ENS 49571

v t e ENS Event
21:41 Nov 21, 2013
Title	Low Casing Cooling System Tank Level Potentially Causes Loss of Npsh to Outside Recirculation Spray Pumps
Event Description	The Casing Cooling system at North Anna Power Station (NAPS) Units 1 and 2 provides cold, borated water to the suction of the Outside Recirculation Spray (ORS) pumps to increase net positive suction head (NPSH) following the initiation of a Containment Depressurization Actuation (CDA). As Casing Cooling tank level decreases to the isolation setpoint, it has been determined that vortexing/air entrainment may occur. This air would then enter the suction of the ORS pumps and potentially cause degradation in design flow and/or loss of NPSH. As a result, this constitutes an event or condition that could have prevented fulfillment of a safety function and is reportable per 50.72(b)(3)(v). A prompt operability determination is in progress that should restore the function of the recirculation spray system. The licensee has notified the NRC Resident Inspector. The licensee will be notifying the Louisa County Administration in the morning.

ENS 49571 +/-
Where
North Anna Virginia (NRC Region 2)
Reporting

10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident
Time - Person (Reporting Time:+0 h0 days <br />0 weeks <br />0 months <br />)
Opened:	Bob Page 21:41 Nov 21, 2013
NRC Officer:	Jeff Rotton
Last Updated:	Nov 21, 2013
49571 - NRC Website
v • d • e

v t e Emergency Notification System
North Anna with 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident
WEEKMONTHYEAR2015-10-08T01:47:00 [Table view]
[ENS list for North Anna]

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