05000270/LER-2022-002, Regarding Automatic Actuation of Emergency Feedwater System Due to Main Feedwater Pump Malfunction
| ML22104A257 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 04/14/2022 |
| From: | Snider S Duke Energy |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RA-22-0132 LER 2022-002-00 | |
| Download: ML22104A257 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 2702022002R00 - NRC Website | |
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Steven M. Snider Vice President Oconee Nuclear Station Duke Energy ON01SC l 7800 Rochester Hwy Seneca, SC 29672 o. 864.873.3478 f: 864.873.5791 Steve.Snider@duke-energy.com RA-22-0132 April 14, 2022 10 CFR 50.73 Attn: Document Control Desk U. S. Nuclear Regulatory Commission 11555 Rockville Pike Rockville, MD 20852-2746 Duke Energy Carolinas, LLC Oconee Nuclear Station Unit 2 Docket Number: 50-270 Renewed Operating Licenses: DPR-49
Subject:
Licensee Event Report 270/2022-002, Revision 00 - Automatic Actuation of Emergency Feedwater System due to Main Feedwater Pump Malfunction Licensee Event Report 270/2022-002, Revision 00, is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event.
There are no regulatory commitments associated with this LER.
There are no unresolved corrective actions necessary to restore compliance with NRC requirements.
If there are questions, or further information is needed, contact Laura Boyce, Regulatory Affairs, at (864) 873-6774.
Sincerely, Steven M. Snider Vice President Oconee Nuclear Station Enclosure: Licensee Event Report 270/2022-002 Rev.00
RA-22-0132 April 14, 2022 Page 2 cc (w/Enclosure):
Ms. Laura Dudes, Administrator, Region II U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, GA 30303-1257 Mr. Shawn Williams, Project Manager U.S. Nuclear Regulatory Commission 11555 Rockville Pike Mail Stop O-08B1A Rockville, MD 20852-2738 Mr. Adam Ruh (Acting)
NRC Senior Resident Inspector Oconee Nuclear Station
NRC FORM 366 (08-2020)
U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)
(See Page 2 for required number of digits/characters for each block)
(See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/2023
- 1. Facility Name Oconee Nuclear Station Unit 2
- 4. Title
- 2. Docket Number 0500000270
- 3. Page 1 OF 4 Automatic Actuation of Emergency Feedwater System due to Main Feedwater Pump Malfunction
- 5. Event Date
- 6. LER Number
- 7. Report Date
- 8. Other Facilities Involved Sequential Rev Facility Name NA Facility Name NA Docket Number 05000 Docket Number 05000
- 9. Operating Mode 3
- 10. Power Level 0
- 11.
This Report is Submitted Pursuant to the Requirements of 10 CFR §: (Check all that apply) 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 50.73(a)(2)(i)(C)
Other (Specify in Abstract below or in CONTINUED state, the pump operated at minimum speed which was at that time adequate to allow steam generator level to be maintained.
However, as speed demand from ICS increased, the 2A FDW pump speed control was unable to respond. This fault state was not visible to the operators when placing the FDW pump in service. Procedure changes were identified include specific checks for FDW pump speed control faults prior to placing each FDW pump in service.
Units 1 and 3 were not affected by this event.
Reportability
This event was reported to the NRC on March 23, 2022, in Event Notification 55800, as an 8-hour notification under 10 CFR 50.72(b)(3)(iv)(A) - Specified System Actuation (EFW). The event is also reportable under 10 CFR 50.73(a)(2)(iv)(A) as a valid EFW system actuation.
CAUSAL FACTORS The cause of this event was a fault state on the 2A FDW pump speed controls which prevented the pump from responding to demand inputs from ICS.
CORRECTIVE ACTIONS
Immediate:
- 1. Replaced knife switch in 2A FDW pump speed control servo circuit
- 2. Reset 2A FDW speed controls and verified no fault conditions present
- 3. Restored 2A FDW pump to service Planned:
Revise FDW pump startup procedures for all three ONS Units to include instructions to ensure no FDW pump speed control faults are present prior to placing a FDW pump in service.
SAFETY ANALYSIS
The ONS Unit 2 EFW actuation on February 13, 2022, was an uncomplicated event that had no impact on public health and safety.
Following the malfunction of the 2A FDW pump speed controls, the 2A and 2B MDEFW pumps automatically started as designed to restore and maintain SG levels for heat removal. There was not a significant plant transient since the reactor was in startup (Mode 3) and subcritical. Additional defense-in-depth to maintain safe shutdown was available from the TDEFW Pump, EFW via cross connects from Units 1 or 3, Protected Service Water (PSW) System, the Standby Shutdown Facility (SSF), and portable FLEX equipment. No Emergency Core Cooling System (ECCS) or other automatic safety system actuations occurred in response to this event.
CONTINUED A post-event review found no procedural or human performance issues with the operator response to the event. There were no maintenance or other safety significant activities being conducted on any of the defense in depth plant systems or equipment at the time of the event. Therefore, it is concluded that the impact on core damage risk was very low, and the event had no impact on public health and safety.
ADDITIONAL INFORMATION
A review of Duke Energys Corrective Action Program did not identify any Oconee LERs or events in the last 3 years that involved the same underlying concerns or reasons as this event.
This event is considered INPO IRIS Reportable. There were no releases of radioactive materials, radiation exposures or personnel injuries associated with this event. Page 4 of 4