ENS 43729
ENS Event | |
|---|---|
04:00 Sep 15, 2007 | |
| Title | Invalid Primary Containment Isolation |
| Event Description | This notification is being made in accordance with 10CFR50.73(a)(2)(iv)(A) to provide information pertaining to an invalid Primary Containment Isolation System (PCIS) Group 3 actuation signal that affected containment isolation valves in more than one system.
On 09/15/07, with the reactor at 100% power, an invalid PCIS Group 3 actuation occurred from a momentary spike of the 'A' Refuel Floor radiation monitor which reached the instrument's high radiation trip setpoint. Radiation protection technicians dispatched to the refuel floor verified dose rates in the vicinity of the 'A' radiation monitors detector to be normal and below the alarm set points. The radiation monitor was verified to be indicating normally to expected radiation levels. Subsequent visual inspection and functional checks of the radiation monitor were completed satisfactory and the instrument channel was returned to service. The cause of the spurious spike is attributed to an unknown source of electrical noise. Both trains of the Standby Gas Treatment System started as designed and Reactor Building ventilation isolated. The train actuation was complete. The PCIS functioned successfully providing a complete Group 3 isolation. The PCIS Group 3 isolation involves the following systems and isolation valves: Drywell and Suppression Chamber air purge and vent: V16-19-6, 6A, 6B, 7, 7A, 7B, 8, 9, 10, 23 Containment Makeup: V16-20-20, 22A, 22B Containment Air Sampling: VG-23, 26, V109-76A, 76B Containment Air compressor suction: V72-38A, 38B Containment Air Dilution: VG-9A, 9B, 22A, 22B, NG-11A, 11B, 12A, 12B, 13A, 13B In accordance with 10CFR50.73(a)(i) a telephone notification is being made instead of submitting a written Licensee Event Report. The licensee will notify the NRC Resident Inspector. |
| 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:+800.6 h33.358 days <br />4.765 weeks <br />1.097 months <br />) | |
| Opened: | Andrew Wisniewski 12:36 Oct 18, 2007 |
| NRC Officer: | Joe O'Hara |
| Last Updated: | Oct 18, 2007 |
| 43729 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
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 | |