ML20214K364
| ML20214K364 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 11/24/1986 |
| From: | Shepard J, Yoon K BABCOCK & WILCOX CO. |
| To: | |
| Shared Package | |
| ML20214K296 | List: |
| References | |
| 32-1167147, 32-1167147--R, 32-1167147-00, 32-1167147-00-R00, NUDOCS 8612020276 | |
| Download: ML20214K364 (21) | |
Text
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( ATTACHMENT 6 )
BWNP 20697 (6 6 S Embcock&Wilcox DOCUMENT
SUMMARY
SHEET a McDermott company 32-1167147-00 DOCUMENT IDENTIFIER Fracture Mechanics Analysis of ANO-1 "B" Pump Case-A Surface Flaw TITLr PREPARED BY:
REVIEWED BY:
K. K. Yoon NAMr J. F. Shepard f
NAMr SIGNATURr StGNATURr 0
i TITLedvisorv Enci er DATEllf24/86 mtr Suoervisory Engineer DATE 11/24/86 310 fr[
TM STATEMENT:
b' A 88/..
REVIEWER INDEPENDENC COST CENTER REF. PAGE(S) -
y, I
PURPOSE AND
SUMMARY
OF RESULTS:
I
Purpose:
To perfonn a fracture mechanics evaluation of ANO-1 "B" Pump Case using a surface flaw model.
Pertinent
Conclusion:
Even a 75% Through-wall surface flaw was found acceptable according to IWB-3612 Criteria.
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o P05 21036 3 (9 es; s bcock a wiscox GENERAL CALCULATIONS a McDermott company 32-1167147-00 Nuclear Power Division o o c. i.o.
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11/24/85 PttPAtto BY RtvitWED BY DAff PAGE NO.
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.DS 21036 3 (9 es secock m==
GENERAL CALCULATIONS
. ucoermeti company 32-1167147-00 Nuclear Power Division po c. i...
i TABLE OF CONTENTS 1.
FLAW DESCRIPTION 2.
MATERIAL PROPERTIES 3.
LOADS /STRES$ES 4.
FRACTURE MECHANICS EVALUATION 4.1 Stress Intensity Factor Calculation 4.2 Fatigue Flaw Growth Analysis 4.3 Safety Factor Assessment 5.
ANO-1 "B" PUMP CASING PRIMARY STRESSES 6.
CONCLUSIONS 7.
REFERENCES Appendix A.
Flaw Description I
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PDS 21036 3 (9 84) s.nc.cu a wuc.x GENERAL CALCULATIONS a McDermott comDany i
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32-1167147-00 FRACTURE MECHANICS ANALYSIS OF ANO-1 "B" PUMP CASE
- A SURFACE FLAW l
1.
FLAW DESCRIPTION In tho'"B" pump a radiographic indication which may be slag or incomplete fusion exists at the volute part of the case as shown in Figures 1 aild decribed in Appendix A.
The indication is 1.5 inches in length along the I
vertical weld seam and begins approximately 1.5 inches below the pump horizontal centerline and continues downward.
The depth of this indication is determined to be at most 1.5 inch co'sidering the UT beam diameter of 1 n
inch.
Assuming this indication is a deep flaw, this indication was conservatively represented by a through-wall fl aw in reference 6 and was shown acceptable by the code criterion.
In this calculation, a semi-elliptical. flaw of 0.75 times the thickness deep and 1.5 times the thickness long was assumed, to include any uncertainties involved in flaw size me asurement.
The objective of this analysis is to demonstrate that this conservattely is acceptable according to the code criteria.
2.
MATERIAL PROPERTIES The ANO-1 pump case was fabricated from ASTM A351-69, type CF8M. Toughness and mechanical properties for similar cast stainless steel and weld materials are available from reference 4 and a part of this information is attached in Appendix B.
The primary interest is in the weld material which contains this indication.
Type CF8A base metal has slightly higher tensile strengths than type CF8M, however, Charpy values at room temperature are approximately equal.
For this evaluation, it is considered reasonable to assume that fracture toughness properties for type CF8M and CF8A weldments are equivalent.
Toughness of Wald Material The CF8A stainle'sh steel weldment specimens were made from a 2 3/8-inch thick compound-butt weld using the filler metal Em08L and E308L.
The JJ of this material is obtained as K. Yoon,,,
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GENERAL CALCULATIONS l 4 MCottmott Company 32-1167147-00 Nuclear Power Division o c c. i.o.
JIC = 1171 in-1b/in2 and this can be converted to an equivalent K by Ic K
=JJICE/(1-p23 179 ksi (
=
where E is Young's modulus (25,000 ksi) and ))is Poisson's ratio (0.3).
I Fatigua Flaw Growth Rate Presentl y a f atigue crack growth rate equation for carbon steel is in i
Appendix A to Section XI, ASME B&PV code.
The Metal Properties Council proposed a unified fatigue crack growth rate equation ' for austenitic j
material. including CF8M (reference 1) and it is under the ASME committee
. review for potential inclusion into Appendix A of Section XI.
The proposed equation is j
i f
= C F S (AK )
y P
I where.
'O coefficient, function of temperature (Figure 3) l F
frequency dependency factor, unity for this application R-ratio correction facter S
S = 1.0 R<0 l
S = 1.0 + 1.8 R 0<R<0.79 S = -43.35 + 57.97 R 0.79<R<1.0 l
0 At 570 F and R= 0, the above crack growth rate equation becomes as shown.
bel ow, U = '1.8 x10-10 (AK )3.3 I
dN K. K. hm emeraneo av OAT Y5 "M L P Ac t N f),
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32-1167147-00 whero da/dN is in inches / cycle and AKI in ksi (in.
It is noted that all different types of stainless steel can be represented by a single fatigue crack growth equation.
The fatigue data for CF8M. in this reference is the 8
same MPC data reported in reference 2.
3.
LOADS / STRESSES 1
The applicable stresses at the flaw location are assumed to be the same as those us'ed for the "A" pump case analys.is (reference 5) and repeated here in Table 1.
Table 1.
Maximum Stresses at the Elaw Location Normal &
Emergency &
Location Upset (ksi)-
Faulted (ksi)
Inside surface 15.9 17.5 Midsurface 12.6 15.0 Outside surface 9.4
-0.6 K. K. Yoon 11/24/85 PREPARED BY og, REVIEWED BY DATE PAoE NO.
V
PDS 21036 3 (9 aan s.n c= a wiscox GENERAL CALCULATIONS e WCDermott Company Nuclear Power Division ooc. i o.
32-1I67I47-00 4.
FRACTURE MECHANICS EVALUATION 4.1 Stress Intensity Factor Calculation From Appendix A, the following input information is available.
WALL THICK. =
3.1 inches FLAW GEOMETRY SURFACE FLAW
_tpg FLAW DEPTH =
a=
2.3 25 g
FLAW LENGTH = el =
4.65 a/e1 =
0.50 el/a =
2.0
$ f +-
From Appendix A,Section XI, ASME B&PV code, 3
9 Pm =
1.11 Mb =
0.3 Q=
2.31 a/t =
0.75 i
For normal and upset conditions; SIGm =
12.60 ksi SIGb =
3.3 ksi SIGy C0DE=
18.5 ksi KI =
(SIGm Mm + SIGb Mb>0SQRT(PAI a/Q) 26.64 ksih
=
l This value is used for the fatigue flaw groth analysis in the following section.
The resulting final flaw size is, af = 2.346 inches 1
and substituting; this flaw size into the above KI equation, Ky =26.76 ksidin................ Normal and upset conditions.
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POS 21036 3 (9 841 s.bc.ek a wncox GENERAL CALCULATIONS L e MCDermott Compemy 32-1167147-00 Nuclear Power Division poc. i.D.
lr For emergency and faulted conditions, SIGm = 15 ksi SIGb = 2.5 ksi and af = 2.346 inch
- yields, KI = 31.3 ksi 5...... Emergency and faulted conditions.
Effect of Ranidual Stranses A welding process introduces residual stresses in a structure.
Eventhough there is no specific pump casing residual stress measurement data, reference 7 provides typical residual stress profiles in austenitic piping.
Figure 2 provides the axial residual stresses which starts out very high" on the inside, surface and rapidly decreases.
At a/t equal 0.2, the axid residual stress becomes compressive.
Because the residual stresses are sel f-equilibrating and 'displacment controlled, the net effect of' the residual stress from the inside surface to the flaw depth of 0.75 (a/t) will be negligible.
The sum of the stresses along this radial distance would be close to zero.
The bending effect at the shallow flaw depth region will be relieved quickly if the flaw actually penetrates through this region by relieving strain in the region.
4.2 Fatigue Flaw Growth Analysis Fatigue crack growth rate is given in section 2 as da/dN = 1.8x10-10 pgy)3.3 i
where da/dN is in inch / cycle and AKI in ksi k For the purpose of h
K. K. Yoon,,,
11/24/85 PRFPARED BY cx=s nmut.
F REVitWED SY DATE PAof No.
. PDS 21336 3 (9 64)
Babcock & WHcom GENERAL CALCULATlONS a McDermott Company 32-1167147-00 Nuclear Power Division poc. i.o.
calculating the stress intensity factor range, twice the tensile stress range will be used to be conservative.
Since the stress intensity-factor for normal and upset conditions is 26.6 ksi in from the preceding section, twice this value will be taken as the KI range.
dKI = 53 ksi@n da/dN= 0.000088 N = 240 cycles for design 11fe.
Assuming a constant KI since the flaw growth rate is so small, tho' amount of crack gr'owth is Aa =
0.021 inch,
- Hence, Initial crack depth = 2.3 25 inch and F.inal crack depth 2.346 inch.
=
Since the amount of flaw growth is very small ( ) jE of the initial flaw depth) for the entire design life, this is acceptable.
4.3 Safety Factor Assessment For normal and upset condition, IWB-3612 requires that KIa/KI > 6 = 3.16.
Since this material is very ductile (33% elongation - reference 4), it can be assLmed that KIa is equivalent to KIc at the operating temperature and the following ratio will be assessed.
179/26.76 = 6.69 >h0 = 3.16.
KIc/KI =
Therefores this flaw is acceptable.
K. K. Yo'on,,,,
11/24/85 raerAmeo av iib s
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PAGe NO.
=
PDS-21036 3 (9 84 Babcock & Wlicox GENERAL CALCULAT10NS e McDermott company 32-1167147-00 Nuclear Power Division o o c. i.o.
For the emergency and faulted condtion, IWB-3612 reutres that KIc/KI >TT=1.414 and since KI for the faulted condition is 27.2 ksi in, KIc/KI = 179/31.3 5.72
>1.414.
=
Therefore, this flaw is acceptabhrfor the emorprcy and-fsulted conditions.
K. K. W on,DATE IMM 5
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THE MEMBRAAE STR ESS AT
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is
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NoR.
THE PUMP C Ast o G-F L A i.O '.
Y= (
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Au A VE R.AG E " h w t.t t.
BE. CALcotATEb As FettotAS :
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= l M ktP5 Q,
=
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=
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F<iP N B'-3 n t i R eG o i RES THAT umr S iu ce F = R 2 2 t i ps < Mss ) = t 2 t. A t<i p3,
TMIS RE Qu tRE MERT is s A.TLS Ft Eb,
14 B - 32. '28. l At.S o REQu t g.ES W AT KtetKug W Att TM L cKuEss REQui R.E M E uTS SE KE T.
SiocE THERE A R.e uo st etP LE Fo R.no t AS Fott P A.ESS O RE T k te x u t.LS OT:
PUMP CAstu 65) TMtS REQ uit.EMEuT CAu G E.
Cou s gt E R.Eb a e T-stece THE G EGEP-AL P lt.t H A P.Y he M G (LAM E Snt.ESS Lt H L T IS HET 14 THE V L C.'t u LTY OF THE F L Atd.
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oF THE APP LtEt L.oAb H uST Ge cA c.R.t eb BY THE met s E c.T s om S EToted M LE Ab l4 G-EbGE OF T H t.
c e. A c K.
Aab THE Ob 0F Twe CA Si te G.
tu REALtTY 'ThE 00 F L AtJ Eb @oRTieos OF 3
TH E cast:4G AGove.
NJD BEtoQ TME FLA G AR.O Av At t A BL E t CAQ.RY A Po R.Ttod oF THE toAb raiPAaro SY oAfe U l2 Y I
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GENERAL CALCULATlONS s ucoermeticomo.nr 32-1167147-00 i.
Nuclear Power Division occ. i.o.
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6.
CONCLUSIONS I
The results of this fracture mechanics analysis using a very conservative flaw size show that the flaw indication found in the volute weld of the ANO-1 "B" pump case is acceptable for the continued operation as per IWB-3612 procedure.
The results are summarized in the following tables.
Fatigua Flaw Growth
' No.
Initial Flaw Final Flaw Cycles Size (in.)
Size (in.)
Period 240 2.325 2.346 design life Strams Intensity Factor for Design Life Load Cat.
KI KIC/K1 Code Criterion Check A&B 26.8 6.7 3.16 OK C&D 31.2 5.7 1.41 OK I
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PDS-21036 3 (9 64) s.ne.ek a wiscox GENERAL CALCULATIONS a McDermott Compey Nuclear Power Division o o c. i.o.
32-1167147-00 7.
REFERENCES 1.
L. A. James and D. P. Jones, " Fatigue Crack Growth Correlations for Austenitic Stainless Steel in Air,"
ASME PVP Vol. 99, November 1985.
2.
E.
I. Landerman and W.
H. Bamford, " Fracture Toughness and FAttgue Characteristics of Cen'trifugally Cast Type 316 Stainless Steel Pipo after Simulated Thermal Service Conditions," ASME WC-8, 1978.
3.
B&W Document 32-1165802-01, "ANO-1 i' ump Case Stress," 11/07/86.
4.
M.
h-Yass11aros et al., " Stainless Steel Compact Data," NRC Piping Material Program at David Taylor Naval Ship Research and Development Center, presented to ASME Section XI, Task Group on Pipe Flaw Evaluation, San Antonio, June 1984.
5.
B&W Document 32-1165797-00, " Fracture Mechanics Analysis of ANO-1 A Pump Case," 11-07-86.
6.
B&W Document 32-1165899-00, " Fracture Mechanics Analysis of ANO-I B Pump Case," 11-7-86.
7.
EPRI Special Report, NP-4690-SR, " Evaluation of Flaws in Austenttic Steel Piping," Prepared by ASME Section XI Task Group for Piping Flaw Evaluation, July 1986.
K. K. Yoon,,,,
11/24/85 PRePAt:0 By
'! f 2 neviewro sY DATE P AGE NO.
Pos 2 0364 (Du s e e.eu a m ic x GENERAL CALCULATIONS a Mcoermott compersy Nuclear Power Division.
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32-1167147-00 occ. i.o.
Figure 1 Flaw Location
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PDS 21036-3 ea 04, GENERAL CALCULATIONS Babcock &idWHcom e McDermott company Nuclear Power _ Division o o c. i.o.
32-1167147-00 Figure 3.
Measured Axial Throughwall Residual Stresses Inside Wall Outside Well 50 40 30' t
., 20 g
a g' 10
- g oa 6
t D
4
$'o oo 01 0 r
"o 7-o 0
b 10 o
C 20 e
u 30 4a e
e I
I I
I I
I I
I I
-40 O
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Normalised Crack Depth (a/t)
K. K. Yoon,,,,
11/24/85 Peeraneo av Yb U f 7 Y /TI, IN neviewto av oAre
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POS 21036 J (9 84) anack m==
GENERAL CALCULATIONS '
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32-1167147-00 Nuclear Power Division o o c. i.e.
Appendix A.
Flaw Description K. K. Yoon 11/24/8 5 PREPAtto SY Daft REVit W ED BY -
DATE PAGE NO.
l 37.~llf}jy]~ng ARKANSAS POWem & UGHT COMPANY Arkanses Nuclear One P. C.. Ben 608 Russellville, Arkansas 72801 November 5, 1988 AND 86-14311 h
Mr. Bill Jones O
y,f.Jo.y,'
Babcock & Wilcox Co.
Nuclear Power Division 3315 Old Forest Rd.
P.O. Box 10935 Lynchburg, Virginia 24506-0935
$UBJECT:
Arkansas Nuclear One - Unit One Revised Request For RCP Flaw Analysis r
REFERENCE:
ANO-86 13461 Dated October 20, 1986 Cear Mr. Jones:
The purpost of this letter is to revise data transmitted to you by the referenced letter and to reque'st additional analyses of both the ANo-1 ' A" and "B" reactor coolant pap casings.
In the "A" pump refined.'neas.*emnts now indicate that the wall thi:a-ness in the area of interest is rpproximately 2.6 inches. Other dimensions are unchanged.
In the "B" pump a adiog sphic indicat'on which may be slag or f ac:,:
e, fusion exists in the same vertical weld as in "A".
The indication s ap; oximately 1.5 inches in length and begins app *o'ximately 1.5 ine es below the pump horf cotal centerMne and conticans downward.
No 'aS -
2 mation is available regarding depth or throughwsil extent for the indication.
The p op casing is app-oximately 3.1 inches thick in t-5 l
area by UT treasy ement, We request that t".e "A" analysis be -epeated using the above revise:
data.. For the ' B" RCP we reqwest that an analysis be performed ass.W ;
that the f adicat'on extends from 0D to ID and which would show acce::-
ability for one eye's of operation.
As before, p! ease c:.-tact me if you have any q' estions about this ee:.e5 S)nJsC4 e,:
Q,, : ' s, f'.
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exander 8. McGregor,,
AIM /jao cc:
E. C. Ewing A. D. Lane bCC yl