ENS 58068

v t e ENS Event
15:13 Oct 6, 2025
Title	60-DAY Optional Telephonic Notification of Invalid Specified System Actuation
Event Description	The following information was provided by the licensee via phone and email: At 0913 CDT, on October 6, 2025, a partial actuation of the division 1 emergency diesel generator (DG1) occurred during the performance of the 4160-volt bus 1F undervoltage relay channel functional test. The DG1 automatic start in the emergency mode was the result of the inadvertent contact between a jumper and another component. However, due to the test configuration, the output breaker for DG 1 did not close and pick up the load of the 4160-volt bus 1F since no actual undervoltage condition was present. DG1 components functioned as expected in response. Following the actuation, DG1 was restored to a standby lineup in accordance with plant procedures. This event is considered an invalid system actuation reportable under 10 CFR 50.73(a)(2)(iv)(A). The actuation was not initiated in response to actual plant conditions or parameters and was not a manual initiation. Therefore, in accordance with 10 CFR 50.73(a)(1), this telephone notification is provided within 60 days after discovery of the event instead of submitting a written licensee event report. The NRC Resident lnspector has been notified.

ENS 58068 +/-
Where
Cooper Nebraska (NRC Region 4)
Reporting

10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation
Time - Person (Reporting Time:+1368.7 h57.029 days <br />8.147 weeks <br />1.875 months <br />)
Opened:	Brian Stander 16:55 Dec 2, 2025
NRC Officer:	Kerby Scales
Last Updated:	Dec 2, 2025
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v • d • e

v t e Emergency Notification System
Cooper with 10 CFR 50.73(a)(1), Submit an LER
WEEKMONTHYEAR2025-10-06T15:13:00 [Table view]
[ENS list for Cooper]

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