ENS 42120
ENS Event | |
|---|---|
21:08 Nov 4, 2005 | |
| Title | Temporary Loss of the Running Rhr Pump During a Bus Transfer |
| Event Description | PCIS Group 4 isolated during Reactor Protection Power Supply bus transfer. The isolation was not expected by control room operators prior to the power supply transfer. The isolation resulted in the trip of the running RHR pump.
Operators verified proper isolation and reset the power supply. Shutdown cooling was re-established. The total time out of service was 18 minutes. The time to boil was calculated to be 68 hours7.87037e-4 days <br />0.0189 hours <br />1.124339e-4 weeks <br />2.5874e-5 months <br /> prior to the event. The temperature at the RHR heat exchanger inlet at the beginning of the event was 90 degrees. The temperature at 22:20 was 92 degrees. The other RHR pump was available during this event. The plant is in refueling with the cavity flooded. The licensee notified the NRC Resident Inspector.
This notification updates the reporting criteria for Event No. 42120. The event was determined to not be reportable per 10CFR50.72 (b)(3)(iv)(A) since it was not due to a valid signal or the result of an intentional manual initiation. This report also satisfies the 60 day telephone notification provisions in 10CFR50.73 (a)(1). This notification is being made in accordance with 10CFR50.73 (a)(2)(iv)(A) due to an invalid Primary Containment Isolation System (PCIS) Group 4 actuation that impacted the availability of the Residual Heat Removal (RHR) shutdown cooling system. On November 4, 2005, with the reactor shutdown for refueling, an invalid actuation of PCIS Group 4 occurred during transfer of 'A' RPS Bus power supply. The actuation occurred because a breaker supplying power to the 'B' logic was tagged open resulting in completing the PCIS actuation logic. The Group 4 actuation resulted in a complete isolation of the single train RHR shutdown cooling suction path by isolation of RHR-17 and RHR -18 isolation valves. The shutdown cooling path was isolated for approximately 18 minutes and the time to boil was approximately 68 hours7.87037e-4 days <br />0.0189 hours <br />1.124339e-4 weeks <br />2.5874e-5 months <br /> at the time of the event. The licensee informed the NRC Resident Inspector. Notified R1DO (Barkley). |
| Where | |
|---|---|
| Vermont Yankee File:NorthStar Vermont Yankee icon.png Vermont (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1.2 h0.05 days <br />0.00714 weeks <br />0.00164 months <br />) | |
| Opened: | Michael Pletcher 22:20 Nov 4, 2005 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | Nov 17, 2005 |
| 42120 - NRC Website
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WEEKMONTHYEARENS 501642014-04-05T11:00:0005 April 2014 11:00:00
[Table view]10 CFR 50.73(a)(1), Submit an LER Invalid Primary Containment Isolation System Actuation ENS 498252013-12-15T05:00:00015 December 2013 05:00:00 10 CFR 50.73(a)(1), Submit an LER 60 Day Optional Telephone Notification of Invalid Pcis System Actuation ENS 493582013-07-23T04:00:00023 July 2013 04:00:00 10 CFR 50.73(a)(1), Submit an LER Invalid Primary Containment Isolation System Group 3 Actuation ENS 492112013-06-14T22:06:00014 June 2013 22:06:00 10 CFR 50.73(a)(1), Submit an LER Invalid Primary Containment Isolation System Actuation Due to a Radiation Monitor Spike ENS 475002011-10-11T21:29:00011 October 2011 21:29:00 10 CFR 50.73(a)(1), Submit an LER Loss of Vital Ac Power While Shutdown ENS 460702010-05-17T04:00:00017 May 2010 04:00:00 10 CFR 50.73(a)(1), Submit an LER 60 Day Report - Invalid Actuation of Hpci and Rcic Systems ENS 450092009-03-24T17:26:00024 March 2009 17:26:00 10 CFR 50.73(a)(1), Submit an LER Primary Containment Isolation System (Pcis) Group 3 Invalid Actuation ENS 437292007-09-15T04:00:00015 September 2007 04:00:00 10 CFR 50.73(a)(1), Submit an LER Invalid Primary Containment Isolation ENS 421202005-11-04T21:08:0004 November 2005 21:08:00 10 CFR 50.73(a)(1), Submit an LER Temporary Loss of the Running Rhr Pump During a Bus Transfer ENS 422352005-11-03T00:01:0003 November 2005 00:01:00 10 CFR 50.73(a)(1), Submit an LER Inadvertent Containment Isolation Signal Affecting Containment Isolation Valves ENS 410042004-07-31T17:56:00031 July 2004 17:56:00 10 CFR 50.73(a)(1), Submit an LER Invalid Pcis Actuation ENS 403712003-10-31T05:00:00031 October 2003 05:00:00 10 CFR 50.73(a)(1), Submit an LER Invalid Group Iii Primary Containment Isolation System Actuation 2014-04-05T11:00:00 | |