08-31-2017 | On July 3, 2017, at approximately 10:15 AM following a grid disturbance, a manual scram was inserted due to degrading main condenser vacuum because of an improper configuration of the Augmented Off-gas (AOG) System.
The loss of main condenser vacuum resulted when Operations personnel failed to execute procedural requirement to align the AOG system into a shutdown lineup. The loss of vacuum was caused by degraded Steam Jet Air Ejectors (SJAE) performance due to a blocked discharge path.
The AOG system tripped 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br /> earlier following a grid disturbance. During the trip, operations personnel failed to re-align the AOG treatment system to a shutdown lineup resulting in the AOG Flame Arrestor siphoning into the inlet piping which filled the lower section of the off-gas hold up line with water. |
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Category:Letter
MONTHYEARML24214A0372024-08-0101 August 2024 License Amendment Request to Revise Renewed Facility Operating License to Add License Condition 2.C.(18) to Include License Termination Plan Requirements ML24179A1842024-07-23023 July 2024 June 20, 2024, Clarification Call on Preapplication Readiness Assessment of the Holtec Decommissioning International License Termination Plan ML24151A6482024-06-0303 June 2024 Changes in Reactor Decommissioning Branch Project Management Assignments for Some Decommissioning Facilities IR 05000219/20240012024-05-14014 May 2024 Decommissioning Intl, LLC Oyster Creek Nuclear Generating Station - NRC Inspection Report No. 05000219/2024001 ML24120A0402024-04-29029 April 2024 Annual Radioactive Effluent Release Report for 2023 L-24-009, HDI Annual Occupational Radiation Exposure Data Reports - 20232024-04-29029 April 2024 HDI Annual Occupational Radiation Exposure Data Reports - 2023 ML24120A0412024-04-29029 April 2024 Annual Radioactive Environmental Operating Report for 2023 ML24094A2142024-04-19019 April 2024 Preapplication Readiness Assessment of the Holtec Decommissioning International License Termination Plan L-24-007, Report on Status of Decommissioning Funding for Reactors and Independent Spent Fuel Storage Installations – Holtec Decommissioning International, LLC (HDI)2024-03-29029 March 2024 Report on Status of Decommissioning Funding for Reactors and Independent Spent Fuel Storage Installations – Holtec Decommissioning International, LLC (HDI) ML24089A2492024-03-29029 March 2024 Reply to Notice of Violation EA-2024-024 ML24085A7902024-03-28028 March 2024 – Preapplication Readiness Assessment of the License Termination Plan ML24081A2882024-03-21021 March 2024 Request Preliminary Review and Feedback on Chapter 6 of the Draft License Termination Plan ML24046A1242024-02-29029 February 2024 – NRC Inspection Report 05000219/2023003 ML24033A3272024-02-0202 February 2024 Request Preliminary Review and Feedback on Chapter 5 of the Draft License Termination Plan ML23342A1162024-01-0909 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 L-23-004, HDI Annual Occupational Radiation Exposure Data Reports - 20222023-04-24024 April 2023 HDI Annual Occupational Radiation Exposure Data Reports - 2022 ML23114A0872023-04-24024 April 2023 Annual Radioactive Environmental Operating Report for 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 ML23025A0112023-01-24024 January 2023 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. 2024-08-01
[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 - 00 002
Plant Conditions Prior To Event
Event Date:
Unit 1 Mode:
July 3, 2017 Event Time: 10:15 hours ET Power Operation Power Level: 100%
Description of Event
On July 3, 2017 at 1015 hours0.0117 days <br />0.282 hours <br />0.00168 weeks <br />3.862075e-4 months <br /> a manual reactor scram was initiated due to degrading condenser vacuum. The loss of vacuum was initiated by the operations department failure to execute the procedural requirement to align the AOG system into a shutdown lineup. The SJAE discharge line was blocked by water from the AOG system. The AOG system tripped eleven hours earlier following a grid disturbance. During the trip, operations personnel failed to re-align the AOG system to a shutdown lineup resulting in the AOG Flame Arrestor siphoning into the lower section of the off-gas delay pipe.
Cause of Event
Operations failed to enter stop work criteria, made a non-conservative decision and did not execute a procedure in response to a trip of AOG. After the AOG system trip from the electrical transient, operations personnel misdiagnosed the AOG system lineup. The AOG system had partially isolated as designed with the recombiner blower still in service. To place the AOG system in a shutdown lineup, the system isolation valve had to be closed to separate the AOG building from the off-gas delay pipe. This isolation valve was left open and flame arrestor water siphoned back into the off-gas delay pipe causing a stall of the SJAEs and a subsequent loss of main condenser vacuum.
Analysis of Event
Following the manual scram actuation, all systems responded as expected; therefore, this event is of low safety significance.
An analysis did not determine an area where early detection via plant observable parameters would have stopped the event. An analysis of water usage and design is below.
A known operating characteristic on the system results in the flame arrestor getting pressurized on the process side up to 5 psig, (stem pressurization air sub-system). This pressure will cause the flame arrestor to siphon back into the AOG inlet line. A siphon will continue to backfill the suction lines due to the automatic makeup from the demineralized water system. Failure to isolate the inlet line to the flame arrestor with the system not in service allows water back flow to the off-gas process piping and fill the delay pipe. The delay pipe is the discharge piping from the SJAE process gas flow. Water filling the line resulted in the stall of the SJAE's that started at 0919 hours0.0106 days <br />0.255 hours <br />0.00152 weeks <br />3.496795e-4 months <br /> on July 3, 2017.
To block SJAE flow this line would have to fill up the lowest elevation of piping. This is approximately 8100 gallons of water. The earliest detection of changes in the plant would occur just as the pipe is filled with water blocking the flow and is consistent with operations observations at approximately 0825 hours0.00955 days <br />0.229 hours <br />0.00136 weeks <br />3.139125e-4 months <br /> on July 3, 2017.
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 - 00 002
Corrective Actions
Exelon took the following corrective actions:
1. Immediate procedure changes to alarm response and operating procedures were performed to provide clear direction for a trip of the AOG system.
2. Industry Benchmarking was completed and the Operations department has implemented an integrated decision-making model.
3. Reinforcement of key operations fundamentals and human performance boards with each operator.
Previous Occurrences
A previous event occurred on July 26, 2012 during startup from Forced Outage 1 F29. The delay pipe filled with water prior to or during plant startup resulting in a six-hour delay in establishing condenser vacuum. A procedure change was put in place to verify the delay pipe is draining correctly prior to every plant start up.
Component Data Component IEEE 805 System ID IEEE 803A Component N/A N/A N/A