ML20058K412

Status Rept,Indian Point Unit 2 Mid-Cycle Steam Generator Insp Presentation to Nrc

ML20058K412
Person / Time
Site:	Indian Point
Issue date:	06/30/1990
From:	WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:
Shared Package
ML100331447	List: ML100331446 ML100331448 ML20058K412 ML20058K415
References
SG-90-06-022, SG-90-6-22, WCAP-12626, NUDOCS 9007060016
Download: ML20058K412 (85)

Text

....

HESTINGHOUSE CLASS 3 HCAP-12626~

SG-90-06-022-f..

STATUS REPORT

'. l INDIAN POINT UNIT NO. 2 MID-CYCLE STEAM GENERATOR INSPECTION PRESENTATION TO NUCLEAR REGULATORY COMMISSION I

Issue date:

June 1990 i

PREPARED FOR CONSOLIDATED EDISON COMPANY i

f HESTINGHOUSE ELECTRIC CORPORATION NUCLEAR SERVICES DIVISION P. O. BOX 355 PITTSBURGH, PENNSYLVANIA 15230 Copyright by Hestinghouse Electric 1990, e All Rights Reserved 9007060016 900627 ADOCK0500g,gg7 DR.

06000:1D/061490 l

l TABLE OF CONTENTS FOREHORD ii OVERVIEH iii

~ TITLE FACE 1

AGENDA 0F PRESENTATION 2

1.

ILTRODUCTION 2

2.. FECENT ACTIONS, OPERATING HISTORY

'(ND RADIATION EXPOSURE 3

[.

3.

MID-CYCLE INSPECTION RESULTS AND

'4 CURRENT. REPAIRS.

16 1

4.

BOAT SAMPLE RESULTS 23 l

L 5.

INTEGRITY ~ ANALYSIS 52 6..

ROOT CAUSE 78 7.

FUTURE PLANS-80 1

l l

l:

l 0600D:1D/061490 i

FOREHORD This non-proprietary report bears a Westinghouse copyright notice.

The NRC is permitted to make the number of copies of this report necessary for its internal use and such additional copies which are necessary in order to have one copy available for public viewing in the appropriate docket files in the public document room in Washington, D.C. and in local public document rooms as may be required by NRC regulations if the number of copies submitted is insufficient for this purpose.

The NRC is not authorized to make copies for the personal use of members of the public who make use of the NRC public l

docament rooms.

Copies of this report or portions thereof made by the NRC must include the copyright notice.

06000:10/061490 11

OVERVIEW In February,1990, Consolidated Edison's Indian Point Unit 2 was taken off line to perform a scheduled mid-cycle inspection of the steam generator girth welds and feedwater nozzles.

This inspection effort included visual (VT) and magnetic particle (MT) of the girth welds, and visual and magnetic particle or liquid penetrant (PT) on the feedwater nozzle inner radius areas.

Cracking was found to exist in all areas inspected.

A meeting was held on March 14, 1990, with the NRC staff to. provide &t update with respect to current field inspections, laboratory examinations, engineering evaluations and analyses, and future mitigating action plans.

The presentation materials entitled " Status Report Indian-Point Unit No. 2 Mid-Cycle Steam Generator Inspection, March 14, 1930" follow.

E l

i l-L 06000:1D/061490 iii

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7 i

STATUS REPORT t

INDIAN POINT UNIT NO. 2 i

MID-CYCLE STEAM GENERATOR INSPECTION 1

i I

MARCH 14, 1990 i

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AGENDA 1.

INTRODUCTION 2.

RECENT ACTIONS, OPERATING HISTORY, AND RADIATION EXPOSURE 3.

MIDCYCLE INSPECTION RESULTS AND CURRENT REPAIRS 4.

BOAT SAMPLE RESULTS 5.

INTEGRITY ANALYSIS 6.

R0or CAUSE 7.

FUTURE PLANS l

t 2

RECENT ACTIONS TO ALLEVIATE STEAn GENERATOR INDICATIONS i

1.

REMOVAL OF DOWNCOMER FLOW RESISTANCE PLATE - JUNE OF 1989 4

2.

INSTALLATION OF TIMER TO DELAY CLOSURE OF THE' MAIN FEEDWATER BYPASS REGULATING VALVES /

REACTOR' TRIP - SEPTEMBER OF 1989-3.

INSTALLED TAPS ON CONDENSATE DISCHARGE AND RETURN LINES FOR OXYGEN SCAVENGING SKID.

1 l

.___,._-_______j

PLANT OPERATING CHARACTERISTICS

" CONSOLIDATED EDISON SHALL MONITOR THE NUMBER OF

TRIPS, HOURS AT HOT STANDBY AND WATER CHEMISTRY EXCURSIONS.

IF ANY OF THE ABOVE EXCEEDS THE PERFORMANCE DURING THE ENTIRE PREVIOUS FULL OPERATING CYCLE, YOU SHALL PROMPTLY INFORM THE STAFF."

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- ~

- ' ' ~

^ -

- - ' ' " ' - - ' ~ ~ - - - ' - - " - -

MAJOR EVENTS 4

i 1.

JUNE 28, 1989 TO JULY 28, 1989

- COVERS RCS HYDRO AND PLANT STARTUP FROM f

1989~ REFUELING OUTAsE i

2.

OCTOsER 24, 1989 TO NOVEMBER 23, 1989

- COVERS SHUTDOWN ACTIVITIES IN CONNECTION f

j WITH REPAIR ACTIVITIES ON INSPECTION PORTS AND STARTUP 3.

DECEMBER 10, 1989 TO DECEMBER 14, 1989 A)

1. 22 STEAM GENERATOR CHEMISTRY LINE LEAK -

c l

HOT SuUTDOwN l

s)

REACTOR TRIP ON low TURBINE OIL PRESSURE q

CONTROL l

4.

DECEMBER 23, 1989 TO DECEMBER 30, 1989

- REACTOR SHUTDOWN FOR REPAIR OF PRESSURIZER SPRAY VALVE 5.

FEBRUARY 23, 1990 TO APRIL 3, 1990

- SHUTDOWN FOR MIDCYCLE STEAM GENERATOR INSPECTION

J i

SUMMARY

1 F

1 1.

FoUR PLANNED SHUTDOWNS AND ONE

'i i

REACTOR TRIP 3

1 2.

183.3 HOURS AT hot STAND 8Y FoR CURRENT i

CYCLE CoMPAIRED WITH 502.2 HOURS FoR THE PREVIOUS CYCLE i

3.

hot STAND 8Y.-DEFINED AS RCS > 200 F WITH

. AUXILIARY FEEDWATER IN OPERATION.

4.

PARAMETERS RECORDED AND EVALUATED.

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CYCLE.10 CHEMISTRY TRANSIENTS

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CONDENSER LEAKS' i

JULY 17,1989 (power reduction to 80% required - 60 ppb Q m)

AUGUST 23,1989 SEMEMIER 11.1989 l

NOVEMIER 24,1989 DECEMBER 26,1989 UNIT START UP JULY 2,1989(8 day,8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> hold at 30% power)

NOVEMBER 16, 1989 (30 hour3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> hold)

DECEMBER 11, 1989 (6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> hold)

DECEMBER 13, 1989 (6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> hold)

DECEMBER 26, 1989 (6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> hold) m

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i INDIAN POINT 11' CHEMISTRY PERFORMANCE INDEX (CPI) r 2-1A -

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1989 - 135 MANRen I

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1990 - 145 MANREM J

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i INDIAN POINT 2 STEAM GENERATORS I

f INSPECTION AND REPAIR i

1 0 INSPECTION PROGRAM j

0 STATUS TO DATE O INSPECTION RESULTS 0 REPAIRS l

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16

1 INDIAN POINT 2 STEAM GENERATORS J

INSPECTION PROGRAM O

GIRTH WELDS 1/3 0F 22 AND 23 IF INDICATIONS FOUND THERE 100% 22 AND 23 AND 1/3 0F 21 AND 24 IF INDICATIONS FOUND, THEN 100%

N0ZZLES / BRACKETS i

LOWER 1/2 0F 22 AND 23 i

IF INDICATIONS FOUND THERE LOWER 1/2 0F 21 AND 24 IF INDICATIONS FOUND, THEN EVALUATE y

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INDIAN POINT 2 STEAM GENERATORS GIRTH WELD SG21 SG22 SG23 SG24

'I 1990 # Or 42**

26 14 10 INDICATIONS MAX.

DEPTH

• 0.36" 0.53" 0.28" 0.34" Ave.

DEPTH 0.13" 0.11" 0.08" 0.16" 4

• DEPTH OF GRINDOUT

• • 4 ADDITIONAL INDICATIONS WERE SEEN BOVE THE MT INSPECTION ZONE IN AN APPARENT TEMPORARY WELD ATTACHMENT d

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$ LOPES 21 31 3

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I INDICATIONS PRESENT SG21 SG22 SG23 SG24 N0ZZLE 0

1 AT FW BRACKET YEs YEs 4

• NoT YET INSPECTED E

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INDIAN POINT 2 STEAM GENERATORS 4

REPAIRS l

0 REMOVE INDICATIONS l

O REWELD AS'NEEDED l

GIRTH WELDS SG 21 REMOVE INDICATIONS ONLY I

SG 22 AFTER REMOVAL OF INDICATIONS BY GRINDING, NO AREA WILL BE LEFT WITH EXCAVATIONS GREATER THAN 0.70 IN.

SG 23 REMOVE INDICATIONS ONLY l

SG 24 REMOVE INDICATIONS ONLY 1

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METALLURGICAL INVESTIGATION OF THE RE-OCCURRENCE OF STEAM GENERATOR GIRTH WELD CRACKING AT IP 2 p

l GUTTI V. RAO WESTINGHOUSE NATD i

23

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NAJOF TASKS l

1.

SURFACE EXAMINATIONS IN THE AS-RECEIVED CONDITION (UGHT OPTICAL &

i SEM TECHNIQUES) 2.

NDE EXAMINATIONS (MT & PT) 3.

METALL.OGRAPHIC EXAMINATIONS BY (LOM, SEM TECHNIQUES) 4.

FRACTOGRAPHIC EXAMINATIONS (LOM, SEM

& TEM TECHNIQUES) 5.

HARDNESS MEASUREMENTS (KNOOP &

ROCKWELL) 6.

CHEMISTRY EXAMINATIONS (EDS &

MICROPROBE ANALYSES) e l

24

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4 METALLURGICAL EXAMINATION 0F BOAT SAMPLES l

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e To ESTABLISH THE CAUSE AND MECHANISM OF CRACKING 0 To ouvrLOP INFORMATION THAT WOULD BE HELPFUL IN FORMING CORRECTIVE ACTIONS l.

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o BOAT B SG #22 PRavIousLY WELD REPAIRED AREA i

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SUNRYl'F HARDNESS TRAVERSE RESULTS BOAT-A. X-N1 SG21 KNOOP ROCKWELL SA HARDNESS'EOUIVALENT LOCATION

~~.~

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A.

Section M1 a

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MicroProbe Analysis of Wald and Base Materials b

Weicht Percent 8 oat Samole Chemistry i

Weld New Weld Base Metal-Old Weld Stock Weld Boat Boat Boat Boat-Element Wire Samole A Samole B Samole A Sample B 51

.644

.416

.473

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.265 i

CR

.008

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.590 MN 1.759 1.244 1.617 1.345 1.276 FE 96.364 96.113 95.422 96.512 95.747 i

L N1 0.090 1.236 0.085 0.127 0.160 CU 0.268 0.292 0.328 0.352 0.459 a

• No Appreciable Differences in Weld Metal Chemistry R

50

J CONCLUSIONS i

oJSURFACE PITTING CAUSED BY THE

-PRESENCE OF 0XYGEN,

COPPER,

?AND LOCAL STRESSES CONTRIBUTED -

TO CRACK INITIATION.

L k@:CRACKINITIATIONBEHAVIOR IN-THE PREVIOUS AND CURRENT

[

BOATS APPEAR-TO BE CONSISTANT WITH STRESS CORROSION MECHANISM.

D TOTAL CRACK GROWTH APPEARS TO BE CUMULATIVE cw ENVIRONMENTALLY l

ASSISTED CRACK GROWTHS UNDER-STATIC AND FLUCTUATING LOADS l.

l 51

INTEGRITY ANALYSIS i

Determination of Critical Flaw Size l

i e

Leak Before Break Demonstration of Operating Safety Margin e

1 l

I-i 02ses os s2so.so.,

gg

CRITICAL CRACK DEPTH DETERMINATION p

h Material: A302B L

[

Fracture Toughness:

Use K a Curve i

1 Upper Shelf Toughness:

200 ksi(In Governing Transient:

Reactor Trip Lowest Temperature: 260 F Critical Flaw Depth:

Exceeds 50 Percent of Thickness, Regardless of Grinding Depth.

g 0259K43129010 2 53

RTwoT DETERMINATION Base Metal (From Matl. Test Cert.)

10 F Weld Metal (Weld Qualification Tests) 10-30 F-HAZ (From Gleeble Testing)

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1 9

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+ !

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l I

SUMMARY

OF GlRTH WELD STRESSES IN GRIND REGION O 9

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1

SUMMARY

OF MAXIMUM AXIAL STRESS PRESSURE LOADING 1

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Stress Intensity Factor vs. Flaw Depth: 1.0 Inch Grind 61

y.

LEAK BEFORE BREAK issue:

Will a Crack Grow to a Through-Wall r

Configuration and Produce a Measureable Leak Before Instability:

Crack Growth Morphology o

instability Flaw Length Calculation e

e Experience o

Results i

li.

n

= 9M9A ujoww 10-8 g

ll:.

CRACK GROWTH MORPHOLOGY Crack Depths Are Uneven - Promotes Penetration e

Locally Mechanism of Crack Penetration is Stress Corrosion /

e Corrosion Fatigue, A Slow Steady Process Material Toughness is Quite High, Ductile Fracture e

Would Be Expected Due To High Temperature Field Experience Supports Leak Before Break e

l l

l l

l J259x 03 f.*W 10-10 l

63

INSTABILITY FLAW LENGTH CALCULATION Percent Of Geometry Critical Length Circumference 0.5 inch Grind 185 in.

36

.75 inch Grind 185 36 1.0 inch Grind 185 36 1.25 inch Grind 175 34 i

1 l

l l

\\

int 9A Os e, w he il 64

CONSEQUENCES OF A THROUGH-WALL CRACK Leakage Occurs No Forces Are Generated, So No Asymmetric Loads No impact On The Primary Pressure Boundary i

3 b

O4

\\hhj\\S 65 1

DEMONSTRATION OF OPERATING SAFETY MARGIN E-e

. Goal e-Overall Approach Crack Growth Rates Determined o

Allowable Flaw Depth ut$vA ultJw 1014 66

r GOAL: To ENSURE THAT AN ADEQUATE MARGIN OF SAFETY IS MAINTAINED THROUGH THE CURRENT OPERATING CYCLE.

i I

67

OVERALL APPROACH Allowable Fracture Toughness = K a + 6 i

200 ksi(Ii1 + ff = 141.4 ksi lii)

Stress intensity Factor Determination: Raju &

i Newman e

Flaw Shapes Considered:

a/l = 0.01,0.1,0.167 L

1

)

1 I

68

i CRACK GROWTH RATE DETERMINATION 0PERATING HIST 0aY USED PnEv10us CYCLE MAXIMUM CRACK GROWTH (388 DAYS)

S/G21 : 0.30 IN.

22 : 0.949 23 : 0.286 24 : 0.339 l

RECENT PANT-CYCLE MAXIMUM GROWTH (212 DAYS)

S/G21 :

.400 IN.

(ZONE 2, #90) e 22 : 0.53 IN.

(ZONE 6, #21) 23 : 0.28 IN.

(ZONE 12,#5) i 24:

0.34 IN.

(ZONE 6, #8)

MAXIMUM CRACK GROWTH pea DAY:

.PnEv10us CYCLE RECENT PART CYCLE l.

S/G 21;: 0.0008 IN/ DAY S/G 21 : 0.0018 IN/ DAY 22 : 0.0024 22 : 0.0025 23 : 0.0013 23 : 0.0013

~

24 : 0.0009 24 : 0.0016 69

TOTAL CRACK GROWTH = GROWTH PER DAY X DAYS OF SERVICE DAYS OF SERVICE ANTICIPATED = 313 TOTAL MAXIMUM GROWTH ESTIMATES FOR 313 DAYS:

S/G 21: 0 56 IN.

22: 0.78 IN.

23: 0.41 IN.

24: 0.50 IN.

l 70

{

ALLOWABLE FLAW DEPTH CALCULATION e

Goal:

What Flaw Size Would Grow to the

)

Allowable Depth During the Next 313 Day Period Allowable Final Depth = Depth at which K = K n/d i

Allowable Final Depth: Flaw Shape a/l = 0.01 e

0.5 inch grind

> 1.0 inch 0.75 inch grind 0.95 inch 1.0 inch grind 0.94 inch Allowable Final Depth: Flaw Shape a/l = 0.1,0.17 o

0.5 inch grind

> 2 inches 0.75 inch grind

> 2 inches 1.0 inch grind

> 2 inch Note: Allowable Finalis From the Base of the Grind l

l O/W A uJ I.'W 19 21 7}

O i

All Ground Areas Meet the Integrity Criteria e

Maximum Projected Growth is Within the Allowable Growth o

What if Flaws Were Missed?

How Big Could These Missed Flaws Be, and Still Meet e

the Acceptance Criteria for Future Growth?

)

The Answer is Dependent on the Specific Generator, e

the Grinding Depth and the Flaw Shape.

i Results are Shown on the Charts Which Follow.

e utsv4 Os tevo iu 2J p

-. ~

0

v. n ig ja 0.g at 0.8 0 0.7

.E

• 0.6 O

$ 0.5 a.

l d 0.4 2E g 0.3 0.2 0.1 -

0.0 0.0 0.1 0.2 0.3 0.4 0.5 FLRW SHPE (c/l)

Allowable Flaw Depth as a Function of Shape: 0.5 Inch Grind 73

f 1.0 te n

0.9 er 0.8 i

0 0.7

.5

• 0.6 O

E 0.5 u.

d 0.4 3g 0.3 0.2 0.1 1

0.0 0.0 0.1 0.2 0.3 0.4 0.5 FLRW SHAPE (c/I)

J Allowable Flaw Depth as a Function of Shape: 0.75 Inch Grind 74

1.0 tl D

0.9 0.8 0 0.7 E

• 0.6 O

$ 0.5 0.4 n

j 0.3 0.2 -

0.1 -

0.0 0.0 0.1 0.2 0.3 0.4 0.5 i

FLRW SHAPE (o/l) 1 l'

Allowable Flaw Depth as a Function of Shape: 1.0 inch Grind 75

AN ILLUSTRATION OF THE USE OF THE ALLOWABLE FLAW DEPTH CHARTS Assume a 1.0 inch Grinding Depth, and S/G 22.

e From the Applied K, We Know that the Maximum e

Allowable Depth for a Flaw With a/l = 0.01 is 0.94 Inch.

From the Projected Growth, We Find that 0.78 Inches of Growth Would Be Calculated (0.0025 x 313).

Therefore, a Crack as Deep as 0.160 In. Could Be e

Missed, and the Acceptance Criteria Would Still Be i

Met For a Flaw With all = 0.01.

l (This Point is Part of the Line on the Chart)

What is the Likelihood That Such a Flaw Could Be e

' Missed?

The Flaw Would Be 0.160 Inch Deep, and 16 Inches e

Long, Which Would Be Extremely Unlikely to Be Missed.

0259K431290 to 27 76

d CONCLUSIONS Cricical Flaw Size is Very Large e

Leak Before Break Has Been Demonstrated o

All Cracks Have Been Removed, Thus Satisfying e

Section XI Postulated Future Growth is Within Allowable o

Guidelines l

.us n,a. sv nu a 77

Roor CAURE SUGGESTIONS o GROWTH IS DUE TO A COMBINATION OF:

- ConnosION FATIGUE CRACK GROWTH

- STATIC LOAD CRACK GROWTH I

i i

l 78

~

CuMutATIva GROWTH bsCC,LT TOTAL dsCC. ACCT b CORROSION

=

+

+

FATIGUE (SL0w, (FAST, INTERMITTANT SLOW, CYCLIC CONTINUOUS HYDRO + HOT STANDBY)

OP Paassune 700 psi) i i

i 8

i n

g h' 79

l FUTURE PLANS 1

1. DETERMINE BEST METHODS TO MINIMIZE OXYGEN.

2. CONTINUE MONITORING CONDITION OF CONDENSERS TO DETERMINE REMAINING LIFE WITHOUT DETRIMENT TO STEAM GENERATOR LIFE.

CONDUCT CORROSION PRODUCT TRANSPORT SURVEY.

j 1991 REFUELING OUTAGE

1. EXAMINE 1/3 0F THE CIRCUHFERENCE OF FOUR STEAM GENERATORS GIRTH WELDS

2. INCLUDE ALL WELDED AREAS IN 22 GIRTH WELD

3. IF INDICATIONS ARE FOUND, THEN GO To 100%

4. EXAMINE N0rztE AREAS

5. REPAIR AS NEEDED

6. EVALUATE WELDED AREAS TO DETERMINE ARRESTING VALUE.

7. REPLACE ONE CONDENSER WITH TITANIUM TUBES i

80

_ _ _.....