ENS 58035: Difference between revisions

v t e ENS Event
13:48 Nov 12, 2025
Title	Actuation of Auxiliary Feedwater System
Event Description	The following information was provided by the licensee via phone and email: At 0748 CST, on November 12, 2025, Callaway Plant experienced an automatic actuation of the auxiliary feedwater (AFW) system in response to auxiliary feedwater actuation signals (AFAS). A low suction pressure signal was also received which aligned the AFW pumps to essential service water (ESW). An unknown amount of water from the ultimate heat sink (UHS) entered the steam generators, necessitating a plant shutdown due to exceeding secondary water chemistry program action levels. During the shutdown, with the plant at approximately 28 percent power, high vibration was received on the main turbine, requiring a manual turbine trip. The cause of the AFAS is not yet known. The plant is currently stable in mode 3. This condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: Decay heat is being removed via steam dump valves to the main condenser.

ENS 58035 +/-
Where
Callaway Missouri (NRC Region 4)
Reporting

10 CFR 50.72(b)(3)(iv)(A), System Actuation
Time - Person (Reporting Time:+2.23 h0.0929 days <br />0.0133 weeks <br />0.00305 months <br />)
Opened:	Daniel Mueller 16:02 Nov 12, 2025
NRC Officer:	Ian Howard
Last Updated:	Nov 12, 2025
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v • d • e

v t e Emergency Notification System
Callaway with 10 CFR 50.72(b)(3)(iv)(A), System Actuation
WEEKMONTHYEAR2025-11-12T13:48:00 [Table view]
[ENS list for Callaway]

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 The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
 Decay heat is being removed via steam dump valves to the main condenser.
-| URL = https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2025/20251113en.html#en58035
+| URL = https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2025/20251114en.html#en58035
 }}{{unit info
 | Unit = 1

Revision as of 07:20, 14 November 2025