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| Entered date | Event description | |
|---|---|---|
| ENS 47939 | 21 May 2012 16:44:00 | The Technical Support Center (TSC) fire protection sprinkler system was isolated and tagged out to perform planned maintenance. In conjunction with the sprinkler system being isolated, the charcoal filtered fan unit for the TSC ventilation was isolated. This prevents placing the TSC ventilation system in 'incident' mode; that is, the air cannot be re-directed through the charcoal filter in an event requiring the TSC atmosphere to be filtered due to an on-site release. The TSC ventilation system remains in service providing proper temperature control to maintain the facility habitable during normal operation; however with the 'incident' mode being unavailable, it may not remain habitable during all postulated scenarios and is, therefore, considered non-functional. The licensee notified the NRC Resident Inspector and will notify the Public Service Commission. |
| ENS 47177 | 19 August 2011 23:54:00 | At 1805 Indian Point Unit 3 experienced a loss of normal 138 KV Offsite Power (LOOP) during a thunderstorm in the area. The Station Auxiliary Transformer (SAT) protection circuitry actuated and de-energized 6.9 KV buses 5 and 6. Thirty two and 33 Emergency Diesel Generators (EDGs) auto-started and loaded onto Safeguards buses 5A and 6A per plant design. The corresponding blackout logic resulted in an auto start of 32 and 33 Auxiliary Feed Water pumps (AFW). The plant remained in Mode 1; however, due to the loss of two 6.9 KV buses, three Circulating Water pumps (CW) tripped as designed, which caused main condenser backpressure to rise (i.e., vacuum degraded). As a result of rising condenser backpressure, a manual turbine load reduction to 75% power was performed. The reactor remains stable at 75% power and buses 5 and 6 have been manually re-energized from the alternate 13.8 KV offsite power source and the Emergency Diesel Generators have been unloaded, shutdown, and realigned for auto start capability. The only unusual system response was 32 Component Cooling Water (CCW) pump did not auto-start on a low pressure signal when the remaining pumps were stripped and re-Ioaded by the EDG sequencing logic due to a problem with the closing spring on the supply breaker. CCW system pressure was observed to be at normal levels when 31 and 33 CCW pumps were loaded on the EDGs. 32 CCW pump remains inoperable due to the breaker issue. There was no impact to the operation of Unit 2 during this event. The licensee has notified the NRC Resident Inspector and the New York State Public Service Commission. |