ENS 43676: Difference between revisions
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| event date = 09/28/2007 22:32 EDT | | event date = 09/28/2007 22:32 EDT | ||
| last update date = 09/29/2007 | | last update date = 09/29/2007 | ||
| title = Automatic Reactor Trip Due | | title = Automatic Reactor Trip Due to Loss of a Startup Transformer | ||
| event text = On September 28, 2007, while reducing power for a planned refueling outage with the reactor at approximately 30 percent power in MODE 1, an unplanned actuation of the reactor protection system occurred. At 2232 a fault pressure trip signal was received on the A Startup Transformer (SUT), causing a loss of power to Aux Buses D, A & C electrical buses as well as the A-SA safety bus. The loss of A & C buses initiated the RCP underfrequency trip which tripped the Reactor and all three RCPs as designed. The A Diesel Generator automatically started and reenergized bus A-SA as designed. The auxiliary feedwater system actuated as expected due to undervoltage on the A-SA safety bus and loss of the main feedwater pumps. All control rods inserted on the reactor trip. The operations staff responded to the event in accordance with applicable plant procedures. The plant stabilized at normal operating no-load reactor coolant system temperature and pressure following the reactor trip. Steam generator water levels are being maintained using auxiliary feedwater. All emergency core cooling system equipment is available. The plant electrical system is being restored at this time. The A SUT remains out of service. The cause of the loss of power from A SUT is under investigation. | | event text = On September 28, 2007, while reducing power for a planned refueling outage with the reactor at approximately 30 percent power in MODE 1, an unplanned actuation of the reactor protection system occurred. At 2232 a fault pressure trip signal was received on the A Startup Transformer (SUT), causing a loss of power to Aux Buses D, A & C electrical buses as well as the A-SA safety bus. The loss of A & C buses initiated the RCP underfrequency trip which tripped the Reactor and all three RCPs as designed. The A Diesel Generator automatically started and reenergized bus A-SA as designed. The auxiliary feedwater system actuated as expected due to undervoltage on the A-SA safety bus and loss of the main feedwater pumps. All control rods inserted on the reactor trip. The operations staff responded to the event in accordance with applicable plant procedures. The plant stabilized at normal operating no-load reactor coolant system temperature and pressure following the reactor trip. Steam generator water levels are being maintained using auxiliary feedwater. All emergency core cooling system equipment is available. The plant electrical system is being restored at this time. The A SUT remains out of service. The cause of the loss of power from A SUT is under investigation. | ||
This condition is being reported as an unplanned reactor protection system actuation and specified system actuation in accordance with 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A). | This condition is being reported as an unplanned reactor protection system actuation and specified system actuation in accordance with 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A). | ||
Latest revision as of 22:15, 1 March 2018
| Where | |
|---|---|
Harris  North Carolina (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| LER: | 05000400/LER-2007-003 |
| Time - Person (Reporting Time:+-0.22 h-0.00917 days <br />-0.00131 weeks <br />-3.01356e-4 months <br />) | |
| Opened: | M. Hinman 02:19 Sep 29, 2007 |
| NRC Officer: | John Mackinnon |
| Last Updated: | Sep 29, 2007 |
| 43676 - NRC Website
| |
Harris with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |