ENS 46816
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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. |
| 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 |
| 46816 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Cold Shutdown (0 %) |
| After | Cold Shutdown (0 %) |
Beaver Valley with 10 CFR 50.73(a)(1), Submit an LER | |
WEEKMONTHYEARENS 556022021-09-30T14:07:00030 September 2021 14:07:00
[Table view]10 CFR 50.73(a)(1), Submit an LER 60-DAY Optional Telephonic Notification for an Invalid Emergency Diesel Generator Actuation ENS 468172011-03-15T21:16:00015 March 2011 21:16:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of the Standby Service Water Pump ENS 468162011-03-07T15:18:0007 March 2011 15:18:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of the Auxiliary Feedwater System ENS 450992009-05-06T17:52:0006 May 2009 17:52:00 10 CFR 50.73(a)(1), Submit an LER Automatic Actuation of Rps, Eccs and Edg Generated by an Invalid Actuation Signal ENS 450012009-04-20T05:53:00020 April 2009 05:53:00 10 CFR 50.73(a)(1), Submit an LER Unexpected Start of the Steam Driven Auxiliary Feedwater Pump During Plant Cooldown ENS 446612008-10-16T14:07:00016 October 2008 14:07:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Steam Driven Aux Feed Pump ENS 411192004-09-10T21:30:00010 September 2004 21:30:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Steam Driven Auxiliary Feedwater Pump 2021-09-30T14:07:00 | |
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