05000458/LER-2022-001, Condition Prohibited by Technical Specifications Due to Residual Heat Removal B Pump Motor Bearing Oil Leak
| ML22137A035 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 05/17/2022 |
| From: | Karenina Scott Entergy Nuclear Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RBG-48172 LER 2022-01-00 | |
| Download: ML22137A035 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| 4582022001R00 - NRC Website | |
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5) entergy RBG-48172 Kent Scott Sile Vice President 225-381-437 4 10 CFR 50.73 May 17, 2022 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
Subject:
Licensee Event Report 50-458 / 2022-01-00, "Condition Prohibited by Technical Specifications due to Residual Heat Removal B Pump Motor Bearing Oil Leak" River Bend Station - Unit 1 NRC Docket Nos. 50-458 Renewed Facility Operating License No. NPF-47 In accordance with 10 CFR 50. 73, enclosed is the subject Licensee Event Report. This document contains no commitments.
Should you have any questions, please contact Mr. Tim Schenk, Regulatory Assurance Manager, at 225-381-4177.
Respectfully, KCS/dmw
Enclosure:
cc:
Licensee Event Report 50-458 / 2022-01-00, "Condition Prohibited by Technical Specifications due to Residual Heat Removal B Pump Motor Bearing Oil Leak" NRC Region IV Regional Administrator - Region IV NRC Senior Resident Inspector - River Bend Station NRC Project Manager - River Bend Station Entergy Nuclear Operations, Inc., River Bend Station, 5485 U.S. Highway 61, St. Francisville, LA 70775
Enclosure RBG-48172 Licensee Event Report 50-458 I 2022-01-00, "Condition Prohibited by Technical Specifications due to Residual Heat Removal B Pump Motor Bearing Oil Leak" Entergy Nuclear Operations, Inc., River Bend Station, 5485 U.S. Highway 61, St. Francisville, LA 70775
Abstract
On March 29, 2022, at 19:00 Central Time (CT) with River Bend Station, Unit 1 operating at 100% power, Residual Heat Removal Pump B was declared inoperable due to an oil leak from the motor lower bearing sight glass that would have prevented the motor from fulfilling its mission time.
The Residual Heat Removal Pump B motor lower bearing sight glass oil leak was caused by improper installation of the sight glass O-ring on March 14, 2022, when the sight glass O-ring was replaced during the performance of a preventative maintenance work order. The leak was discovered on March 18, 2022.
The oil leak was corrected by replacing the sight glass assembly and O-ring on March 30, 2022.
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EVENT DESCRIPTION
On 03/29/2022, at 1900 Central Time (CT) with River Bend Station, Unit 1 operating at 100% power, Residual Heat Removal Pump 8 (RHR 8) [BO] was declared inoperable when it was confirmed that the leakage rate from the motor lower bearing oil reservoir would prevent RHR 8 from meeting its mission time.
The oil leak began following sight glass O-ring replacement performed on 03/14/2022. An oil leak was identified in condition reports on 03/18/2022 and 03/26/2022. In both cases, the oil level was low, but above the minimum required level and oil additions were made to bring the level up to the standstill mark.
An analysis performed on 03/29/2022 determined that the identified leakage would not have supported the mission time of RHR 8.
On 03/30/2022, a new sight glass assembly and O-ring were installed. Engineering verified that the installation and post maintenance test were both satisfactory.
RHR 8 was determined to be inoperable from the time of the original sight glass O-ring replacement on 03/14/2022 until the sight glass assembly and O-ring was replaced and re-tested satisfactorily on 03/30/2022. This resulted in inoperability for a time longer than allowed by Technical Specifications. There is no record of an oil leak prior to maintenance performed on 03/14/2022.
This condition is being reported as an operation or condition prohibited by Technical Specifications in accordance with 10 CFR
- 50. 73(a)(2)(i)(B).
SAFETY ASSESSMENT
The actual consequence of this event was the potential inability of RHR B to fulfill its mission time following a Design Basis Accident.
Residual Heat Removal Pump A (RHR A) [BO] was Operable for the duration of this event; therefore, this event was of minimal significance to the health and safety of the public.
EVENT CAUSE
The direct cause of this event was improper installation of the sight glass O-ring during the performance of preventative maintenance.
CORRECTIVE ACTIONS
Complete:
The condition was corrected by replacing the sight glass assembly and O-ring on 03/30/2022.
Planned Actions tracked in the Corrective Action Program:
Update all affected ECCS model work orders for sight glass and O-ring replacement to include further guidance to prevent future occurrences.
Adjust the scope of the preventative maintenance work orders for sight glass and O-ring replacement to reflect the manufacturer recommendations.
Timeliness of identification, evaluation, and resolution of this condition are being driven to resolution by individual condition reports within the Corrective Action Process.
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