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

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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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Inspection Charter

• . Assess facility coordination of offsite activities

• • Overall risk assessment of event

I-s SEQUENCE OF EVENTS

• Fault Initiation

• . Electrical Transmission and Grid

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• s SEQUENCE OF EVENTS

• . Plant Transients and Challenges

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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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PERFORMANCE OF PLANT SYSTEMS

• + Unit 2 Emergency Diesel Generator failure

• .+.Other minor 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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j7:;ji Apparent Causes

-. Electrical fault isolation failure

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Transmission lines between Hassayampa and Palo Verde switchyard

• . Unit 2 Emergency Diesel Generator failure

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Technical Support Center Emergency Diesel Generator failure

• • Others

Maintenance Related Aspects

• Maintenance of switchyard and substation equipment good

• . Implementation of facility maintenance processes

SUEDAMINOs A.C 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*

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Overall Risk Assessment

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