Nine Mile Point Unit 2 Shut Down Satruday 8/6/2011
On Saturday 8/6/2011 an emergency level event was issued by operators of the Nine Mile Point Nuclear Generating Station. The Notification of Unusual Event (NOUE), or least severe of four emergency classifications, was registered with the Nuclear Regulatory Commission regarding leakage in the Unit 2 drywell containment of greater than 10 gallons/minute. Here is an excerpt of the event text as it appears on the
NRC site:
UNUSUAL EVENT AND PLANT SHUTDOWN DUE TO DRYWELL UNIDENTIFIED LEAKAGE GREATER THAN 10 GPM
"At 0152 [EDT], Nine Mile Point Unit 2 received red alarms for containment monitoring cabinets 10A and 10B along with a rise in drywell floor drain leakage and drywell pressure.
"At 0205 [EDT], Nine Mile Point Unit 2 entered technical specification action statement (TS 3.4.5 B) due to unidentified leakage rise of greater than 2 gpm within 24 hours.
"At 0217 EDT, the control room commenced power reduction to mitigate the rise in drywell leakage and drywell pressure.
"At 0322 EDT, Nine Mile Point Unit 2 declared an Unusual Event (EAL 2.1.1) due to unidentified drywell leakage greater than 10 gpm. Actual drywell floor drain leakage reached 11.3 gpm.
"The cause of the rise in unidentified leakage is unknown at this time.
"At 0345 EDT, Nine Mile Point Unit 2 has commenced a plant shutdown."
The licensee has notified State and local authorities. The NRC Resident Inspector has been notified.
On the same day, the event was terminated (e.g. emergency cleared) after readings returned back to normal after steps to power down the reactor began. The operator (Constellation Energy Nuclear Group) continued with power down procedures after the emergency had been cleared to facilitate drywell inspections and repairs.
According the following
Reuters article dated 8/9/2011, a spokesperson for Constellation said that the repairs to Unit 2 had been completed and that workers were doing "post maintenance testing":
NEW YORK, Aug 9 (Reuters) - Constellation Energy Nuclear Group
completed the repairs on the 1,148-megawatt Unit 2 at the Nine Mile Point
nuclear power plant in New York and were doing post maintenance testing, a
spokeswoman for the plant said Tuesday.
She could not say when the unit, which shut over the weekend, would
return to service.
Electricity traders guessed it would restart over the next day or so.
...
Apparently the Unit 2 reactor was restarted but had to be shut down again Thursday morning (8/11/2011) due to a different leak in a feedwater pump.
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