ENS 51423: Difference between revisions
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| event date = 09/17/2015 12:22 EDT | | event date = 09/17/2015 12:22 EDT | ||
| last update date = 09/24/2015 | | last update date = 09/24/2015 | ||
| title = Valid Actuation | | title = Valid Actuation of Uv Relays Following Loss of Unit 2 Startup Transformer | ||
| event text = On September 17, 2015, at 1222 hours, with Unit 2 in Mode 5 at the beginning of a refueling outage, an electrical fault on the 2A 6.9 kV bus resulted in the loss of the 2A startup transformer and its associated non-safety related 2A2 and safety related 2A3 busses. At the time of the event, the 2A Emergency Diesel Generator (EDG) had been properly removed from service for scheduled maintenance. The loss of the 2A start up transformer initiated the under voltage relays, which resulted in a valid actuation signal that would have started the 2A EDG. | | event text = On September 17, 2015, at 1222 hours, with Unit 2 in Mode 5 at the beginning of a refueling outage, an electrical fault on the 2A 6.9 kV bus resulted in the loss of the 2A startup transformer and its associated non-safety related 2A2 and safety related 2A3 busses. At the time of the event, the 2A Emergency Diesel Generator (EDG) had been properly removed from service for scheduled maintenance. The loss of the 2A start up transformer initiated the under voltage relays, which resulted in a valid actuation signal that would have started the 2A EDG. | ||
Additionally, the 2A train of shutdown cooling (SDC) was de-energized; the 2B (protected) train of SDC was not affected by the event and remained in service to remove decay heat. The 2A shutdown cooling train was restored and made available on September 19, 2015 at 0030. The 2B EDG and 2B startup transformer remained operable. | Additionally, the 2A train of shutdown cooling (SDC) was de-energized; the 2B (protected) train of SDC was not affected by the event and remained in service to remove decay heat. The 2A shutdown cooling train was restored and made available on September 19, 2015 at 0030. The 2B EDG and 2B startup transformer remained operable. | ||
Latest revision as of 20:46, 1 March 2018
| Where | |
|---|---|
Saint Lucie  Florida (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+168.2 h7.008 days <br />1.001 weeks <br />0.23 months <br />) | |
| Opened: | J. Breen 16:34 Sep 24, 2015 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Sep 24, 2015 |
| 51423 - NRC Website
| |