View source for 05000348/LER-2025-001, Nuclear Plant, Unit 1 and 2, Emergency Diesel 1C Unable to Achieve 110% of Maximum Load

{{Adams
| number = ML25287A034
| issue date = 10/14/2025
| title = Nuclear Plant, Unit 1 and 2, Emergency Diesel 1C Unable to Achieve 110% of Maximum Load
| author name = Berry E
| author affiliation = Southern Nuclear Operating Co, Inc
| addressee name = 
| addressee affiliation = NRC/NRR, NRC/Document Control Desk
| docket = 05000348, 05000364
| license number = 
| contact person = 
| case reference number = NL-25-0382
| document report number = LER 2025-001-00
| document type = Letter, Licensee Event Report (LER)
| page count = 1
}}
{{LER
| Title = Nuclear Plant, Unit 1 and 2, Emergency Diesel 1C Unable to Achieve 110% of Maximum Load
| Plant = 
| Reporting criterion = 10 CFR 50.73(a)(2)(i)(B)
| Power level = 
| Mode = 
| Docket = 05000348
| LER year = 2025
| LER number = 1
| LER revision = 0
| Event date = 
| Report date = 
| ENS = 
| abstract = 
}}

=text=
{{#Wiki_filter:>-, Southern Nuclear October 14, 2025 Docket No.:
50-348 50-364 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Earl Berry Vice President - Farley Joseph M. Farley Nuclear Plant Unit 1 & 2 Licensee Event Report 2025-001-00 Joseph M. Farley Nuclear Plant 7388 North State Hwy 95 Columbia, Alabam11 36319 334.661.2100 tel 334.661 2512 fax EBcny(@southcrnco.com NL-25-0382 Emergency Diesel 1 C Unable to Achieve 110% of Maximum Load Ladies and Gentlemen:
In accordance with the requirements of 10 CFR 50.73(a)(2)(i)(B), Southern Nuclear Company is submitting the enclosed Licensee Event Report for Unit 1 & 2. The enclosed LER describes a condition which was prohibited by Technical Specifications.
This letter contains no NRC commitments. If you have any questions regarding this submittal, please contact Gene Surber, Licensing Manager, at (334) 661-2265.
ROflZmitted, EarlBerry ~
Vice President - Farley EB/rgs/cbg Enclosure: Unit 1 & 2 Licensee Event Report 2025-001-00 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 1 & 2 Licensee Event Report 2025-001-00 Emergency Diesel 1C Unable to Achieve 110% of Maximum Load Enclosure Unit 1 & 2 Licensee Event Report 2025-001-00 

=Abstract=
On August 13, 2025, at approximately 2126 CDT with Unit 1 and Unit 2 in Mode 1 at 100% power the 1C Emergency Diesel Generator (EOG) was unable to be loaded to 3100 kilowatts (kW) as required by Surveillance Requirement (SR) 3.8.1.12 (24 hour run). The 1C EOG can be aligned to Farley Nuclear Plant (FNP) Unit 1 or Unit 2.
During the 24 hour run, SR 3.8.1.12 requires operating the 1 C EOG at a load greater than or equal to 110% (3100 kW) capacity for a time of greater than two hours of the 24 hour requirement. When operators were adding the additional load to the 1 C EOG, the generator was only capable of reaching 2950 kW. Per SR 3.0.1 failure to meet the SR means the Limiting Condition of Operation (LCO) is not met. FNP operators declared the 1C EOG inoperable.
It was determined that during the 1 C EOG outage in October of 2024 that the EOG governor linkage was removed and re-installed to the fuel rack. The fuel rack was found limited in movement by the governor linkage preventing further loading.
The 1 C EOG governor linkage was corrected and the 1 C EOG successfully completed post maintenance testing on August 14, 2025, and was declared operable.
Plant Conditions / Event Description:
: 2. DOCKET NUMBER I
348
: 3. LER NUMBER SEQUENTIAL NUMBER 001 REV NO.
1-G On August 13, 2025, at approximately 2126 CDT, with Farley Nuclear Plant (FNP) Unit 1 and Unit 2 in Mode 1 at 100%
power, the 1C Emergency Diesel Generator (EOG) [EIIS: DC/ DG] was unable to reach a load of 3100 kilowatts (kW) during the Technical Specification (TS) Surveillance Requirement (SR) 3.8.1.12 (24 hour run). The 1C EOG can be aligned to Farley Nuclear Plant (FNP) Unit 1 or Unit 2 thus both units were affected. 

==Event Analysis==
During the 24 hour run, SR 3.8.1.12 requires operating the 1 C EOG [Manufacturer: Fairbanks Morse] at a load of 2850 kW or higher. The SR also requires that the 1 C EOG run loaded greater than or equal to 3100 kW for a time of greater than two hours of this 24 hour requirement. When operators were adding the additional load to the 1 C EOG the diesel generator was only capable of reaching 2950 kW. FNP operators declared the 1 C EOG inoperable due to failure to meet the SR.
Reportability and Safety Assessment:
Per SR 3.0.1, failure to meet the SR means the Limiting Condition of Operation (LCO) is not met. Since the LCO for Technical Specification 3.8.1 was not met, FNP had been in a condition prohibited by TS since October 25, 2024. The event was within the analysis of UFSAR Chapter 15 and is reportable per 10 CFR 50.73(a)(2)(i)(B) for the 1 C EOG being inoperable for longer than allowed by TS 3.8.1. The Safety Function was met as the 1 C EOG provides loads for Loss of Offsite Power (LOSP) which was met by meeting 100% load demand of 2850 kW. 

==Cause(s)==
It was determined that during the 1 C EOG outage in October of 2024 that the EOG governor linkage was removed and re-installed to the fuel rack. Following the August 13, 2025, run of the 1 C EOG, the investigation found that the fuel rack was limited in movement by the governor linkage preventing further loading. It was determined that the FNP PMT guidance did not require a PMT of 110% (3100 kW) capacity upon the replacement of the fuel injector pump. Additionally, maintenance procedures did not require a 110% loaded run upon the adjustment or replacement of equipment that could adversly impact EOG performance criteria.
Corrective Actions Planned/ Completed:
The 1C EOG governor linkage was corrected and the 1C EOG successfully completed PMT on August 14, 2025, and was declared operable.
Fleet and site procedures are being revised to ensure 110% load PMT occurs when work is performed on systems that affect combustion engine performance. Revisions are being tracked in the site's Corrective Action Program.
An extent of condition was performed on all 4 remaining diesel generators which determined the same condition did not exist. 

==Previous Similar Events==
No known previous events. Page 2
of 2
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