ENS 47809: Difference between revisions
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| event date = 04/05/2012 12:20 CDT | | event date = 04/05/2012 12:20 CDT | ||
| last update date = 04/05/2012 | | last update date = 04/05/2012 | ||
| title = Unplanned Systems Actuations While Performing | | title = Unplanned Systems Actuations While Performing a Surveillance Test | ||
| event text = Unit 1 was performing a planned refueling outage surveillance test, FNP-1-STP-40.0, 'Safety Injection with Loss of Off-Site Power [LOSP].' The systems were being returned to normal following the actuation portion of the test. When the B1F Sequencer Test Trip Override Switch was taken to the 'ON' position, the 1-2A Diesel Generator output breaker opened, which caused a loss of power to the 'A' Train 4 kV busses. Prior to the event, the 1-2A Diesel Generator was running at normal speed and voltage carrying the 'A' Train 4kV busses. When the diesel generator output breaker opened, it then reclosed upon receipt of the LOSP signal causing the LOSP sequencer loads to automatically start. This included the 1C Component Cooling Water Pump, the 1A High Head Safety Injection Pump (discharge isolation was closed prior to the event), and the 1A and 1B SW pumps. Therefore, during the test, the system actuated in a way that was not part of the planned surveillance testing. The 1A RHR pump was in shutdown cooling mode at the time of the event and was load shed. RHR was restarted manually by the operating crew approximately 1 minute later (no auto start [signal] present due to a loss of site power - LOSP signal without a safety injection signal present). | | event text = Unit 1 was performing a planned refueling outage surveillance test, FNP-1-STP-40.0, 'Safety Injection with Loss of Off-Site Power [LOSP].' The systems were being returned to normal following the actuation portion of the test. When the B1F Sequencer Test Trip Override Switch was taken to the 'ON' position, the 1-2A Diesel Generator output breaker opened, which caused a loss of power to the 'A' Train 4 kV busses. Prior to the event, the 1-2A Diesel Generator was running at normal speed and voltage carrying the 'A' Train 4kV busses. When the diesel generator output breaker opened, it then reclosed upon receipt of the LOSP signal causing the LOSP sequencer loads to automatically start. This included the 1C Component Cooling Water Pump, the 1A High Head Safety Injection Pump (discharge isolation was closed prior to the event), and the 1A and 1B SW pumps. Therefore, during the test, the system actuated in a way that was not part of the planned surveillance testing. The 1A RHR pump was in shutdown cooling mode at the time of the event and was load shed. RHR was restarted manually by the operating crew approximately 1 minute later (no auto start [signal] present due to a loss of site power - LOSP signal without a safety injection signal present). | ||
The investigation revealed that a step in the procedure sequence was not performed during the restoration portion of the test. The operator did not parallel the diesel with off-site power prior to operating the B1F Sequencer Test Trip Override Switch which opened the diesel output breaker without off-site power aligned to the 'A' Train 4kV busses. The 1-2A Diesel Generator was subsequently paralleled to the grid and properly shutdown per the test procedure restoration. | The investigation revealed that a step in the procedure sequence was not performed during the restoration portion of the test. The operator did not parallel the diesel with off-site power prior to operating the B1F Sequencer Test Trip Override Switch which opened the diesel output breaker without off-site power aligned to the 'A' Train 4kV busses. The 1-2A Diesel Generator was subsequently paralleled to the grid and properly shutdown per the test procedure restoration. | ||
Latest revision as of 22:04, 1 March 2018
| Where | |
|---|---|
Farley  Alabama (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
| LER: | 05000348/LER-2012-003 |
| Time - Person (Reporting Time:+1.02 h0.0425 days <br />0.00607 weeks <br />0.0014 months <br />) | |
| Opened: | Alton Deweese 18:21 Apr 5, 2012 |
| NRC Officer: | Vince Klco |
| Last Updated: | Apr 5, 2012 |
| 47809 - NRC Website
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