ENS 45017
ENS Event | |
|---|---|
16:41 Apr 24, 2009 | |
| Title | Automatic Reactor Trip During Instrument Calibration |
| Event Description | At 1141 CT, Braidwood Unit 2 experienced an automatic Reactor Trip. The Reactor Trip red first out annunciator was Over Temperature Delta Temperature (OTDT). At the time of the Reactor Trip the Instrument Maintenance Department was performing a scheduled calibration of a Pressurizer Pressure channel (2PT-456) which is in the B loop of reactor protection. During the calibration a spike occurred on the D loop of reactor protection. Specifically, the RCS [Reactor Coolant System] temperature for the D loop. This caused a Reactor Trip on a 2 of 4 coincidence.
After the reactor trip occurred, all four steam generators reached their low-2 Reactor Trip setpoints and pressurizer pressure reached its low pressure Reactor Trip setpoint all of which is an expected response on a trip from full power. Steam Generator levels and Pressurizer pressure have been restored. Both the 2A and 2B Auxiliary Feedwater pumps auto started on the low-2 steam generator levels as expected. All control rods fully inserted into the core. No secondary relief valves lifted and no secondary steam released as a result of the Reactor Trip. Steam Generators are now being filled by the 2A Main Feedwater pump and the Auxiliary Feedwater pumps have been placed in standby. The main steam dumps are in service to the main condenser to provide heat sink cooling. The plant is being maintained at normal operating pressure and temperature. This report is being made per 10 CFR 50.72(b)(2)(iv)(B) for RPS actuation, 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> notification, and per 10 CFR 50.72(b)(3)(iv)(A) for automatic actuation of the Auxiliary Feedwater System, 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> notification. The electrical line up transferred to the normal shutdown configuration with the standby diesel generators and safety systems available. There is no Unit 1 impact. The licensee plans on issuing a press release and has notified the NRC Resident Inspector. |
| 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:+-1.43 h-0.0596 days <br />-0.00851 weeks <br />-0.00196 months <br />) | |
| Opened: | Mike Deboard 15:15 Apr 24, 2009 |
| NRC Officer: | Karl Diederich |
| Last Updated: | Apr 24, 2009 |
| 45017 - NRC Website | |
Unit 2 | |
|---|---|
| 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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