Following a planned shutdown to investigate the source of elevated Primary Coolant System (
PCS)
Unidentified Leakage, the Mode 3
PCS walk-down identified a steam leak on CRD-24,
Control Rod Drive Mechanism (
CRD), pressure housing. The leak is ~ 1 foot above the
CRD to Reactor Head
flange. The leak was observed from the Refueling floor deck and appears to be coming from an area of the
CRD with no bolted connections. Leakage from this area is unexpected and the mechanism of failure is not understood at this time. Closer examination of the leak is expected to occur in parallel with plant cool-down.
The plant entered T.S. 3.4.14 (PCS Operational Leakage) Condition B. at 0418 EDT hours this morning and this requires the plant to be placed in Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The leakage is considered Pressure Boundary Leakage. Operations is in progress of performing the plant cool-down from Mode 3 to Mode 5.
The licensee discovered this condition following a shutdown the morning of 8/12/12 to investigate unidentified primary coolant leakage of about 0.3 gpm that had been recently trending upwards. Plant conditions are currently 400 degrees F with primary system pressure at about 1000 psi.
The licensee has notified the NRC Resident Inspect
