ML17310A876

Summary of 931109 Meeting W/Util to Discuss Results & Conclusions from Recently Completed Unit 1 Steam Generator Eddy Current Testing

ML17310A876
Person / Time
Site:	Palo Verde
Issue date:	12/29/1993
From:	Brian Holian Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
NUDOCS 9401070363
Download: ML17310A876 (66)

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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C; 20555-0001 December 29, 1993 Docket Nos. 50-528, 50-529, and 50-530 LICENSEE:

Arizona Public Service Company FACILITY:

Palo Verde Nuclear Generating Station

SUMMARY

OF MEETING HELD ON NOVEMBER 9,

1993, TO DISCUSS UNIT 1

STEAM GENERATOR EDDY CURRENT TEST RESULTS APS representatives summarized the steam generator eddy current testing.

The results of the Unit 1 inspection were different'rom the last Unit 2 inspection (that was conducted following the March 14,

1993, steam generator tube rupture) in that no free span axial cracks were identified.

However, several volumetric indications were identified in the freespan area.

Additionally, the Unit 1 steam generators exhibited an unusually high number of circumferential defects at the tubesheet region (primarily in the sludge pile region).

The inspection resulted in the plugging of 56 tubes in steam generator No.

1, and 126 tubes in No. 2.

Steam generator hand holes were installed during this outage, enabling the performance of sludge lancing for the first time on these generators.

Eighteen tubes were selected for ultrasonic examination, to verify the readings taken by both the "bobbin" and "rotating pancake" coils.

Overall, the correlation was good (although ultrasonic missed picking up one indication), with the rotating pancake coil length readings typically being conservative.

The licensee performed engineering

analyses, and conducted in-situ pressure tests on five tubes, to confirm that Regulatory Guide

1. 121 safety factors were maintained.

The staff requested that the licensee submit additional information for review.

The licensee had performed a qualitative assessment to verify that the RG 1. 121 safety factors would be met for a full cycle duration.

However, in order to better assess tube integrity, the staff requested quantitative data regarding "crack profiles" on six of th e tubes with the worst Ind>catlons ZIII:HI..= C<HEe ~V OGOot,v 940i070363 931229 PDR'DQCK'05000528 PDR

<<,~',,"'n November 9, 1993, the NRC staff met with representatives of Arizona Public Service Company (APS) to discuss the results and conclusions from the recently completed Unit 1 steam generator eddy current testing.

The licensee met with the NRC staff to present the inspection results, an engineering evaluation of the results, an assessment of its compliance with Regulatory Guide 1. 121, and its current operating plan to extend the economic life of all three units'team generators.

Persons attending the meeting are listed in Enclosure 1.

Selected viewgraphs that summarize important information from the meeting are contained in Enclosure 2.

The entire set of viewgraphs presented at the meeting comprises Enclosure 3.

(based on ultrasonic data).

Additionally, the staff requested the licensee's analysis of several non-expanded tubes present in both steam generators (the licensee referenced a contractor analysis of those tubes).

The licensee committed to provide the additional information and meet again to discuss cycle length.

The staff is interested in obtaining data from both of the other upcoming mid-cycle steam generator eddy current inspections (Unit 3, December 1993; Unit 2, January 1994) in order to better assess the steam generator tube degradation mechanisms present in the Palo Verde steam generators.

Enclosures:

1.

Attendance List 2.

Select viewgraphs 3

Entire viewgraph set

'c w/encl,osures:

See next page Brian E. Holian, Project Manager Project Directorate V

Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation

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(based on ultrasonic data).

Additionally, the staff requested the licensee's analysis of several non-expanded tubes present in both steam generators (the licensee referenced a contractor analysis of those tubes).

The licensee committed to provide the additional information and meet again to discuss cycle length.

The staff is interested in obtaining data from both of the other upcoming mid-cycle steam generator eddy current inspections (Unit 3, December 1993; Unit 2, January 1994) in order to better assess the steam generator tube degradation mechanisms present in the Palo Verde steam generators.

Original Signed By:

Enclosures:

1.

Attendance List 2.

Select viewgraphs 3

Entire viewgraph set cc w/enclosures:

See next page DISTRIBUTION: w enclosures 1

2 Brian E. Holian, Project Manager Project Directorate V

Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation PDV Reading File LJCallan, Acting EAdensam BHolian EBarnhill

EJordan, 3701 ACRS (10),

P315

KPerkins, RV THurley/FHi.raglia JRoe NRC Participants LTran

OGC, 15B18 JHitchell, 17G21 DISTRIBUTION: w enclosures 1

2 3 NRC lE Local PDRs Docket File SEE PREVIOUS CONCURRENCE*

OFFICE NAME PDV LA EBarnhill*

'PDV PH BHolian*

EHCB PDV/0 JStrosneider*

Tguay DATE 12/14 93 OFFICIAL RECORD, COPY 12 14 93 lw

~0 93 12/22 93 DOCUMENT NAME:

PVMTGSUH.119

Arizona Public Service Company CC:

Mr. Steve Olea Arizona Corporation Commission 1200 W. Washington Street

Phoenix, Arizona 85007 IF Palo Verde Jack R.

Newman, Esq.

Newman

& Holtzinger, P.C.,

1615 L Street, N.W., Suite 1000 Washington, D.C.

20036 James A. Beoletto, Esq.

Southern California Edison Company P. 0.

Box 800

Rosemead, California 91770 Senior Resident Inspector Palo Verde Nuclear Generating Station 5951 S. Wintersburg Road

Tonopah, Arizona 85354-7537 Regional Administrator, Region V

U'. S. Nuclear Regulatory Commission 1450 Maria Lane Suite 210 Walnut Creek, California 94596 Mr. Charles B. Brinkman, Manager Washington Nuclear Operations ABB Combustion Engineering Nuclear Power 12300 Twinbrook Parkway, Suite 330 Rockville, Maryland 20852 Mr. Aubrey V. Godwin, Director Arizona Radiation Regulatory Agency 4814 South 40 Street

Phoenix, Arizona 85040 Chairman Maricopa County Board of Supervisors 111 South Third Avenue

Phoenix, Arizona 85003 Mr. Curtis Hoskins Executive Vice President and Chief Operating Officer Palo Verde Services 2025 N. 3rd Street, Suite 220

Phoenix, Arizona 85004 Roy P.

Lessey, Jr.,

Esq.

Bradley W. Jones, Esq.

Akin, Gump, Strauss, Hauer and Feld El Paso Electric Company 1333 New Hampshire Ave., Suite 400 Washington, D.C.

20036 Mr. Ronald J. Stevens, Director Nuclear Regulatory Affairs Arizona Public Service Company P. 0.

Box 52034 Phoenix, Arizona 85072-2034

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Enclosure 1

ovember 9

1993 MEETING TO DISCUSS UNIT 1

STEAM GENERATOR EDDY CURRENT TEST RESULTS List of Attendees Name Hark Radspinner W.

E. Ide Jack A. Bailey Rick Schaller Guy Bucci Joseph Provasoli Kevin Sweeney Doug Hansen John Hall J.

A. Begley Brian Holian Linh Tran

. W.

P.

Ang Ted Sullivan Emmett Murphy Jack Roe Jack Strosnider Kevin Neese Joe Donoghue Or anization APS APS APS APS APS APS APS APS/ISI ABB/CENO Packer Engr. Inc.

NRC/NRR/PDV NRC/NRR/PDV NRC/RV NRC/NRR/EHCB NRC/NRR/EHCB NRC/NRR/DRPW NRC/NRR/EMCB NRC NRC/NRR/DSSA

f 1

INTRODUCTION APS STAFF INTRODUCTION OVERVIEWOF MATERIAL METHODS OF INSPECTION RESULTS NO FREE SPAN AXIALCRACKS IDENTIFIED NO CRACKS VIOLATINGREGULATORYGUIDE 1.121 LIMITS CONCLUSIONS NO ACTIONS REQUIRED TO SATISFY R.G. 1.121 LIMITS ACTIONS WILLBK TAKENTO EXTEND ECONOMIC LIFE OF PVNGS STEAM GENERATORS NO RESTRICTIONS ARE PLACED ON THE OPERATING INTERVALBEFORE THE NEXTINSPECTION

Unitl Eddy Current Testing l993 Palo Verde Unit 1 Eddy Current Exa 'tion SCOPE AND RESULTS

Unitl Eddy Current Testing 1993 INITIALEDDY CURRENT PLY%

~ 100o/o FULLLENGTH BOBBIN

~ 20% TSH AND 01H RPC

~ 20% UPPER HOTLEG RPC SG 11 FINALSCOPE

~ 100% FULLLENGTH BOBBIN

~

21% (2209 TUBES) 01H RPC

~ 100% TSH RPC

~.23% (2519 TUBES) UPPER HLRPC

~ -3.5% (390 TUBES) MISC RPC SG 12 FINALSCOPE

~ 100% FULLLENGTH BOBBIN 20% (2192 TUBES) 01H RPC

~ 100% TSH RPC

~

1P/o (2114 TUBES) TSC RPC

~ <<23% (2519 TUBES) UPPER HL RPC

~

3% (339 TUBES) MISC RPC

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20-29%

30-39%

>40%

NQI NBI REMARKS WEAR ANDSMALL IMPERFECTIONS 146 121 19 AXIAL(SAI,MAI) 7 (ALL TSH)

CIRC (SCI, MCI) 7 (ALLITSH)

VOL(SVQ 45 6-NEW 2-CHANGED 2-TSH/C 8-MBM 27-BLI

'1 (9%)

1 5-NTE, 1-ETL, 1-TEH 5-ID, 2-OD 2-OD 5-ADR PLI I-CODE RESOLUTIONS NQI 138 DTI DSI 20 ADR 76 NDD-71 SVI-5 NDD-127 SAI-2 NDD-36 NDD-20 MAI-1 WEAR-3 SVI-5 BOW/PDP BOW 144 TOTAL PDP 266 TOTAL BW1+ 114 09H+ 12 BW1+ 118 09H+ 42 08H+ 14 08H+ 81 07H+ 4 07H+ 25 NOTE: <<ABOVENUMBERS ARE TUBE COUNT

SG l2 INDICATION SUMMART'0-29%

30-39%

>40%

NQI NBI REMARKS WEAR ANDSMALL IMPERFECTIONS 211 168 36 AXIAL(SAI,MAI) 10 (ALLITSH)

CIRC (SCI, MCI) 76 (ALLITSH)

VOL (SVQ 66 8-NEW 0-CHANGED 18-TSH/C 18-MBM 22-BLI 13 9-NTE, 1-TSH 31-ID, 37-OD, 8-ID/OD

<<DSI OR NQI 18-OD 1-ADR PLI I-CODE RESOLUTIONS NQI 114 DTI 74 DSI 21 ADR 54 NDD-95 NDD-68 NDD-16 NDD-53 SAI-3 SCI-6 SVI-2 SVI-1 MAI-4 WEAR-3 WEAR-1 SVI-Il BOW/PDP BOW 378 TOTAL PDP 344 TOTAL BW1+ 277 09H+ 41 BW1+ 123 09H+ 73 08H+ 57 07H+ 3 08H+ 124 07H+ 24 NOTE: <<ABOVENUMBERS ARE TUBE COUNT

ECT/UTRESULTS o

DETEENK%E CIRCUMFERENTIALEXTENT USING MRPC o

ASSMCED 100% THROUGH-WALLDEPTH OVER ENTIRE CIRCMiCFERENTIAL EXTENT o

SELECTED UT CANDIDATESBASED ON 1.6 INCH LIMIT ALLCIRC INDICATIONS) 1.0 INCH ALLMOLTIPLEINDICATIONSX> 1.0 INCH 17 TUBES INSPECTED WITH CIRC INDICATIONS o

SELECTED IN-SITUPRESSURE TEST CA'NDIDATESBASED ON ECT/UT RESULTS LONGEST CRACKS POTENTIALTHROUGH-WALLPER UT

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Unit1 Eddy Current Testing 1993 ULTRASONIC E ATIONS Y

~ 18 TOTALTUBES (17-TSH CIRCUMFERENTIAL, 1-BW1 VOLUMLTRIC)

~ PROCEDURE UTILIZEDLONGITUDINALAND SHEAR WAVES

~ TEST CONDUCTED WITHOUTEDDY CUXGtENT DETAILEDRESULTS

~ CALIBRATIONSTANDARD REDESIGNED TO INCLUDEID EDM NOTCHES

~ VENDOR ANDUTILITYPERFORMED DETAILEDREVIEW EXPECTATIONS

~ ID/OD ORIENTATION

~ LENGTH COMPARISON WITHRPC

~ DEPTH ESTIMATION

~ VERXF'Y CRACK LIKEOR VOLUMETRIC CONCLUSION

~ ID/OD COMPARISON WITHRPC WAS VERY GOOD

~ LENGTH COMPARISON GOOD, WITHRPC TYPICALLYCONSERVATIVE

~ VOLTE:TRIGINDICATIONCONFIRINED

~ OVERALLFAVOXUbBLECORRELATION

Regulatory Guide 1.121 %valuation Approach DETERMBIEDalAXDHIM SAFETY FACTORS CIRCUMFERENTIALCRACK SIZE TO MEET RG 1. 121 IDENTIFIEDALLCRACKS THATEXCEED OR APPROACH CALCULATED5GGG-5KMBASED ON MRPC RESULTS PERFORMED UT TO FURTHER CHARACTERIZE FLAWS PERFORMED IN-SITUPRESSUIM TESTS TO CONFIRM RG 1.121 SAFETY FAC-TORS 5GGNTAINED

IN-SITUPRESSURE TEST RFWULTS o

5 TUBES TESTED TO 3 TIlNES NORRGU OPERATING DIFFERENTIALPRElSSURE ROW COL MRPC LENGTH IN MAXUT DEPTH %

54/75 54/73 54/71 35/60 48/79 2.01 1.9*

1.67 1.31*

1.33 100 100 100 100 70 o

TEST PROCEDURE TUBE ENDS CAPPED. HYDRO-PUMP INCRF~ES INTERNALPRESSUHE UNTIL TARGET (3900) DIFFERENTIALPRESSURE IS ACHIEVED.

FEEEEORE HELD FOR ROEEOFE GET PRESSURE PLATEAUS.

2 MINUTESAT 1000, 2000, 3000, AND TAR-o ALLTUBES PASSED. ONE TUBE (R35/C60) LEAKEDDUBXVGTEST

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CONCLUSIONS OF RG 1.121 EVALUATION o

SAFETY FACTORS RfhINTAINEDDURING LAST CYCLE o

EXPECT TO MAINTAINSAFETY FACTORS DURING NEXT CYCLE PWSCC TEMPERATURE AND STRESS DEPENDENT EXPERIENCE INDICATESA CONTROLLED RATE OF PROGRESSION SLUDGE LANCINGPERFORMED ODSCC DEFECTS TYPICALLYMUCH Shan% LER THAI%ID DEFECTS SLUDGE PILE EI%VIRONINENTDID NOT CAUSE ACCELERATED GROWTH SLUDGE LANCINGPERFORMED BORIC AGIO TBBATBBBT CHEMISTRY CONTROL

OPERATINGPLANTO EXTENDECONOMICLIFEOF STEAM GENERATORS MODIFICATIONSTO STEAM GENERATORS PLAN TO REDUCE TEMPERATURE TO RETARD PWSCC ACTIONS TO RETARD ODSCC CIRCUMFERENTIALCRACKING ACTIONS TO PREVENT FREE SPAN ODSCC LEAKRATE MONITORING

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ACTIOiVSTO RETARD ODSCC CIRCUMFERE1VTIALCRACEIiVG SLUDGE LANCING REDUCED TEMPERATURE MOLARRATIO CONTROL IRON TRANSPORT REDUCTION ELEVATEDHYDRAZINE BORIC ACIDTREATMENT

ACTIONS TO PREVENT FREE SPAN ODSCC ACTIONS THATRETARD ODSCC CIRCUMFERENTIALCRACKS REDUCED POWER OPERATION PERIODIC POWER REDUCTIONS EXTENDEDPERIODS OF REDUCED POWER

OPERATING INTE'RVALAND

SUMMARY

FREE SPAN AXIALCRACKINGPHENOMENON WAS NOT OBSERVED IN UNIT 1 DIFFERENCES WERE IDENTIFIEDWHICH CANACCOUNT FOR LACKOF FREE SPAN CRACKING NO RESIN INTRUSION IN UNIT 1 DIFFERENT OPERATING HISTORY EARLIERIMPLEMENTATIONOF ELEVATEDSECONDARY PH EARLIERIMPLEMENTATIONOF ELEVATEDHYDRAZINE

OPERATINGINTERVALANDSUMMARF CIRCUMFERENTIALCRACKS DID NOT EXCEED REG. GUIDE 1.121 LIMITS ANALYTICALDETERMINATION FIELD VERIFICATIONBY PRESSURE TEST SLUDGE LANCINGREMOVED PRIMARYCONTRIBUTOR FULLOPERATING CYCLE IS TECHNICALLYJUSTIFIED IMPROVEDLEAKDETECTION HAS BEEN IMPLEMENTED ACTIONS TO EXTEND THE ECONOMIC LIFE OF THE STEAM GENERATORS WILLREDUCE CRACK GROWTH RATE

PViVGS Unit 1 Inspection MEETINGAGENDA INTRODUCTION-RICH SCHALLER t

STEAM GENERATOR INSPECTION RESULTS - DOUG HANSEN ENGINEERING EVALUATIONOF INSPECTION RESULTS - KEVINSWEENEY REGULATORYGUIDE 1.121 COMPLIANCE-MARKRADSPINNER OPERATING PLAN TO EXTEND ECONOMIC LIFE-RICH SCHALLKR OPERATING INTERVALAND

SUMMARY

- BILLIDE

INTRODUCTION APS STAFF INTRODUCTION OVERVIEWOF MATERIAL METHODS OF INSPECTION RESULTS NO FREE SPAN AXIALCRACKS IDENTIFIED NO CRACKS VIOLATINGREGULATORYGUIDE 1-.121 LIMITS CONCLUSIONS NO ACTIONS REQUIRED TO SATISFY R.G. 1.121 LIMITS ACTIONS WILLBK TAKENTO EXTEND ECONOMIC LIFE OF PVNGS STEAM GENERATORS NO RESTRICTIONS ARKPLACED ON THK OPERATING INTERVALBEFORE THE NEXTINSPECTION

November 7993 Palo Verde Unit 1 Steam Generator Inspections Engineering Evaluation

MajorDegradation MecItanissns PVNGS Steain Generators Mechanical Fretting Upper Eggcratc BWI VSI 2

3 4

5 6

7 BW2 Mechanical Fretting Vertical Support OD AxialIndication in thc Frecspan ARC Region 09H 08 07H 08C 45" 45" 07C OD AxialIndication At Flosv Distribution Plate 06H 05H 41" 06C 42" 05C AIcchanical Fretting Babving 04H 43" 04C 41" 24" 03C Cold Leg Corner WUear OD AxialIndication AtHot LcgYubcshect 43 02H 15.5" 01H 16.5" 32.5" OIC TUBESHEET 23.5" OD/ID Circ Indication AtHot LegTubeshcct INLET OUTLET SUPPORT SPACINGS ARE IDENTIFIEDININCHES BETWEEN THE SUPPORT IDENTIFICATION

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PIGS PLUGGING CRITEMA UIR4 PVNGS TECHNICALSPECIFICATIONS 4.4.4.4.a.6 requires Steam Generator tubes to be removed from service iftube defect is greater than 40% ofthe nominal tube wall thickness PVNGS Engineering Plugging Criteria applied for UIR4 is as follows:

20% for Stay Cylinder Batwing and Cold Leg Corner wear 35% for all other tubes previously examined with no indications detected or not inspected 39% > x > 35% for tubes thathad previous indications

> 20% need not beplugged AllPLPs with any detectable wear Allsuspected cracks Volumetric Indications (SVI's) meeting PVNGS evaluation criteria

Disposition ofSVI Indications SVI Eddy current designations are given to tube indications with signals on both the circumferential and axial coils ofthe three coil MRPC A SVI indication may be:

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MBM-Manufacturing BuffMark - OD BLI-Baseline Indication - TypicallyID, possibly mandrel mark from pilgering process Wear from foreign object no longer present OD corrosion related damage such as IGA or pitting SVI Indications are classified by Engineering as new, changed or unchanged

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when compared to previous ECT inspections

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Disposition ofSVI Indications SVI indications are plugged based on the followingcriteria:

Ifthe SVI indication is new or changed from the previous inspection, the tube is a candidate for plugging. Additional factors considered include:

Location - Freespan, support, tubesheet Region Susceptibility for defect growth - ARC, Hot side Associated with a deposit SVI's at fhe tubesheet not considered dents or transition geometry indications are plugged SVI's in the ARC region associated with deposits are plugged regardless of previous inspection results MBMand BLIindications are only plugged ifthe signal is sufficiently strong to mask the presence of a future defect.

SVI indications associated with a PLP location

Unit l SG 1-1 Plugging Sumo>ary 3 TUBES - ARC REGION SVIs (2 NEW, 1 PREVENTATIVE)ASSOCIATED WITHPDP 7 TUBES - STAY CYLINDERBATWINGWEAR-PLUGGED 3 TUBES - BATWINGWRAPPER WEAR PLUGGED 3 TUBES - VERTICALSUPPORT WEAR -

PLUGGED 3 TUBES - COLD LEG CORNER WEAR -

PLUGGED 1 TUBE - MANUFACTURINGBUFF MARK(MBM) INDICATION - PREVENTATIVELYPLUGGED 7 TUBES-AXIALINDICATIONS ATTUBESHEET - PLUGGED 6 TUBES - FOREIGN OBJECTS 4 TUBES WITHWEAR - PLUGGED AND STAKED 2 TUBES WITHPLPS NO WEARPREVENTATIVELYPLUGGED AND STAKED 7 TUBES - CIRCUMFERENTIALINDICATIONS ATTUBESHEET - PLUGGED>

5 TUBES (ID) 2 TUBES (OD) 7 TUBES - NEW OR CHANGED SVIs (NON-ARC), 2 TUBES WITHTUBESHEET INDICATIONS TOTAL TUBES REMOVED FROMSERVICE - 41

Unit 1 SG 1-2 Plugging SnInsnary 7 TUBES - THEORETICALARC REGION SVIs - ASSOCIATED WITHPDP 2 TUBES - STAY CYLINDERBATWINGWEAR - PLUGGED 2 TUBES - BATWINGWRAPPER WEAR PLUGGED 3 TUBES - VERTICALSUPPORT WEAR -

PLUGGED S TUBES - COLD LEG CORNER WEAR -

PLUGGED 13 TUBES - OD VOLUMETRICINDICATION(SVI) ATTUBESHEET 10 TUBES-AXIALINDICATIONS ATTUBESHEET - PLUGGED 2 TUBES - VOLUMETRICINDICATIONS(SVI)AT01H SUPPORT 2 TUBES - ID INDICATIONS (1 BLI, 1 GOUGE) - PREVENTATIVELYPLUGGED 76 TUBES - CIRCUMFERENTIALINDICATIONS ATTUBESHEET - PLUGGED<

31 TUBES (ID) 37 TUBES (OD) 8 TUBES (ID/OD)

TOTAL TUBES REMOVED FROMSER VICE-IZS

TUBESHEET INDICATIONS Circumferential defects found primarily in "Kidney Bean" sludge pile region 80 of 83 tubes affected in sludge pile region Defects found to be divided equally as ID (PWSCC) and OD (ODSCC)

Axialdefects found primarily in tubes with no or incomplete tube expansion Consistent with pattern found in U1R3 inspection Engineering evaluation included "tiered" approach to addressing root cause and RG 1.121 issues 100% MRPC Confirmatory UT examination Industry Review In-Situ Pressure Test Sludge Pattern Review Sludge Lancing performed via handholes installed during U1R4

- Amount removed consistent with sludge map Sludge sample analysis Unit 1 and Unit 2 comparison Review ofIndustry data - Effect ofsludge on stress field/Defect Rate

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FIGURE V-3, CIRCUMFERENTIALINDICATIONS,SG 12.

10/93, ARIZONA PUBLIC SERVICE CO.,

PALO VERDE, UNIT 1

STEAM GENERATOR:

i2 OUTAGE DATA SET Percent:

MCI, SCI CURRENT DATE:

iO/26/93 TIME:

15: 2i: 07 STAYS PLUG620 67

+

MCi 2

o SC1 74 a

150 150 140 140 130 130 120 120 110 110 100 100 90 90 80 80 70==*

70 60 --

50 50 40 40 30 30 20 20 10 10 I

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10 20 30 40 50 60 70 80 90 100 1 10 120 130 140 150 160 170 180 CONAN NUCLEAR.

INC. 8$

FIGURE V-5, SLUDGE LOCATIONAND DEPTH, SG 12 iO/93, ARIZONA PUBLIC SERVICE CO.,

PALO VERDE, UNIT S

STEAM GENERATOR:

i2 OUTAGE DATA SET CURRENT Indication Location:

TSH 0.00 to TSH +i0.00 AND Percent:

SLG DATE:

i'0/22/93 TIME: ii:36: 3B STAYS 67 a

0.0 in - 1.0 in 696 a

1.1 in - l.5 in 610 a

1.6 in - 2.0 in:292 a

2.1 in - 2.5 in 26 a

) 2.5 in 1

a 150 140 150 140 120 iio 100 90 80 70 60 50 4o 30 lD 20 io 130 120 110 100 90 80 70 50 50 40 30 20 10 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 PLP ANALYSIS CONAN NUCLEAR, INC.

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Unit1 Sludge Sampling Table 1: Unit I Sludge Analysis Species Lead Copper Sodium Chloride Sulfur Iron U1R3 Flow Distribution Plate 78 ppm 106 ppm 230 ppm 30 ppm

<50 ppm as SO3 98%

UlR4 Tubesheet 98 ppm 1214 ppm 22 ppm

<9ppm

<9 ppm as SO4 N/A U1R4 Flow Distribution Plate N/A 74 ppm N/A N/A N/A N/A Plant A N/A 50,000 ppm N/A N/A N/A N/A

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Figure 3.

Predicted PWSCC at Explosive Transitions HTMA Tubing 90 Welbull Plot Predlctlons lor HTMATubing Tf ~ 3.4 x Tf of LTMA

.63

.50

.10 Fraction of Tubes

.01

.001 From Figure 1

Thot ~ 615 4F LTMATubing a 2.91 Note:

No PWSCC observed at 611 'F p ant at 6.7 EFPY and 595 4F plant at 9.3 EFPY 611 'F 600 OF 595 oF

.05 02

.005

.002 10 Sewice Time (EFPY) 100

Figure 6.

Time to 10% PWSCC for LTMAand HTMA Tubing 160 150 140 130 120 110 100 90 to 10%

80 PWSCC 8 60 50 40 30 20 10 0

600 HTMATubing High Susceptlblllty LTMATubing 605 HTMATubing 8est Estlma te 610 Temperature,

'F TMA Tubing Low Susceptlblllty 615 620

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ARCRE'GION INDICATIONS Based on 100% Bobbin Coil ECT and comprehensive MRPC program ofthe highly susceptible region - No axial crack indications were found in the Unit 1 steam generators The ARC inspection program found:

Evidence of deposit formation Evidence of"bowing" Evidence ofslight, slow growing corrosion damage (SVI's) associated with deposits UT inspection of RI22C101 with B%1+0.06 SVI confirmed indication was not an axial crack Engineering Evaluation

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ARC theory based on ATHOS modeling considered valid for all PVNGS Units, Unit 1 provides evidence that improved chemistry designed to control tube/tube support ODSCC may be effective in controlling ARC defect growth rate.

No evidence of resin intrusion based on secondary side inspections Introduction ofBoric Acid Treatment fo further control defect growth rate.

Power Reduction Program - additional intermediate defect management action

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FOSAR INSPECTION First Time Visual Inspection ofTubesheet -FOSAR (Foreign Object Search and Retrieval)

FOSAR Results correlate well with "known" PLP (loose part) locations based on ECT FOSAR found objects not identified by ECT To be expected based on material and location of object First Indication ofOperationally Introduced Foreign Objects Brass Castle Nuts - Feedwater Heaters Feedwater heaters inspected - nuts replaced with alternative material Unwedged nuts removed via FOSAR equipment Nuts left in Steam Generator not believed fo be ofsize or material to wear Alloy600 tubing Archard Equation V=KFD Bounded by Study 02-MS-A72 Post Sludge Lancing FOSAR indicated sludge was removed - no evidence of tenacious sludge

Conclusions No axial cracks found in the ARC region - Comprehensive KCT inspection ofsusceptible region Circumferential PWSCC and ODSCC found at fop of tubesheet in sludge pile region Defect mechanism understood Defect Rates within industry estimates No defects exceeded Reg Guide Structural Limits Axial Cracks in unexpanded tubes consistent with findings from UlR3 Limited family of tubes affected Sludge Lancing and FOSAR Program accomplished objectives Chemistry program may control ARC defect initiation and growth

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FIGURE Vll-1 Circumferential Fiaw Size Evaluation 10000-9000-8000-Q)

CL 7000-6000-D.

E (D

5000-4000-0)

CL g

3000-CQ 2000-Unflawed Burst Pressure I I I I ~ I ~ ~ I ~ I ~ I I I I I I I I I I I I I I I I I I I I I I IIIIII I I I I IIII I I IIII I I I I IIIgIIIIIIIII~ I ~III I I ~ ~ I I I I ~ ~ ~ ~ ~ I ~ I I I ~ ~ I I I I I I ~ I I I I I ~ ~ ~ I I I I I I I ~ I I I Axial Lateral Force Limit Restraint ~~I

\\

3x~P No Lateral Restraint~I 1000-ap

\\

CA 0

'928 93

)QZ F'~9" I

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0 30 60 90 120 150 180 210 240 270 300 330 360 Total Throughwall Crack Angle P;tIle 37

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o R35/C60 TEST RESULTS LFAKAGENOTED AT 2000 PSI HMKRATE MEASURED AT 16 GPD AT 3000 PSI LF~ RATE MEASURED AT 90 GPD AT 3900 PSI, EQUALTO CAPACITYOF MK)ROPUMP.

LFdiKRATE EXCEEDED PUMP CAPACITYDURING IK:TEST. 3500 PSID PRES-SURE ACHIEVED.

0 ALLTUBES INSPECTED BYMRPC FOLLOWINGPRESSURE TEST. NO CHAIWGE IN DEFECT SIGNAL o

CONCLUDED ALLTUBES hDQNTA]WEDSPECIFIED SAFETY 1LDiRGINAGAINSTRUP-TURE

SVI &TUBESHEETAXIAK.1.121 EVALUATION SVI EVALUATION ALLINDICATIONSLESS THAN 63% ALLOWABLEDEPTH PER PREVIOUS ANALYSISWXGCHASSUMED 360 '5HFORM WALLTHINNING 0

AXIALCRACKS IN TUBESHEET ALLINDICATIONS,WITHONE EXCEPTION, LESS THAN0.787 INCH LONG ALLOWABLEFOR 100% THROUGH-WALLDEFECTS PER PREVIOUS ANAL-YSIS FOR UNIT2 AXIALCRACKS EXCEPTION IS ASINGLE ID DEFECT 1.03 INCHES LONG, LOCATED WITHINTHE CONFINES OF THE TUBESHEET AND 7P/o THROUGHWALL.

CONSIDERED TO BE WITHINRG 1. 121 REQUQu< MENTS SINCE STRUC-TURALINTEGRITYIS MAINTAINEDBYTHE TUBESHEET. DEFECT NOT INDICATIVEOF AN ON-GOING DAMAGEMECHANISM

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