ENS 50565: Difference between revisions
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| event date = 08/27/2014 11:09 CDT | | event date = 08/27/2014 11:09 CDT | ||
| last update date = 10/24/2014 | | last update date = 10/24/2014 | ||
| title = Invalid Actuation | | title = Invalid Actuation of General Containment Isolation Signals | ||
| event text = This 60-day telephone notification is being made per the reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe an invalid actuation of general containment isolation signals affecting containment isolation valves in more than one system. | | event text = This 60-day telephone notification is being made per the reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe an invalid actuation of general containment isolation signals affecting containment isolation valves in more than one system. | ||
On August 27, 2014, at 1109 hours Central Daylight Savings Time (CDT), while in a forced unit outage with the reactor noncritical (Mode 3) and with all control rods fully inserted, instrument mechanics were attempting to backfill reactor water level transmitter (LT) 3-53 sensing lines following performance of LT replacement. During this effort, water levels in both the variable and reference legs of the LT were disturbed resulting in a Browns Ferry Nuclear Plant (BFN) Unit 1 full scram and Primary Containment Isolation System (PCIS) Groups 2, 3, 6, and 8 isolation signals due to receipt of an invalid low reactor water level signal. The PCIS Groups 2, 3, 6, and 8 isolations caused the initiation of Trains B and C of the Standby Gas Treatment (SBGT) System and Control Room Emergency Ventilation (CREV) Subsystem 'A'. The Reactor and Refuel Zone ventilation fans tripped and the secondary containment dampers isolated. Train A of the SBGT System was tagged out of service during the event. | On August 27, 2014, at 1109 hours Central Daylight Savings Time (CDT), while in a forced unit outage with the reactor noncritical (Mode 3) and with all control rods fully inserted, instrument mechanics were attempting to backfill reactor water level transmitter (LT) 3-53 sensing lines following performance of LT replacement. During this effort, water levels in both the variable and reference legs of the LT were disturbed resulting in a Browns Ferry Nuclear Plant (BFN) Unit 1 full scram and Primary Containment Isolation System (PCIS) Groups 2, 3, 6, and 8 isolation signals due to receipt of an invalid low reactor water level signal. The PCIS Groups 2, 3, 6, and 8 isolations caused the initiation of Trains B and C of the Standby Gas Treatment (SBGT) System and Control Room Emergency Ventilation (CREV) Subsystem 'A'. The Reactor and Refuel Zone ventilation fans tripped and the secondary containment dampers isolated. Train A of the SBGT System was tagged out of service during the event. | ||
Latest revision as of 21:49, 1 March 2018
| Where | |
|---|---|
Browns Ferry  Alabama (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1390.67 h57.945 days <br />8.278 weeks <br />1.905 months <br />) | |
| Opened: | Emily Cole 14:49 Oct 24, 2014 |
| NRC Officer: | John Shoemaker |
| Last Updated: | Oct 24, 2014 |
| 50565 - NRC Website
| |
| 60-Day Optional Telephonic Notification of an Invalid Actuation of a General Containment Isolation Signal Affecting More than One System | 60-Day Optional Telephonic Notification of an Invalid Specified System Actuation [Table view] | ||