05000328/LER-2025-002, Manual Reactor Trip Due to a Failed Closed Main Feedwater Regulating Valve
| ML25233A006 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 08/20/2025 |
| From: | Michael K Tennessee Valley Authority |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| LER 2025-002-00 | |
| Download: ML25233A006 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(b)(3)(iv)(A) |
| 3282025002R00 - NRC Website | |
text
Sequoyah Nuclear Plant, Post Office Box 2000, Soddy Daisy, Tennessee 37384 August 20, 2025 10 CFR 50.73 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Sequoyah Nuclear Plant, Unit 2 Renewed Facility Operating License No. DPR-79 NRC Docket No. 50-328
Subject:
Licensee Event Report 50-328/2025-002-00, Manual Reactor Trip due to a Failed Closed Main Feedwater Regulating Valve The enclosed licensee event report provides details concerning a manual reactor trip due to a failed closed main feedwater regulating valve that resulted in lowering steam generator water levels. This report is being submitted in accordance with 10 CFR 50.73(b)(3)(iv)(A) as an event that resulted in actuation of the Reactor Protection System and Auxiliary Feedwater System. A supplement to this LER will be submitted following completion of the associated root cause.
There are no regulatory commitments contained in this letter. Should you have any questions concerning this submittal, please contact Mr. Rick Medina, Site Compliance Manager, at (423) 843-8129 or rmedina4@tva.gov.
Respectfully, Kevin Michael Site Vice President Sequoyah Nuclear Plant Enclosure: Licensee Event Report 50-328/2025-002-00 cc:
NRC Regional Administrator - Region II NRC Senior Resident Inspector - Sequoyah Nuclear Plant
Abstract
On June 24, 2025, at 0351 eastern daylight time, SQN Unit 2 operators performed a manual reactor trip.
Unit 2 was manually tripped due to lowering water level in the Loop 1 Steam Generator caused by a Loop 1 Main Feedwater Regulating Valve malfunction. All plant safety systems responded as designed. This event did not adversely affect the health and safety of plant personnel or the general public.
The root cause for this event is still under investigation. When the final investigation is complete a supplement will be provided with the identified cause and associated corrective action(s).
Page 5 of 5 C. For failure that rendered a train of a safety system inoperable, estimate of the elapsed time from discovery of the failure until the train was returned to service There was no failure that rendered a train of a safety system inoperable.
VI.
Corrective Actions
This event was entered into the Tennessee Valley Authority Corrective Action Program under condition report number 2021907.
A. Immediate Corrective Actions
Once troubleshooting discovered that MFRV 2-FCV-03-35 failed, an extent of condition review was completed for the Unit 2 and Unit 1 MFRVs.
B. Corrective Actions to Prevent Recurrence or to reduce the probability of similar events occurring in the future The root cause for this event is still under investigation. When the final investigation is complete a supplement will be provided.
VII. Previous Similar Events at the Same Site
There were no previous similar events at SQN occurring within the last three years.
VIII. Additional Information
There is no additional information.
IX.
Commitments
There are no new commitments.