ENS 42494

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v t e ENS Event
13:13 Apr 12, 2006
Title	Uf6 Release Detection System Failed During Testing
Event Description	At 0813 CDT on 04/12/2006, the Plant Shift Superintendent (PSS) was notified that immediately following routine test firing of the C-333 Unit 4 cell 7 UF6 Release Detection System (TSR surveillance requirement 2.4.4.1-1), smoke and sparks were observed coming from the UF6 Release Detection System control module and the system ready light was extinguished. The Area Control Room alarm locked in and the system was declared inoperable by the PSS. The cell and associated piping were above atmospheric pressure (Cascade Mode 2) at the time of the failure. The UF6 Release Detection System is a TSR system that is required to be operable per TSR 2.4.4.1, when a cascade cell and associated piping are in Cascade Mode 2. After discovery of failed system condition, a continuous UF6 smoke watch was initiated on the areas affected by the loss of detection capability in accordance with LCO Required Actions 2.4.4.1.B.1 and 2.4.4.C.1. This event is reportable as a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> event in accordance with 10CFR 76.120(c)(2)(i). This is an event in which equipment is disabled or fails to function as designed when: a.) the equipment is required by a TSR to prevent releases, prevent exposures to radiation and radioactive materials exceeding specified limits, mitigate the consequences of an accident, or restore this facility to a pre-established safe condition after an accident; b.) the equipment is required by a TSR to be available and operable and either should have been operating or should have operated on demand, and c.) no redundant equipment is available and operable to perform the required safety function. The NRC Senior Resident Inspector has been notified of this event. PGDP Problem Report No. ATRC-06-1197; PGDP Event Report No. PAD-2006-03. There was no release from this event. The failure was shorted contacts in the alarm reset relay. * * UPDATE FROM WALLACE TO KNOKE AT 19:04 EDT on 04/18/06 * * * This report is being retracted. Subsequent to the event, Maintenance and System Engineering determined that the alarm disable switch control module faulted when the operator attempted to reset the ACR PGLD alarm. This fault caused the system power supply to fail. Resetting the alarms is the last step in the test procedure being performed when the failure occurred. Only after the alarms are cleared is the PGLD system returned to normal operating condition and testing complete. In this case, the evidence clearly indicated that the failure occurred during the conduct of the surveillance and the successful firing of the detectors and the start of the test provides positive evidence that the failure did not exist prior to the surveillance. Therefore, the in-service safety system failure reporting criteria of 10CFR 76.120(c)(2)(i) is not applicable. The Senior Resident Inspector has been notified of this retraction. Notified R2DO(Lesser) and NMSS (Janosko).

ENS 42494 +/-
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:+4.28 h0.178 days <br />0.0255 weeks <br />0.00586 months <br />)
Opened:	Eric Walker 17:30 Apr 12, 2006
NRC Officer:	Mark Abramovitz
Last Updated:	Apr 18, 2006
42494 - 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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