05000416/LER-2025-002, Automatic Emergency Diesel Generator Actuation Caused by Grid Transient
| ML25133A192 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 05/13/2025 |
| From: | Hardy J Entergy Operations |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| GNRO2025-00015 LER 2025-002-00 | |
| Download: ML25133A192 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 4162025002R00 - NRC Website | |
text
E) entergy GNRO2025-00015 May 13, 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 2025-002-00, Automatic Emergency Diesel Generator Actuation Caused by Grid Transient Grand Gulf Nuclear Station, Unit 1 Docket No. 50-416 Renewed License No. NPF-29 Attached is Licensee Event Report (LER) 2025-002-00, Automatic Emergency Diesel Generator Actuation Caused by Grid Transient. This report is being submitted in accordance with 10 CFR 50.73(a)(2)(iv)(A), for any event that resulted in automatic actuation of an emergency diesel generator.
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, GA ~0--
JAH/saw Attachments: Licensee Event Report 2025-002-00
GNRO2025-00015 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
GNRO2025-00015 Page 3 of 3 Attachment Licensee Event Report 2025-002-00
Abstract
On March 15, 2025, Grand Gulf Nuclear Station (GGNS), Unit 1 was in MODE 1 at 100 percent power with all safety systems operable. At 12:48 CDT, a grid transient caused the 17AC breaker to trip open. In response, the division Ill emergency diesel generator automatically started and repowered the 17 AC safety-related electrical bus as designed.
The grid transient was caused by degraded voltage of the offsite grid. The 17 AC breaker was successfully closed after the grid transient with no further issues.
No other safety systems actuated, and no radiological release occurred. All remaining offsite power sources remained energized.
This report is being made in accordance with 10 CFR 50.73(a)(2)(iv)(A) for any event that resulted in automatic actuation of an emergency diesel generator.
Plant Conditions
Estimated b'urden 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 NRG 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. LEA NUMBER SEQUENTIAL NUMBER 002 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 March 15, 2025, at 12:48 CDT, a grid transient caused the 17AC breaker to trip open. In response, the division Ill emergency diesel generator (EOG) automatically started and repowered the 17 AC safety-related electrical bus as designed.
No other safety systems actuated, and no radiological release occurred. All remaining offsite power sources remained energized.
Reportability
This report is being made in accordance with 10 CFR 50.73(a)(2)(iv)(A) for any event that resulted in automatic actuation of an emergency diesel generator.
Cause(s)
A degraded voltage of the offsite grid caused the event to occur.
Corrective Actions
Completed Actions:
After the grid transient passed, the 17 AC offsite source feeder breaker was successfully closed in and the division Ill EOG was secured with no further issues.
Safety Significance
There were no actual safety consequences associated with this condition. Plant systems responded as designed and the plant remained at 100 percent power.
Previous Similar Events
None identified. Page 2 of 2