ENS 47500: Difference between revisions
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| event date = 10/11/2011 16:29 EST | | event date = 10/11/2011 16:29 EST | ||
| last update date = 12/06/2011 | | last update date = 12/06/2011 | ||
| title = Loss | | title = Loss of Vital Ac Power While Shutdown | ||
| event text = This 60-day telephone notification is being made pursuant to 10CFR50.73(a)(2)(iv)(A) and 10CFR50.73(a)(1) to describe an invalid actuation of a containment heat removal system. | | event text = This 60-day telephone notification is being made pursuant to 10CFR50.73(a)(2)(iv)(A) and 10CFR50.73(a)(1) to describe an invalid actuation of a containment heat removal system. | ||
On October 11, 2011, with the reactor shutdown for refueling, a partial loss of vital AC power was experienced which resulted in a loss of shutdown cooling as well as PCIS group 2, 3, 4, and 5 half isolations. The actuation was determined to be invalid as it occurred because a breaker supplying power to the 'A' vital AC was manually opened, resulting in actuation of the associated PCIS logic circuitry. The Group 4 actuation resulted in a complete isolation of the single train Residual Heat Removal shutdown cooling suction path. The shutdown cooling path was isolated for approximately 12 minutes resulting in a coolant temperature increase of approximately 2 degrees F. At the time of the event, the reactor cavity was flooded with the spent fuel pool gates removed and the normal fuel pool cooling system in operation to provide reactor cavity cooling. Based on this, there was no impact on public health and safety. | On October 11, 2011, with the reactor shutdown for refueling, a partial loss of vital AC power was experienced which resulted in a loss of shutdown cooling as well as PCIS group 2, 3, 4, and 5 half isolations. The actuation was determined to be invalid as it occurred because a breaker supplying power to the 'A' vital AC was manually opened, resulting in actuation of the associated PCIS logic circuitry. The Group 4 actuation resulted in a complete isolation of the single train Residual Heat Removal shutdown cooling suction path. The shutdown cooling path was isolated for approximately 12 minutes resulting in a coolant temperature increase of approximately 2 degrees F. At the time of the event, the reactor cavity was flooded with the spent fuel pool gates removed and the normal fuel pool cooling system in operation to provide reactor cavity cooling. Based on this, there was no impact on public health and safety. | ||
Latest revision as of 22:05, 1 March 2018
| Where | |
|---|---|
Vermont Yankee  Vermont (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1331.77 h55.49 days <br />7.927 weeks <br />1.824 months <br />) | |
| Opened: | Kevin Murphy 10:15 Dec 6, 2011 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | Dec 6, 2011 |
| 47500 - NRC Website
| |