United States Nuclear Regulatory Commission - Protecting People and the Environment

Morning Report for July 5, 2007

Headquarters Daily Report

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Ginna Loss of Control Room Annunciators


Dockets: 05000244
[1] W-2-LP
License No:

MR Number: 1-2007-0016
Date: 07/04/2007


At 2:14 a.m. (EST) on July 4, Ginna declared an Unusual Event due to the loss of four control room annunciator panels in accordance with Emergency Action Level (EAL) 7.3.1 (unplanned loss of annunciator panels for greater than 15 minutes). The affected panels included alarms for reactor trip and protective functions as well as emergency core cooling and reactor coolant system parameters. Throughout the event, all control board indications and the plant process computer (which has many independent and redundant alarm functions) remained available.

The annunciator panels were subsequently returned to service following troubleshooting; replacement of affected alarm, flasher, and horn annunciator cards; and appropriate testing. The licensee identified the preliminary cause for loss of the panels as a failure of a resistor in one of the alarm cards. Since the annunciator panels share common electrical circuitry, the resistor failure was able to impact four panels. The licensee exited the Unusual Event at 3:42 p.m.

This Morning Report provides additional detail to Event Report #43473 and is being submitted for information only. The NRC resident inspectors (with support from the Region I Incident Response Center) responded to the site to monitor licensee response to the event. In addition, the Regional State Liaison Officer provided several updates to New York State officials throughout the event and a Commissioner Technical Assistant briefing was conducted.


Name Office Abbrev Phone No E-Mail
DENTEL, GLENN R1 (610) 337-5233 GTD@nrc.gov
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