05000348/LER-2023-003, Emergency Diesel Generator (Eog) Lube Oil Pwnp Outlet Coupling Leak
| ML23341A206 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 12/07/2023 |
| From: | Dean E Southern Nuclear Operating Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| NL-23-0892 LER 2023-003-00 | |
| Download: ML23341A206 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3482023003R00 - NRC Website | |
text
A Southern Nuclear December 7, 2023 Docket Nos.: 50-348 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Regulatory Affairs Joseph M. Farley Nuclear Plant - Unit 1 Licensee Event Report 2023-003-00 3535 Colonnade Parkway Birmingham, AL 35243 205 992 5000 NL-23-0892 Unit 1 Emergency Diesel Generator Lube Oil Pump Outlet Coupling Leak Ladies and Gentlemen:
In accordance with the requirements of 10 CFR 50.73(a)(2)(i)(B), Southern Nuclear Operating Company is submitting the enclosed Licensee Event Report for Joseph M. Farley Nuclear Plant, Unit 1. The enclosed LER describes a condition with a support component of the emergency diesel that rendered it inoperable for longer than allowed by Technical Specification.
This letter contains no NRC commitments. If you have any questions regarding this submittal, please contact Gene Surber at (334) 661-2265.
Respectfully submitted, Edwin Dean 111 Vice President - Farley Nuclear Plant ED/alr/cbg Enclosure: Unit 1 Licensee Event Report 2023-003-00 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 1 Licensee Event Report 2023-003-00 Unit 1 Emergency Diesel Generator Lube Oil Pump Outlet Coupling Leak Enclosure Unit 1 Licensee Event Report 2023-003-00
Abstract
On February 26, 2023 at 23:42, with Unit 1 in Mode 1 at 100 percent power, the 1 B Emergency Diesel Generator (EOG) circulating lube oil pump outlet coupling connection developed an oil leak resulting in the inoperability of the 1 B EOG.
The cause of the leak was inadequate restraints on the piping, which allowed movement of the piping and resulted in a failure of the lube oil pressure boundary by the piping separating from the coupling. An additional cause was determined to be inadequate troubleshooting from a similar issue which occurred on November 4, 2022.
To correct the issue, the existing lube oil pipe restraint for the 1 B EOG was modified, and a new additional restraint was installed. The condition was later eliminated with the implementation of rigid piping. The troubleshooting process deficiencies and implementation weaknesses were corrected by revisions to the procedures that clearly define roles, responsibilities and required documentation for issue response, troubleshooting and corrective actions addressing deficient conditions.
This event is reportable under 10 CFR 50.73(a)(2)(i)(B) due to the 1B EOG being Inoperable, which failed to meet the LCO in accordance with TS 3.0.1 and 3.8.1 between December 7, 2022, and March 3, 2023.
EVENT DESCRIPTION
- 2. DOCKET NUMBER 3, LER NUMBER I
MB D
NUMBER NO.
I YEAR SEQUENTIAL REV
- - 1 003 1-0 On February 26, 2023 at 23:42, with Unit 1 in Mode 1 at 100 percent power, the 1B Emergency Diesel Generator (EOG)
{EIIS Code: DG] circulating lube oil pump outlet coupling connection {EIIS Code: LL, CPLG] developed an oil leak when the 2 inch lube oil piping became separated at the Flexmaster coupling location resulting in the inoperability of the 1 B EOG. The cause of the leak was inadequate restraints on the piping, which allowed movement of the piping and resulted in a failure of the lube oil pressure boundary by the piping separating from the coupling.
EVENT ANALYSIS
The root cause analysis determined that the 1 B EOG lube oil leak was caused by inadequate restraints on piping adjacent to the circulating lube oil pump outlet Flexmaster coupling connection. The lack of adequate restraints allowed movement of the adjacent piping which resulted in a failure of the lube oil pressure boundary by the piping separating from the coupling. The 1B EDG Circulating Lube Oil Pump Discharge piping moved because the designed piping restraint was inadequate to prevent movement.
An additional cause was determined to be troubleshooting process deficiencies and implementation weaknesses that led to not identifying and correcting the 1 B EOG circulating lube oil system failure mode in November 2022. The February event was the second failure involving the 1 B EDG coupling connection. The original leak occurred on November 4, 2022, following the replacement of a flexible coupling on the 1 B EOG as part of a new preventive maintenance (PM) activity during an equipment outage. During the return to service maintenance run, the circulating lube oil pump discharge coupling separated from the oil piping causing in an oil leak. The station leaders' oversight of the lube oil leak evaluation and resolution activities was less than adequate to identify and correct the coupling assembly failure.
REPORTABILITY AND SAFETY ASSESSMENT
As a result of the inadequate trouble shooting of the November 4, 2022 1 B EOG lube oil leak and coupling assembly separation, the 1 B EOG was vulnerable to initiating events which could adversely affect the ability to supply emergency power. From December 7, 2022 to March 3, 2023 while the plant was In the modes of Applicability, the 1B EOG was inoperable. Based on the availability of redundant onsite power, no loss of safety function occurred during the inoperability of the 1 B EOG.
This event is reportable under 10 CFR 50.73(a)(2)(i)(B) due to the 1B EOG being inoperable, which failed to meet the LCO in accordance with TS 3.0.1 and 3.8.1 between December 7, 2022, and March 3, 2023.
CORRECTIVE ACTIONS PLANNED OR COMPLETED
The following corrective actions were taken
- 1. In February 2023, the existing lube oil pipe restraint for the 1 B EOG was modified, and a new additional restraint was installed. The condition was eliminated in October 2023 with the implementation of rigid piping.
- 2. Troubleshooting process deficiencies and implementation weaknesses were corrected by revisions to the procedures that clearly define roles, responsibilities and required documentation for issue response, troubleshooting and corrective actions addressing deficient conditions.
PREVIOUS SIMILAR EVENTS
There were no events from the last three years with either the same or similar cause to this event. Page 2
of 2