ENS 58109

v t e ENS Event
13:48 Nov 12, 2025
Title	Invalid Specified System Actuation
Event Description	The following information was provided by the licensee via phone and email: This report is being made in accordance with 10 CFR 50.73(a)(2)(iv)(A), using the telephone option in 10 CFR 50.73(a)(1) in lieu of a written licensee event report, concerning an event in which Callaway experienced an automatic actuation of the auxiliary feedwater (AFW) system in response to invalid AFW actuation signals. The reactor protection system was not involved. A low suction pressure signal was also received which aligned the AFW pumps to essential service water. An unknown amount of water from the ultimate heat sink entered the steam generators, necessitating a plant shutdown after secondary water chemistry program action levels were exceeded. This AFW actuation was complete and the AFW system started and functioned successfully in accordance with the initiating actuation signals. This actuation occurred at 0748 CST on November 12, 2025, and was reported (and later retracted) as event notification 58035. The most probable cause of the actuations was the intermittent failure of a 15V DC logic power supply within engineered safety features actuation system logic cabinet SA036D. The power supply was replaced.

ENS 58109 +/-
Where
Callaway Missouri (NRC Region 4)
Reporting

10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation
Time - Person (Reporting Time:+1323.4 h55.142 days <br />7.877 weeks <br />1.813 months <br />)
Opened:	Trevor Gladback 17:12 Jan 6, 2026
NRC Officer:	Ernest West
Last Updated:	Jan 6, 2026
58109 - NRC Website Loading map...
v • d • e

v t e Emergency Notification System
Callaway with 10 CFR 50.73(a)(1), Submit an LER
WEEKMONTHYEAR2025-11-12T13:48:00 [Table view]
[ENS list for Callaway]

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