05000382/LER-2025-002, Auxiliary Pressurizer Spray Train Inoperable Resulting in a Condition Prohibited by Technical Specifications
| ML25149A137 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 05/29/2025 |
| From: | Twarog J Entergy Operations |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| W3F1-2025-0024 LER 2025-002-00 | |
| Download: ML25149A137 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability |
| 3822025002R00 - NRC Website | |
text
John Twarog Manager Regulatory Assurance 504-739-6747 Entergy Operations, Inc., 17265 River Road, Killona, LA 70057 W3F1-2025-0024 10 CFR 50.73 May 29, 2025 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
Subject:
Licensee Event Report 50-382/2025-002-00, Auxiliary Pressurizer Spray Train Inoperable Resulting in a Condition Prohibited by Technical Specifications Waterford Steam Electric Station, Unit 3 NRC Docket No. 50-382 Renewed Facility Operating License No. NPF-38 Entergy Operations, Inc. (Entergy) submits the enclosed Licensee Event Report (LER) 50-382/2025-002-00 for Waterford Steam Electric Station, Unit 3 (WF3). The event reported herein is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B), Operation or Condition Prohibited by Technical Specifications.
This letter contains no new commitments.
Should you have any questions concerning this issue, please contact me at 504-739-6747.
Respectfully, John Twarog JRT/ahv Enclosure: LER 50-382/2025-002-00
W3F1-2025-0024 Page 2 of 3 cc:
NRC Region IV Regional Administrator NRC Senior Resident Inspector - Waterford Steam Electric Station, Unit 3 NRC Project Manager - Waterford Steam Electric Station, Unit 3 Louisiana Department of Environmental Quality
Enclosure W3F1-2025-0024 Licensee Event Report 50-382/2025-002-00
- 11. This Report is Submitted Pursuant to the Requirements of 10 CFR §:
(Check all that apply) 10 CFR Part 20 20.2203(a)(2)(vi) 10 CFR Part 50 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 73.1200(a) 20.2201(b) 20.2203(a)(3)(i) 50.36(c)(1)(i)(A) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 73.1200(b) 20.2201(d) 20.2203(a)(3)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A) 73.1200(c) 20.2203(a)(1) 20.2203(a)(4) 50.36(c)(2) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x) 73.1200(d) 20.2203(a)(2)(i) 10 CFR Part 21 50.46(a)(3)(ii) 50.73(a)(2)(v)(A) 10 CFR Part 73 73.1200(e) 20.2203(a)(2)(ii) 21.2(c) 50.69(g) 50.73(a)(2)(v)(B) 73.77(a)(1)(i) 73.1200(f) 20.2203(a)(2)(iii) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(C) 73.77(a)(2)(i) 73.1200(g) 20.2203(a)(2)(iv) 50.73(a)(2)(i)(B) 50.73(a)(2)(v)(D) 73.77(a)(2)(ii) 73.1200(h) 20.2203(a)(2)(v) 50.73(a)(2)(i)(C) 50.73(a)(2)(vii)
Other (Specify here, in abstract, or in NRC 366A).
Abstract
On March 31, 2025, at 1309 CDT, Charging Pump A tripped on low lube oil pressure 30 seconds after starting.
Charging Pump A was declared inoperable and Technical Specification (TS) 3.4.3.2 Action A and Technical Requirements Manual 3.1.2.4 Action A were entered. The condition was entered into the sites corrective action program and a subsequent evaluation completed on April 17, 2025, determined reasonable assurance of past operability could not be justified between February 23 and March 31, 2025. The period of inoperability resulted in a condition prohibited by TS; therefore, this report is being made in accordance with 10 CFR 50.73(a)(2)(i)(B). There is no corresponding requirement in 10 CFR 50.72 for this event.
The direct cause of the Charging Pump A trip was due to degraded packing in the lube oil pump which resulted in oil recirculating back to the oil sump. The failure was corrected by replacing the failed oil pump. Two contributing causes identified from the causal evaluation for this event: (1) Troubleshooting failed to fix the true cause of the equipment failure because the oil pump was not initially investigated when determined to be a probable cause and (2) The organization missed an opportunity to have a Failure Mode Analysis performed after multiple repeat equipment failures.
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Background===
Waterford Steam Electric Station, Unit 3 (WF3) has three charging pumps (A, B, and AB) [P] that make up part of the Chemical and Volume Control System (CVCS) [CB]. The purpose of the CVCS is to maintain the volume and makeup of water in the Reactor Coolant System (RCS) [AB]. The charging pumps are used to pressurize the RCS to design pressure and provide auxiliary pressurizer spray.
Technical Specification (TS) 3.4.3.2, Auxiliary Pressurizer Spray, specifies two auxiliary pressurizer spray trains shall be OPERABLE consisting of the following: at least two independent charging pumps shall be operable in MODES 1, 2, and 3.
TS 3.4.3.2 Action A, states, With only one of the above required auxiliary pressurizer spray trains OPERABLE, restore both trains to OPERABLE status within 30 days or be in HOT STANDBY with the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in HOT SHUTDOWN with the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
Event Description
On March 31, 2025, at 1309 CDT, in preparation for a charging pump pulsation dampener pressure check and lube oil sample on Charging Pump AB, Charging Pump A was started. Thirty seconds later Charging Pump A tripped on low lube oil pressure. Charging Pump A was declared inoperable and TS 3.4.3.2 Action A (Auxiliary Pressurizer Spray) and Technical Requirements Manual 3.1.2.4 Action A (Charging Pumps - Operating) were entered, and the condition was entered into the corrective action program. An Analysis Team determined replacement of the oil pump was required. During oil pump replacement activities, maintenance discovered the oil pump packing gland was damaged allowing oil to leak past the packing and back to the reservoir. The oil pump was replaced on April 1, 2025 and Charging Pump A was declared operable on April 8, 2025.
An engineering evaluation completed on April 17, 2025 determined that Charging Pump A had been inoperable since February 23, 2025, approximately 36 days. The duration of inoperability exceeded the allowable completion time specified in WF3s TS by six days, while in the Mode of Applicability, therefore, WF3 operated in a condition prohibited by TS.
The discovery time for the purpose of reporting this event is considered the time at which the engineering evaluation necessary to determine the impact to past operability was completed and approved (April 17, 2025).
Event Cause
The investigation identified the direct cause of the trip of Charging Pump A was due to degraded packing in the lube oil pump which resulted in oil recirculating back to the oil sump. Two primary causal factors leading to this event were; (1)
Troubleshooting failed to fix the true cause of the equipment failure and (2) The organization missed an opportunity to have a Failure Mode Analysis (FMA) performed after multiple repeat equipment failures.
Safety Assessment
There were no radiological, environmental, or industrial impacts associated with this event. The health and safety of the public and site personnel were not impacted during this event. At least one Charging Pump remained available during the period of inoperability to supply Auxiliary Pressurizer Spray.
Corrective Actions
Completed:
Charging Pump A oil pump replaced on April 1, 2025 24-hour run of Charging Pump A after oil pump replacementPage 3 of 3(04-02-2024)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 04/30/2027
LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing this form https://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
- 3. LER NUMBER Waterford Steam Electric Station, Unit 3 050 00382 YEAR SEQUENTIAL NUMBER REV NO.
052 2025 002 00 Planned:
Revise MM-006-021, Charging Pump Bravo and Alpha/Bravo Maintenance, and MM-006-215, Charging Pump Alpha Maintenance, to ensure the OE from troubleshooting described in CR-WF3-2025-00782 and CR-WF3-2025-01195 is captured, including a statement that for low lube oil pressure it may require allowing the charging pump to sit for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to ensure the charging pump can successfully restart.
Revise the maintenance guidelines in operating instruction, OI-037-000, Operations Risk Assessment Guideline, to include a prompt for Shift Managers to evaluate the need for performing a FMA to assist with resolution of emergent issues.
Share lessons learned to Site Duty Managers from recent emergent issues to include Refuel Outage 26 on how to effectively manage and drive emergent issues to resolution in accordance with EN-FAP-WM-107, Emergent Issues Process.
Previous Occurrences
The events below were opportunities to identify the degraded lube oil pump and investigate the issue beyond adjustment of lube oil pressure, filter and relief valve replacement.
September 15, 2024 - During operator rounds, Charging Pump A lube oil pressure was found to be 28 psig, which is below the acceptable range identified in the operator logs.
October 28, 2024 - Upon starting Charging Pump A for PME lubrication the field operator reported local oil pressure gauge pegged high.
December 16, 2024 - Charging Pump A tripped on low lube oil pressure upon starting.
January 31, 2025 - Charging Pump A tripped on low lube oil pressure upon starting.
February 4, 2025 - Charging Pump A tripped approximately 30 seconds after a start following performance of OP-904-007 on suspected low lube oil pressure.
March 3, 2025 - Charging Pump A tripped on low lube oil pressure upon starting.
March 31, 2025 - Charging Pump A tripped on low lube oil pressure upon starting.