ENS 46816

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v t e ENS Event
15:18 Mar 7, 2011
Title	Invalid Actuation of the Auxiliary Feedwater System
Event Description	On March 7, 2011 at 1118 hours0.0129 days <br />0.311 hours <br />0.00185 weeks <br />4.25399e-4 months <br /> with Beaver Valley Power Station Unit 2 in Mode 5 during a scheduled refueling outage an invalid actuation of the Auxiliary Feedwater (AFW) System occurred. Instrumentation & Control (I&C) technicians were using a procedure to place simulated signals in two out of three channels of the narrow range level indication on all three steam generators (SG). During this activity, I&C technicians repositioned the input test relays to the test position on both channel 1 and channel 2 in two out of three SGs before inserting the simulated signals. This action resulted in a zero level input to the SG level circuits in two out of three SGs. An Engineered Safety Feature Actuation System (ESFAS) actuation signal for the Auxiliary Feedwater (AFW) System was generated based on having a two out of three low-low level signal in at least one SG (starts turbine driven AFW pump) and subsequently having a two out of three steam generators low-low level signal in at least two SGs (starts motor driven AFW pumps). The AFW initiation signal resulted in a successful automatic start of both the Train A and Train B motor driven AFW pumps. The AFW pump discharge flow control valves were closed per procedure prior to this event, so the motor driven AFW pumps operated on 100% recirculation flow following their automatic start. The turbine driven AFW pump did not start since steam pressure was not present in the main steam lines due to the plant being in Mode 5. A Reactor Protection Signal (RPS) signal was also generated due to having a two out of three low-low level signal in at least one SG. The RPS actuation signal did not result in opening of the reactor trip breakers since the breakers were previously opened as part of the plant shutdown procedures. The reactor control rods had been fully inserted into the reactor core prior to this event. Plant operators took appropriate actions to secure AFW flow after determining that the actuation was invalid and the issue was entered into the corrective action program for evaluation. The initiation of an ESFAS and RPS actuation signal, due to a SG low-low level signal, was not in response to any valid system or plant condition. There was no event, transient or condition that required any type of mitigation in Mode 5. Plant equipment responded as expected based on the conditions prior to the event. 'The invalid actuation of the AFW system is reportable pursuant to 10 CFR 50.73(a)(2)(iv)(A) since it involved an actuation of a PWR auxiliary feedwater system train per 10 CFR 50.73(a)(2)(iv)(B)(6). Per 10 CFR 50.73(a)(2)(iv)(A)(2)(ii), the actuation of the RPS due to a SG low-low signal is not reportable since the actuation was invalid and occurred after the safety function had already been completed (i.e. the RPS actuation occurred after the control rods had already been inserted in the core). Pursuant to 10 CFR 50.73(a)(1), this event is being reported via this telephone notification, in lieu of a written Licensee Event Report, since the automatic actuation of both trains of AFW was invalid. The licensee has notified the NRC Resident Inspector.

ENS 46816 +/-
Where
Beaver Valley Pennsylvania (NRC Region 1)
Reporting

10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation
Time - Person (Reporting Time:+1388.12 h57.838 days <br />8.263 weeks <br />1.901 months <br />)
Opened:	David Haser 10:25 May 4, 2011
NRC Officer:	Howie Crouch
Last Updated:	May 4, 2011
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v • d • e

v t e Emergency Notification System
Beaver Valley with 10 CFR 50.73(a)(1), Submit an LER
WEEKMONTHYEAR2021-09-30T14:07:00 [Table view]
[ENS list for Beaver Valley]

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