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At noon on 06/11/2009 Browns Ferry Unit 2 … At noon on 06/11/2009 Browns Ferry Unit 2 experienced a rise in drywell leakage during reactor startup. The 4 hour unidentified leak rate from 0800 to 1200 on 6/10/2009 was 0 GPM, while the 4 hour unidentified leak rate from 0800 to 1200 on 6/11/2009 was 3.88 GPM. This increase in leak rate exceeded the allowable limit of a 2 GPM increase in unidentified leakage in a 24 hour period per Technical Specification 3.4.4. At 1555 (CDT) on 06/11/2009, Unit 2 inserted a manual reactor SCRAM to comply with Technical Specification 3.4.4 Condition C to be in Mode 3 in 12 hours and Mode 4 within 36 hours. </br>All systems responded as required except that when reset of the SCRAM was attempted after all control rods had inserted, a portion of the 'B' RPS channel (B2/B3) failed to reset. The 'A' RPS channel was then actuated by a spike on the Intermediate Range Monitors while they were being driven into the core resulting in a full RPS SCRAM actuation.</br>The licensee notified the NRC Resident Inspector." </br>Unit 2 is currently removing decay heat using normal feedwater with bypass steam to the main condenser. The electrical system is in a normal shutdown configuration. The licensee has not identified the source of the unidentified leakage and anticipates taking Unit 2 to Cold Shutdown (Mode 4).</br>* * * UPDATE AT 1730 EDT ON 6/15/09 FROM HUNTER TO SANDIN * * * </br>Plant personnel entered the drywell after the reactor was shutdown. The resulting investigation revealed two sources of increased drywell leakage. One source of leakage was from 2-CKV-10-511 and 2-CKV-10-526, SRV Tailpipe Vacuum Breakers, which were apparently damaged by leakage past the pilot valve for 2-PCV-001-0023, Main Steam Safety Relief Valve. The combination of damaged vacuum breakers and a leaking pilot valve resulted in steam leakage into the drywell atmosphere. The other source of leakage was noted through the packing for 2-DRV-10-505, RPV Drain to RWCU. The vacuum breakers, pilot valve, and drain valve have been repaired.</br>The 'B' RPS contactors were repaired and the scram reset.</br>The NRC Resident Inspector has been notified." </br>R2DO (McCoy) notified.s been notified."
R2DO (McCoy) notified.
20:55:00, 11 June 2009 +
45,124 +
18:24:00, 11 June 2009 +
20:55:00, 11 June 2009 +
At noon on 06/11/2009 Browns Ferry Unit 2 … At noon on 06/11/2009 Browns Ferry Unit 2 experienced a rise in drywell leakage during reactor startup. The 4 hour unidentified leak rate from 0800 to 1200 on 6/10/2009 was 0 GPM, while the 4 hour unidentified leak rate from 0800 to 1200 on 6/11/2009 was 3.88 GPM. This increase in leak rate exceeded the allowable limit of a 2 GPM increase in unidentified leakage in a 24 hour period per Technical Specification 3.4.4. At 1555 (CDT) on 06/11/2009, Unit 2 inserted a manual reactor SCRAM to comply with Technical Specification 3.4.4 Condition C to be in Mode 3 in 12 hours and Mode 4 within 36 hours. </br>All systems responded as required except that when reset of the SCRAM was attempted after all control rods had inserted, a portion of the 'B' RPS channel (B2/B3) failed to reset. The 'A' RPS channel was then actuated by a spike on the Intermediate Range Monitors while they were being driven into the core resulting in a full RPS SCRAM actuation.</br>The licensee notified the NRC Resident Inspector." </br>Unit 2 is currently removing decay heat using normal feedwater with bypass steam to the main condenser. The electrical system is in a normal shutdown configuration. The licensee has not identified the source of the unidentified leakage and anticipates taking Unit 2 to Cold Shutdown (Mode 4).</br>* * * UPDATE AT 1730 EDT ON 6/15/09 FROM HUNTER TO SANDIN * * * </br>Plant personnel entered the drywell after the reactor was shutdown. The resulting investigation revealed two sources of increased drywell leakage. One source of leakage was from 2-CKV-10-511 and 2-CKV-10-526, SRV Tailpipe Vacuum Breakers, which were apparently damaged by leakage past the pilot valve for 2-PCV-001-0023, Main Steam Safety Relief Valve. The combination of damaged vacuum breakers and a leaking pilot valve resulted in steam leakage into the drywell atmosphere. The other source of leakage was noted through the packing for 2-DRV-10-505, RPV Drain to RWCU. The vacuum breakers, pilot valve, and drain valve have been repaired.</br>The 'B' RPS contactors were repaired and the scram reset.</br>The NRC Resident Inspector has been notified." </br>R2DO (McCoy) notified.s been notified."
R2DO (McCoy) notified.
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Unit 2 Initiated a Tech Spec Required Shutdown Due to a Rise in Unidentified Drywell Leakage +
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