ENS 48319
ENS Event | |
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00:57 Jul 24, 2012 | |
Title | Invalid System Actuations |
Event Description | On July 23, 2012, at 2057 hours0.0238 days <br />0.571 hours <br />0.0034 weeks <br />7.826885e-4 months <br />, the Perry Nuclear Power Plant experienced a loss of the normal power supply to the Reactor Protection System (RPS) A electrical bus. The loss of RPS bus A caused an actuation of several Division 1 containment outboard isolation valves. The actuation signal caused full closure of one or more valves in each of the following Division 1 subsystems: Main Steam line drains, Containment Radiation Monitor, Drywell Radiation Monitor, Reactor Water Cleanup, Fuel Pool Cooling and Cleanup, Liquid Radwaste Sumps, Containment Vessel Chilled Water, Containment Vacuum Relief, Condensate Transfer and Storage, Mixed Bed Demineralizer and Distribution, Containment Personnel Airlocks, Service Air, and Instrument Air. Division 2 components and valves were not affected.
This event is considered an invalid system actuation reportable under 10 CFR 50.73(a)(2)(iv)(A). The isolation was not initiated in response to actual plant conditions or parameters, and was not a manual initiation. Therefore, this notification is provided via a 60 day optional phone call in accordance with 10 CFR 50.73(a)(1) instead of submitting a written Licensee Event Report. The event meets reporting criteria specified in 10 CFR 50.73(a)(2)(iv)(B)(2) as a general containment isolation valve signal affecting containment isolation valves in more than one system. All affected systems functioned as expected in response to an outboard isolation signal. The valves were reopened in accordance with plant procedures. The failure mechanism that caused the loss of RPS bus A was a degraded voltage regulator. The voltage regulator was replaced and retested with satisfactory results. The NRC Resident Inspector has been notified. |
Where | |
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Perry Ohio (NRC Region 3) | |
Reporting | |
10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
Time - Person (Reporting Time:+1356.02 h56.501 days <br />8.072 weeks <br />1.857 months <br />) | |
Opened: | Lloyd Zerr 12:58 Sep 18, 2012 |
NRC Officer: | Dong Park |
Last Updated: | Sep 18, 2012 |
48319 - NRC Website
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Unit 1 | |
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Reactor critical | Critical |
Scram | No |
Before | Power Operation (96 %) |
After | Power Operation (96 %) |
WEEKMONTHYEARENS 552632021-03-23T04:37:00023 March 2021 04:37:00
[Table view]10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephonic Notification for an Invalid Diesel Generator Initiation ENS 510842015-03-26T20:29:00026 March 2015 20:29:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephonic Notification for an Invalid Primary Containment and Drywell Isolation Valve Actuation ENS 504502014-07-26T17:13:00026 July 2014 17:13:00 10 CFR 50.73(a)(1), Submit an LER Electrical Transient Causes an Invalid System Actuation ENS 483192012-07-24T00:57:00024 July 2012 00:57:00 10 CFR 50.73(a)(1), Submit an LER Invalid System Actuations ENS 434522007-05-03T05:58:0003 May 2007 05:58:00 10 CFR 50.73(a)(1), Submit an LER Invalid System Actuation ENS 405982004-02-22T15:16:00022 February 2004 15:16:00 10 CFR 50.73(a)(1), Submit an LER Partial Rps Actuation During Testing at Perry ENS 404692003-11-29T20:26:00029 November 2003 20:26:00 10 CFR 50.73(a)(1), Submit an LER Invalid System Actuation ENS 401262003-08-02T01:18:0002 August 2003 01:18:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Division 2 Balance-Of-Power Inboard Isolation Valves 2021-03-23T04:37:00 | |