ML20077M949

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Rev 2 to SI-83-002, Fracture Mechanics Evaluation of Observed Flaw Indication in 22-Inch Pipe to End Cap Weld 22-02-2-22
ML20077M949
Person / Time
Site: FitzPatrick Constellation icon.png
Issue date: 08/18/1983
From: Gerber T, Giannuzzi A, Riccardella P
STRUCTURAL INTEGRITY ASSOCIATES, INC.
To:
Shared Package
ML20077M911 List:
References
SI-83-002, SI-83-002-R02, SI-83-2, SI-83-2-R2, NUDOCS 8309120462
Download: ML20077M949 (25)
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Text

4 f}.

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REPORT NO. SI-83-002 Revision 2 i

St Project No. PASNY-02 1

1 FRACTURE MECHANICS EVALUATION OF OBSERVED FLAW INDICATION IN 22-INCH PIPE TO END CAP WELD 22-02-2-22 James A. Fitzpatrick Nuclear Power Plant j ,,

~l Prepared By: N1 -

Abf55te: 8!//!f)

" /'

Anthony J. gynuzzi /

l Prepared By:

Date: 8 .!8 3 g '

! Thomas L. Gerber 1

Reviewed and g/

Approved By: Date: 6 //

.1 Peter C. Ricchfdella' ,

/ /

I J

8309120462 830824 PDR ADOCK 05000333PDR G 7 g ,.,,_

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TA. zA,t

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REVISION CONTROL SHEET I

DATE REVISION REMARKS SECTION PARAGRAPH (5)

All All 7/28/83 0 Initial Issue

, All. All 8/10/83 1 Editorial Modifications 2.0, 3.0 All + Tables 2-7 8/18/83 2 Modified Pressure Stress n . f r^ 4.0, 5.0- All 8/ 18/ 83 2 Added Safety Margin q c '4, 3.: ^

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I 1 TABLE OF CONTENTS

-1 1

P_ age 1.o . Introduction . . . . . . . . . . . . . . . . . . . . I

- .. ..e. - ..

4 2.0 Allowable Flaw S:sa Determination. . . . . . .

! ',' ,3.6.'.. Creek. Growth Analysis . . . . . . . . . . .6

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y, p- ,' :, p<.

  • ,1 l ! - '"f b.. ,' .

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.0 ,. Safety Margin . . . . . . . . . . . . . . .

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1.0 INTRODUCTION

1 A fracture mechanics evaluation was performed on an ultrasonic indication detected in the recirculation system manifold at the Fitzpatrick Nuclear Station. 'Ihe analysis I is based on the recently approved ASME Section XI flaw evaluation procedures and .y acceptance criteria for austenitic steel piping QWB-3640 and Appendix X). As a ..

conservative assumption, the indication was assumed to be an intergranular stress ,

corrosion crack QGSCC), and the analysis,was perform,ed to' produce a best estimate

.-. ": .'.::4.'3 . u upper bound for the crack growth,' rate.,of this suspected;IGSC,C.agwell . .;. as determine -

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the allowable end-of-life flaw size for this location. ,,',

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'Ihe indication was located in the manifold to end cap girth weld, identified int 22-02-2-22 in Figure 1-1. As illustrated in Figure .1-2, the indicatiod was 1

1

,u m ,

conservatively sized at a depth of 0.195 inches and a length (20% DAC to 20% DAC) of 1.9 inches. 'Ihe UT indication was reported as a circumferential indication adjacent to the weld fusion line on the weld inside diameter at approximately the two o' clock position Gooking out from the manifold).

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S TRUCTUR AL i

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- _ _ _ _ . . _ , _ . _ - . . - . _ , ~ _ _ _ . , - . _ . . _ . _ _ _ . - - , . . . _ _ _ _ _ . _ _ . _ _ _ _ _ . . . . . _

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- 12" Diameter Risers ~

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End Cap y

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n G Weld No. 22-02-2-22 22" Diameter Manifold

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FIGURE 1-1. PARTIAL ISOMETRIC OF RECIRCULATION 59 ma MANIFOLD 8tiDWING  ?

SUBJECT WELD -

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4 ' 22" Diameter End' A 4 Manifold Cap 1 _ ,

CROSS SECTION VIEW I

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.96" 195" 1

dW A-A FIGURE 1-2. CROSS SECTION OF WELD 22-02-2-22 3 SHOkilNG ULTRASONIC INDICATION 3 > S r QUCTLR AL

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2.0 ALLOWABLE FLAW SIZE DETERMINATION, De maximum allowable size for the observed indication, at the end of a defined period of operation. has been determined using the net section collapse theory of structural failure to ensure that the presence of the flaw does not reduce the margin r .

  • to fallwe below that implicit in the original design code for construction of the f ,g piping.

- his analysis was performed using ASME Section XI, Table IWB-3641-1

2. hated here as Table'i). For a circumferential end cap flaw of the type being

. 54

  • esud,here, the only primary stress condition is due to internal pressure which

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,dI-[Ihas been conservatively. calculated using a 1274 PSI de

..w m' ef d4 measwed wau thicknessJof 0.94 inches. his, the presswe stress is 6994 PSI, and

~the primary stress ratio is given by:

y <.-

. .; g .

Pm + Pb = 6,994 , y

.Sm 16,900 g g Mf 4 1 ..

w. mpg 3y.a , 4,..m . .

De non-dimensional flaw length is:

E =

I9 cire 1T(22) = .03 Conservatively entering Table 1 at the lowest tabulated values of these parameters

(.6 and .1), results in an allowable end-of-period flaw of 75% of the wall thickness or 0.72 inches. ,

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ASME SECTION XI TABLE IWB-3641-1 1 - ,

l ALLOWA8LE ENDOFINSPECTION PERIOD i! -

SIZE FOR CIRCUMFERENTIAL FLAWS i

1..,,,_i. .

3i:c'd.m up.y .e NORMAL CONDITIONS

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Ratio of Length to Circumference (1)

Pan + Pb 0.1 0.2 + 0.3 0.4 0.5 or more

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N s hhNd h,, , r :u. Ratie of Fisw Depth to Thickness .

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.- F g.9 0.75 0.75 0.68 0.56 0.48

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' O.S 0.75 0.75 0.72 0.62 0.52 0.75 0.75 0.75 0.68 0.58 0.7 0.75 0.75 0.75 0.73 0.83 j 0.8 l (1) Pm e Primary Membrane Stress J Pb = Primary Bending Strepe Sm = ASME Code Design Stress at Temperature (2) Crack Depth = a for a Surface Flaw 2a for a Subsurface Flaw j (4 IWB3514-3 Standarda Govern '

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3.0 CRACK GROWTH ANALYSIS Fracture mechanics crack growth calculations were then performed to determine the permissible period of operation during which the observed fla.w is predicted to grow to the above allowable. 'Ihese calculations assumed a finite length eliptical flaw subjected to inside surface weld resadual stress of 30 Ksi and a membrane pressure stress of 6.994 Ksi. Best estimate and upper bound crack growth laws for use in the calculations were obtained from Electric Power Research Institute generated crack

_ growth rate data for IGSCC in sensitized stainless steel in a BWR environment J (Figure 3-1). 'Ihese data include both furnace sensitized and weld sensitized 1 material, which are represented by the upper bound and best estimate curves in Figure 3-1, respectively. 'the through wall residual stress distributions used for these calculations are illustrated in Figure 3-2. Also shown in this figure are a large body

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of residual stress data for large diameter, stainless steel pipe welds which have been obtained from laboratory prepared pipe specimens as.well as from one field pipe to -

safe end joint removed from a boiling water reactor after 13 years of operation. 'Ihe best estimate residual stress curve (curve A) provides a reasonably conservative

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bound of the experimental data for pipe sizes comparable to the 22 inch manifold.

'Ihe upper bound residual stress distribution curve (curve B) approximates residual stress data cbtained for smaller diameter pipes (of the order of 6 inch to 12 inch Schedule 80 pipe), and is much more conservative than the large pipe data from the I

crack growth standpoint.

g' Figures 3-3 and 3-4 and the supporting Tables 2 through 7 present the analytical crack growth rate results for this pipe to end cap joint. In Figure 3-3, best estimate, weld sensitized crack growth rates for the observed indication are presented as a ,

1 function of time for various initial crack depths. These curves are based on the best )

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estimate residual stress distribution for 22 inch diameter pipe (curve A in Figure 3-2). For the UT reported flaw depth, the crack (assuming it is IGSCC) may grow to a depth of approximately 30% of wall in 20,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> and to a depth of approxi-mately 40% of wall in approximately 50,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />. As the flaw size approaches 50%

or more of wall, however, the crack is predicted to arrest since the stress intensity approaches zero. Dus the observed flaw is not predicted to exceed the 75% of wall allowable for the entire plant design life on a best estimate basis.

Parametric studies were also performed to evaluate the sensitivities of the above analysis to uncertainties in the crack growth law or residual stress. Figure 3-4 presents crack growth rate results for a 20% of wall crack using the furnace sensitized, upper bound crack growth law (Figure 3-1) and the best estimate residual stress distribution. One observes from this curve that the crack growth rates are increased only slightly compared to the best estimate crack growth rate case, and the same conclusion applies regarding not exceeding the 75% allowable. D us the above result is not very sensitive to uncertainties in crack growth law.

If, however, the upper bound residual stress distribution is used to predict the crack growth behavior (curve B in Figure 3-2), the crack is predicted to grow to a depth of 75% of wall within approximately 10,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> even with the weld sensitized crack r

growth law. However, it is noteworthy that, even in the very unlikely case that this worst case residual stress pattern occurs in the 22 inch diameter manifold weld, it ,

will only occur on a localized basis due to local weld repairs, and will not be a general, 3600 condition. De crack would thus grow locally through wall (resulting 1 Even in this very I in a leak) in approximately 15,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> under this scenario.

i conservative case, the plant will be able to operate for an additional 18 month fuel cycle (approximately 13,700 hours0.0081 days <br />0.194 hours <br />0.00116 weeks <br />2.6635e-4 months <br />) without any leakage or reduction in piping system safety margins.

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Upper Bound (Furnace Sensitizod) da/dt = 5.65x10'9(K;3.07 y

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~ da/dt = 2.27x10-8(g}2.26

)A y 5843;Ts280 AT 1190'8. 2 m. 0 2 posen

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gg-1 9 i as e ** ** 'e e to se STmt35 tNTtseSITY. E thelM FIGU RE 3-1. CR ACK GROWTil> RATE CURVES USED IN AN ALYSIS AND SUPPORTING DATA (FROM EPRI NP-2472) 8

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0 0.1 0.2 03 04 0.5 0.6 01 0.8 0.9 1.0 '[M Normanzed Ciack Cepth (a/t)

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1 LEGEND: O GE 26 in NP944-1

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A ANL 26 in ND 944-2 (2 azimutiu)

A ANL 26 in KRB 1 e ANL 20 in T-114 4 SWRI 28 in (3 azimuths)

Structural Integrity Curves Used in Analysis 1

2 FIGU RE 3-2. RES!DU AL STRESS CURVES USED IN ANALYSIS AND SUPPORTING EXPERI-MENTAL DATA 1

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< ao = .4075 in.

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ao = .39 in.

s = .293 in.

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10,000 20,000 1 TIME OF' PLANT OPERATION

! ( HOURS )

l FIGURE 3-3. BEST ESTIMATE CRACK GROWTH RATES FOR FITZPATRICK 22 INCH PIPE-TO-END CAP WELD J

10

1 1

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1.2 1.1 -

1.0 3 .9 .

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ALLOWABLE E-A-

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< ao = .4875 in.

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ao = .39 in.

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ao = .293 i n.

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a = .195 in. --

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10,000 20,000 1 TIME OF' PLANT OPERATION

( HOURS )

i FIGURE 3-3. BEST ESTIMATE CRACK GROWTil RATES FOR FITZPATRICK 22 INCH PIPE-TO-END CAP WELD 1

10

1 1

Weld Sensitized Crack Growth Law + Upper Bound Residual Stress Case (Curve B in Fig. 3-2)

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Furnace Sensitized Crack Growth

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A .2 3-*~~~~~'~ BEST ESTIMATE CASE (FROM FIGURE 3-3)

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10,000 20,000 TI%1E Of PLANT OPERATION (HOU RS)

FIGURE 3-4. COMPARISON OF BEST ESTIMATE CRACK GROWTH RATE WITil UPPER BOUND CASES FOR FITZPATRICK J

22 INCli PIPE-TO-END CAP WELD.

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TABLE 2 JAMES A. FITZPATRICK IGSCC CRACK GRONTH CALCULATION 1 END CAP TO PIPE 02-2-22 BEST ESTIMATE CASE VISICRACK-IGSCC-5 PCR-8/17/83 AINIT = .19 5 NPS = 22 A/L= .1026316 1 LINIT = 1.9 THKNESS = .96 0= 1 ORIENT = CIRC TIM INC = 1000 A/T= .203125

] MEM STR= 6.994 CO = 36.994 l DA/DT = C(K)^N BEN STR= 0 STRESS C1 = -252.140 C= 2.27E-8 RES STR= 30 COEFFICIENTS C2 = 427.7333 N = 2.26 RES PAT = 9 C3 = -197.012

=======m==w==========================n======================

TIME CRACK DEPTH STRESS INTENSITY DA/DT DT DA A A/T

] 0 .195 .203125 1000 .2017456 .2101516 12.42353 6.746E-6 12.13129 6.392E-6 1000 .0067456 1000 .0063923 3 2000 .2081379 .2168103 11.95E75 6.189E-6 1000 .0061886 3000 .2143265 .2232568 11.78450 5.987E-6 1000 .0059867 4000 .2203132 .2294929 11.61199 3.790E-6 1000 .0057905 5000 .2261037 .2355247 11.44188 5.601E-6 1000 .0056005 g 6000 .2317043 .2413586 11.27470 5.417E-6 1000 .0054173 7000 .2371216 .2470016 11.11089 5.241E-6 1000 .0052410 8000 .2423626 .2524610 10.95074 5.072E-6 1000 .0050719 9000 .2474345 .2577442 10.79446 4.910E-6 1000 .0049098 1 10000 .2523442 .2628586 10.64219 4.755E-6 1000 .0047546 11000 .2570988 .2678113 10.49402 4.606E-6 1000 .0046063 12000 .2617052 .2726096 10.34997 4.465E-6 1000 .0044647 13000 .2661698 .2772602 10.21004 4.329E-6 1000 .0043294 14000 .2704992 .2817700 10.07420 4.200E-6 1000 .0042003 15000 .2746995 .2861454 9.942385 4.077E-6 1000 .0040771 l 16000 .2787767 .2903924 9.814526 3.960E-6 1000 .0039596 17000 .2827363 .2945169 9.690532 3.847E-6 1000 .0038474 18000 .2865837 .2985247 9.570306 3.740E-6 1000 .0037404 3

19000 .2903241 .3024209 9.453744 3.638E-6 1000 .0036382 20000 .2939623 .3062108 9.340737 3.541E-6 1000 .0035407 21000 .2975030 .3098990 9.231173 3.448E-6 1000 .0034475 22000 .3009505 .3134901 9.124940 3.359C-6 1000 .0033585 l 23000 .3043090 .3169886 9.021927 3.273E-6 1000 .0032734 24000 .3075825 .3203584 8.922021 3.192E-6 1000 .0031921 25000 .3107745 .3237235 8.825113 3.ll4E-6 1000 .0031143 1

1

'f TABLE 3 JAMES A. FITZPATRICK IGSCC CRACK GROWTH CALCULATION 1 EUD CAP TO PIPE 02-2-22 BEST ESTIMATE CASE VISICRACK-IGSCC-5 PCR-8/17/83 AINIT = .293 NPS = 22 A/L= .1542105 LINIT = 1.9 THKNESS = .96 Q= 1 ORIENT = CIRC TIM INC = 1000 A/T= .3052083 MEM STR= 6.994 CO = 36.994 1 DA/DT = C(K)"N BEN STR= 0 STRESS C1 = -252.140 C= 2.27E-8 RES STR= 30 COEFFICIENTS C2 = 427.7333 RES PAT = 9 C3 = -197.012 I======N=2.26 ==================================================================

CRACK DEPTH STRESS INTENSITY DA/DT DT DA TIME A A/T

] 0 .293 .3052083 9.438019 3.625E-6 9.257212 3.470E-6 1000 .0036246 1000 .0034695 1000 .2966246 .3089839 3 2000 .3000941 .3125980 9.151304 3.380E-5 1000 .0033805 3000 .3034746 .3161194 9.047475 3.294E-6 1000 .0032944 4000 .3067690 .3195510 8.946800 3.212E-6 1000 .0032121 1 5000 .3099811 .3228970 8.849150 3.133E-6 1000 .0031335 6000 .3131146 .3261610 8.754417 3.058E-6 1000 .0030582 l 8.662497 2.986E-6 1000 .0029861 7000 .3161727 .3293466 8000 .3191588 .3324571 8.573237 2.917E-6 1000 .0029170 9000 .3220758 .3354956 8.486688 2.851E-6 1000 .0028508 '

10000 .3249267 .3384653 8.402603 2.787E-6 1000 .0027874 11000 .3277141 .3413688 8.320939 7.727E-6 1000 .0027266 12000 .3304406 .3442090 8.241609 2.668E-6 1000 .0026682 I 13000 .3331088 .3469883 8.164524 2.612E-6 1000 .0026121 14000 .3357209 .3497093 8.089604 2.558E-6 1000 .0025582 15000 .3382792 .3523741 8.016768 2.506E-6 1000 0025065 g

j 16000 .3407856 .3549850 7.945940 2.457E-6 1000 .0024567 17000 .3432423 .3575441 7.877047 2.4005-6 1000 .0024088 18000 .3456512 .3600533 7.810020 2.363E-6 1000 .0023628 y

19000 .3480139 .3625145 7.744790 2.318E-6 1000 .0023184 20000 .3503323 .3649295 7.681295 2.276E-6 1000 0022757 21000 .3526080 .3673000 7.619472 2.234E-6 1000 .0022345 22000 .3548425 .3696276 7.559262 2.195E-6 1000 0021948 1 23000 .3570372 .3719138 7.500609 2.156E-6 1000 .0021565 24000 .3591937 .3741601 7.443459 2.120E-6 1000 0021195 25000 .3613132 .3763680 7.387761 2.084E-6 1000 .0020838 1

1 13 4 a

-
.- 'T

~_ - - - - . _ _ - _ _ _ . - _ _ - -

TABLE 4

~f JAMES A. FITZPATRICK IGSCC CRACK GROWTH CALCULATION 1 END CAP TO PIPE 02-2-22 BEST ESTIMATE CASE VISICRACK-IGSCC-5 PCR-8/17/83

--isi;;-;;--------;;;:ii----------------------:-i;5;;ii---------

] LINIT = 1.9 THKNESS = .96 0= 1 ORIENT = CIRC TIM INC = 1000 A/T= .40625

] MEM STR= 6.994 CO = 36.994 l 1 DA/DT = C(K)^N BEN STR= 0 STRESS C1 = -252.140 1 C= 2.27E-8 RES STR= 30 COEPPICIENTS C2 = 427.7333 N = 2.26 RES PAT = 9 C3 = -197.012

============================================================

, TIME CRACK DEPTH STRESS INTENSITY DA/DT DT DA

} A A/T 0 .39 40625 4.160182 5.691E-7 1000 5.691E-4 1000 .3905691 .4068429 4.138971 5.626E-7 1000 5.626E-4 0 2000 .3911317 .4074289 4.121729 5.573E-7 1000 5.573E-4 3000 .3916891 .4080094 4.104679 5.521E-7 1000 5.521E-4 4000 .3922412 .4085846 4.087827 5.470E-7 1000 5.470E-4 5 5000 .3927882 .4091544 4.071168 5.420E-7 1000 5.420E-4 j 6000 .3933302 .4097190 4.054698 S.370E-7 1000 5.370E-4 7000 .3938672 .4102784 4.038415 5.322E-7 1000 5.322E-4 8000 .3943994 .4108327 4.022315 5.274E-7 1000 5.274E-4 9000 .3949268 .4113821 4.006395 5.227E-7 1000 5.227E-4 10000 .3954495 .4119266 3.990652 5.181E-7 1000 5.181E-4 11000 .3959676 .4124662 3.975032 5.135E-7 1000 5.135E-4

. 12000 .3964811 .4130011 3.959682 5.090E-7 1000 5.090E-4

} 13000 .3969901 .4135314 3.944450 5.046E-7 1000 5.046E-4 14000 .3974947 .4140570 3.929382 5.003E-7 1000 5.003E-4 g 15000 .3979950 .4145781 3.914477 4.960E-7 1000 4.960E-4 j 16000 .3984910 .4150948 3.899730 4.918E-7 1000 4.918E-4 17000 .3989828 .4156070 3.885140 4.876E-7 1000 4.876E-4 18000 .3994704 .4161150 3.870703 4.835E-7 1000 4.835E-4 4 19000 .3999539 .4166187 3.856417 4.795E-7 1000 4.795E-4 20000 .4004334 .4171182 3.842280 4.756E-7 1000 4.756E-4 21000 .4009090 .4176135 3.828290 4.716E-7 1000 4.716E-4 22000 .4013806 .4181048 3.814443 4.678E-7 1000 4.678E-4 1 23000 .4018484 .4185921 3.800737 4.640E-7 1000 4.640E-4 24000 .4023124 .4190755 3.787170 4.603E-7 1000 4.603E-4 25000 .4027727 .4195549 3.773741 4.566E-7 1000 4.566E-4 1 -

I l 2

ff

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i -

l .

I TABLE 5 JAMES A. FITZPATRICK IGSCC CRACK GROWTH CALCULATION I END CAP TO PIPE 02-2-22 BEST ESTIMATE CASE VISICRACK-IGSCC-5 PCR-8/17/83

--~isi-~;-- 87i--~~~~~s;-~~ ii-~~~--~~~~~~--~~~~~~-- :- iis578s-------~~

] LINIT = 1.9 THKNESS = .96 Q= 1 ORIENT = CIRC TIM INC = 1000 A/T= .5078125 MEM STR= 6.994 CO = 36.994 DA/DT = C(K)"N BEN STR= 0 STRESS C1 = -252.140 C= 2.27E-8 RES STR= 30 COEFFICIENTS C2 = 427.7333 N = 2.26 RES PAT = 9 C3 = -197.012

============================================================

TIME CRACK DEPTH STRESS INTENSITY DA/DT DT DA A A/T

] _________0

.4875 .5078125 1.818984 8.775E-8 1.817188 8.755E-8 1000 8.775E-5 1000 8.755E-5 1000 .487S877 .5079039 ,

8 2000 .4876753 .5079951 1.815741 8.740E-8 1000 8.740E-5 3000 .48776?.7 .5080861 1.814297 8.724E-8 1000 8.724E-5 4000 .4878499 .5081770 1.812857 8.708E-8 1000 8.708E-5 g 5000 .4879370 .5082677 1.811421 8.693E-8 1000 8.693E-5

] 6000 .4880239 .5083583 1.809988 8.677E-8 1000 8.677E-5 7000 .4881107 .5084487 1.808559 8.662E-8 1000 8.662E-5 3 8000 .4881973 .5085389 1.007135 8.646E-8 1000 8.646E-5 9000 .4882838 .5086289 1.805713 8.631E-8 1000 8.631E-5 10000 .4883701 .5087189 1.804296 8.616E-8 1000 8.616E-5 11000 .4884563 .5088086 1.802882 8.600E-8 1000 8.600E-5 j 12000 .4885423 .5088982 1.801472 8.585E-8 1000 8.585E-5 1 13000 .4886281 .5089876 1.800066 8.570E-8 1000 8.570E-5 14000 .4887138 .5090769 1.798663 8.555E-8 1000 8.555E-5 g 15000 .4887994 .5091660 1.797264 8.540E-8 1000 8.540E-5 j 16000 .4888848 .5092550 1.795869 8.525E-8 1000 8.525E-5 17000 .4889700 .5093438 1.794477 8.510E-8 1000 8.510E-5 18000 .4890551 .5094324 1.793089 8.495E-8 1000 8.495E-5

, 1000 8.480E-5 19000 .4891401 .5095209 1.791705 8.480E-8 20000 .4892249 .5096092 1.790324 8.465E-8 1000 8.465E-5 21000 .4893095 .5096974 1.788946 8.451E-8 1000 8.451E-5 22000 .4893940 .5097854 1.787573 8.436E-8 1000 8.436E-5 1 23000 .4894784 .5098733 1.786202 8.421E-8 1000 8.421E-5 24000 .4895626 .5099610 1.784836 8.407E-8 1000 8.407E-5 25000 .4896467 .5100486 1.783472 8.392E-8 1000 8.392E-5 a'

4 i

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TABLE 6 JAMES A. FITZPATRICK IGSCC CRACK GROWTH CALCULATION I E!!D CAP TO PIPE 02-2-22 UPPER BOUtID-RESIDUAL STRESS CASE VISICRACK-IGSCC-5 PCR 8/17/83 AINIT = .195 NPS = 22 A/L= .1026316 1 LINIT = 1.9 THKNESS = .96 Q= 1 ORIENT = CIRC TIM INC = 1000 A/T= .203125 MEM STR= 6.994 CO = 36.994 DA/DT = C(K)"N BEN STR= 0 STRESS C1 = -62.5000 C= 2.27E-8 RES STR= 30 COEFFICIENTS C2 = 0 N = 2.26 RES PAT = 5 C3 = 0

============================================================

TIME CRACK DEPTH STRESS INTENSITY DA/DT DT DA A A/T

}, 0 .195 .203125 25.93838 3.561E-5 1000 .0356071?'

1000 .2306071 .2402158 26.93143 3.876E-5 1000'.03876254 a 2000 .2693696 .2805934 28.52361 4.414E-5 1000 .0441355 3000 .3135051 .3265678 30.01031 4.951E-5 1000 .0495059 4000 .3630111 .3781365 31.38854 5.479E-5 1000 .0547934

, 5000 .4178045 .4352130 32.59683 5.968E-5 1000 .0596763 y 6000 .4774808 .4973759 33.56528 6.376E-5 1000 .0637585 7000 .5412393 .5637909 34.21219 6.657E-5 1000-40665694 8000 .6078087 .6331341 34.45100 6.762E-5 1000 .0676242 9000 .6754329 .7035759 34.20515 6.654E-5 1000 .0665385 1 10000 .7419713 .7728868 33.43107 6.318E-5 1000 .0631838 11000 .8051551 .8387032 32.14176 5.781E-5 1000 .0578100 12000 .8629651 .8989220 30.41778 5.104E-5 1000 .0510380 13000 .9140032 .9520866 28.39495 4.369E-5 1000 .0436868 14000 .9576900 .9975938 26.23151 3.652E-5 1000 .0365230 15000 .9942130 1.035639 24.07132 3.008E-5 1000 .0300757 j

16000 1.024289 1.066967 22.01981 2.459E-5 1000 .0245915 17000 1.048880 1.092584 20.13842 2.010E-5 1000 .0200966 18000 1.068977 1.113518 18.45194 1.G49E-5 1000 .0164923 s 19000 1.085469 1.130697 16.96051 1.363E-5 1000 .0136319

$ 20000 1.099101 1.144897 15.65055 1.137E-5 1000 .0113674 21000 1.110469 1.156738 14.50256 9.570E-6 1000 .0095695 22000 1.120038 1.166706 13.49571 8.133E-6 1000 .0081333 g 23000 1.128171 1.175179 12.61025 6.977E-6 1000 .0069769 24000 1.135148 1.182446 11.82857 6.037E-6 1000 .0060374 25000 1.141186 1.188735 11.13546 5.267E-6 1000 .0052673 1 ..

1 J

16 'T* S raucTLR AL j ] INTEGRITY mcn

m m. - -

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TMM 7 JAMES A. FITZPATRICK IGSCC CRACK GROWTH CALCULATION 1 END CAP TO PIPE 02-2-22 UPPER BOUND-CRACK GROWTH LAW CASE VISICRACK-IGSCC-5 PCR-8/17/83 1 __AINIT = .195 NPS = 22 A/L= .1026316 LINIT = 1.9 THKNESS = .96 Q= 1 q ORIENT = CIRC TIM INC = 1000 A/T= .203125 MEM STR= 6.994 CO = 36.993 DA/DT = C (K) "N BEN STR= 0 STRESS C1 = -252.140 C= 5.65E-9 RES STR= 30 COEFFICIENTS C2 = 427.7333 N = 3.07 RES PAT = 9 C3 = -197.012

============================================================

TIME CRACK DEPTH STRESS INTENSITY DA/DT DT DA A A/T

] 0 .195 .203125 l'.42353 1.292E-5 1000 .0129235

, 1000 .2079235 .2165870 11.85621 1.120E-5 1 1000 .0111960 2000 .2191195 .2282495 11.55903 1.036E-5 1000 .0103566 3000 .2294761 .2390376 11.26087 9.558E-6 1000 .0095582 4000 .2390343 .2489940 10.97922 8.843E-6 1000 .0088431

! 5000 .2478773 .2582055 10.71396 8.203E-6 1000 .0082034 I 6000 .2560807 .2667508 10.46497 7.632E-6 1000 .0076321 7000 .2637128 .2747009 10.23163 7.122E-6 1000 .0071216 8000 ,2108345 .2821192 10.01305 6.665E-6 1000 .0066648 9000 .2774993 .2890617 9.808263 6.255E-6 1000 .0062551 I 10000 .2837544 .2955775 9.616249 5.887E-6 1000 .0058868 11000 .2896412 .3017095 9.436024 5.555E-6 1000 .0055546 12000 .2951957 .3074956 9.266654 5.254E-6 1000 .0052541 l 13000 .3004499 .3129686 9.107266 4.982E-6 1000 .0049816 14000 .3054315 .3181578 8.957057 4.734E-6 1000 .0047336 3 15000 .3101651 .3230887 8.815292 4.507E-6 1000 .0045074 j 16000 .3146725 .3277839 8.681299 4.300E-6 1000 .0043003 17000 .3189729 .3322634 8.554471 4.110E-6 1000 .0041104

s. 18000 .3230832 .3365450 8.434253 3.936E-6 1000 .0039356 19000 .3270188 .3406446 8.320146 3.774E-6 1000 .0037744 20000 .3307933 .3445763 8.211695 3.62SE-6 1000 .0036254 21000 .3344187 .3483528 8.108486 3.487E-6 1000 .0034873 22000 .3379060 .3519854 8.010145 3.359E-6 1000 .0033591 I 23000 .3412651 .3554845 7.916332 3.240E-6 1000 .0032398 24000 .3445049 .3588593 7.826737 3.129E-6 1000 .0031285 25000 .3476335 .3621182 7.741075 3.025E-6 1000 .0030246 I

J 17 "P S mucTus At h-brtamry......

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4.0 SAFETY MARGIN

'Ihe analyses in Sections 2.0 and 3.0 of this report are discussed in this section in terms of the impact on original design safety margins for the Fitzpatrick recirculation piping system.

'!he net section collapse theory which is used to determine maximum allowable end-of-period flaw size is illustrated schematically in Figure 4-1. 'Ihis approach determines the theoretical collapse load of the pipe cross section under applied membrane (Pm) and bending (P b ) loads, with the area of the crack removed (i.e. the

~

" net" section). The results can then be plotted as a locus of allowable flaw depth (as a fraction of pipe wall thickness) and allowable flaw length (as a fraction of circumference) for a particular set of loads Pm and Pb . Such a plot, for Fitzpatrick end-cap to manifold weld 22-02-2-22, is illustrated in Figure 4-2. Any flaw whose I length and depth lie above and to the right of the " net section collapse line"in this figure would lead to structural failure of the weld. Because the applied loads on this weld are relatively low, the net section collapse line corresponds to extremely large flaws (on the order of 80% of the pipe cross section).

1 Two additional collapse lines are also slown in this figure, which correspond to net section collapse with safety margins of 3 and 3.51 on load, respectively. The safety margin of 3 corresponds to the safety factor on burst pressure implicit in ASME Section llI design rules, and the safetypin of 3.51 corresponds to that in ANSI B31.1, which was the design construction code for the Fitzpatrick recirculation system. Also shown on this figure is the size 'of the observed indication, and best estimate 18 month crack size from Section 3.0 of this repert. Note that this J

J 18 S' STRUCTURAL INTEGR!TY u.m..

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t] i.

f indication, and its predicted growth do not even come close to impacting the B31.1 l safety margin curve.

1 Furthermore, even if the cbserved flaw is assumed (because of uncertainty either in flaw sizing or crack propagation rate) to be completely through the pipe wall, with a proportionate increase in crack length, it still would not impact the design safety margin curve. Such growth is indicated by the dashed line in Figure 4-2.

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ih * *' ', V FIGdRE 4-1 Schematic Hlustration of Net Section Collapse Failure I 'Iheory For Austenitic Steel Piping ,

1 uncracked sechon of pips] HP.+ f5

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l f R I"-* \" h i A ~I I g-- l j---------c N

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Neutral 4 -

'j,g&+: :a. r ants' at = Flow m -*{ e_P. ,

[ FIGURE 4-2 Imus of Allowable Flaw Depths and lengths For Fitzpatrick'

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  • Weld 22-02-2-22 Showing Appropriate Safety Margins i . *un.

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LEAK BEFORE w 1w l l NET SECEON COLLAPSE LINE l COLLAPSE LIN 1 0.8 - f WITH SAFETY E MARGIN OF 3 7

J E i s (SEC. III) 0.8 -

f COLLAPSE LINE

- WITH SAFETY MARGIN j l OF 3.51 (B31.1)

'6 0.4 $ ,

.b h 3 SBEST ESTIMATE e ,, _

SIZE AT 18 MO. ,

PRESENT CRACK SIZE ..

O J 0 02 04 08 08 1.0 Fraction of Cucumference (h)

S TRUCTUR Au 20 l  ; I N TEG R,TY ., . ....

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5.0 CONCLUSION

S In conclusion, the indication identified by inservice ultrasonic examination at the Fitzpatrich Nuclear Station is predicted conservatively to grow only slightly during the next fuel cycle-of plant operaticn and is not predicted to exceed the ASME

1. Section XI allowable ~ for the design life of the plant. Moreover, even if the

. : , .. .a ultrasonie crack depth.astimate is substantially in error, the crack is still predicted to arrest at crack depthe near 50% of pipe wall, and this conclusion is not altered

., ..-/, p if a furnace sensitized upper bound crack growth law is used.

1 _

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Even using a highly conservative residual stress distribution applicable to smaller diameter pipe, the joint will survive an additional cycle of operation without leaking -

- 4 ; ..: : ;

} '

or impacting piping system safety margins. One must note that this upper ' Sound

_ n residual stress case is. far more conservative than any of the field or laboratcry

,e .m , r, .

residual stress data would predict for this size piping, and therefore, is highly I

unlikely.

'Ihis analysis demonstrates that the observed indication does not alter the original 4 piping system design margins even assuming unrealistically large crack growth to a 2

complete through-wall flaw. It therefore provides a conservative design basis for I continued, safe operation of the plant, without repair of the observed indication.

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I 21

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STaucTURAL L INTEG RITY -,,

- - -- -. - - . . . _ _ _ __ _ _ . _ _ _ _ _ _ _ _ _ , , _ _

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