ENS Event | |
|---|---|
23:29 Apr 27, 2011 | |
| Title | Both Offsite Power Sources Declared Inoperable Due to Effects of Inclement Weather |
| Event Description | At 1929 EDT, both off-site A.C. power sources to Sequoyah were declared inoperable due to the effects of inclement weather on the TVA transmission system. This determination was made after a review of grid conditions confirmed that pre-analyzed grid/offsite power requirements could not be met. Both Sequoyah Units have entered TS LCO 3.8.1.1, action d, for two inoperable offsite power sources. It has not been determined when this condition will no longer exist.
Although inoperable, off-site A.C. sources remain connected to Sequoyah; emergency diesel generators are not running nor required to be at this time. T.S. LCO 3.8.1.1, action d, requires verifying EDG operability within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and restoration of both offsite power sources within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or placing both Units in mode 3. The licensee informed the NRC Resident Inspector.
As of 0119 EDT the licensee has two operable offsite power sources qualified through transmission and reliability analysis. The licensee exited their LCO Condition. The grid condition is now yellow. Notified R2IRC (Gody). |
| Where | |
|---|---|
Sequoyah  Tennessee (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor | |
| Time - Person (Reporting Time:+-3.17 h-0.132 days <br />-0.0189 weeks <br />-0.00434 months <br />) | |
| Opened: | Jeff Epperson 20:19 Apr 27, 2011 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Apr 28, 2011 |
| 46797 - NRC Website
Loading map... | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (92 %) |
| After | Power Operation (92 %) |
WEEKMONTHYEARENS 485842012-12-13T00:14:00013 December 2012 00:14:00
[Table view]10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Risk of Possible Flooding to Ercw Building During Design Basis Flood ENS 467972011-04-27T23:29:00027 April 2011 23:29:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor Both Offsite Power Sources Declared Inoperable Due to Effects of Inclement Weather 2012-12-13T00:14:00 | |