Palo Verde Nuclear Generating Station

DiscussionRelief Request

HPSI 3B5/22/08

Enclosure 2

Discussion Topics

• Overview of Reason for Request• Pump Description• Maintenance Performed 3R14• Problem Description / Repairs Performed

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• Problem Description / Repairs Performed• Code Requirements• Current Plant Status• Proposed Pump Demonstration Testing• Basis for Relief Request

Overview of Reason for Request

• High Pressure Safety Injection Pump 3B – New Pump Seal Installed – Installation Difficulties Required Replacement– Bearing Replacement Performed

• Code Requires Full Flow Test

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– Normally Conducted Open Vessel (Reactor Defueled)– Unit 3 Approaching Mode 4 When Discovered

• Request Deviation from Full Flow Test– Conduct Maxi Flow Test Approx 80% Full Flow– No Impact to Pump Flow Characteristics during Maintenance– Full Flow Test Conducted this Outage– Plant not in Optimal Alignment to conduct Full Flow Test

Pump Description

• High Pressure Safety Injection Pump– Centrifugal Pump

– Ingersol – Rand Model 4X11CA-8

PM being performed to Upgrade Seal

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– PM being performed to Upgrade Seal

– Pump Performance Acceptable Prior to Refuel

– Post Maintenance Full Flow Test Acceptable Results

Maintenance Performed 3R14

• 4/25-4/30/09 – Scheduled PM

– Removal/replacement of mechanical seal

• 5/3 – Initial Fill - Outboard Mech Seal Leak

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– Small Piece of Carbon Material Found

– Reassembled outboard seal/bearing

– ISLT and Section XI testing completed

satisfactorily

Maintenance Performed 3R14

• 5/6 – 5/19 HPSI ‘B’ Pump Sat Idle

• 5/19 – Started HPSI ‘B’ for SIT fills.

– Observed Leakage from outboard seal

– Initially ~ ½ gpm

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Initially ½ gpm

– Reduced to ~ 1 drop/sec at End of 4 hrs

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Repairs Performed

• Entered Level “B” Troubleshooting Plan

– OEM Vendor Support

– Determined Cause of Seal Leakage –Improper Alignment of Seal Faces

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Improper Alignment of Seal Faces

– Outboard Seal Damaged Due to Misalignment

– Thrust Bearing (damaged during removal)

• Performed repairs to HPSI ‘B’ outboard seal w/ replacement of thrust bearing

Code Requirements

• ASME OM Code 2001 Edition through 2003 Addenda

• ISTB-3310 Effect of Pump Replacement, Repair, and Maintenance on Reference ValuesIf R f V l S t f V l M h

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• If Reference Value or Set of Values May have been effected by repair or replacement– Bearing Replacement May Affect

• New Reference Values shall be determined– By a Comprehensive or Group A Test Run– Prior to declaring pump operable

Current Plant ConditionsAt Time of Determining Retest

• Reactor Reassembly Complete

• Primary Plant Solid

• Drawing a Bubble in the Pressurizer

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• RCP Sweeps in Progress

• Normal Full Flow Test Conducted with– Fuel Off Loaded

– Reactor Vessel Open

Proposed Pump Demonstration Testing

• 2 Hour Run– Verify Correct Seal Operation– Change Bearing Oil– Collect vibration data

Additi l 2 h R (1 dditi l

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• Additional 2 hour Run (1 additional as a minimum)– Vibration measured and analyzed at each point

• Utilize “Max Recirc” Flow Alignment– At least 750 gpm versus 1040 gpm design– Acceptable in Mode 5

Basis for Relief Request

• New Bearing is Only Cause for Comprehensive Flow Test

• No Change to Pump Characteristics

• Successful Comprehensive Flow Test

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Successful Comprehensive Flow Test Performed this Refuel Outage

• Vibration Data at Min Flow Generally worse than Full Flow

• Testing Under Current Plant Conditions Not Typical Configuration for Full Flow Testing