ENS 43449
ENS Event | |
|---|---|
14:21 Jun 27, 2007 | |
| Title | Reactor Trip Due to Off-Site Power Fluctuation |
| Event Description | Switchyard line 2001 tripped and re-energized during a thunderstorm. This caused main generator output breaker, ACB 3-4, to trip open. At this time '1D' reactor coolant pump (RCP) tripped and caused a reactor trip. Cause for the '1D' RCP trip is under investigation.
The heat sink is being provided by Aux Feedwater and the use of Steam Dumps. Electrical power is being provided by offsite power. All rods inserted. There were no complications during the trip and all systems functioned as required. Offsite power remained available throughout the transient. The electrical transient had no impact on Unit 2. The licensee notified the NRC Resident Inspector.
This is a revision to a previously transmitted ENS call on 6/27/07 EN# 43449. Braidwood Unit 1 Reactor automatically tripped on a loss of '1D' RCP greater than P-8 setpoint. The cause of the RCP trip was an electrical disturbance during a thunderstorm. The reactor trip automatically caused a main turbine and generator trip. Auxiliary feedwater system automatically started on the low-2 S/G water level that is expected from a full power reactor trip. Auxiliary feedwater and main steam dumps are providing a heat sink. A switchyard line also tripped during this electrical transient causing multiple switchyard breakers to open. Electrical power is being provided by offsite power. All control rods fully inserted. There were no complications during the trip and all systems functioned as required. Offsite power remained available throughout the transient. The electrical disturbance had no impact on Unit 2. The licensee notified the NRC resident inspector." R3DO (Louden) notified. |
| Where | |
|---|---|
Braidwood  Illinois (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| Time - Person (Reporting Time:+-2.78 h-0.116 days <br />-0.0165 weeks <br />-0.00381 months <br />) | |
| Opened: | Randall Rahrig 11:34 Jun 27, 2007 |
| NRC Officer: | Jason Kozal |
| Last Updated: | Jun 28, 2007 |
| 43449 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | A/R |
| Before | Power Operation (100 %) |
| After | Hot Standby (0 %) |
Braidwood with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
WEEKMONTHYEARENS 553202021-06-21T05:51:00021 June 2021 05:51:00
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