ML042960506

Augmented Inspection Team Exit Meeting with Palo Verde Nuclear Generation Station

ML042960506
Person / Time
Site:	Palo Verde
Issue date:	10/18/2004
From:	NRC Region 4
To:
References
FOIA/PA-2004-0307
Download: ML042960506 (15)

Text

Nuclear Regulatory Commission Augmented Inspection Team Exit Meeting with Palo Verde Nuclear Generation Station

I. I C.

Inspection Charter

• Basis of Augmented Inspection

• Develop a complete sequence of events

• Assess performance of plant systems

• . Assess adequacy of plant procedures

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I - -, - - -- -- MF*.Wfm Inspection Charter

• • Assess facility response to event

• Assess facilities determination of apparent cause

+.*Assess maintenance related contributions

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bm -~ '1gs Inspection Charter

• . Assess facility coordination of offsite activities

• • Overall risk assessment of event

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SEQUENCE OF EVENTS

• Fault Initiation

• . Electrical Transmission and Grid

• - ge i * *s SEQUENCE OF EVENTS

• .Plant Transients and Challenges

• +Other Challenges

A-N PERFORMANCE OF PLANT SYSTEMS

• .*Transmission system protection

• .*All three reactors were safely shut down

• Each unit was stabilized by operators

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2.2S- 2 PERFORMANCE OF PLANT SYSTEMS

• +Unit 2 Emergency Diesel Generator failure

• .+.Otherminor equipment problems noted during shutdown

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Plant Procedures

• .Procedures used during event were generally acceptable

• • Some issues noted

MMW Facility Response

• Conduct of operations generally good

• .Emergency response organization challenges

• Some other problems noted by the team

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4 s.'?, *y-,.t'V't j7:;ji Apparent Causes

-. Electrical fault isolation failure

• + Transmission lines between Hassayampa and Palo Verde switchyard

• .Unit 2 Emergency Diesel Generator failure

+:+Technical Support Center Emergency Diesel Generator failure

• • Others

Maintenance Related Aspects

• Maintenance of switchyard and substation equipment good

• .Implementation of facility maintenance processes

- ...... A.C SUEDAMINOs Off-Site Coordination

• .Good coordination of actions following event

• t Unrecognized design issue with Hassayampa to Palo Verde transmission line protection

Overall Risk Assessment

• • Given the loss of approximately 5,500 MWe of electrical generation, the grid performed well

• Electrical power was restored in a timely*

manner

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T.,;4~ ~ *~ 22 2 Overall Risk Assessment

• • All three units were stabilized and placed in a safe shutdown mode of operation