ENS 57629

v t e ENS Event
05:00 Mar 26, 2025
Title	Part 21 - Software Error in Transient Stability Program
Event Description	The following information was provided by Southern Nuclear Operating Company via email: This is a non-emergency notification required by 10 CFR 21.21(d)(3)(i). A written report in accordance with 10 CFR 21.21(d)(3)(ii) will be provided within 30 days. Based upon the information provided by Operation Technology, Inc. (OTI) in [electrical transient analyzer program] (ETAP) error report ERCA-24-003, revision 1, Southern Nuclear Operating Company (SNC) has determined that a substantial safety hazard could have been created by the error introduced in the transient stability program in the current release of ETAP software utilized at Edwin I. Hatch Nuclear Plant (HNP) and Vogtle Electric Generating Plant Units 1 and 2 (VEGP1-2) were it to go uncorrected. While the nature of the software error detailed by OTI in ETAP error report ERCA-24-003, revision 1 had the potential to impact bus transfers and degrade essential safety-related equipment, SNC has verified that none of the HNP or VEGP1-2 calculations that utilized the transient stability program had false favorable results. The NRC Senior Residents at HNP and VEGP1-2 have been notified. Affected plants: Hatch Nuclear Plant Units 1 and 2 Vogtle Electric Generating Plant Units 1 and 2

ENS 57629 +/-
Where
Hatch 1 And 2, Vogtle 1 And 2 Birmingham, Alabama (NRC Region 2)
Organization:	Southern Nuclear, Fleet Regulatory
Reporting

10 CFR 21.21(d)(3)(i), Failure to Comply or Defect
Time - Person (Reporting Time:+12.82 h0.534 days <br />0.0763 weeks <br />0.0176 months <br />)
Opened:	Catherine Galloway 17:49 Mar 26, 2025
NRC Officer:	Josue Ramirez
Last Updated:	Mar 26, 2025
57629 - NRC Website
v • d • e

v t e Emergency Notification System
Hatch 1 And 2, Vogtle 1 And 2 with 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect
WEEKMONTHYEAR2025-03-26T05:00:00 [Table view]
[ENS list for Hatch 1 And 2, Vogtle 1 And 2]

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