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| Entered date | Event description | |
|---|---|---|
| ENS 41183 | 9 November 2004 13:52:00 | The following information is provided as a 60 day telephone notification to NRC under 10 CFR 50.73(a)(1) in lieu of submitting a written LER to report a condition that resulted in an invalid actuation of the WBN (Watts Bar Nuclear) Train A Containment Vent Isolation signal. NUREG1022 Revision 2 identifies the Information that needs to be reported as discussed below. (a) The specific train(s) and system(s) that were actuated. On September 15, 2004, at 0914 EDT, a Train A Containment Vent Isolation (CVI) signal was received when the A Train Containment Purge Radiation Monitor momentarily spiked above the High Radiation Trip set-point. The B Train Containment Purge system was in operation at the time of the CVI signal and automatically shutdown as designed. (b) Whether each train actuation was complete or partial. The actuation was considered complete. The CVI signal for Train A automatically isolated the containment ventilation system as designed. The A Train Containment Purge Radiation Monitor was removed from service and considered inoperable due to no supporting indication of actual radiation by redundant radiation monitors or recorded trend data. (c) Whether or not the system started and functioned successfully. Train A Containment Vent Isolation signal automatically actuated and functioned successfully. The CVI signal was not in response to an actual plant condition. Maintenance on the Train A Containment Purge Radiation Monitor, revealed a loose connection in the detector cable. The radiation monitor was repaired and returned to service and the containment ventilation air cleanup unit was also returned to service." The NRC Resident Inspector was notified of this by the licensee. |