ML20042D114

From kanterella
Jump to navigation Jump to search
Forwards Response to NRC Request for Feedwater Check Valve V28B Flaws Evaluation.Evaluation Addresses Two Flaws Detected During Cycle 13 Outage Inservice Insp of Valve.Util Will Repair or Replace Valve
ML20042D114
Person / Time
Site: Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date: 03/28/1989
From: Murphy W
VERMONT YANKEE NUCLEAR POWER CORP.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BVY-89-31, NUDOCS 8904120412
Download: ML20042D114 (53)
v • d • e


Text

{{#Wiki_filter:--- ERMONT YANKEE NUCLEAR POWER CORPORATION BVY 89-31 RD 5 Box 169, Ferry Road. Brattleboro, VT 05301 ENGINEERING OFFICE / $80 MAIN STREET BoLToN. M A 01740 (508)7794 711 March 28, 1989 U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attention: Document Control Desk Reference a) License No. DPR-28 (Docket No. 50-271) Char Sir:

Subject:

Response to USNRC Request for Veamont Yankee Feedwater F. heck Valve V28B Flaws Evaluation In accordance with the NRC staff's recent request, Vermont Yankee herewith provides, as Enclosure 1 to this letter, the subject evaluation. This eva-luation addresses two flaws detected during the Cycle 13 outage in-service inspection of feedwater check valve V288. These two flaws exceeded ASME Section XI acceptance criteria, as provided in IWB-3500, and accordingly this further evaluation was initiated. As detailed in the enclosed evaluation, Vermont Yankee has concluded that the flaws are stable, static flaws in the stellite wear pads resulting from cracking coincident with casting defects. A detailed fracture mechanics eva-luation was performed and compared against materials properties. Based on the results of our conservative analyses and comparisons with published industry data and related acceptance criteria, Vermont Yankee has determined that the reported worst case flaw is acceptable for service without repair during the next cycle of operation. Although Vermont Yankee does not believe that rapid flaw growth is pro-bable, at the request of the NRC staff, an evaluation of a 3" long through wall flaw was performed. The results show that the flaw is stable. Even conser-vatively assuming a gross failure of the feedwater check valve, the resulting break is bounded by the plant design basis accident analysis, thus no unreviewed safety question exists. The enclosed evaluation demonstrates stable crack behavior in all cases up to and including a through wall flaw. However, as an added assurance of safe plant operation, Vermont Yankee will implement the enhanced leakage monitoring program specified in Appendix D of the enclosed evaluation. Further, Vermont Yankee will commit to repeir or replace feedwater check valve V20B during the next scheduled refueling outage, f0*f 8904120412 890328 ( PDR ADOCK 05000271 P PDC

i t VERMONT YANKEE NUCLEAR POWER CORPORATION o s U.S. Nuclear Regulatory Commission March 28, 1989 Page 2 We trust this submittal is sufficient and fully responsive to your needs; however, should you have any questions or require further information concerning this matter, please do not hesitate to contact us. Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION h MM Warren P. Murp Vice Pre ident an Manager of Operations i l Enclosure - Evaluation (Figures and Appendices A-D) l /dm l cc USNRC Regional Administrator, Region I l USNRC Resident Inspector, VYNPS USNRC NRR Project Manager, VYNPS l

50-271 ]xnaunff'c;njeu N f. NER-6 90 f/lo 4 /z boc b 4 TE s/2 e/so TM sGmva-x wha-Qpdb)ow23rOf LJ Lf d6 D K & de Jag M, Th + 4 4 xs x4 udya ~~ af ce C+f [d C d&> @Q u Sd w/ 7dktp <eh f )( / I' [ @ue6geso

...... -..... _.. ~ ~ I~ ~ L I' I I l l-i l-. EVALUATION OF TEEDWATER t CHECK VALVE V28B FLAWS I g l. l I. l:. I l l 7570R I

~ p l-l l l

SUMMARY

OF FINDINGS lI ~ l-Feedwater Check Valve V28B was opened for verification of f ree piston movement as part of the Vermont Yankee In-Service Test Program. While the valve was open, a visual examination of the inside surfaces of the valve was performed l as required by ASME Section XI. Visual cracking was observed in the Stellite No. 6 wear pads in the piston guide portion of the valve (see Figure 1). The cracking was located within the approximately 1 inch wide Stellite No. 6 wear I pads. The wear pads were created by machining a shallow groove in the bore of the piston housing and weld depositing Stellite No. 6 alloy. The bore was then machined to provide a cylindrical bore for the piston. Ultrasonic inspections were performed on the valve. The thickness of the valve in the region of the flaws is approximately 2 inch to 2.1 inch. In valve V28B two flaws were identified, one with a maximum flaw depth of .65 inch and the other was a 0.40 inch deep flaw on the other sade of the valve. The deeper flaw was radiographed, confirming the fact that the flaw I was contained entirely within the width of the Stellite No. 6 pad. The ultrasonic examiners reported that casting inclusions made it difficult to ( discern the crack tip from the inclusions (i.e., the flaw could be shallower l than reported). The casting inclusions were also seen in the radiograph. Since the repc #<i flaw depths were in excess of Section XI acceptance 1 l criteria. Melho flaw evaluations were required. Discussi% d m All of tb !lexs we4 contained entirely within the width of the Stellite No. 6 wear pads (se c2gure 1). Since the majority of the flaws are very shallow, this implies a very slow or nonexistent growth mechanism. Stellite No. 6 is a brittle material, and Stellite No. 6 cracking is not an uncommon occurrence. Inspection of the Stellite No. 6 showed visible evidence of "between bead" cracking and slag inclusions. (The Stellite No. 6 serves no pressure retaining function.) Possible flaw initiation mechanisms have been evaluated. The thermal expansion coefficients of carbon eteel and Stellite No. 6 are similar, so differential thermal expansion stresses and consequently thermal fatigue crack ~ 7570R

propa6ation will be low. It is highly likely that the majority of cracks remain in the Stellite No. 6 or extend slightly into the residual stress region resulting from the Stellite No. 6 weld deposit. (The Stellite No. 6 thickness is approximately 90 mils). Pressure cycling has been evaluated and I shown to produce negligible flaw growth. The two deeper flaws in Valve V2c5 may be linked up to casting inclusions, or may even be 4 up)y in front of nonconnected casting inclusions. I Vermont Yaritta concludes that 4.1 the flaws are stable, static flaws resulting stem Stellite No. 6 cracking coincident with casting defects. The indications are in a region of the valve body that will see high pressure induced stresses, and it is possible that the flaws developed during the original -I volve hydrotest at 3,250 psig. In any event the flaws are evaluated considering the full reported flaw depth. Flaw Evahtations I The region of the valve body containing the flaw is more complex than a simple cylinder, and the valve body material (AS*IN A216 WCB cast carbon steel) is not I a low alloy pressure vessel steel, so the " cookbook" flaw evaluation techniques of ASME Section XI cannot be utilized. Instead, a detailed frecture mechanics evaluation was performed utilizing a bench-marked, industry-accepted computer code (pc-CRACK, developed by Structural Integrity Associates). In order to better represent the stress condition in the intersection region of the valve where the flaws are located, a two-dimensional finite element model was developed using ANSYS. The details and conservatisms associated with this model are discussed in Appendix A of this report. Since the region of the valve containing the flaw is not a standard geometry, several fracture mechanics cases bounding the actual case were performed. The table below sununarizes the cases evaluated and the K for a flaw 0.65 inch g deep. Flaw evaluation reports are contained in Appendix B. 7570R l I

l The flaws were evaluated for two conditions using a design pressure for the piping system of 1,900 psig; and, using an operating pressure for the system of 1,100 psig. The design condition could only occur when the downstream manual isolation valve is shut, subjecting the piping to the combined shut off ' heads of the condensate and feedwater pumps. This is classified as a. test ' condition. The following table lists the conditions that were evaluated and the K ( y values at 1,100 psig and 1,900 psig K at a = 0.65 inches y l Flaw Evaluation Model 1.900 psig 1.100 psig (Units of ksi - /in) Elliptical Flaw in Cylinder (a/1 = 0.2) 10.1 5.8 l Elliptical Flaw in cylinder (a/1 = 0.5) 6.7 3.9 - i Fully Circumferential Flaw in cylinder 13.9 8.0 Infinite Longitudinal Flaw in cylinder 17.4 10.1 l Elliptical Flaw in Flat Plate Subject to 11.2 6.5 Bending and-Tension Limit 24.5 12.2 The above listed K values must be compared against the K va ues for the y Ic valve material. Since no impact testing was performed on the valve bodies at the time of manufacture, typical data from published reports have been used. L ASME Code Case N-463 provides a lower bound K value for ferritic steel g piping, such as A106, Grade B. NRC Contractor Report NUREG/CR-3009 and NRC Report NUREG-0577 show that A216 WCB has superior toughness properties compared to A106, Grade B; therefore, it is conservative to use the lower p

l. 7570R l

-.~ I' bound value from Code Case N-463; the lower bound K, is 36.7 ksi u n. y Utilizing the appropriate factor of safety for the normal and test condition provides an acceptance criteria of K equals 24.5 ksi /in for the test y condition and 12.2 ksi /in for the normal condition. As can be seen, both i conditions satisfy their respective acceptance criteria by a significant margin. l As a worst case evaluation, we have considered the possibility that a flaw grows through wall. Figure 2 shows the hypothetical flaw sizes for the different evaluation models, as compared to the assumed initial flaw. The limiting mode of operation for this condition is RCIC injection. RCIC initially draws from the condensate storage tank. After the condensate storage tank is drawn down, suction is switched to the torus. For conservatism, we have assumed the RCIC injection water could be at 80'F, the minimum reported condensate storage tank temperature in winter. Figure 3 shows the calculated K values for the various flaw models compared to y typical K data at 80'F extracted f rom WREWCR-3009. Significant margin Ic j g. exists. (Note that the center cracked plate flaw K is artificially high y since the model does not allow a varying stress field. The peak stress had to be applied across the full thickness of the plate.) .CONCLUS10B Flows were detected during in-service inspection in the feedwater check valve. The valve had two flaws exceeding ASME Section XI acceptance criteria. Fracture mechanics evaluations were performed and compared against conservative materials properties. In all cases up to and including a through wall flaw, stable crack behavior is demonstrated and, therefore, gross failure will not occur. As added assurance of safe plant operation, an enhanced leakage monitoring program will be implemented. The specifics are discussed in Appendix D. In addition, repairs g or replacement of V28B will be performed at the next scheduled refueling E outage. 7570R I

s. c Finally, even if the feedwater check valve were to be conservatively assumed to experience a gross failure during operation, the resulting could be equivalent to a feedwater line break inside containment, which is within the plant accident analysis, so no unreviewed safety question existe. I I eg I I I I I I I. I I 7570R .I

I;

a u4Ae 4A-d4a-o.--.. r, .-J a---.3 8ad.Aub-6+Aawa-UL ab.J4. .--..= .-A-4m .es M A,e ~_A.4wey. New,a..aw.Aw.m4 .w._ mmh.u-m---.rm -.weW4,4 h< r am,g. .. _.,4 p. i I t I LI J i i 1 + l. l:l r e l l FIGURES l LI I - l

I LI g

,sze, I

y.

'f,:s.;y.', QA'.:..?.. J. A, *. 'v'*M...h .M .c-. 'i ' / *,,,,,;h.,6 .,..,. * ' ~ .v.,ff.W: .4 ,,;i.

  • ? ?.

.3

e i.,

. c i.?.'t.:;'. s s. g' ';; .. g . ; *:3 ... /..*....m :.~4: T '). .....n*.. ' ' f o'.p ". :, ,,'i.

  • r:@. j a 3.,c,,;

,'n. ~... < n.16, + t 4- .. '.. a. A.' :!.r....., 4. v.z. c&... '.... .. P* W. . y ;.;;i n '...

,f. -

c. .;, y +. a.

2...

.s m.u .~ 4' n.;7 ..p., -s,. .r.r.:.,:f .. / <. < V. a,.. O.%. i.<:' .: n e;'... c .w.,.. $4.,... r:q.v..s]- m.. :. $.a.p.E.,, M.. o... a. .. w. v.;..Q.,,Q&S.,.Wi ,t s -.i S -i.sg&g .. 7 ... p. ' /. $ :...':.? *.)7 p.?:.e... n n.'..;r o. u.,%. *s.s.? }t'N.s.,k'. %~..n. :. %y r:p. %

a..y L &..

I(..S. wt e n...n.. y .: u.,c.- m. ..y$.Y... 9..y. .y Y $~$,.iql.;5. ...,.,.. y, t. .m .. fs.c. -. ~.n.. .,.....n ..i.<';',G: y Y:

  • Y,.{.'

-4.. W'-{','?. D. 'h',7. $*' '. 5,'Q.} *". T.* . 3'Q Q.'K;'T$$ 'h. 'O. 4./', f;.P - s$ Y.%

    • M...:,k"I' ;b,n[. : <. 4 J.o:

d 'se '- + '. '

I *.8. ..i

,'{ .., l.i.,*

J;7e Q

/.% 4 Mf .;g. t. Q.4.?': ', 3.a f.>Y. 4'. ? g - -t* . i !* * $< g/.D.dw 'e' .Jf,;.-Q... '/ ; *

  • i..'

. e, l".%.".. ; ~pJ...;,.1:. d w... g. '..'.n..:.".,..-+-

  • .f
  • t.,,

ye -l Jr t ,, ' g 4:;pn s,,,

p,g ;y.j ;

,,. ad; Q..3,'.'s~ll, s ~- .~. .e u*

p. w.....f.. a i

..N* i ~, g.. .s.... 8.... .e s f, 4. ...a.,4

,G6

,4,..'.W *M *,t /d 'l =...... ~....... ..,./.,',c,... ~

w. ..

.. Q.,'.% n..

c.,,
;; x.%g.

..e:.1 .x n,o... m:..

G,

. p..,.. .. 1; ?.,n-3.. q,, . y* .,, y.: e s. /,. - g: , y...y,.., y W,D:-.J.j*.

  • a

.g y-s. 4.:% &. m.Q. QK;,., ?,'@.-4.y,;;'. pi.'.'s p:, ;; . i. r,,.. y e q; ,;

  • 4, 5

,--.,7 . 't i,. 'nd R .? ' cy&y. ~ I s W,g'. T.. ,.'A.;d e.y . '.M,,

d. <

ss x, ', ;;;. c..... %, e t ..ys 9 I.i e;9.M ".. %~t,.,. D.. s. j.'q. . e --. W.,.'t

g. i. Q.

%'***$, T.,'.,'h.,, n s

'. l

. r... v. %.r.. s ..:, p. af ). a. y

h. * -

3; N,

A,p;;,.,. g.~.,1 s-

.n. . p.. ;y ,s,

  • p.e>s v.

,4. v. .) n. .;.3.: .,..s ~v,. a :. e s <,.w,.. % a vl.A ,7 y .h,., /. .t. i.. ,-y %w c(n. v..s. .y .~f v[ ;;,. .. " ::..,;.. z, %. % 's.W..td.; .1,. ~., ;;y,. o3.n. .a.., i + 6 r. . e..g -

3 a';....

r , c,.;,

4..;..ej, c p L +-

n p p,y 4 {.,,,,,;.%.:,;. $ ' ,L.. 1 . f:s. n...,(,:p 1..y. c.w.~e \\ .u . :p.x. E,, f?...f.w.w&.. .!,.r'. * ' M. u. ' ~.,.. .,.,r., ' ~

-s f.

~'.v..,sk. g'..

."r.A?>$*af..r

. :.Q,.y. n f.,d.', l d. .;ep g.. :.: f... .,..l .. y :. s.- N,',., :..... >. c.. 3.. a,. S rm ., w.,. 4.y.

..y..,~.a.s.

e;<h.n.. . >,s,d,.,y 4,.f. ;. ' t -t . g, g. s N...,.. +- J .!' ; *%i...e.. A f,..'.N .. k, &.,. l.0 w. f....,w,i,?.h.' U$..... .c %.r.. c..p...r.t,. lqi.y y..,,^ ,..e... .'g f,g:;.,,. Q't ; -. t., r:.. %,.;.u.r. y c... .. i.. v.~ ; p-p:; ' m- ..L...,.. .. s.

o... t

..a..u... . c.. ~, C's:.f..c. ; m,.,..: c ...Qa.s p> .y .'l . v :;s. '*?.'.lTf,'A s t lQ / y ; ';,$%y ,.....y <s.h.,. d*' ., ;*<. * - n.,.

  • 4:'i.

.,n. s' ~.!,:g.

  • m

-V.r:., % .. ..c d. 1 ,x ', urig. .J, o3;:.y : -.. ..G f{f;f.it:Q.]3

1..

W,*:,s k l:: s ~ .f. ' *,'b.1 y' + c i s >/,. v..- ~ -:. .*?:;.p '.:n ~P;.,, {, M..,;,~... s..;,o .a;

,*;....n.,

s..,. , /e . :s ' c. ; e.p, F ;.. . /... :.', , 1.. 4 .v.,,......<g,,.i,.. ..s... , i e ' @.'3, ,,.ry. , t. ... -e....>.w..,., i*,, --t '. 4 '. . N. t .s... s ./ -..,...c,. . t. /- C. '3 4c sg o w. 7,....-- " " '. p f* s i o ga,.s.g 6, w,e 1 Q. -4 o-g /\\ ppk Q. ' t ]*h,j., _ MP 5' e . ' g,. u.n 4 .;e. g4 f,.., ... g.,. 0,, s.. .n g i d..- .,N '. ~ ~ ig,.

  • l,.,.

, 4 > * *. % { ' *' \\} /.j.l, } ' *);, ' ~ ~. g j I ,_z* 8 K s )/.S ' Y , j / d 5 ( g j /l k / ~ ^ / ~\\

    • 4 @

.$. U ,;f ^ } r te ,;f 3 .e4 .i jc '. .s ~..f ,l ..r Y, s s o I.- sQ 4. g.1 ..o

'... -. o..*.6

\\ . ~ q g ..s.. us. y... .4. 4,w*. +. < ,,.,~s. %s . ; Wl + ..' 4- .m..,' ]. m ../ st...t.!P. e., / . m f ,A..2 . a,. ..: n. .t u? '... 3. / ;,.c,y,,-. Is. _j. a .a- ..l i, P '/. .e - l . m,.. - s ;.'. ;g.. t;, ,~ ',u. l.. f.

  • W/Y.. i.o.,*
y.. e z
  • m,,.f

<. *. g,,. i.' r v,,y s. 3 f. .4. V ' ,,,'aj, C a t '.... 'l !'.., b {... . '.X g / ;." %).j d.l; Q(* t i .< \\ [.'

  • I
  • i. + ]d -

,.4* i.,s,.. j.. pN. f e,. ~ ' *. .4 a.- s s b' .* a*. j,*, 'y,,, 't, E I 1 / / sC.E ~ ,"/ c4 ) *J *J j ~"*'/' OOC i I I 'y & & I FIGURE 1 1 - -- i

E S ~ g yl r.W.<...,. ( ' M,2 - ,...; ;,d*..'~' * %,0, /*t", .'. fl. ,C

  • h.,$','*

W%'-h-i lr: - f ' 1 ;i.N.. i,'Tef. b ?' i o. ..\\ y 5., y.y.. ,...,J.' . I E.* .+:.'*,.'~.- .n. . o. vm.'.

  • Mr,1 i !

.s

. v u <:. s.

.o.,. . si. ; j~ g; !.,y,r. - ...e. r..s.. 9,,,p-.- t .. <;. 3 q t.

t. % : v<. "

~r s..> \\ n t ,l.,.8J,,:(.,I,..g,.

  • 3.,t e

A. s.4 - .vi.J... V..f ~ .:l. f. L,.," er . ? ...M *me l ... r O '. 'l y...c.. /.- ../ r x n ,M &,,,W:,'.? E ' N.y.?. d: i.. i : yi w a.s 3l* #.'g ' '.' q;s\\.. Q t.#..:. Q. f 8,w.;f;[6:.',b

  • - ?.

~. Y!; 1-Q :*q ~e '!.I.r'- ..is, 1 }f *.t d.,$ "., 4.? 'V-{4: K *; v

  • w m.i..e.M,w.:N;y.b.h I.4','

..M y ,s. k.

  • r '. &.

%.,q 3 NJe s7.h. i.Mf,:.R. ft.- 3 n $..n.M.;x.ddpa; i.. s s k.w$;b:.* w .s.r... my.; y a. ~M< v..p 7. ~.v '., ,. v.... d; 'q' v u .w q.. y A . n m.... r .c .. g * *. '5.,1her.: .,. h ['.t. k'h, N ' b y* y., 1 ~

  • f.'..

'j.

  • h*

$.' A. ;l,% *hr.:. l~:k, l ' .e. .'Ye % ^

  1. 5

).

  • fj,,3'$* i D

.' O.* V'~i .. W M' A * ** *, (.'..

  • 1'T. !>:.

\\

  • ('Q> - {.t?.Q,' 6 ?~i?.W '.) f$f*m ephh*.h.N.. :. /,:h.m m g.s:n.'.

.) p.:p. w. nl f.* 9'%. y? { f i hh kNNU I O' M.. .. s D

/

. :.":p,7..! *. /O./,s y,T. % . '.. ' + P.v.,a.a*u., - .' V.;g.'; y

.%.. u.

r sv.s. ap. . y. - .. p;, y g.. - c g ry. \\.s:, .p, s .. +,,.:, - J 4.Q.;.,.2.1\\.% 1"lc.4 *.k -. ;,1h.g .e.. r*.'. @;,p W y y' to. :..n. %.n,

.V W,.s.). gr,u;;

'.>,~.19.. \\,. ) L ~..a.' \\s ;v'.,. o .s" 3 y F s. r . ' :$n.. s. e ~.- .pe .;pv s-- a

n., g :

.e

u. m.. w..w..+. w
m.,,;m., e.m.

't i ),.s, K.T. ,,.I;,. y er . d,',. 1 ', "p$w/.h,Ng&g.. Q:g4gg. h,x:

e ;

..n<..,.,.... -$,g.,s.

.g@jEQ.

y y .a. yrr: y...y mn g f.. w, ) ,, s <f. /. . q, c M.p.: R,i l: w:. T. . ; a e g. ?. T.aa,. .m ..%.,w:M.1 .%r i.. .h, o...,x.. n n,s, 4.

,lm,,p.

s... , o. v L,}4. :]'&;a; . L "' '. gU.,..;,'. i. .. s,u . m m.3.. gl' f.hg;,5 *ll'f.p:Ut% Eff)}..b'.n;'/k.. - . ~. <. .' ;u. M i':. a .M.%:' :., hfy%;<,'n fR ; s , Nh h. (.. V'l'.,e,. k.".h. I'/ I .a .y g. Ni h$ j

...m?.5,,1..,W..7,P,

W,.g k } l@.h.h., d;.,e.. t ~ n +. L o .d.. & ..:s.. . c., G, a y-..,.q L.- : J 4 ..m ,.1.. c,.; T .v 3...,e,,a,'7)' i %. 3 >- + :? r ~;p

,l6 W,F.,

t .s. ,i :.. v?,,/ ?,; E[&.+y.,]. N. M 'd" ' Y T 2. M ? O : '. W D 'r'.'M. N. n.>se,

w. c

, g v... ~.4., N [.r V 'l'.. T.h.. ,r. ..a,... c.:,. s...,.. !..*!N? .. g., e.n.n '. ;'N,.,..

,, C ' ls.f.65'J hs '

t,....k. . n, =.# .,ys 9" *.0 N. 'a' C..- I...' r-1"

6. Sj$[3 RfllJ['fi3 ' 7$";

g.$. .M (' ,l c ~.c... n 'c ~.5. ',: '" / .f 44 1 t I fc x . >. m e rs. g,,. ?.., a,.;1.$.':.1, h. *. p*-)1 ~;. s 'S,.. '% "

  • g,.

.M ..,' y,G v / ..s. t. < 8?'. T,, ?. ..;d,.**j,g',**.,j;;\\; gd*..l:'.',;t, y$ ;. '..ll C .s , '/' 4, 4 ..Q '* <7 g _.j q ./ s. EQ* j i n,.,'. g. f,j Q" Sn., .....( .i. +s ,a 3-s gy W.S4. q,' V, - A. x<ou - ,4*..,. a

  • i.t er: 1 s,

. N..r*,..,.i.a-s'i, g...x, 5., C. A@1;.%c,1 4 e N' [ ~ % 1-j' / ji , ;w . q.. .a ../, .'N ,we r Y } b [ v)J !f r=4 ,e j t lIa e=1 . 7^., r o (. - s .U f }, ,p .ar------- ~ e 7,1 x ** .,/ i Np / .s. h + N 7. s ,,,.. n .s i s g,.- a . %@ V e gr. ....f;e-N..... ". '. J eu. N. 4-8 .s.

    • i

,;.{O :.g ir 'v ',, f.,,, /. ' g, Y.. - Q. ' ' il,? 'l4 j; l / ~,s < f ' :4,q. c c. >..s.,,.,s - t,y p., o ): ;* .:. ;Q.q&%l.ik.Qi.l..'.'. * . c*. 3 ' n y., y,m.:.v..q \\ m ig..' n :. 'b .p'..., [...,,.,u.%g.p+ f.k. U

Pe a
  • -1 i

V' b ,y J.,,.c. '.,w;4 s. 6 ., n .~ .s +. g.. g. p g., b* I. a ,/ a.- i 333 i:. 00m j. N.,- e4 r-I b FIGURE 1 m.

.T Jy JA,,,,,, ~ Comaarison of Flow Saapes for Fracture Wecionics Eva uation of \\ eecwo:er Ciec< Vo ve V28B i a g 2 u I ^ a/ = 0.2 i f as,-- ci eu.s aj l = 3.5_/ j Center-Crac<ed P, ate t i .i r-. .as f g _.,.m.- ~...- -. - - .,w,

~ x W g i 100.00 - i O Z Typical KIC Valve for A216 WCB at Minimum Valve _Tegperature 8 [ (T = 80 F for RCIC Injection Mode) h m i I t I f ~ g 60.00 Center Craded Plate 'Ihru-wall Flaw 3 Inches Wide "8 Y c -Oe l ~ e E Plate under bending i I ' and tension / an =tical flaw in cylinder Ellip 40.00 - o.2 / h -p / / Elliptical flaw in cylinder l l ( , / a/1 = 0.5 3 q) -w 20.00 C m m O 0.00 ,,,,,,,,,,,,L .........i........., ~ M 0.00 0.50 1.00 1.50 2.00 m ~~h ru-Wal De at, neles e f -4 w. sc--

I

I g

APPENDIX A STRESS ANALYSIS OF FEEDWATER CHECK VALVE V28B l B I. E. J. Betti I J. C. Fitzpatrick I I 3:

l l

I -7570R l'

'I i-APPENDIX A Stress Analysis of Feedwater Check Valve V28B .A. APPLICABLE LOADINGS 1. Pressure 1 a. Design pressure 1,900 psig (G-191167). This valve is based on feedwater pump dynamic head plus condensate pump head (G-191139). I~ b. Operating pressure in this region is limited to reactor operating pressure plus the pressure drop across the feedwater spargers. 1 During full feedwater flow, 1,250 psig is assumed, 200 psig over I RPV operating pressure. During low feedwater (<10% of rated) 1,100 psig feedwater operating pressure is assumed. t 2. Mechanical Loads I Mechanical loads are from the attached piping. The section of the check valve in question has a 20 inch OD with a 2 inch wall I thickness. The attached piping is 16 inch SCH 120; t = 1.218 inch. The'section modulus of the valve is as a minimum 2.4 times larger than the attached pipe in the region of the flaws. From combined Lg dead weight, thenna1, and seismic piping moments at the valve g (VYC-634), valve stress was calculated to be less than 1,200 psi in the side region of the, valve in the area of the detected flaws. In l this region, the valve profile is flat. Therefore, localized through wall bending is not a concern. I 3. Water h-er and Valve Impact Both water hammer or piston impact-induced stress were considered small.. This system has not been subject to water hammer events. Also, with the exclusion of a double-ended pipe break upstream of the check valves, the Feedwater System is not subject to rapi'd pressure j. decreases which could result in rapid valve closure. Finally, the I piston structure is much lighter than the valve body. Therefore, in ll the. event of rapid valve closure, the piston, not~the valve, would [u absorb the majority of impact energy. 4. Ihgrmal Transient-Induced Stress I Full power and partial power transients do not result in severe l temperature transients in the region of the 28B check valve. The largest potential thermal gradient that this valve could experience j would be during a zero power hot standby condition when feedwater is l in the low flow control mode (<10% of rated flow). l; The B feedwater line is also used for RCIC, clean-up water return, L and CRD return. The following is a summary of the system capacities: o RCIC - 416 gpm capacity at 80'F o CUW - 130 gpm at 430'F o CRD - 60 gpm at 115'F o FDW - 7,700 gpm at 375'F A-1 7570R

I. L MPENLIX A - (Continued) 3: The region of the valve in question is subject to membrane and through L , g; wall bending due to pressure. Hot-to-cold transients tend to decrease j l the through wall bending while cold-to-hot transients would add to pressure stress. Therefore, the following cold-to-hot transient was ll selected for-investigation: Feedwater at 10% flow,100'F with CW water at 100% flow, 430'F. (Combined temperature of 152'F). Interruption of feedwater flow, continue 100% CW flow at 430*F. The pressure is assumed to be at 1,100 psig. B. STRESS MODEL FOR ANALYSIS From field walk down of the feedwater check valve and in situ dimensions, !I it was apparent both membrane and local bending were important in the flaw region. The two dimensional constant strain model shown in l Figure Al was used for both stress and themal analysis. The ANSYS lg finite element code was used to perform calculations and plots. This g simplified, two dimensional model provides approximations of local membrane and bending stress in the flaw region. C. STRESS PROFILE FOR FRACTURE MECHANICS ANALYSIS l. The first case evaluated with the model was the effect of 1,900 psig 'g internal pressure, the design pressure of the valve. This condition l 3 resulted in compressive forces on the inside face in the flaw region. A section stress profile for a 1,000 psig case-is shown in Figure A2. The 1,900 psig stress profile was interpreted from these results. I l_I i From the finite element model results, an enveloping stress profile for i. fracture mechanics study was developed. The compressive stress profile i-on the inner face was changed to a constant 7,500 psi tensile stress to l-approximately mid-thickness. Toward the outside wall,.a linearly increasing stress profile from the model was used. Changing the compressive portion of the stress profile to tensile provides a I conservative " design" envelop for fracture mechanics evaluation. To assure that the " design" stress profile is conservative, the maximum stress profile under thermal transient conditions was also studied (see-Figure A3). The transient stress was combined with mechanical stress from piping and pressure stress and plotted on Figure A4 for comparison I with the " design" stress profile. Figure A4 demonstrates that the " design" profile was an appropriate choice for fracture mechanics evaluation. I l l g A-2 l g_ 7570R I

M,9,_ jM M M M M M M M M - M. M M' : ' M rca -.._cw+cvwe z-t t+,ai uh.~t % ss )

  1. D
  2. 7/7

- i 7,... efe r,.- ff m o C L. Seeg,g.,[A. A) ANSYS 4.3A2 MAR 27 1989 17: Eli 2 ELEMENTS ZV -i \\ \\ \\ DIST-16.5 N \\ -\\ \\ xn -s N \\.\\ \\ YF --i y~ \\\\\\\\ \\\\\\\\ l vau t_ \\\\\\\\ l \\\\\\\\ \\\\\\\\ \\\\\\t \\\\\\ \\ \\\\\\\\ % Lees,,a 3t33 x iIL l Ill lli ^ III di,s.- Illi 4m Illl Ill! Illi ///I ^ .///I -//// gt / y) ~ ~ FEEDWATER_ CHECK VALVE. VY .~.,n'.. .~.s .w .m.. . _.,. _. ~. _. n-. - n.., n,_.

- m W ' M M M M M :W _ mm ~ Axaf 316>;: 6co+. uci;. 2 <a rex <o (p pig luvric,;rl Pff C,00F_(, 1 ANSYS 4.3A2 MAR 27 1989 17:17:56 POSTi gy STEP-1 l ITER-1. I 15000 TIME-30 OT + BEND N001-35 12500 TOTAL N002-31 SY S 00AL 10000 ZV -i DIST-0.6666 7500 XF- =0.5 YF -0.5 g ZF -0.5 3559 pi' __yggggggg / 2500 / / / / 0 ~ ~ '~ / -- / / -2500 /, -5000 I F -7500 DIST -10000 .[ g g g g 0 0.5 i 1.5 2 2.5 0.25 -0.75 1.25 1.75 2.25 FEEDWATER CHECK. VALVE. VY

W. m' W..m W m ~m m m m m' W W -m W W W W W Tem pex.n,ag c2 coa & _W12gd _Sc gjides '"[n',yg' Ficvrie A3e: G Vf AtJ f~i}FAJT " $N TfA. u P 7t OyJF_jppf(M~c/r.ir?G,* AA E9 3 TEMP /2,.o o 340 ZV -1 DIST-0 6666 43D */~ TEMP. YF. -0.5 320 ,38-TEMP ZF -0.5' p /50 F TEW 300 ~ f / 280 // / / / 240 //! 7 220 .i 200 l / 1eo 160 ~ A T m u e 1.2. h b II"" 140 0 - l .i l l l l l l l l 2. 4 6 8 10 1 3 5 7 9 FEEDWATER CHECK VALVE. VY g

e sua t, a s 6 am L T A O B 6 ^ L O 6 P L 6 's 0 G

6555,

^ N5i i m ol1 O33 S i000o_ =- A ~I S P Ti2 E T E CDD R S T EOOyT VIFFp s SISNNSS ZDXY7 es m T e S ID 5 l2 a D I-E e ma o. N G N 52 e E A s 2 - T B L R n M A7 B 2 l8 T M o n r E O l-E A T M e Q S W r A s l2 e m 1 s W e 5 u b, 7 9 fr E S 1 ls m Q o,c.__W 5 C o s 6' c L "T l1

  • s _ I 5

e J 2 s o u k m_ ! j l8 1 T go / s s u '7 / u P a f_ p /< / li M' b u 's f c v g 5

S i S o

/ 7 O { ML lA N / c 0 lI y 5 s V 5 y/ lo E_ a L r m 4 n 1 K F V "7 3_ l v 5 L l E d 2 V A J 03 / 0 K lI / C b t> E E h H t m h y / C \\ a g o R 7t!. n W ETA 0 0 W a 0 0 0 0 0 0 0 m G D 0 0 0 0 0 0 0 0 0 5 u 5 0 0 0 0 5 0 5 0 2 E_ E 2 0 5 0 5 2 5 7 1 1 F_ 1 1 7 5 2 o sa m i

I KEE ATOMIC ELECTRIC COMPANY YAN cateutaT a no. exoE or SUEUECT' , ' PREPARED BY khb DATE 3 2 80 REVIEWED BY DATE WORK ORDER NO. Ficurts A4: - Axk Thyogh Lauu s,uc4 g raw e I [ C 1900 P5'6 I"'T" ' ' f l gfi p \\ulLe u v u. 1 7 l E I is X TrA mirut + t&cbim,] ! JDan Curve -da r- + Pfecsute, f g g,j . (; N (m er.,ec Eva cvar,oe 3 n i //' /f L I. / .,./ /f C - d,; o-i f CuYs tSc - p ,l e ,// o wm ') 4 gg w Imier suceAce -2o -N i htt%$vg g" ~/2650 ~/Yo4 7739 /6/89 ital 7 to e /900psq w t.

======.u..-=:. /4Gc4Hel /2.0 a /2 o o / Loo /L.0 0 /Z 0 0 ( t 1 [ 7;c N n tp.,7 -//S o o -5700 /y00 5600 6700 f //oR '., ~ 7 7.2 4 - Sly 4490 9 70 /3/78 3 u. fv 7 brat ' -s7 7; y -23/p 7oFo /6/7e R /o7 8

E,.- l 1

=

^ APPENDIX B FLAW EVALUATION RESULTS I LI ll il I-J. C. Fitzpatrick J. R. Hoffman 9 LI I: I I i 7570R ,me, W'--

L I' i. A - Plot of Stress Profiles ( B - Comparison of Flaw Profiles ( E' C - Least Square Curve Fit Profile -g D - Elliptical Flaw in cylinder - a/1 = 0.2 i 1'[E E - Elliptical Flaw in cylinder - a/l = 0.5 L F - Full Circumferential Flaw in Cylinder G - Infinite Longitudinal Flaw in Cylinder H - Elliptical Flaw in Flat Plate I - Center Cracked Plate J - Extrapolation of Elliptical Flaw to a Thru-Nall Flaw ,l K - Fatigue Crack Growth for Semi-Elliptical Flaw 1.5 Inches Deep 5 at Three Times Applied Stress LI .g I

I I

I I I I. I

a' I; I O -D. (n I N g 3 l .! E$g 8 b I 8t $3 O '(t E

  • B t C

- o BT~ 8 MB$ 0 9 I us u -N a s 'g

  • s N

N t -o

E N.

.S e -o E N

4 O g

N e gu s UN ~_ C s./ O t_A. 3

o (n v

..g y -O \\ l 5 38 .I <x t 8 8 7 1 8m .d j I dl

O O I

%udB 8~ -0 3: 93 82 1 is E-

o l

E.- g 1 bu $2 J j@ t-- [ o, e. O O o o O O o o o o. o. O D D O .g s sseJ;s !sy I 1 I

l ~ Com)arison of Flow S103es for T acture Mecianics Evaluation r 0 eecwater CaeccVa ve V283 7 )) a/ = 0.2 ^ " " ' " ' ' " ' ' all=0.5 Center-Crac<ec Plate

pc-CRACK (C)= COPYRIGHT 1984. 1987 STRUCTURAL INTEGRITY ASSOCIATES, INC. g. 'g-SAN JOSE, CA (408)978-8200 VERSION 1.2 LEAST SQUARE CURVE FIT OF STRESS PROFILE ERMONT YANKEE FEEDWATER' CHECK VALVE V28B ' TERM COEFFICIENT - -CO 8.0867E+00 C1 -5.335E+00 C2 5.8800E+00-C3. 4. 017 7 E- 01 L COEFFICIENT OF DETERMINATION R*2= 0.9845 ORRELATION COEFFICIENT = 0.9692 X'VALUE .Y VALUE Y CALC DIFF 0.0000E+00 7.5000E+00 8.0867E+00 -5.867E-01 .1. 2 5 0 0 E- 01 7.5000E+00 7.5124E+00 -1.240E-02 -2.5000E-01 7.5000E+00 7.1266E+00 3.7340E-01 7.5000E+00 0.9340E+00 5.6604E-01 83.7500E-01 5.0000E-01 7'.5000E+00 6.9392E+00 5.6080E-01 6.2500E-01 7.5000E+00 7.1470E+00 3.5298E-01 7.5000E-01 7.5000E+00 7.5621E+00 -6.213E-02 ..B,8.7500E-01 7.5000E+00 8.1892E+00 -6.892E-01 1.0000E+00 7.5000E+00 9.0331E+00 -1.533E+00 1.2500E+00 1.1515E+01 - 1.1390E+01 1.2535E.1.5000E+00 1.5530E+01 1.4670E+01 8.6043E-01 ,1.' 7 5 0 0 E+ 0 0 1.9545E+01 1.8910E+01 6.3452E-01 '2.0000E+00 2.3560E+01 2.4150E+01 -5.900E-01 I END OF pc-CRACK B. I I g

s I

I

tm [) I pc-CRACK ( C '- COPYRIGHT 1984, 1987 STRUCTURAL INTEGRITY ASSOCIATES, INC. I SAN JOSE, CA (408)978-8200 -VERSION 1.2 LINEAR ELASTIC' FRACTURE MECHANICS EVALUATION VERMONT YANKEE FEEDWATER CHECK VALVE V28B CRACK MODEL: ELLIPTICAL LONGITUDINAL CRACK IN CYLINDER (T/R=0.1,A/L=0.2) WALL THICKNESS = 2.0000 STRESS COEFFICIENTS .g CASE ID' CO C1 C2 C3 3.- THRUWALL- -23.5000 O.0000 O.0000 O.0000 FWNRC' O.0867 -5.3350 5.8800 0.4018 I CRACK ---------------STRESS INTENSITY FACTOR---------------- DEPTH CASE CASE THRUWALL FWNRC O.0320 6.475 2.198 I. O.0640 9.216 3.089 0.0960 11.360-3.761 0.1280 13.200 4.321 0.1600 -14.851 - 4. 8 1 1' O.1920 16.370 5.251 O.2240 17.789 5.655 0.2560 19.132 6.033 l -0.2880 20.413 6.390 B-0.3200 21.645 6.732 0.3520 22.836 7.062-O.3840 23.991 7.384

B 0.4160 25.133 7.705 0.4480 26.268 8.027 0.4800 27.383' 8.348 I

O.5120 28.479 8.670 0.5440 -29.561 8.993 0.5760 30.629 9.320 'g 0.6080-31.686 9.651 g 0.6400 32.736 9.990 0.6720 33.777 10.336 1I 0.7040 34.811 10.690 0.7360 35.836 11.053 0.7680 36.856 11.426 0.8000 37.870 11.810 'lt 0.8320 38.874 12.202 B 0.8640 39.874 12.607 0.8960 40.869-13.024 .B. -0.9280 41.861 13.456 B i---um-um um------h

- pc -CR ACK -- VERSION 1.2-PAGE' 2 ~~ 0.9600

42.849 13.901

.O.9920 43.835 14.362 1.0240 44'.-866 14.857 I 1'.0560 45.913 15.375 1.0880 46.960 15.912 '1.1200 48.'008 16.470

(

1.1520-49.056 17.048- ~5 1.1840 50.104 17.649 1.2160 51.151 18.269 1.2480 52.195 18.911 I 1.2800 53.240 19.576 1.3120 54.286 20.266 1.3440 55.333 20.982

l.-

1.3760 56.382 21.724 m' 1.4080 57.434 22.494 1.4400 58.493. 23.297

l' 1.4720 59.554 24.130 1.5040 60.'618 24.992 1.5360 61.683-25.885 1.5600 62.750 26.810 1.6000 63.820 27.768 y
e. Or c-Ce m I

g I II I I IL I I B-I:

tm (( pc-CRACK (C) COPYRIGHT 1984, 1987 STRUCTURAL INTEGRITY ASSOCIATES, INC.. l SAN JOSE, CA (408)978-8200 VERSION 1.2 1 LINEAR ELASTIC FRACTURE MECHANICS-EVALUATION . I_ i VERMONT YANKEE FEEDWATER CHECK VALVE V28B I ACK 'MODEL: ELLIPTICAL LONGITUDINAL CRACK CR IN CYLINDER (T/R=0.1,A/L=0.5) WALL THICKNESS = 2.0000 1 STRESS COEFFICIENTS CASE ID CO C1 C2 C3 i -THRUWALL 23.5000 0.0000 O.0000 O.0000 FWNRC 8.0867 -5.3350 5.8800 0.4018 CRACK ---------------STRESS INTENSITY FACTOR---------------- ' DEPTH CASE CASE THRUWALL FWNPC '.I O.0320 4.726 1.602 O.0640-6.695 2.238 'I O.0960 8.214 2.710 0.1280 9.501 3.095 O.1600 10.641 3.427 -g 0.1920 11.678 3.720 i 3-0.2240 12.634 3.985 L O.2560 13.528 4.229 l 0.2880 14.371 4.457 j O.3200 15.173 4.672 0.3520 15.939 4.879 O.3840 16.674 5.078 I O.4160 17.385 5.273 0.4480 18.075 5.466 0.4800 18.744 5.657 0.5120 19.395 5.848 O.5440 20.030 6.041 0.5760 20.649 6.235 O.6080 21.253 6.433 ' I~ 0.6400 21.843 6.632 0.6720 22.420 6.837 0.7040 22.987 7.047 I 0.7680 O.7360 23.544 7.263 24.091 7.486 0.8000 24.629 7.717 I O.8320 25.164 7.958 0.8640 25.691 8.208 0.8960 26.211 8.468 0.9280 26.724 8.738 I I

pc -CRACK VERSION 1.2 g PAGE: .22 0.9600 27.232 .9.019 L 0.9920' 27.733' 9.311-l 1.0240: 28.232 9.616 l 1.0560. '28.726 9.935 -1.0880 29.216 10.268 ~1.1200' 29.701 10.614 3..' 1.1520 30.182 10.976 ~1.1840 30.658 11.352 1.2160 31.133 11.744 1.2480 31.606 12.152 8 1.2800 32.076 12.5'/7 1.3120 32.542 13.018 1.3440 33.005 13.478 . l. 1.3760 33.466 13.955 .5 1.4080' 33.922 14.452. 1.4400 34,371 14.968 .3 1.4720-34.818 15.504 - g~ 1.5040 35.263 16.060 1.5360 35.704 16.638 1.5680 36.144 17.236 1.6000 36.581 17.857 END OF pc-CRACK 8; I: LI I g I I I g I .I

tm pc-CRACK (C) COPYRIGHT 1984. 1987 STRUCTURAL INTEGRITY ASSOCIATES, INC. I SAN JOSE, CA (4081978-8200 VERSION 1.2 LINEAR ELASTIC FRACTURE MECHANICS EVALUATION ERMONT YANKEE FEEDWATER CHECK VALVE V28B CRACK MODEL CIRCUMFERENTIAL CRACK IN CYLINDER (T/R=0.2) ALL THICKNESS = 2.0000 STRESS COEFFICIENTS I CASE ID CO C1' C2 C3 FWNRC 8.0867 -5.3354 5.8800 0.4018 CRACK ---------------STRESS INTENSITY FACTOR---------------- DEPTH CASE FWNRC I 0.0320 ~2.799 0.0640 3.930 8 0.1280 0.0960 4.781 5.487 0.1600 6.100 0.1920 6.649 I O.2240 7.181 O.2560 7.692 'O.2880 8.178 I 0.3200 8.646 0.3520 9.100 0.3840 9.545 0.4160 10.017 . I 0.4480 10.523 0.4800 11.032 0.5120 11.545 I 0.5440 12.064 0.5760 12.590 0.6080 13.138 I 0.6400 13.736 e 0.6720 14.349 0.7040' 14.978 0.7360 15,624 I'0.7680 16.288 O.8000 16.972 0.8320 17.705 I 0.8640 18.460 0.8960 19.239 0.9280 20.042 0.9600 20.871 I I

e-CRACK VERSION 1 3 PAGE 3 0.9920 21.737 1.0240 22.686 1.0560 23.704 I 1.0880 24.758 1.1200 25.850 1.1520 26.981 I 1.1840 28,153 1.2160 29.406 1.2480 30.747 I 1.3120 1.2800 32.137 33.578 1.3440 35.073 4 36.623 I a.3760 1.4080 38.251 1.4400 40.002 1.4720 41.816 I 1.5040 43.695 1.5360 45.642 1.5680 47.659 a.6000 49.747 END OF pc-CRACK lI L, I I 1 I I I I 1 L I. II lI

tm pc-CRACK (C) COPYRIGHT 1984, 1987 I STRUCTURAL INTEGRITY ASSOCIATES. INC. SAN JOSE, CA (4081978-8200 VERSION 1.2 LINEAR ELASTIC FRACTURE MECHANICS EVALUATION ERMONT YANKEE FEEDWATER CHECK VALVE V28B RACK HODEL LONGITUDINAL CRACK IN CYLINDER (T/R=0.2) ALL THICKNESS = 2.0000 I CASE ID STRESS COEFFICIENTS CO C1 C2 C3 FWNRC 8.0867 -5.3354 5.8800 0.4018

I l

CRACK ---------------STRESS INTENSITY FACTOR---------------- DEPTH CASE FWNRC 0.0320 2.693 I 0.0640 3.848 0.0960 4.763 0.1260 5.561 0.1600 6.288 I 0.1920 6.970 0.2240 7.651 i 0.2560 8.324 I 0.2880 8.986 0.3200 9.642 i 0.3520 10.295 j 1 I 0.3840 10.948 i 0.4160 11.630 l 0.4480 12.346 0.4800 13.073 l. 0.5120 13.810 l 0.5440 14.560 O.5760 15.325 ll 0.6080 16.141 15 0.6400 17. 0 8 7 4E--- O.6720 18.060 19.058 l I 0.7040 0.7360 20.085 0.7680 21.141 O.8000 22.227 I 0.8320 23.523 l 0.8640 24.860 0.8960 26.239 I 0.9600 0.9280 27.662 29.131 I 3 4

c-CRACK VERSION 1 3 PAGE 2 0.9920 30.647 m 1.0240 32.401 5 2 o66o 34.278 1.0880 36.217 1.1200 38.223 I 1.1520 40.295 1.1840 42.438 1.2160-44.778 3 a.2480 47.329 3 1.2800 49.971 1.3120 52.708 1.3440 55.543 I 1.3760 58.480 1.4080 61.637 1.4400 65.258 ' 3 1.4720 69.006 3 1.5040 72.884 1.5360 76.896 5 5680 81.048 I 1.6000 85.343 END OF pc-CRACK I I I I I I I I I I I

H tm pc-CRACK (C) COPYRIGHT 1984, 1987 STRUCTURAL INTEGRITY ASSOCIATES, INC. I SAN JOSE, CA (408)978-8200 VERSION 1.2 I LINEAR ELASTIC FRACTURE MECHANICS EVALUATION VERMONT YANKEE FEEDWATER CHECK VALVE V28B I CRACK MODEL ELLIPTICAL SURFACE CRACK PLATE UNDER MEMBRANE 84 BENDING STRESSES WALL THICKNESS = 2.0000 Y3 ELD STRESS = 30.0000 CRACK ASPECT RATIO (A/L)= 0.2500 STRESS COEFFICIENTS CASE ID CO C1 FWNRC B.0807 O.0000 CRACE ---------------STRESS INTENSITY FACTOR---------------- DEPTH CASE FWNRC I O.0200 1.854 O.0400 2.623 J I 0.0600 3.214 0.0800 3.713 O.1000 4.154 O.1200 4.552 I O.1400 4.919 O.1600 5.261 O.1800 5.583 i I O.2000 5.887 O.2200 6.197 O.2400 6.496 l I 0.2600 6.785 0.280C 7.067 O.3000 7.341 O.3200 7.609 I O.3400 7.871 O.3600 8.127 I O.3000 8.379 I O.4000 8.627 O.4200 8.844 O.4400 9.056 i I O.4600 9.264 3 O.4800 9.467 i O.5000 9.667 O.5200 9.862 I I 1 o

pc-CRACK VERSION 1.2 PAGE 2 0.0400 10.055 0.5600 10.244 O.5800 10.429 I 0.6000 10.612 O.6200 10.849 0.6400 11.084 I O.6600 11.319 0.6800 11.553 0.7000 11.787 O.7200 12.019 I 0.7400 12.252 O.7600 '12.484 0.7800 12.715 I O.0000 12.947 0.8200 13.199 0.8400 13.452 O.8600 13.705 I 0.8800 13.959 l O.9000 14.212 O.9200 14.467 I 0.9400 14.721 0.9600 14.976 0.9800 15.232 1.0000 15.407 END OF pc-CRACK I I I I-I I I I I I ..,,m...

tm pc-CRACK (C) COPYRIGHT 1984, 1987 STRUCTURAL INTEGRITY ASSOCIATES, INC I SAN JOSE, CA (408)978-8200 j VERSION 1.2 LINEAR ELASTIC FRACTURE MECHANICS EVALUATION I VERMONT YANKEE FEEDWATER CHECK VALVE V28B 11 CRACK MODELtCENTER CRACK PLATE UNDER REMOTE TENSION STRESS HALF PLATE WIDTH = 10.0000 STRESS COEFFICIENTS CASE ID CO C1 FWNRC B.0867 THRUWALL 23.5000 I CRACK ---------------STRESS INTENSITY FACTOR---------------- DERTH CASE CASE FWNRC THRUWALL I O.0400 2.867 8.331 O.0B00 4.054 11.702 0.1200 4.966 14.430 I O.1600 5.734 16.664 0.2000 6.412 18,632 O.2400 7.024 20.413 O.2800 7.588 22.051 I 0.3200 8.113 23.577 023600 8.607 25.011 O.4000 9.074 26.368 I 0.4800 0.4400 9.519 27.661 9.944 28.897 0.5200 10.352 30.084 I O.5600 10.746 31.228 0.6000 11.126 32.333 0.6400 11.495 33.403 O.6800 11.852 34.442 I 0.7200 12.200 35.452 0.7600 12.538 36.437 0.8000 12.869 37.397 I 0.8800 O.8400 13.192 38.336 13.508 39.254 0.9200 13.817 40.153 I O.9600 14.121 41.035 1.0000 14.419 41.901 1.0400 14.712 42.752 1.0800 14.999 43.588 I I

pc -CR ACK. VERSION 1.2 PACE 2 1.1200 15.283 44.412 1.1600 15.562 45.223 1.2000 15,837 46.022 8 1.2400 16.108 46.810 1.2800 16.376 47.588 1.3200 16.640 48.356 I 1.3600 16.901 49.115 1.4000 17.159 49.865 1.4400 17.415 50.607 1.4800 17.667 01.342 I 1.5200 17.918 52.069 1.5600 18.165 52.789 1.6000 18.411 53.502 I 1.6400 18.654 54.210 1.6800 18.896 54.911 1.7200 19.135 55,607 1.7600 19.373 56.298 I 1.8000 19.609 56.984 1.8400 19.843 57.665 1.8800 20.076 LB.342 I 1.9200 20.308 59.014 1.9600 20.538 59.603 2.0000 20.767 60.348 I END OF pc-CPACK I I I I I I I I I I e

as as aus se aus as as sus sur aus me m Jun m em ene as es aus t W Ltl i i 100.00 - O i Z -i i 80*00 '"* ' " '* ' " ' ' E'

  • 9 * ' "i "i"" '*l"- * **"" --

~ 1 l (T = 80 F for RCIC Injection Mode) i O W I 60.00 h I center cracked piete g Wru-wall Flaw 3 Inches Wide V .g t Plate under bending { I ' and tension " i 'i**' "*" i" "Y' i"d" t / a"/1 = 0.2 P 40.00 - j \\ / ) / / e- / Elliptical flaw in cylinder ~ l C ' a/1 = 0.5 l 20.00 h 0 -4 > C i l m m ~ O 0.00 ..i...... M 0.00 0.50 1.00 1.50 2.00 9 m Thru-Wall Jepth incles 1

tm ( pc-CRACK (C) COPYRIGHT 1984, 1987 i STRUCTURAL INTEGRITY ASSOCIATES, INC. SAN JOSE, CA (4081978-8200 VERSION 1.2 L FATIGUE CRACK GROWTH ANALYSIS 'ERMONT YANKEE FEEDWATER CHECK VALVE V28B 2NITIAL CRACK SIZE = 1.5000 RALL THICKNESS = 2.0000 E X CRACK SIZE FOR FCG= 1.6000 FATIGUE CRACK GROWTH LAW (S) I ASME SECTION XI BILINEAR LAWS FOR WATER ENVIRONMENT R = Kmin / Kmax IFR<0.25THENR'=0.25 F R > 0.65 THEN R' = 0.65 ELSE R' = R et = 26.9 = R' - 5.725 QU = 3.75

  • R' + 0.06

' IRAN = ( D

  • QU / QL )
  • 0. 2 5 dx = Kmax - Kmin F dK < KTRAN THEN do/dN = CL
  • QL
  • dK'5.95 F dK > KTRAN THEN da/dN = CU
  • QU
  • dK'1.95 HERE:

CL = 1.020000E-12 CU = 1.010001E-07 3 D = 9.902034E+04 WRE FOR THE CURRENTLY ASSUMED UNITS OF: FORCE: kips LENGTH: inches STRESS COEFFICIENTS ' CASE ID CO C1 C2 C3 FWNRC 8.0867 -5.3354 5.8800 0.4018 l UMBER OF CYCLE BLOCKS = 18 RINT INCREMENT OF CYCLE BLOCK = 1.0 I NUMBER OF CALCULATION PRINT FCG SUBBLOCK CYCLES. INCREMENT INCREMENT LAW ID 1 1.0 1.0 1.0 SECT XI LAW I I G

-CRACK VERSION 1.2 PAGE 2

Km2x Kmin SUBBLOCK CASE ID SCALE FACTOR CASE ID SCALE FACTOR 1 FWNRC 3.0000 FWNRC 0.0000 CRACK MODEL: ELLIPTICAL LONGITUDINAL CRACK JN CYLINDTR(T/R=0.1.A/L=0.5) CRACK ---------------STRESS INTENSITY FACTOR---------------- DEPTH CASE FWNRC I 0.0320 1.602 0.0640 2.238 I 0.1280 0.0960 2.710 3.095 0.1600 3.427 0.1920 3.720 1 O.2560 0.2240 3.985 4.229 0.2880 4.457 I 0.3200 4.672 0.3520 4.878 0.3840 5.078 0.4160 5.273 I 0.4480 5.466 0.4800 5.657 0.5120 5.848 0.5440 6.041 4 0.5760 6.235 0.6080 6.432 I 0.6400 6.632 0.6720 6.837 0.7040 7.047 0.7360 7.263 I 0.7680 7.486 0.8000 7.717 0.8320 7.958 8 0.8960 0.8640 8.208 8.468 0.9280 8.738 I .0.9600 9.018 0.9920 9.310 1.0240 9.616 1.0560 9.935 I 1.0880 10.267 1.1200 10.614 1.1520 10.975 g 1.1840 11.352 , g 1.2160 11.744 1.2480 12.151 I .1.2800 12.576 1.3120 13.018 1.3440 13.477 1.3760 13.955 1.4080 14.451 I I

-.. -. -._- _ _ ~ _. - c-CRACK VERSION 1.2 PAGE 3 5 1.4400 14.967 i 1.4720 15.503 16.060 l I 1.5040 1.5360 16.637 l 1.5680 17.236 1.6000 17.856 I TOTAL SUPBLOCK l CYCLE CYCLE KMAX KMIN DELTAK R DADN DA A A/T LOCK 1 1.0 1.0 47.97 0.00 47.97 0.00 1.9E-04 0.0002 1.5002 0.75 BLOCK 2 1.0 47.98 0.00 47.98 0.00 1.9E-04 0.0002 1.5004 0.75 I 2.0 JLOCK 3 3.0 1.0 47.99 0.00 47.99 0.00 1.9E-04 0.0002 1.5006 0.75 g FLOCK 4 4.0 1.0 48.00 0.00 48.00 0.00 1.9E-04 0.0002 1.5006 0.75 hLOCK 5 5.0 1.0 48.01 0.00 48.01 0.00 1.9E-04 0.0002 1.5010 0.75 LOCK 6 6.0 1.0 48.02 0.00 48.02 0.00 1.9E-04 0.0002 1.5011 0.75 LOCK 7 ,.e e. e, e.ee 48.e, e.0 1.9E.04 e. _, ,.501, e.75 7.e BLOCK 8 8.0 1.0 48.04 0.00 48.04 0.00 1.9E-04 0.0002 1.5015 0.75 LOCK 9 9.0 1.0 48.05 0.00 48.05 0.00 1.9E-04 0.0002 1.5017 0.75 FLOCK 10 10.0 1.0 48.06 0.00 48.06 0.00 1.9E-04 0.0002 1.5019 0.75 I I I

e-qRACK VERSION 1.2 PAGE 4 MLOCK 11 i 11.0 1.0 48.07 0.00 48.07 0.00 1.9E-04 0.0002 1.5021 0.75 LOCK 12 12.0 1.0 48.08 0.00 48.08 0.00 1.9E-04 0.0002 1.5023 0.75 ELOCK 13 13.0 1.0 48.09 0.00 48.09 0.00 1.9E-04 0.0002 1.5025 0.75 LOCK 14 14.0 1.0 48.10 0.00 48.10 0.00 1.9E-04 0.0002 1.5027 0.75 $ LOCK 15 W 15.0 1.0 48.11-0.00 48.11 0.00 1.9E-04 0.0002 1.5029 0.75 LOCK 16 16.0 1.0 40.12 0.00 48.12 0.00 1.9E-04 0.0002 1.5031 0.75 LOCK 17 17.0 1.0 48.13 0.00 48,13 0.00 1.9E-04 0.0002 1.5033 0.75 1 l BLOCK 18 18.0 1.0 48.14 0.00 48.14 0.00 1.9E-04 0.0002 1.5035 0.75 l END OF pc-CRACK I I I I I E R 8 l

1

s

!I l l (- APPENDIX C FRACTURE TOUGHNESS DATA FOR I A216 WCB CAST MATERIAL Lg iI 'I I r 'I Lg !I I I ' I

NOREG/CR-3000 g SAND 782347 -g: I ' Fracture Toughness of PWR Components Supports I I REC 9VED I mass l a.xut mn nem em c" I Prepared by G. A. Knorovski, R. D. Krieg, G. C. Allen, Jr. ~ Sandia National Laboratories r Regulatory g . c o..N ci

i. ion

'I F g"

De Table 3.2 Classification of Wrought Grades into Groups i Plain carbon: A-7, A-5 3, A-106, A-201, A-212, A-2 8 3, A-28 4 ' I ~ A-285, A-306, A-307, A-501, A-515 i Carbon-manganese A-36, A-105, A-516, A-537 High-strength low-alloy: A-441, A-572, A-588, A-618 Low alloy (not quenched & tempered): A-302, A-322, A-353, A-387 Quenched & tempered: A-193, A-194, A-325, A-354, A-461, A-490, A-508, A-514, A-517, A-533, A-537, A-540, A-543, A-563, A-574. i I I l' E \\ I l 15 L . ~

e i Table 4.4 Computation of NDT Results t Material NDT e IUiY + 1.30 NDT + 2e l Cast Steels A-27, A-216 l' - 65F 12*F 10*F 18*F (heat treated >1" 35 17 57 69 C i condition) max. -20 A-352 I Wrought Steels all " mild" steels

  • 27 31 67 89 l

all " mild

  • steels except A-201 40 28 77 96 C-Mn*(as-hot rolled) 22 13 39 48 5

8 (normalized) -28 18 i~ HSLA* (as-hot rolled) 25** 12** 41** 49** L (normalized) -50** 18** -27** -14** low alloy non O&T A-302 8 28 45 64 max. -320 A-353 65** A-387 Quenched & Tempered max. 40*F A-508 C12 max. -10'F A-514 max. -20

  • F A-517 max.

20*F I A-5338 Cll max. -60*/ A-537 C12 max. -60*F A-543

  • See table 3.2 for ASTM specs included in this category I
    • See discussion in Appendix B 4.4.3 Fracture Toughness Minimum values for fracture toughness of the material groups are indicated in Table 4.5.

These are usually dynamic values or static values obtained at lower temperatures equivalenced via the Barsom temperature shift (see section 4.2). Data at the reference tempera-ture, 75'F, was not always obtainable. If data was not obtainable, l 23

E, APPENDIX B - MATERIAL DATA B.1 Data obtained l The sources of material data for the various groups are listed in Tables B.1 through B.7. Included in these tables are data sour-ces which were not used in the body of the report. The actual data ty (NDT and K-type) have been plotted in Figs. B.1 through B.25. Tab-ulation of NDT data and standard deviations (where possible) are indicated in Table 4.4. NDT data for several grades of steel were not located. Assign-ment into susceptibility groups for these materials were based j on the minimum requirements of the appropriate standards under which the materials were procured (see Appendix C), as compared to materials for which data were obtained. ~ B.2 Cast Steels Four grades of cast steels were listed in the utility submit-tals (not counting a stainless steel casting for Yankee, considered not to have a probicm with respect to fracture toughness or lamellar tearing). Two of the grades, A-27 Gr 70-40 and A-216 Gr WCB are carbon manganese-silicon types; one, A-148 (Gr 80-40 and Gr 80-50) is not chemically specified (which indicates it may be either C-Mn or low-alloy depending upon the heat treatment and/or section size) and the last, A-352 Gr LC3, is a high ( 3-4%) nickel content heat-treated alloy requiring CVN testing. (Note: all % are by weight) The A-352 Gr LC3 grade in either the double normalized and tempered, or quenched and tempered condition is expected to show excellent fracture toughness with NDT's in the range of -100*F for E I

1" section size (Fig. B.1). Some utility data (Ref. B-1) indicated thick section NDT's in the -100 to -60'F range with a maximum value (one example) of -20*F. A-27 Gr 70-40 and A-216 Gr WCB are both C-Mn-Si type alloys varying only slightly in chemical composition allowables, and pri-marily in minimum yield strength (40 vs 36 ksi, respectively). Of the two, the A-27 Gr 70-40 allows less carbon (.25% vs.30%) but more manganese (1.2% vs 1.0%). A-216 Gr WCC is virtually identical to A-27 Gr 70-40 in this respect. A histogram of NDT values for A-27 Gr 70-40 heats mainly in the normalized and tempered condition I (five were normalized and four were quenched and tempered) plus five 4 heats of A-216 Gr WCB is shown in Fig. B.2. This is taken from a I compilation made by the Steel Founder's Society of America (Ref. B-2). The statistics of these data imply that 95% of all heats have NDT's below 20'F. However, these data are taken from 1" thick test castings, and a section size effeet may be expected. A second source of data (Ref. B-3) for these materials indicated that NDT was 35'F i with a standard deviation (c) of 17'F for 12 specimens of varying thickness (from 2-1/2" to 5") poured from two heats in the normalized and tempered condition. This still indicates that 95% have their NDT below 70*F, but not with as much margin as the 1 in. thickness case. Finally, these two specifications allow the possibility of producing heats in the annealed condition, if the mechanical proper-ties can be met. This would be expected to further degrade their fract.ure._ toughness properties since a coarser microstructure..would . result. This implies the only way to meet st'rength requirements would be by increasing carbon content. I 115 1

i I. Finally, A-148 Gr 80-40 and Gr 80-50 (40 and 50 ksi yield I strength, respectively) are more difficult to evaluate, since chemical specifications and data are lacking. The added strength requirements over A27 Gr 70-40 could be met in a number of ways; via heat treatment, via additional carbon content, or via alloy Since additional carbon is usually the least expensive I content. route, the implication is that these sub-grades of A-148 would have less desirable NDT values than the previously discussed A-27 and A-216. However, A-148 was specified by only one plant and was part of a wire rope system, which is probably not as critical a location i as the other cast grades, which were typically in the sliding pedes-tal category of plants. In Fig. B.1 some NDT data (Ref. B-4) is available for normalized and tempered A-148 Gr 80-50 which indicate excellent NDT's around -10F; however, these heats contained approx-imately 2% Ni. Thus these data would be indicative of the best practices in meeting the mechanical property requirements. K data were located for two heats of A-216 Gr WCC (Ref s B-5, yc B-6). These are shown in Figs. B.3. Applying a temperature shift values at 75'F are roughly 40 ksi /'iii. of about 150*F, equivalent kid These specimens were taken from immense (20"x20'x48")* castings, and probably represent the worst possible section size effect. t l B.3 Weld Consumables The weld metals are also in the cast steel category. It is difficult to evaluate weld metal properties separately from the base materials being joined, since dilution effects can occur which signi-i ficantly change the chemical composition of the fused metal. Further-5 116 t

i FIG. B.2 NOT FOR CAST GRADES (NDT) FOR A-27 IS -7

  • F 13 'F a

i i h A-27 GR 70140 A-216 GR WCB ~ NORMAllZED K F e NORMAllZED & TEMPERED x g in 15 QUENCHED & TEMPERED E 9 E a l T ~ a s g t W l ~ I l ~ 10 7 ? \\ N W x x i g x E 5 e m K X X X X X x j i e i i -30 -20 -10 0 10 20 30 40 t NDT (* F ) l I j

t 280 i i i i i i i i i i ~ ASTM A 216 STEEL-HEAT 4394 lg 240 1 l @2W l l l, y 5 i 160 8 g e 6 i2 120 I E E b .GEND ~ l a g 80

oam, ALID K

~ IC h '^ a IT, U, 4T, 8T, IUCT - 5 o@ T LINEAR BREAK 40 e a@ T LINEAR BREAK - o-

  • 3

,ITCT E II E d I i l i I i i i l i h - 200 -100 0 100 200 300 Lg TEST TEMPERATURE *F -FRACTURE TOUGHNESS VERSUS TEST TEMPERATURE FIGURE B.3(a ) A-216 K DATA g IC B E

- - -.. -.. -.. -. ~...... -. -. -.. _ - r 5 1 I APPENDIX D ENRANCED LEAKAGE MONITORING PROGRAM E FOR TEEDWATER CHECK VALVE V28B g I I t t

I l

l E 7570R I I

E' 1 APPENDIX D l ENHANCED LEAKAGE MONI'IORING PROGRAM FOR FEEDWATER CHECK VALVE V28B I To augment Vermont Yankee's existing Primary Containment Leakage Monitoring System, a Local Leak Detection System has been installed on the FDW-2BB valve. This additional system is a Techmark Leak Detection System to provide constant leakage monitoring during i the next operating cycle. The system consists of three moisture sensitive tape (MST) transducers mounted on the mirror insulation below the valve (V28B). To install the transducers, a h" hole l I was drilled through the insulation for the transducer sensor tube I to be inserted. The sensor tube provides a path for moisture from under the insulation to contact the MST. The transducers have the ability to detect leakage as low as 0.1 gpm. The transducers l provide a multiplex signal to an indicator / control unit (TUM 700) mounted in the Reactor Building. The control unit interrogates E all sensors once per second and provides a digital display of sensor i E location (s) for alarm or trouble conditions. The unit also provides l remote alarm indication in the main control room. l l The Local Leak Detection System will be utilized by operations personnel to initiate further a tinistrative actions / controls which have been developed as part of this enhanced plan. These administrative I controls identify, in part, operator action upon receipt of an alarm on the MST unit, compensatory action if the unit experiences trouble as well as establishing additional leakage rate criteria below that contained in Technical Specifications. As stated above, the Local Leak Detection System is intended to augment the existing systems and provide additional assurance that I any leakage from the FDW-28B valve will not go undetected. This i system will provide operators with an "early warning system" to initiate additional measures of this augmented program. - g I l I l I I -}}

Retrieved from "https://kanterella.com/w/index.php?title=ML20042D114&oldid=4542579"