ENS 42176

v t e ENS Event
14:45 Nov 29, 2005
Title	Faulty Switch Rendered Criticality Accident Alarm System Inoperable
Event Description	At 0845 CST, on 11/29/2005 the C-337 process building Criticality Accident Alarm System (CAAS) was being tested when a building horn control switch in C-300 Central Control Facility which supplies voltage to actuate the building CAAS evacuation horns was found to not be properly made up. This switch caused the building CAAS horns not to sound when a cluster was actuated. The test which revealed this problem, was the initial 'as found' test, which means the failure most likely occurred prior to today's testing. The C-337 CAAS system is a TSR system which is required to be operable in the current operating mode unless LCO actions are in place. The C-337 CAAS system was last tested on 11/05/2005 and indications are that the switch problem has existed since that time. During testing the CAAS alarm was received in C-300, but the evacuation horns did not automatically sound. Per procedure if a criticality alarm had occurred the C-300 operator would have actuated the horn switch manually which would have sounded the evacuation horns. To ensure that not only the C-337 switch was properly repaired, but also to verify all other building horn control switches were in the proper state, a plant wide LCO was implemented and switch outputs were checked to verify the proper voltage output. The NRC Senior Resident has been notified of this event.

ENS 42176 +/-
Where
Paducah Gaseous Diffusion Plant Paducah, Kentucky (NRC Region 2)
License number:	GDP-1
Reporting

10 CFR 76.120(c)(2)
Time - Person (Reporting Time:+8.85 h0.369 days <br />0.0527 weeks <br />0.0121 months <br />)
Opened:	Tony Hudson 23:36 Nov 29, 2005
NRC Officer:	John Knoke
Last Updated:	Nov 29, 2005
42176 - NRC Website
v • d • e

v t e Emergency Notification System
Paducah Gaseous Diffusion Plant with 10 CFR 76.120(c)(2)
WEEKMONTHYEAR2014-05-08T15:24:00 [Table view]
[ENS list for Paducah Gaseous Diffusion Plant]

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