 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation ML23362A0602023-11-29029 November 2023 ISFSI, Submittal of Cask Registration for Spent Fuel Storage IR 05000339/20234022023-11-27027 November 2023 Security Baseline Inspection Report 05000338 and 05000339/2023402 IR 05000338/20230032023-11-13013 November 2023 Integrated Inspection Report 05000338/2023003 and 05000339/2023003 ML23311A2042023-10-0909 October 2023 Annual Submittal of Technical Specification Bases Changes Pursuant to Technical Specification 5.5.13.d IR 05000338/20234032023-10-0505 October 2023 Reissue - North Anna Power Station - Cyber Security Inspection Report 05000338/2023403 and 05000339/2023403 (Cover Letter) ML23279A0612023-10-0505 October 2023 Paragon Energy Solutions LLC, Part 21 Final Report Re Potential Defect with Eaton Jd and Hjd Series Molded Case Circuit Breakers (Mccbs) ML23230A0502023-10-0202 October 2023 5 of the Quality Assurance Topical Report - Review of Program Changes ML23275A0992023-09-28028 September 2023 Subsequent License Renewal Application Third 10 CFR 54.21(b) Annual Amendment IR 05000338/20230112023-09-26026 September 2023 Quadrennial Focused Engineering Inspection Commercial Grade Dedication Report 05000338/2023011 and 05000339/2023011 ML23242A3482023-09-11011 September 2023 Cyber Security Inspection Report 05000338/2023403 and 05000339/2023403 - Cover ML23254A0242023-09-0606 September 2023 Paragon Energy Solutions LLC, Potential Defect with Eaton Jd and Hjd Series Molded Case Circuit Breakers (Mccbs) ML23249A2592023-09-0606 September 2023 Core Operating Limits Report Cycle 30, Pattern Ukr, Revision 0 ML23214A2022023-09-0505 September 2023 Staff Assessment of Updated Seismic Hazards Following the NRC Process for the Ongoing Assessment of Natural Hazards Information 2024-02-01
[Table view] Category:Licensee Event Report (LER)
MONTHYEAR05000339/LER-2016-0012016-09-21021 September 2016 Technical Specification Required Shutdown Due to Reactor Coolant System Leak, LER 16-001-00 for North Anna Power Station, Unit 2 Regarding Technical Specification Required Shutdown Due to Reactor Coolant System Leak 05000338/LER-2016-0032016-06-16016 June 2016 1 OF 3, LER 16-003-00 for North Anna, Unit 1, Regarding Engineered Safety Feature Actuation Due to Loss of Power to "A" Reserve Station Service Transformer 05000338/LER-2016-0022016-05-0505 May 2016 , Chemical Addition System Outside of Technical Specification Due to Excessive Unseating Thrust on MOVs, LER 16-002-00 for North Anna, Unit 1, Regarding Chemical Addition System Outside of Technical Specification Due to Excessive Unseating Thrust on MOVs 05000338/LER-2016-0012016-03-16016 March 2016 1 OF 3, LER 16-001-00 for North Anna, Units 1 and 2, Regarding Emergency Diesel Generators Automatic Start Due to Loss of Power to "C" Reserve Station Service Transformer ML0229604192002-10-11011 October 2002 Ventilation Radiation Monitor System Special Report 2016-09-21
[Table view] |
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 intemet 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.
1.0 DESCRIPTION OF THE EVENT On January 23, 2016,
- at approximately 1703 hours0.0197 days <br />0.473 hours <br />0.00282 weeks <br />6.479915e-4 months <br />, Switchyard breaker L102 (EIIS System — EA, Component — BKR), supply to 34.5kV bus #3, tripped open from the' Sulfur Hexafluoride (SF6) gas pressure switch. This resulted in the loss of "C" Reserve Station Service Transformer (RSST) (EIIS System — EA, Component — XFMR) which supplies "F" transfer and 2G intake structure 4160VAC buses (EIIS System — EB, circulating water, pumps to continue to run being supplied by Unit 1. The "F" transfer bus supplies the 1H and 2J emergency buses (EIIS System — EK, Component — BU).
Their associated Emergency Diesel Generators (EDG) (EIIS System —EK, Component — DG) started and loaded to recover those buses. The 1H bus.was swapped to its alternate supply from 1B station service and the 1H EDG was shutdown and returned to auto standby. Limiting actions on Unit 1 were cleared at that time. The 2J EDG continued to carry the 2J bus. At 1948 hours0.0225 days <br />0.541 hours <br />0.00322 weeks <br />7.41214e-4 months <br /> on January 23, 2016, an 8-hour Non- Emergency Report was made to the NRC in accordance with 10 CFR 50.72(b)(3)(iv)(A) .as a condition that resulted in valid actuation of ESF.
As a result of the event, the Unit 2 Moisture Separator Reheater (MSR) flow control valves (FCVs) (EIIS System — SB, Component — FCV) went closed and reactor power reduced to approximately 96 percent. In addition, the Unit 1 "B" Charging pump (EIIS System — CB, Component — P) auto-started due to the under-voltage condition on the 1H bus. The pump was secured and returned to auto at 1720 hours0.0199 days <br />0.478 hours <br />0.00284 weeks <br />6.5446e-4 months <br /> on January 23, 2016. The MSR FCVs were reopened at 0332 hours0.00384 days <br />0.0922 hours <br />5.489418e-4 weeks <br />1.26326e-4 months <br /> on January 24, 2016. At 1528 hours0.0177 days <br />0.424 hours <br />0.00253 weeks <br />5.81404e-4 months <br /> on January 24, 2016, the "C" RSST was energized and normal power restored to the 2J Emergency bus. The 2J EDG was secured at 1541 hours0.0178 days <br />0.428 hours <br />0.00255 weeks <br />5.863505e-4 months <br />. Repairs to breaker L102 were completed and the Unit 2 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> limiting action was exited at 1706 hours0.0197 days <br />0.474 hours <br />0.00282 weeks <br />6.49133e-4 months <br /> on January 24, 2016.
2.0 SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS Units 1 and 2 continued to operate, as designed, following the loss of offsite power. No significant safety consequences resulted from this event because the 1H and 2J EDGs powered the emergency busses, as designed. Offsite power sources were restored in a timely manner and the associated EDGs were secured and returned to automatic. The health and safety of the public were not affected by this event.
3.0 CAUSE The direct cause for the opening of the L102 breaker was an internal switch contact.
failure due to moisture. Snow/moisture intrusion inside the cabinet likely shorted across the electrical terminals for the SF6 gas pressure switch (63G) and caused the 63X relay to pick up, which tripped and locked out the breaker.
The SF6 pressure switch vendor was unable to find anything wrong with the calibration of the switch. Subject matter experts (SME) within the company along with the breaker manufacturer were also unable to find anything physically wrong, with the switch.
4.0 IMMEDIATE CORRECTIVE ACTION(S) The L102 SF6 gas pressure switch was replaced and the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> limiting action for Unit 2 was exited.
5.0 ADDITIONAL CORRECTIVE ACTIONS In accordance with the manufacturer's and Dominion SME recommendations, all 34.5KV breakers in the North Anna switchyard have had weather sealant applied to prevent moisture intrusion (rain/snow) where air gaps were noted to be around the conduit access plate and the mechanism access plate .at the bottom of the breaker cabinet which .are the most likely intrusion areas. Additionally the L102 and .L202 breakers had weather sealant applied to the area where the breaker cabinet top meets the breaker cabinet side walls along the front and two sides.
6.0 ACTIONS TO PREVENT RECURRENCE The preventive maintenance procedure is being revised to include an additional check for snow and moisture intrusion paths into cabinets and seal as appropriate for the breakers in question. Monitoring of all the 34.5KV breakers for moisture intrusion will occur to determine if additional actions to seal the breakers are required for the remaining. nine (9) breakers. Inspections of the sealant will also be performed to ensure it remains intact. The monitoring period will be for approximately one year to allow the breakers to be exposed to all seasonal conditions.
7.0 SIMILAR EVENTS None 8.0 ADDITIONAL INFORMATION Component: 63G pressure switch Manufacturer Solon Model 6TC Bulb type
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05000339/LER-2016-001 | Technical Specification Required Shutdown Due to Reactor Coolant System Leak LER 16-001-00 for North Anna Power Station, Unit 2 Regarding Technical Specification Required Shutdown Due to Reactor Coolant System Leak | | 05000338/LER-2016-001 | 1 OF 3 LER 16-001-00 for North Anna, Units 1 and 2, Regarding Emergency Diesel Generators Automatic Start Due to Loss of Power to "C" Reserve Station Service Transformer | | 05000338/LER-2016-002 | , Chemical Addition System Outside of Technical Specification Due to Excessive Unseating Thrust on MOVs LER 16-002-00 for North Anna, Unit 1, Regarding Chemical Addition System Outside of Technical Specification Due to Excessive Unseating Thrust on MOVs | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | 05000338/LER-2016-003 | 1 OF 3 LER 16-003-00 for North Anna, Unit 1, Regarding Engineered Safety Feature Actuation Due to Loss of Power to "A" Reserve Station Service Transformer | |
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