05000458/LER-2025-004, Unsecured Pressure Boundary Door Resulting in Condition That Could Have Prevented Fulfillment of a Safety Function
| ML25259A219 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 09/16/2025 |
| From: | Mccoy J Entergy Operations |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| RBG-48374 LER 2025-004-00 | |
| Download: ML25259A219 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 4582025004R00 - NRC Website | |
text
- ) entergy RBG-48374 September 16, 2025 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Jack McCoy Manager Regulatory and Emergency Planning River Bend Station 225-381-3310 10 CFR 50.73
Subject:
Licensee Event Report 50-458 / 2025-004-00, Unsecured Pressure Boundary Door Resulting in Condition That Could Have Prevented Fulfillment of a Safety Function River Bend Station - Unit 1 N RC 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. Jack McCoy, Regulatory and Emergency Planning Manager, at 225-381-3310.
Respectfully, Jack McCoy JM/hpk
Enclosure:
cc:
Digitally signed by Jack McCoy ON: cn=Jack McCoy, o=REP Manager, ou=RBS, email=jmccoy1@entergy.com Date: 2025.09.16 12:38:48 -05'00' Licensee Event Report 50-458 / 2025-004-00 NRC Region IV Regional Administrator - Region IV NRC Senior Resident Inspector - River Bend Station NRC Office of Nuclear Security and Incident Response Entergy Operations, Inc., 5485 U.S. Highway 61N. St. Francisville, LA 70775
Enclosure RBG-48374 Licensee Event Report 50-458/2025-004-00
Abstract
On July 21, 2025, at 1548 CDT, River Bend Station, Unit 1 (RBS) was operating in Mode 1 at 100% reactor power when the Central Alarm Station (CAS) received a door alarm indicating that an auxiliary building pressure boundary door, PW 123-01 (T-Tunnel Access to 114' Aux West Access), was not fully secured. A security officer was dispatched and found the door closed with the dogs not engaged. PW 123-01 is a Secondary Containment door. With the dogs not engaged, Secondary Containment was declared inoperable.
At 1551 CDT, a security officer fully engaged the dogs, which restored Secondary Containment.
This event is reportable in accordance with 10 CFR 50.73(a)(2)(v)(C), as any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to control the release of radioactive material.
Event Description
- 2. DOCKET NUMBER YEAR 00458 2025
- 3. LER NUMBER SEQUENTIAL NUMBER 004 REV NO.
00 On July 21, 2025, at 1548 CDT, River Bend Station, Unit 1 (RBS) was operating in Mode 1 at 100% reactor power when the Central
~larm Station (CAS) received a door alarm indicating that an auxiliary building [NF] pressure boundary door [DR], PW 123-01 (T-rrunnel Access to 114' Aux West Access), was not fully secured. A security officer was dispatched and found the door closed with the dogs not engaged. PW 123-01 is a Secondary Containment door. With the dogs not engaged, Secondary Containment was declared inoperable.
~t 1548 CDT, Technical Specifications (TS) Limiting Condition for Operation (LCO) 3.6.4.1 Condition A, Secondary Containment inoperable was entered. When the security officer fully engaged the dogs at 1551 CDT, restoring Secondary Containment, LCO 3.6.4.1, Condition A, was exited.
rThe event was reported on July 21, 2025, at 2151 CDT in accordance with 10 CFR 50.72(b)(3)(v) for an event or condition that could have prevented fulfillment of a safety function due to the inoperability of Secondary Containment (EN 57820).
Event Cause
rThe direct cause of this event was a personnel error. PW123-01 was left unsecured because the individual passing through the door closed it but failed to fully engage the dogs.
Safety Assessment
rThe River Bend Updated Safety Analysis Report describes the sequence of events postulated to occur following a Loss of Coolant
~ccident (LOCA). Part of that analysis is a projection of the maximum radiation dose received by a person at the site boundary. The LOCA dose calculation assumes that the standby gas treatment system is initiated 20 minutes into the event, and that Secondary Containment is at the required negative pressure within 30 minutes, such that filtration may be credited. As such, the safety function of Secondary Containment is maintained as long as the boundary is secured (or capable of being secured) within 20 minutes of the
~ime of the security alarm. Since the subject door was secured within approximately 3 minutes of the time of the alarm, the safety
~unction of Secondary Containment was maintained. This event was of minimal significance with respect to the health and safety of
~he public. While the corresponding functions were declared inoperable from a TS perspective, functionality was maintained,
~herefore, this event is not considered a safety system functional failure.
Corrective Actions
Completed:
- - A Performance Analysis was utilized to evaluate if any training deficiencies exist that could have contributed to this event.
- - Verified Engineering Pre-Job Briefs include door management and traversing to work locations.
In Progress:
- - Performance management actions will be used to reinforce proper behaviors with the individual to prevent future errors.
Previous Occurrences
rrwo similar events were reported by RBS in LER 050/458-2013-002-00 and LER 050/458-2017-009-00. Both LERs document individual(s) failing to properly secure a door in the auxiliary building pressure boundary. The audible tamper alarms installed as a result of LER 2017-009-00, operated as designed. The tamper alarms are designed to be audible when the door is opened and extinguished upon closure. In the event described in this LER the door was closed but not properly latched. Page 2 of 2