ENS Event | |
|---|---|
19:43 Sep 13, 2009 | |
| Title | Automatic Reactor Trip Following Turbine Trip for Loss of Condenser Vacuum |
| Event Description | The SONGS Unit 2 reactor automatically tripped from approximately 94% power at 1243 PDT due to loss of turbine load caused by lowering main condenser vacuum. Prior to the reactor trip, personnel were attempting to conduct a heat treat on Unit 2. During this evolution, Gate 5 in the main circulating water system was being repositioned when it stopped moving at 45 percent. This resulted in a recirculation and subsequent increase in circulating water temperature, a lowering main condenser vacuum, a loss of load on the main turbine, and an associated automatic reactor trip.
All rods inserted on the automatic reactor trip and the electric grid is stable. This event report is being made under 10CFR50.72(b)(2)(iv)(B) as a valid Reactor Protection System actuation. Decay heat is being removed via normal feedwater to steam generators steaming through the condenser bypass valves to the main condenser. At the time of this event, SONGS Unit 3 was operating at approximately 99% power. The licensee notified the NRC Resident Inspector. |
| Where | |
|---|---|
San Onofre  California (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation | |
| Time - Person (Reporting Time:+-3.52 h-0.147 days <br />-0.021 weeks <br />-0.00482 months <br />) | |
| Opened: | Bill Poirier 16:12 Sep 13, 2009 |
| NRC Officer: | Pete Snyder |
| Last Updated: | Sep 13, 2009 |
| 45347 - NRC Website | |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | A/R |
| Before | Power Operation (94 %) |
| After | Hot Standby (0 %) |
WEEKMONTHYEARENS 476282012-02-01T01:30:0001 February 2012 01:30:00
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