| 01-03-2018 | On 10/09/17, during the bi-weekly Emergency Diesel Generator ( EDG) #2 Load Test, a Generator Lockout signal (86G) was received which tripped the EDG output breaker. This failure resulted in EDG #2 being declared inoperable, and entry into an unplanned 7-day Limiting Condition for Operation (LCO) at 0312.
Troubleshooting identified a broken electrical ring lug connector on a current transformer that provides an input to the protective relay logic. The investigation determined the connector failure was due to fatigue cracking that was initiated by stresses caused by bending and twisting of the electrical lug beyond limits specified in industry guidelines. The ring lug was most likely distressed during initial installation in the 1990's. The condition that led to the EDG #2 trip existed for greater than the allowed outage time in the plant's Technical Specification (TS) and is reportable under 10 CFR 50.73(a)(2)(i)(B). |
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Category:Letter
MONTHYEARML23342A1162024-01-0909 January 2024
Independent Spent Fuel Storage Installation Security Inspection Plan
L-23-019, Proof of Financial Protection 10 CFR 140.152023-12-18018 December 2023
Proof of Financial Protection 10 CFR 140.15
IR 05000219/20230022023-11-0909 November 2023
EA-23-076 Oyster Creek Nuclear Generating Station - Notice of Violation and Proposed Imposition of Civil Penalty - $43,750 - NRC Inspection Report No. 05000219/2023002
ML23286A1552023-10-13013 October 2023
Defueled Safety Analysis Report (DSAR)
ML23249A1212023-09-0606 September 2023
NRC Inspection Report 05000219/2023002, Apparent Violation (EA-23-076)
ML23242A1162023-08-30030 August 2023
Biennial 10 CFR 50.59 and 10 CFR 72.48 Change Summary Report January 1, 2021 Through December 31, 2022
ML23214A2472023-08-22022 August 2023
NRC Inspection Report 05000219/2023002
IR 05000219/20230012023-05-31031 May 2023
NRC Inspection Report No. 05000219/2023001
IR 07200015/20234012023-05-16016 May 2023
NRC Independent Spent Fuel Storage Installation Security Inspection Report 07200015/2023401
ML23114A0912023-04-24024 April 2023
Annual Radioactive Effluent Release Report for 2022
ML23114A0872023-04-24024 April 2023
Annual Radioactive Environmental Operating Report for 2022
L-23-004, HDI Annual Occupational Radiation Exposure Data Reports - 20222023-04-24024 April 2023
HDI Annual Occupational Radiation Exposure Data Reports - 2022
L-23-003, Report on Status of Decommissioning Funding for Reactors and Independent Spent Fuel Storage Installations2023-03-31031 March 2023
Report on Status of Decommissioning Funding for Reactors and Independent Spent Fuel Storage Installations
ML23088A0382023-03-29029 March 2023
Stations 1, 2, & 3, Palisades Nuclear Plant, and Big Rock Point - Nuclear Onsite Property Damage Insurance
ML22361A1022023-02-24024 February 2023
Reactor Decommissioning Branch Project Management Changes for Some Decommissioning Facilities and Establishment of Backup Project Manager for All Decommissioning Facilities
IR 05000219/20220022023-02-0909 February 2023
NRC Inspection Report No. 05000219/2022002
ML23031A3012023-02-0808 February 2023
Discontinuation of Radiological Effluent Monitoring Location in the Sewerage System
ML23033A5052023-02-0202 February 2023
First Use Notification of NRC Approved Cask RT-100
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LLRW Late Shipment Investigation Report Per 10 CFR 20, Appendix G
ML22347A2732022-12-21021 December 2022
Independent Spent Fuel Storage Installation Security Inspection Plan Dated December 21, 2022
ML22297A1432022-12-15015 December 2022
Part 20 App G Exemption Letter
L-22-042, Oyster, Pilgrim, Indian Point, Palisades and Big Rock Point - Proof of Financial Protection 10 CFR 140.152022-12-14014 December 2022
Oyster, Pilgrim, Indian Point, Palisades and Big Rock Point - Proof of Financial Protection 10 CFR 140.15
IR 07200015/20224012022-12-0606 December 2022
NRC Independent Spent Fuel Storage Installation Security Inspection Report 07200015/2022401 (Letter & Enclosure 1)
ML22280A0762022-11-0202 November 2022
Us NRC Analysis of Holtec Decommissioning Internationals Funding Status Report for Oyster Creek, Indian Point and Pilgrim Nuclear Power Station
ML22276A1762022-10-24024 October 2022
Decommissioning International Proposed Revisions to the Quality Assurance Program Approval Forms for Radioactive Material Packages
ML22286A1402022-10-13013 October 2022
NRC Confirmatory Order EA-21-041
IR 05000219/20220012022-08-11011 August 2022
NRC Inspection Report 05000219/2022001
ML22215A1772022-08-0303 August 2022
Decommissioning International (HDI) Proposed Revisions to the Quality Assurance Program Approval Forms for Radioactive Material Packages
ML22214A1732022-08-0202 August 2022
Request for Exemption from 10 CFR 20, Appendix G, Section Iii.E
ML22207B8382022-07-26026 July 2022
NRC Confirmatory Order EA-21-041
ML22130A6882022-05-10010 May 2022
Late LLRW Shipment Investigation Report Pursuant to 10 CFR 20, Appendix G
L-22-026, Occupational Radiation Exposure Data Report - 20212022-04-29029 April 2022
Occupational Radiation Exposure Data Report - 2021
ML22118A6122022-04-28028 April 2022
Annual Radioactive Environmental Operating Report for 2021
ML22118A5822022-04-28028 April 2022
Annual Radioactive Effluent Release Report for 2021
ML22091A1062022-04-0101 April 2022
Nuclear Onsite Property Damage Insurance (10 CFR 50.54(w)(3))
L-22-022, and Indian Point Nuclear Generating Stations 1, 2, & 3 - Report on Status of Decommissioning Funding for Reactors and Independent Spent Fuel Storage Installations - Holtec.2022-03-25025 March 2022
and Indian Point Nuclear Generating Stations 1, 2, & 3 - Report on Status of Decommissioning Funding for Reactors and Independent Spent Fuel Storage Installations - Holtec.
ML22069A3762022-03-10010 March 2022
Late LLRW Shipment Investigation Report Pursuant to 10 CFR 20, Appendix G
ML22032A0582022-03-0808 March 2022
EA-21-139; EA-150: Oyster Creek Nuclear Generating Station - NRC Investigation Report Nos.. 1-2021-002 & 1-2021-014
ML22060A2202022-03-0202 March 2022
NRC Office of Investigations Case No. 1-2021-009
ML22049B2452022-02-19019 February 2022
Late Low Level Radwaste Shipment Report Pursuant to 10 CFR 20 Appendix G
IR 05000219/20214022022-01-26026 January 2022
EA-21-041: Confirmatory Order Related to Oyster Greek Nuclear Generating Station - NRC Investigation Report I-2020-007; NRC Inspection Report Nos. 05000219/2021402 & 07200015/2021401
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and Big Rock Point - Changes to Site Organization
ML22025A2182022-01-25025 January 2022
Late LLRW Shipments Investigation Report Pursuant to 10 CFR 20, Appendix G
ML22021B5512022-01-21021 January 2022
Compensatory Measures Not Implemented Per Site'S Physical Security Plan Due to Multiplexer (Mux) Power Supply Failure
L-21-134, and Indian Point Nuclear Generating Stations 1, 2, & 3 - Report on Status of Decommissioning Funding for Independent Spent Fuel Storage Installations2021-12-17017 December 2021
and Indian Point Nuclear Generating Stations 1, 2, & 3 - Report on Status of Decommissioning Funding for Independent Spent Fuel Storage Installations
ML21349A5192021-12-15015 December 2021
Commitment Change Summary Report
ML21285A1912021-11-30030 November 2021
Nrc'S Analysis of Holtec Decommissioning International'S Decommissioning Funding Status Report for Oyster Creek Nuclear Generating Station and Pilgrim Nuclear Power Station, Docket Nos 50-219 and 50-293
IR 05000219/20210032021-11-16016 November 2021
NRC Inspection Report No. 05000219/2021003
L-21-118, Changes to Signature Authority & Addressee for Holtec Decommissioning International, LLC Correspondence Re to Oyster Creek Nuclear Generating Station, Pilgrim Nuclear Power Station, Indian Point Nuclear Generating Units 1, 2, 3, & Palisades2021-11-0909 November 2021
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IR 05000219/20214042021-08-26026 August 2021
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2024-01-09
[Table view]
Category:Licensee Event Report (LER)
MONTHYEARML22021B5512022-01-21021 January 2022
Compensatory Measures Not Implemented Per Site'S Physical Security Plan Due to Multiplexer (Mux) Power Supply Failure
05000219/LER-2017-0052018-01-0303 January 2018
1 OF 3, LER 17-005-00 for Oyster Creek Nuclear Generating Station Regarding Failure of the Emergency Diesel Generator #2 During Surveillance Testing Due to a Broken Electrical Connector
05000219/LER-2017-0032017-08-31031 August 2017
Automatic Scram while Suberitical due to Low Reactor Level, LER 17-003-00 for Oyster Creek Regarding Automatic Scram while Subcritical due to Low Reactor Level
05000219/LER-2017-0022017-08-31031 August 2017
Manual Reactor Scram due to Degrading Main Condenser Vacuum, LER 17-002-00 for Oyster Creek Regarding Manual Scram due to Degraded Main Condenser Vacuum
05000219/LER-2016-0022017-06-23023 June 2017
Control Rod Drive Cooling Water System Isolation Scram Time Testing Was Not Performed, LER 16-002-01 for Oyster Creek Regarding Control Rod Drive Cooling Water System Isolation Scram Time Testing Was Not Performed
05000219/LER-2017-0012017-05-0303 May 2017
Automatic SCRAM due to APRM High Flux during Turbine Valve Testing, LER 17-001-01 for Oyster Creek, Regarding Transfer of Automatic SCRAM due to APRM High Flux during Turbine Valve Testing
ML17129A6032017-05-0303 May 2017
LER 16-S01-01 for Oyster Creek, Regarding Special Nuclear Material Discovered Outside of Material Access Area
05000219/LER-2016-0012017-01-24024 January 2017
1 OF 4, LER 16-001-01 for Oyster Creek Nuclear Generating Station Regarding Failure of the #1 Emergency Diesel Generator During Surveillance Testing due to a Cooling Water System Leak
RA-16-107, LER 16-S01-00 for Oyster Creek Nuclear Generating Station Regarding Special Nuclear Material Discovered Outside of Material Access Area2016-12-0505 December 2016
LER 16-S01-00 for Oyster Creek Nuclear Generating Station Regarding Special Nuclear Material Discovered Outside of Material Access Area
05000219/LER-2016-0052016-11-17017 November 2016
Technical Specification Prohibited Condition Caused by One Electromatic Relief Valve Inoperable for Greater than Allowed Outage Time, LER 16-005-00 for Oyster Creek Nuclear Generating Station Regarding Technical Specification Prohibited Condition Caused by One Electromatic Relief Valve Inoperable for Greater than Allowed Outage Time
05000219/LER-2016-0032016-06-29029 June 2016
Manual SCRAM Inserted due to Leakage from the D' Reactor Recirculation Pump Seal, LER 16-003-00 for Oyster Creek, Unit 1, Regarding Manual SCRAM Inserted due to Leakage from the 'D' Reactor Recirculation Pump Seal
RA-16-001, Special Report for Inoperability of the Turbine Building High Range Radioactive Noble Gas Monitor2016-01-15015 January 2016
Special Report for Inoperability of the Turbine Building High Range Radioactive Noble Gas Monitor
ML1015505702009-08-26026 August 2009
Event Notification for Oyster Creek on Offsite Notification Due to a Water Leak Containing Tritium
ML0932006252009-07-24024 July 2009
NRC Operations Center Event Report - Oyster Creek
ML1015505672009-04-15015 April 2009
Event Notification for Oyster Creek on Offsite Notification Due to Potential Release of Tritium
ML0506107132005-02-16016 February 2005
LER 04-03-001 Oyster Creek, Unit 1, Regarding Actuation of Reactor Protection System Due to Spurious Hi-Hi Trip Signals on Intermediate Range Monitors Caused by Electromagnetic Interference
2022-01-21
[Table view] |
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 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.
Oyster Creek Nuclear Generating Station
3. LER NUMBER
2017 - 00 005
Plant Conditions Prior To Event
Event Date:
October 09, 2017 Event Time: 03:12 hours ET Unit 1 Mode: Run Power Level: 100%
Description of Event
On 10/09/17, during the bi-weekly EDG #2 Load Test (station procedure 636.4.013), a Generator Lockout (86G) signal was received which tripped the EDG output breaker. The diesel had run for 4 minutes loaded in the procedurally prescribed band of 2600-2800 KW prior to receiving the 86G lockout signal. The EDG #2 trip is documented under Issue Report (IR) 04060815. This failure resulted in EDG #2 being declared inoperable, and entry into an unplanned 7-day LCO (TS Section 3.7.D) at 0312.
Troubleshooting identified a broken electrical ring lug connector on one current transformer (CT5) that provides an input to a differential current relay (87G). When the ring lug connector became detached from the terminal point, the relay sensed a current imbalance and the protective relay logic actuated. The differential current relay (87G) provided an input to the Generator Lockout circuit, causing the lockout relay (86G) to trip the EDG#2 output breaker. Repairs were completed on 10/10/17 at 0557. EDG #2 was satisfactorily tested and declared operable at 0805, and the 7-day LCO was exited.
Cause of Event
The investigation determined the electrical ring lug connector failure was due to fatigue cracking that was initiated by stresses caused by bending and twisting of the electrical lug beyond limits specified in industry guidelines.
Analysis of the Event
The ring lug that failed was sent to a metallurgical lab for failure analysis. The metallurgical analysis determined the ring lug had failed due to fatigue cracking. The investigation performed for the EDG#2 trip concluded the fatigue cracking was initiated by historical stresses caused by bending and twisting of the electrical lug beyond limits specified in industry guidelines. Based on a review of recent maintenance records for EDG#2 and a review of plant procedures and work practices, the investigation concluded the ring lug was most likely distressed during initial installation in the 1990's.
Assessment of Safety Consequences
Two EDG units serve as the Standby Power Supply for Oyster Creek Nuclear Generating Station (OCNGS) by providing an emergency source of power to the 4.16 kV buses 1C and 1D in the event of a loss of normal power.
The EDG units are designed to start and load automatically, if required. Non-essential loads are automatically shed by under-voltage sensing devices on loss of offsite power to ensure that the EDG units are not overloaded. The capacity of the EDG units is sufficient to sequentially energize for starting all safety-related pumps and auxiliaries required for a safe shutdown of the reactor in the event of a Design Basis Accident. The EDG units are independent of each other, except for a common bulk fuel storage supply, and are provided with auxiliary systems to ensure reliable starting and continuous operation with no Operator attention. Power to start the EDG units is self-contained and is not dependent on the availability of any other source of normal plant power at the moment of initiation.
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 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.
Oyster Creek Nuclear Generating Station
3. LER NUMBER
2017 - 00 005 The Generator Lockout relay (86G) is an auxiliary relay that is operated upon the occurrence of abnormal conditions to maintain associated equipment out of service until it is reset. The lockout (86G) relay is sealed-in when the Differential Current Relay (87G) is initiated. The failure of the wire lug would not have prevented EDG #2 from being able to start. However, in the as found condition EDG#2 was unable to start and load to supply power to the safety buses for the required mission time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. Because EDG #1 was operable and available to supply power to its associated loads in the event of a loss of offsite power, there was no loss of safety function.
Corrective Actions
1. The broken ring lug connector forthe current transformer (CT5) was replaced. EDG#2 was tested and restored to operable status on 10/10/17 at 0805 hours0.00932 days <br />0.224 hours <br />0.00133 weeks <br />3.063025e-4 months <br />.
2. All ring lug connectors were inspected in the current transformer and potential transformer cabinet for EDG#2.
Four other bent and/or twisted ring lug connectors were identified and replaced on 10/10/17.
3. Extent of condition inspections were performed on all ring lug connectors in the current transformer and potential transformer cabinet for EDG#1.
4. Two bent and/or twisted ring lug connectors were replaced on EDG#1 on 12/28/17.
5. Revise electrical ring lug installation and EDG inspection procedures to include inspection for bent and/or twisted lugs.
Previous Occurrences
There have been no similar, previous events resulting from a failure of a wire lug on an EDG at Oyster Creek.
Component Data Component IEEE 805 System ID IEEE 803A Component Emergency Diesel Generator EK DG