05000416/LER-2025-005, Loss of Secondary Containment Due to Unsecured Roof Hatch
| ML25307A235 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 11/03/2025 |
| From: | Hardy J Entergy Operations |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| GNRO2025-01000 LER 2025-005-00 | |
| Download: ML25307A235 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 4162025005R00 - NRC Website | |
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entergy GNRO2025-01000 November 03, 2025 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Entergy Operations, Inc.
P.O. Box 756 Port Gibson, Mississippi 39150 Jeffery A. Hardy Manager Regulatory Assurance Grand Gulf Nuclear Station Tel: 802-380-5124 10 CFR 50.73
SUBJECT:
Grand Gulf Nuclear Station, Unit 1 Licensee Event Report 2025-005-00, Loss of Secondary Containment Due to Unsecured Roof Hatch Grand Gulf Nuclear Station, Unit 1 Docket No. 50-416 Renewed License No. NPF-29 Attached is Licensee Event Report (LER) 2025-005-00, Loss of Secondary Containment Due to Unsecured Roof Hatch. This report is being made in accordance with 10 CFR 50.73(a)(2)(v)(C) as a condition which could have prevented the fulfillment of the safety function of structures or systems that are needed to control the release of radioactive material.
This letter contains no new Regulatory Commitments. Should you have any questions concerning the content of this letter, please contact me at 802-380-5124.
Sincerely, JAH/der Attachments: Licensee Event Report 2025-005-00
GNRO2025-01000 Page 2 of 3 cc:
NRC Senior Resident Inspector Grand Gulf Nuclear Station Port Gibson, MS 39150 U.S Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001
GNRO2025-01000 Page 3 of 3 Attachment Licensee Event Report 2025-005-00
Abstract
On September 4, 2025, at 0855 CT while at 100 percent power Grand Gulf Nuclear Station (GGNS) Unit 1 staff discovered the Enclosure Building Roof Hatch was unsecured and slightly open which resulted in inoperability of secondary containment. The hatch had last been accessed at 0845 CT. After discovery, the hatch was secured, and secondary containment was restored.
A lack of proper oversight and failure of the watch team to properly understand their duty resulted in the Enclosure Building Roof Hatch becoming unsecured. Supervisor and paired observations will be periodically performed to prevent recurrence of the issue and an engineering barrier will be added to indicate when the hatch is open.
This report is being made in accordance with 10 CFR 50.73(a)(2)(v)(C) as a condition which could have prevented the fulfillment of the safety function of structures or systems that are needed to control the release of radioactive material.
Plant Conditions
Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />. Reported lessons learned are incorporated into the licensing process and fed back to industry. Send comments regarding burden estimate to the FOIA, Library, and Information Collection Branch (T-6 A10M), U.S.
Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to lnfocollects.Resource@nrc.gov, and the 0MB reviewer at: 0MB Office of Information and Regulatory Affairs, (3150-0104), Attn: Desk Officer for the Nuclear Regulatory Commission, 725 17th Street NW, Washington, DC 20503. The NRC may not conduct or sponsor, and a person is not required to respond to, a collection of information unless the document requesting or requiring the collection displays a currently valid 0 MB control number.
- 2. DOCKET NUMBER YEAR 00416 2025
- 3. LER NUMBER SEQUENTIAL NUMBER 005 REV NO.
00 At the time of the event, Grand Gulf Nuclear Station (GGNS) Unit 1 was in MODE 1 at 100 percent power, and all safety systems were operable.
Description of Event
On September 4, 2025, at 0855 CT, operators discovered the Enclosure Building Roof Hatch was unsecured and open by approximately one inch. This resulted in inoperability of secondary containment. Following the discovery, the hatch was immediately closed and latched, and secondary containment was restored to operability at 0940 CT. Based on available information the hatch had been last accessed at 0845 CT.
Reportability
This report is being made in accordance with 10 CFR 50.73(a)(2)(v)(C) as a condition which could have prevented the fulfillment of the safety function of structures or systems that are needed to control the release of radioactive material.
Cause(s)
Failure of the hatch watch to properly understand their duty and inadequate oversight by supervisors resulted in the Enclosure Building Roof Hatch becoming unsecured.
Corrective Actions
The Enclosure Building Roof Hatch was closed and secured.
Daily observations will be performed by supervisors to ensure that the hatch watch is properly fulfilling their functions.
Additional paired observations of roof hatch usage will be performed.
Engineering barrier will be developed to provide indication and alarm when the hatch is open.
Safety Significance
There were no actual safety consequences associated with this condition.
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