05000364/LER-2025-003, Automatic Reactor Trip Due to Low Steam Generator Level
| ML25230A239 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 08/18/2025 |
| From: | Carroll J Southern Nuclear Operating Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| NL-25-0307 LER 2025-003-00 | |
| Download: ML25230A239 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(iv)(B), System Actuation |
| 3642025003R00 - NRC Website | |
text
~ Southern Nuclear August 18, 2025 Docket No.:
50-364 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Joshua W. Carroll Vice President - Farley Joseph M. Farley Nuclear Plant - Unit 2 Licensee Event Report 2025-003-00 Joseph M. Farle> Nuclear PIJnl 7388 N011h State H" > 95 Columbia, Alabama ~6319 3.'4.661.2101 td
.B4.661.25 I'.!
fox JCARROLL@southemco.com NL-25-0307 Automatic Reactor Trip Due to Low Steam Generator Level Ladies and Gentlemen:
In accordance with the requirements of 10 CFR 50.73(a)(2)(iv}(A), Southern Nuclear Company is submitting the enclosed Licensee Event Report for Unit 2.
This letter contains no NRC commitments. If you have any questions regarding this submittal, please contact Mandy Ludlam, Licensing Engineer, at (334) 661-2668.
Respectfully submitted, Vice President - Farley JC/mml/cbg Enclosure: Unit 2 Licensee Event Report 2025-003-00 Cc:
Regional Administrator, Region II NRR Project Manager - Farley Nuclear Plant Senior Resident Inspector-Farley Nuclear Plant RTYPE: CFA04.054
Joseph M. Farley Nuclear Plant - Unit 2 Licensee Event Report 2025-003-00 Automatic Reactor Trip Due to Low Steam Generator Level Enclosure Unit 2 Licensee Event Report 2025-003-00
RC FORM 36 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 04/30/2027 4-0 -2
- 4)
- 2. DOCKET NUMBER
- 3. LER NUMBER 364 I
YEAR SEQUENTIAL REV NUMBER NO.
~-I 003 1-~
On June 19, 2025, at 2027 CDT while in Mode 1 and at 100% power, an automatic reactor trip occurred on Unit 2 upon low water level in the "A" Steam Generator [EIIS: AB/SG] due to the 2A Feedwater [EIIS: SJ] Flow Control Valve (FCV) [EIIS:
FCV] failing closed.
EVENT ANALYSIS AND CAUSE The 2A FCV had been procured new and installed on April 18, 2025, during the previous outage. Investigation determined that the newly installed 2A FCV was assembled by the vendor using incorrect torque values for the actuator (Manufacturer:
Fisher, Model: 667-80) top hat casing nuts, and the internal diaphragm nut was found hand-tight instead of 400 foot-pounds, as required. Improper torquing resulted in a tear in the internal diaphragm, and the valve failed closed on a loss of air.
Improper torquing was determined to be caused by inadequate oversight to ensure enhanced procurement requirements.
REPORTABILITY AND SAFETY ASSESSMENT
There were no safety consequences as a result of this event. The operating crew responded appropriately to the event. The event was within the analysis of the Updated Final Safety Analysis Report (UFSAR) Chapter 15. This event is reportable per 10 CFR 50.73(a)(2)(iv)(A) due to the automatic actuation of multiple systems listed in 10 CFR 50.73(a)(2)(iv)(B), including the Reactor Protection System (RPS) [EIIS: IG] and Auxiliary Feedwater (AFW) [EIIS: BA]. Unit 1 was not affected during this event.
CORRECTIVE ACTIONS PLANNED OR COMPLETED
The 2A FCV actuator was rebuilt and installed, and as-left torque values were in accordance with applicable procedures.
Unit 2 exited the forced outage on June 23, 2025. Increased observations of new item request forms will be performed, and procedure revisions to specify oversight responsibilities are planned.
PREVIOUS SIMILAR EVENTS
There were no events from the last ten years with the same or similar cause as this event. Page 2
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