ENS 57844

v t e ENS Event
21:44 Jul 31, 2025
Title	Both Trains of Control Room Emergency Ventilation/Control Room Emergency Temperature System Inoperable
Event Description	The following information was provided by the licensee via phone and email: At 1744 EDT, on 7/31/2025, it was discovered both trains of control room emergency ventilation (CREVS) and control room emergency temperature system (CRETS) were simultaneously inoperable due to a damper going shut in the control room ventilation system. The damper went back to its normal open position in less than a minute. Due to this inoperability, the system was in a condition that could have prevented the fulfillment of a safety function; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(D). 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: Multiple technical specification limiting conditions for operation (LCOs) such as LCO 3.0.3, 3.7.8, and 3.7.9 were entered as a result of this event.

ENS 57844 +/-
Where
Calvert Cliffs Maryland (NRC Region 1)
Reporting

10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident
Time - Person (Reporting Time:+2.25 h0.0938 days <br />0.0134 weeks <br />0.00308 months <br />)
Opened:	Kerry Hummer 23:59 Jul 31, 2025
NRC Officer:	Tenisha Meadows
Last Updated:	Aug 1, 2025
57844 - NRC Website Loading map...
v • d • e

v t e Emergency Notification System
Calvert Cliffs with 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident
WEEKMONTHYEAR2025-07-31T21:44:00 [Table view]
[ENS list for Calvert Cliffs]

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