ENS 41004
ENS Event | |
|---|---|
17:56 Jul 31, 2004 | |
| Title | Invalid Pcis Actuation |
| Event Description | This notification is being made in accordance with 10CFR50.73(a)(2)(iv)(A) to provide the NRC with information pertaining to the invalid Primary Containment Isolation System (PCIS) Group III actuation signal that affected containment isolation valves in more than one system.
On July 31, 2004 at 1356 [EDT] with the reactor at full power, the power supply that provides power to the Reactor Protection System (RPS) Channel 'A' of the Reactor Building Ventilation Exhaust Rad Monitor and RPS Channel 'A' of the Refuel Floor Rad Monitor was momentarily lost causing an invalid PCIS Group III actuation. Operators immediately verified the plant response to the loss of RPS 'A', backed up the Group III actuation manually, walked down the control room panels, shifted RPS 'A' bus to the alternate power supply, secured 'A' RPS MG set and restored the affected plant equipment to a normal line-up. The following systems were observed to have performed as follows: The PCIS functioned successfully providing a complete Group III isolation. Both trains of the Standby Gas Treatment System started and operated as designed. The PCIS Group Ill isolation involved isolation of valves in the following systems: Drywell Air Purge and Vent, Drywell and Suppression Chamber Main Exhaust, Suppression Chamber Purge and Vent, Containment Air Compressor Suction Valve, Exhaust to Standby Gas Treatment, Containment Purge Supply and Makeup, Containment Air Sampling, Air Dilution Subsystem Valves, Vent Subsystem Valves, and Containment Air Dilution Vent System MOV VG-22 A/B. Repairs were subsequently made to the 'A' RPS power supply and the system was returned to normal status. This event has been entered into Entergy Nuclear Vermont Yankee's Corrective Action Program. The licensee will notify the NRC Resident Inspector. |
| Where | |
|---|---|
Vermont Yankee  Vermont (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+764.3 h31.846 days <br />4.549 weeks <br />1.047 months <br />) | |
| Opened: | David Hallouquist 14:14 Sep 1, 2004 |
| NRC Officer: | Jeff Rotton |
| Last Updated: | Sep 1, 2004 |
| 41004 - NRC Website | |
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 | |