Emergency Feedwater System (EFWS)
See also Emergency Feedwater Actuation System
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| | Site | Start date | Title | Description |
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| ENS 57159 | Oconee | 3 June 2024 04:51:00 | Automatic Actuation of Emergency Feedwater System | The following information was provided by the licensee via phone and email:
At 0051 EDT on June 3, 2024, with Unit 3 in Mode 3 at 0 percent power, an actuation of the emergency feedwater system (EFW) occurred as main steam pressure was being lowered as part of reactor coolant system (RCS) cooldown for a planned shutdown. The reason for the EFW auto-start was lowering levels in the 3A and 3B steam generators following loss of the operating main feedwater pump. The main feedwater pump automatically tripped when main steam pressure was lowered below the automatic feedwater isolation system (AFIS) actuation setpoint before AFIS channels were taken to bypass. The 3A and 3B motor driven emergency feedwater pumps automatically started as designed when the low steam generator level signal was received for the 3A and 3B steam generators.
This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of the EFW system.
There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | | IR 05000269/2023003 | Oconee
07200040 | 14 November 2023 | Integrated Inspection Report 05000269/2023003, 05000270/2023003, and 05000287/2023003; and IR 07200040/2023001; and Exercise of Enforcement Discretion | | | RA-23-0268, Transmittal of Sixth 10-Year Inservice Testing Interval Program Plan | Oconee | 29 September 2023 | Transmittal of Sixth 10-Year Inservice Testing Interval Program Plan | | | IR 05000269/2023001 | Oconee | 12 May 2023 | Integrated Inspection Report 05000269/2023001 and 05000270/2023001 and 05000287/2023001 | | | ENS 56612 | Summer | 11 May 2023 16:50:00 | Part 21 - CAP Screw Improper Length | The following information was provided by the licensee via email:
This is a non-emergency notification required by 10 CFR 21.21(d)(3)(i). A written notification in accordance with 10 CFR 21.21(d)(3)(ii) will be provided within 30 days. Steam generator emergency feedwater header discharge isolation check valves (XVC01009A-EF, XVC01009B-EF, and XVC01009C-EF) were designed specifically for and supplied to VC Summer Nuclear Station (VCSNS) by Flowserve under purchase order 4500653391 to replace the previous valves in the emergency feedwater system during refueling outage 27. On May 11, 2023, after valve installation, but prior to initial service, the socket head cap screws were identified as being shorter than the required design length. Valve drawings indicate a design length of 1.25" while the socket head cap screws received were 0.875". The correct length cap screws were installed prior to initial service. VCSNS completed a substantial safety hazard evaluation and determined that the improper length of the cap screws constituted a substantial safety hazard. This deviation in cap screw length resulted in a partial engagement of the cap screw to the cylinder rod extension and could potentially affect valve operation.
The NRC Senior Resident Inspector has been notified. | | ENS 56453 | Summer | 5 April 2023 10:51:00 | Manual Reactor Trip | The following information was provided by the licensee via email:
At 0651 EDT on April 5, 2023, with Unit 1 in mode 1 at 85 percent power, the reactor was manually tripped due to loss of main feedwater pump 'C'. The trip was not complex, with all systems responding normally post-trip. Main feedwater pump 'B' had previously been removed from service in preparation for a planned shutdown as a part of refueling outage RF27.
Operations responded and stabilized the plant. Decay heat is being removed by the emergency feedwater system.
Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B) and an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A) resulting from valid actuation of the reactor protection and emergency feedwater systems.
There was no impact on the health and safety of the public or plant personnel.
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
The licensee continues to investigate the loss of main feedwater pump 'C'.
The licensee notified the NRC Resident Inspector. | | IR 05000269/2022003 | Oconee | 7 November 2022 | Integrated Inspection Station 05000269/2022003 and 05000270/2022003 and 05000287/2022003 | | | IR 05000270/2022002 | Oconee | 29 July 2022 | Integrated Inspection Report 05000269/ 2022002 and 05000270/2022002 and 05000287/2022002 | | | ML22096A187 | Oconee | 15 July 2022 | Issuance of Amendment Nos. 424, 426, and 425 Revise TS 3.7.7, Low Pressure Service Water (LPSW) System to Extend the Completion Time for One Required Inoperable LPSW Pump | | | RA-22-0121, Submittal of Updated Final Safety Analysis Report (UFSAR) Revision 29, Technical Specifications Bases Revisions, Selected Licensee Commitment Revisions, 10 CFR 50.59 Evaluation Summary Report, and 10 CFR 54.37 Update, and Notification of | Oconee | 29 June 2022 | Submittal of Updated Final Safety Analysis Report (UFSAR) Revision 29, Technical Specifications Bases Revisions, Selected Licensee Commitment Revisions, 10 CFR 50.59 Evaluation Summary Report, and 10 CFR 54.37 Update, and Notification of Co | |
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