ML20058K415

From kanterella
Jump to navigation Jump to search
Steam Generator Insp,Repair & Restoration Program Presentation to Nrc
ML20058K415
Person / Time
Site: Indian Point Entergy icon.png
Issue date: 06/30/1990
From:
WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:
Shared Package
ML100331447 List:
References
SG-90-06-024, SG-90-6-24, WCAP-12628, NUDOCS 9007060018
Download: ML20058K415 (92)
v • d • e


Text

HESTINGNOUSE CLASS 3 HCAP-12628 SG-90-06-024 INDIAN POINT UNIT 2 STEAM GENERATOR INSPECTION, REPAIR, Ai4D RESTORATION PROGRAM PRtSENTATION TO NUCLEAR REGULATORY COMMISSION 1

Issue date: June 1990 PREPARED FOR CONSOLIDATED EDISON COMPANY HESTINGHOUSE ELECTRIC CORPORATION NUCLEAR SERVICES DIVISION P. O. BOX 35S PITTSBURGH, PENNSYLVANIA 15230 Copyright by Hestingbouse Electric 1990, e All Rights Reserved 1

l 06000:10/061490 l

COO 7660018 900627 7 DR ADOCK 0500 1

I j

TABLE OF CONTENTS FOREHORD 11 OVERVIEH iii TITLE PAGE 1 AGENDA 0F PRESENTATION 2

1. INTRODUCTION 2
2. RECENT ACTIONS, OPERATING HISTORY AND RADIATION EXPOSURE 3
3. MID-CYCLE INSPECTION RESULTS AND CURRENT REPAIRS 16
4. BOAT SAMPLE RESULTS 23
5. INTEGRITY ANALYSIS 52
6. ROOT CAUSE 78 j
7. FUTURE PLANS 80 i

i 06000:10/061490 i

FOREHORD This non-proprietary report bears a Westinghouse copyright notice. The NRC is permitted to make the number of copies of this report necessary for its internal use and such additional copies which are necessary in order to have one copy available for public viewing in the appropriate docket files in the public document room in Washington, D.C. and in local public document rooms as may be required by NRC regulations if the number of copies submitted is insufficient for this purpose. The NRC is not authorized to make copies for the personal use of members of the public who make use of ths NRC public document rooms. Copies of this report or portions thereof made by the NRC must include the copyright notice.

/

06000:10/061490 ii

OVERVIEW l

In February, 1990, Consolidated Edison's Indian Point Unit 2 was taken off line to perform a scheduled mid-cycle inspection of the steam generator girth welds and feedwater nozzles. This inspection effort included visual (VT) arid magnetic particle (MT) of the girth welds, and visual and magnetic particle or liquid penetrant (PT) on the feedwater nozzle inner radius areas. Cracking cas found to exist in all areas inspected, l During a March, 1990, meeting with the NRC to discuss these inspection findings, con Ed was instructed to provide details on further inspections and repair plans. Subsequent inspections caused the scope of the program to be further expanded to include sections of the transition cones, all feedwater nozzles ID bores, feedring supports, feedring brackets and straps, feedwater piping as well as other miscellaneous appurtenences welded to the inside diameter surface of the steam generator. Consolidated Edison was also required to justify the next startup with an analytical assessment based on the maximum observed crack growth rate for each steani generator to demonstrate all code requirements were met, and by using the square root of 10 rather than the square root of 2 to determine maximum allowable stress intensity.

Additionally, Con Ed was to ensure that all repairs satisfied the requirements identified in Code Case N-432 or follow Section XI criteria.

As a result of these inspections, indications in all areas were removed by grinding.

In certain girth weld locations, the depth of some ground out areas were either partially or completely restored by welding utilizing qualified weld procedures in full compliance with the requirements of the ASME Code Case N-432 or Section XI. In addition to repairs, analysis was performed to justify continued operation of Indian Point Unit 2. The analysis approach used to demonstrate adequate margin in the steam generator girth weld for continued operation was based on a. modification of the fracture mechanics criteria of Section XI.

0600D:lD/061490 iii

r; The repair of indications observed in the feedwater nozzle area was accomplished by grinding to remove all indications and restoring to the original geometry by welding. An integrity evaluation (based upon an alternative fracture toughness criterion as discussed in detail in Reference

1) demonstrated adequate margin in the feedwater nozzle region for continued operation.

After all of the analytical effort was completed and a significant portion of the field repairs were implemented, a meeting on May 21, 1990, was held with the U.S. NRC NRR and Region I staff to provide an update of the restoration program with respect to current field inspection, laboratory examination, engineering evaluation and analyses, and mitigating action plans.

The presentation materials entitled " Consolidated Edison /Hestinghouse Steam  ;

Generator Inspection, Repair, and Restoration Program for Indian Point Unit 2" follow.

Reference:

1. WCAP-12573, Indian Point Unit 2 Steam Generator Inspection, Repair, and Restoration Program; prepared for Consolidated Edison Company of New York, May, 1990.

1 I'

06000:1D/061490 iv

INDIAN POINT UNIT 2 STEAM GENERATOR INSPECTION, REPAIR AND RESTORATION PRESENTATION TO THE NUCLEAR REGULATORY COMMISSION MAY 21, 1990 CONSOLIDATED EDISON COMPANY OF NEW YORK 1

.i INDIAN POINT UNIT 2 STEAM GENERATOR INSPECTION, REPAIR AND RESTORATION MAY 21, 1990 AGENDA

1. INTRODUCTION
2. MID-CYCLE INSPECTION AND REPAIRS
3. BOAT SAMPLE (S) ANALYSIS AND ROOT CAUSE
4. INDUSTRY EXPERIENCE
5. STEAM GENERATOR INTEGRITY EVALUATIONS A) GIRTH WELD B) FEEDWATER N0ZZLE
6. MITIGATING ACTIONS
7. OTHER ISSUES
8. FUTURE PLANS -

l 2

1 MEETING OBJECTIYE 1

DEMONSTRATE STEAM GENERATOR  !

INTEGRITY FOR RETURN TO POWER ;

i AND CONTINUED OPERATION.

l l

BASIS FOR STEAM GENERATOR INTEGRITY o CAUSATIVE MECHANISMS ARE KNOWN AND PERMIT BOUNDING 0F CAUSATIVE FACTORS AND RELATIVE SENSITIVITY BASED ON STEAM GENERATOR LOCATION

- MECHANISM o ENVIRONMENTALLY ASSISTED CRACKING (STRESS CORROSION CRACKING AND CORROSION FATIGUE)

CONTRIBUTING FACTORS o SECONDARY SIDE CHEMISTRY

- OXYGEN

- OXIDIZING SPECIES (COPPER) o APPLIED (OPERATING) STRESS o RESIDUAL STRESS 4

l BASIS FOR STEAM GENERATOR INTEGRITY (CONTINUED) o ALL AREAS OF CONCERN HAVE BEEN INSPECTED, AND REPAIRED AS REQUIRED.

i o MATERIAL SAMPLE TESTS SHOW N0 SERVICE AGING OF BASIC MECHANICAL PROPERTIES.

l l o MITIGATING ACTIONS FOR AUXILIARY FEEDWATER OXYGEN CONTROL AND THE FEEDWATER CONTP.0L VALVE REDUCE THE POTENTIAL FOR CRACK INITIATION AND PROPAGATION.

o ALL REPAIRS HAVE BEEN PERFORMED IN ACCORDANCE WITH THE REQUIREMENTS OF ASME CODE AND CODE CASE N-432.

o EVAULATION OF STEAM GENERATOR INTEGRITY HAS SHOWN N0 UNREVIEWED SAFETY QUESTIONS.

5

STEAM GENERATOR INSPECTIONS FIVE MAJOR CATEGORIES e GIRTH WELDS e N0ZZLES e FEEDWATER PIPE e BRACKETS e OTHER AREAS COMED

  • 3 0

I k

i STEAM GENERATOR GIRTH WELD INSPECTIONS i

INSPECTION PLAN -

1/3 0F t $.S.'s 2005 0F t 5.8.'s + 1/3 2 ADD'l S.G's L

1005 0F ALL 4 5.8.'s INSPECTION NETH00 -

N. T.

i i

l A00'L. INFORMATION -

BOAT $ANPLES TO

$ PAN CONDITIONS '

l l REPAIR NETH00 -

GRIND OUT, MT CLEAR REPAIR BY TEMPER BEAD WELDING IN

$8 12. N0 AREA l

A .68' FRON i

ORIG 1RAL WALL f

ACCEPTANCE HDE -

NT, UT, RT OF WELDS

+ 10' ALL AROUND 1

1 7

l 1

{ _

1

INDIAN POINT 2 STEAM GENERATORS GIRTH WELD SG21 SG22 SG23 SG24 1990 # OF 42 26 14 10  ;

INDICATIONS MAX.

DEPTH

  • 0.36" 0.53" 0.28" 0.34" Ave.

DEPTH 0.13" 0.11" 0.08" 0.16" 1

  • DEPTH OF GRIND 00T l

. l I

ADDITIONAL GIRTH REGION INSPECTIONS INSPECTION PLM

]

l e UT 10' BELOW 81RTH WELD ALL SG's 360 j e

SANPLEUT1/30FENTIRETRAN$lTIONCONEt$8's e

INCLUDES 1/2 0F EACH ADJACENT PLAfts  ?

e INCLUDES TOTAL LENGTH OF 10F 3 .

LONGITUDINAL WELOS e INCLUDES LOWER 81RTH WELD e INCLUDES WELDt0 INTERIOR WELDED ATTACHMENT $ <

e t

f a

l

1.

STEAM GENERATOR TRANSITION CONES UPPLR QtR%

) , WELO

, /

g l LON G t Y UO6*lhL g W E LOS .

I L

\ I

\ r

\ I

'. I LOWER QiR1H WELO UNFOLDED VIEW O AV t o

UPPER QIRT&4

. to

'd

~% . t.oucit uoium,.

  1. wet.oS e

CONED 15 Low &R GIRTH O' 3 g,o=

10

DIAGRAMATIC

SUMMARY

0F TRANSITION CONE INSPECTION AREAS o

SG 22 <

25' 4,-

i o,,

- ~ ~ - - - - - '-

... / / sr. . . 1 s .'. .._ :.;.+-

} Gint

- gT

' vt MT I ' ' ' '

'\ \ a I 1

D'. ./

,N N ,

\'Ys

'/\ '

ut \ ,~' . ,f 'Y.}'

r: . . ...Q

_ 'x. x y, >

/' , ' 'A. '

j  !

l N yy Afs/ y K } ointl SG 21

- rm y;,. ' . .',- Q ' O. & '. y'. Q. ' N n'x . i .'y. '.g.x .,Q.,;. G ' .;o. '.N,q
, .q, y,. ~' .) y is )snask UT MM Y go a 1....._..,_,

1 '.::',..

sr l

/

X A/X ANY A }ci=ru

% 23,4 g L. , . .... . . . . . . . .

........... .......),,,,a N

s N. , . . : . )

MT I

l co m a '

}w='L

- 11

,s, - - - - - ',2 A- 9 a m 4'+m kmam.n a- 4 A umoG.e d si, + a kMm+4A4-n &-b- a 1en s em s'4 J *t -s4 4,, de- asua L va- .Aa sw.sw ADDITIONAL GIRTH RELATED INSPECTIONS INSPECTION PLAN -

SAMPLE ADDITIONAL CIRCUMFFERENTIAL WELD COMPARE TO PREVIOUS EXAM RESULTS METHOD -

UT RESULTS -

NO RELEVANT INDICATIONS SAME AS 1986 l

~

k f

12

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

STEAM: GENERATOR SHELL WELDS d T

/ \

. j 1

l l

/ \

~

i

< GIRTH WELD  ;

i l

- l 1

C LOWER GIRTH WELD l

I I

[', STUB BARREL WELD w>

- 1 13

E i

l.

l N0ZZLE EXAMINATIO.N INSPECTION PLAN i

2 0F 4 N0ZZLE FACES -

ALL N0ZZLE FACES' ALL N0ZZLE B0RES REMOTELY INSPECTION METHOD P.T., M.T. FACES REMOTE V.T. N0ZZLE B0RE EXPANDED INSPECTION REMOVE ALL THERMAL SLEEVES

\

EXAMINE ALL 80RES EXAMINE ALL N0ZZLE TO PIPE WELDS 1 INSPECTION METHODS P.T., N.T., B0RE,.

P.T...M.T., R.T., WELDS ADD'L. INFORMATION BOAT SAMPLE j

)

l 14 CoelED -

  • 9 .

/ l l

4 5

N0ZZLE EXAMINATION (CONTINUED)  ;

REPAIR NETHOD GRIND OUT M.T. CLEAR REPAIR BY NALF BEAD - B0RE REPAIR BY GTAW - COUNTERBORE i REPLACE N0ZZLE TO PIPE WELD i

NACHINE TO ORIGINAL ,

)

CONFIGURATION ACCEPTANCE NDE N.T., U.T., R.T., 0F WELDS PLUG 5' ALL AROUND ESTABLISH NEW SECTION XI  ;

BASE - LINE U.T., R.T. 'I ADD'l INFORNATION N.T. THERMAL SLEEVES 0.0.

& I.D.

1 15

l INSPECTION RESULTS N0ZZLE AREA GRINDING DEPTH, IN. MAX, SG FACE KNUCKLE BORE PIPE WELD AT BRACKET 21 0.44 0.40 0.198 0.318 22 0.40 0.00 0.295 0.388

'23. 0.70 0.13 0.217 0.200 24- 0.70-

  • 0.347 0.270-0 GRINDING BEGAN BEFORE BASELINE MEASUREMENTS 16

1 FEEDWATER. PIPE I 1

INSPECTION PLAN - EXAMINE ALL FOUR PIPES AT i

N0ZZLES.

METHODS. - V.T., P.T., R.T.

REPAIR - REMOVE PIPE UNTIL EXISTING PIPE l IS M.T. CLEAR I 1

ACCEPTANCE OF l

REPLACEMENT l

WELDS - M.T., R.T i

1 i

i 17 l \

l l.

t BRACKETS INSPECTION PLAN - 100% ALL FEEDWATER SUPPORTS ALL STEAN GENERATORS o INCLUDES FEEDWATER RING SUPPORTS o THERNAL SLEEVE SHELF BRACKETS o FEEDWATER TEE RESTRAINTS

.NETH00 - N.T.. P.T REPAIR o GRIND & CONT 0UR INDICATIONS o WELD A THROUGH G BRACKETS AS REQUIRED o REN0VE AND NODIFY N0ZZLE SHELF BRACKETS ACCEPTANCE o N.T., U.T f.

18 ,

i INDIAN POINT 2 STEAM GENERATORS zone IDENT1FICATON AND PEEDRH3 SUPPORTS 1

i~

=i FW N0ZZLE PA05 D & E 32 B ACKET STRAP BRACKET e PADS F 6 G S

f .

l 11' I

10 BRAOxET A l

3 I \ j 17 1 P d b d i 4

HEADER SHELL 7%

.6 BRACKET C I

19

3 TEAM bENERATORS

/

I N

k, ),

/

\ ..'N N s{ ,

g  %

/

r, - >

l N. /  !

N. ,

I- h

s. -

-l i

N

' s;

~

a . A i

.( '

/ j

! ~)

/

i .

ls

.,.- f  ;

'/

/'

ej i

FEEDWATER RING'  ;

SUPPORT BRACKET A-B-C LOCATIONS r i

h l

t. 20

EXPANDED INSPECTIONS

.STEAN SPACE DENISTER TO HEAD SG 24 , VT

{

NANWAY- SG 21 NT l

I 3/4" PENETRATION SG 21 , VT PLATE WELDS VT i

-T SECTIONS VT WATER SPACE 3/4" INSTRUNENT PENETRATION -

SG 22. 3VT 3

LOWER' GIRTH WELD (TRANS. CONT) -

SG 21,22, 1/3 UT l CONE. LONGIT. WELD -

SG 21.22 VT l l CONE PLATE- -

SG 21,22 1/3 UT .

8" HANDH0LE -

SG 23 PT l

6" HAN0 HOLE -

SG 23 PT 52" PENETRATION- -

SG 22 PT T.B.D l STU8 BARREL ATTACHNENT WELD -

SG 21 UT '

I

'T SECTIONS:

SG 21.24 VT L

FEEDWATER'LINE/N0ZZLES THERNAL' SLEEVE -

ALL VT

-l AT SG -

ALL VT

,'AT<.AFW INJECTION- -

22 VT 21

i l .

J Indian Point 2 Steam Generator wg _

.h

,_ m ,

) g DEMISTER ,

.- ,s I

- k, >1 8 - l

)i l i,, ,

C m-f F-

,,i_

-MANWAY l 3/4" PENETRATION

. . A

.Q

]

^ 6e 4' 44 kh ' " \ TEE SECTIONS

,M ; M' g-

. I

/  :

3/4" PENETRATION -

-y =

,) '

u-CIRTH WE2 i ,

F kJ v i I

a%b , l ruTE vEtD t0WER GIRTH WELD - /

. v

$ d5

-i I

'l

-l 7

2

- y y ,.

STUB RARREt WELD- -

S -)(

a ... #t.

k a, d M l

~

22

l r,

./

~

_g l. g

!)

' li  :

4, g-

  • -q- ,

+ 1-

! ~,f y l

.; l f i4l 'E N \ x xx g

i,3 '

  1. ! 'l

.i.b.I'.j_

l L I l;

'. ( g_' '.-~ i C-( .g ,,,..__ _- ...- Q-

? '.' l_ .

).-  ;

, w

.h. %' -

"- _/  !

u 4- l A-Gib >-@ggg h,7

.+_,

'* ,/

/

3 / .\ ,

f ,

1 ---

_n

_ % p'.

~~

ido . -pN P,, T

_. ~, -

m e.. r x1, e .r _a _ _ s 1 3r T

& +-

i X wa ,i q--

t l l } l \

t  ! ""i j ,

[ iN .

I' . . - _ . _ .... _ ..,._f, J I- , y  ;  !

j (l l l'  %, -  :

3

 % '. .m i ll m-

,,i

(...

,! ., .} .

0

, I) r

' l /.. -

I i i i H t- ,

b- 'I

._Q A M

/

E !l '

A

/'

[']

e Il rFMG j ,'/

l

__(

M /j}-m--p.w s . _ . . ._ .. ~~

.S pi iy ,a m-

. . ,. i ,_, 1

\

N

'h s

e o

23 i

CONCLUSIONS OF 1990 INSPECTIONS L

l L -

CRACKS WERE FOUND ONLY IN THE UPPER AREA 0F THE TRANSITION REGION u

NO CRACKS WERE FOUND ABOVE OR BELOW THIS AREA l

INSPECTIONS AT THE LOWER TRANSITION GIRTH WELDS AND AT THE STUB BARREL i L TOOPCYLINDER WELD BOUND THE LOWER L CYLINDER SHELL WELDS 1

l l

24 1

l

- ;j

~

Il METALLURGICAL EVALUATIONS TO ESTABLISH THE CAUSE AND MECHANISM OF CRACKING -l TO ESTABLISH MECHANICAL PROPERTIES OF THE MATERIAL  ;

TAKEN FROM SERVICE i

i i

i l

1 i

25

______ _____--________-~

METALLURGICAL EVALUATIONS 0 INVESTIGATION OF BOAT SAMPLES  !

O MECHANICAL PROPER'Y MEASUREMENTS L i

i i

26 1

i I

METALLURGICAL INVESTIGATIONS t

1989 OUTAGE:

ONE BOAT FROM GIRTH WELD OF SG #22 ONE BOAT FROM GIRTH WELD OF SG #24 1990 OUTAGE:

ONE BOAT FROM GIRTH WELD OF SG #21 .

ONE BOAT FROM GIRTH WELD OF SG #22 ONE BOAT FROM TRANSITION CONE OF SG #22 ONE BOAT FROM N0ZZLE BORE OF SG #24 FEEDRING SUPPORTS FROM SG #21 AND #24 SURFACE DEPOSITS TAKEN FROM GIRTHWELD, -

N0ZZLE BORE AND LOW RANGE LEVEL TAP.

l 27

l METALLURGICAL INVESTIGATION OF CRACKING SURFACE EXAMINATIONS i.

METALLOGRAPHIC EXAMINATIONS 1

1 FRACTOGRAPHIC EXAMINATIONS HIGHER RESOLUTION REPLICA TEM EXAMINATIONS CHEMISTRY EVALUATIONS a

t

+

20

as.

(65O - - -

7 m.o "h

y;gg

7; M n

< =;e n ;;

S

  • M k" % ;i

~

[. .- ,

[ .'

tes FIGURE 1 As-received surface appearance of the Boat I sample from Steam Generator 24 girth weld , illustrating the surface pitting and cracking seen on the ID surface.

e

,t J. I a

-1

-,s a as.

(658) --

i ro

, e - ;;

l .

\

pne  :{ t 'ints c.t M . s %- -

l -3*_pk . ,

.. m, .-

y""- . 2

' ;7d'C O ~$

'j' ^--T .,

.- * *$~ 'Qkg y

. ~~g :. _. -

t e,.

~ .

. . un .

l l I frGURE 1 As-received surface appearance of the Boat I cample from Steam i Generator 24 girth weld , illustrating the surface pitting and l cracking seen on the ID surface.

i l l l

l l

A8EE8 Q-4

\

l

.se I w i~S? ~

/ .

y. ? .

c

, "/

.. $g.- _

.: s 3.4j
l. k

,I8'

-i l 4 ,

3.
% e 9

.. 30 a

i S.G. 24 BOAT 1 l

c.) &2 l'

W y 7~.-.2 ' .

.m .

v..

s . . -

. . , .,-....,y.',. .

1

  • . *  ? ,

' , .; g ' v_ i ~

.:.~ E '4

's .

\( 2.yg g

((f

. % _]!-g.y .. .. . 9(,, , ;

. 3,.m -

j.

}

.(

.ru

-+

- 5jf-lhfh' x:.

yg _

- y; 1.. ,-

yNy ;r 1:f c- .lV. qq

,+ dig ^

3.:3.f p ('

~

^

l, ' ~~~

. : ' p. , .y c v- t, -

y a,

. ,c,:h 4 J :~p .

C-1 14x A-2 14x FIGURE 4 Metallographic examination resuits illustrating the cracking j morphology and microstructure seen in Boat 1.

l

-- -- --~

X  : h 6

_ ~

, c -

I

~

.h. *

,; f . '

? .

- 3 e__

^

./

_ d ,

_ C ' '

J ,

,. u t .

4,.

4,

.  :.3 _

b.

. ) w

g. -

K '

= '

C .

A _

_ R ._

W C . __

E N

O _

4 i;  ;

C .

~

n..

N . ,

s O

' . (

I T

I S

N _

A _

R _

T l.

4 ., m r

2 2 n m_

G

/

l .

r3y

_ S "

_4 5

s k

)v)

.~ r w .&t ,

, f .

+

l 4 . N' 'q-c l' _

, . a

~ .

^ .

,t,'*_ . ..

4 l * .,. _

-a .

y

  • _

b 4 C

. .,4 ~

~

9 .

.t

. s; s)s ..

E~ ,

~

.,. ' L.' -

$)

4. ph.~ . . ,

f .

$ g

i~

j.? .

r. .

l ~

j v'. ..k*s.

i;

?

i

^

' ' . 'l v -

g

bOM 1 lor 20>

w . . . .

. pp .

~

E' .

.- + , .

h ,,ppy ,.,

s .;

i k?h(?

,) $ c-w);$.4, s

  • lpl p r, p 5 FIGl'RE 11 Light optical fractography results illustrating the beach marks seen in the endoxed fracture face in Boat 1.

l

E

~ -

z;. s.

I

' 7 __

l I g--.y

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

l . ..

. . . . . , . . . :. s , . :! .. . ,

A . J- c , , 1.

. -[. , . . .- fseONCm Ah -

k9 A%s. l9 ,

SECONDARY CRACK

?l$'

]

V t '$

. J'4

*N '

, ..(, m: :,1 .;;

=. _.=e _~ q%, "_; y, w

y .f $ ,

\ M e ;_O <

  • fry;,r. g
. ~[ ,

{p ;. '),'.

I

-. 8574Ch E! q  :

wen.

~=4w v o

&. % . . . ., x4;3:>.s13+efq.,4yc .

.L t -

)M
4. .

Ihi [;h-(([ .

4 p.. . . .% .

g.m x

,- ')#

9 . , o 6e  ::t y&p*  : .,i

.c; J y ; 2 n. f

~;

. g L 1, p,:g. s

?

gf f'

[ l' ;. l 3

)

1 On ;, .y  :

- g FIGURE 15 Scanning electron fractograph of the endoxed fracture face in Boat 1 l' illustrating the presence of fatigue striations.

, y & .-- - -- - - - - - - - - - - - , _ - - , , - - , - - - , - - - , - - - - - - - - - - - - - - - - - - - - - -

g . .- . . . , . . . . , - . ' ' ' ~ - " ' "

,. - w .

g ig g 9 4  %. '

7

.y !4.'

-h- ' ,

, #4

  • M .

g,,, '. ,.,

e .. .'#  %

3

..J' .

-..  % s

- r 4f . . . * . 4. l t .

.y ,

i

'e'. y

  1. ~ '

M

,,,f

. :. -4 ,

g ,g . s. .. . . , ,

, 4 3 .

?

w 't .

GM

:( , , . 4' ?4 , .g Of.
L '..

=

.p;: %. .7 g

~;. -

U -

t p: ,.

l u f) .

j M ' + '?

- y;i. o

$> . , fL;. ' . .

}'

.s . _

>=s -

m - j = . , 9, Q $

- o g. , #

W .'- ..* :m E-w .

y' f'_. ,f

~

.e -

e N

+ .. lE .: .. ..

t t ,-

l 2*h[, '

e

~

f '.

. . --; _Q; m.,y . g(

( 4;.-... ' -

Q', .

  1. u

. l' 'Tl

. *r .

"W

's ,

i .:l

. 1 m_ _e.,

M W,&,4P-n -

y, ..

~ , _.

L y +.+4,Q.,%~

a :: -

l l

35

l l

ORIGIN ORIGIN

{

g

's. " i '

SURFACE l" ',

, v ,

l 4 . .. $ ,

'A %f, -

a 1 l

1 .. ,, i BOAT 2 ON C-2 i

i FIGURE 12 Light optical fractograph illustrating the fracture morphology seen in Boat 2. .

l l

36 l

L ___ __ - -

m.MS E%DW'MWQfMV 5$aamK.cel.su uw.h adudida$adKmeMh.s2 Y S l %7

!u.Pw..m.m.. MNf4$

H 0 T e f s @m .d.ua L a w$,ouwaJ.d.dhu MRMWMVW u:qggg3gpyyyy u u . % . m a:w b m.gagy h . g ubn pAmyy . . .

ndJa.u((. gp i

I Jc. yu..1.w.c.m

- g y g g Q @ cu T

g bp &,g[lglgd .t gg1g gA O,x.,

ua pogg n pp.m

' a, a%ataalid Mg V;!.% wj;DQb.4 a m m,n g/QlliQ D 'b M.Iyl@L ma.am. y':dha.au.1h.qh mm$ e.,. h;p'l W Jy.n.9 pyp 1

u xC. .-

. mcy, crg. "g

.u.aC! yp, aid.7 . gup,,ng,@d.Marldk MA,,ah.

a. Alt n r w pi#rt y m p

o.,xprg,,,A,4 mg!,,,a

.y y, m& p;h.3,u,y ad g a u ,44 S.pgggqq&gggdki y id%py&gj gy M ,

n n Ms M::a kW ma

, mi or p i "

, .,9 u ,c 1:,

y, wp

,, .,4. plpgi/p.

yi.w' -.m,~.

hf2 gJ. n ,,{. $ p, t.j;E- i ,. 3: i, . . 4,, . j;, y 'ja ,, y; gy 4 _ ic y pJ H. ok l10 y

L}g.JtlQgp &g g(ig%"g},Q Q'n g 1

. g

< 0.00 KEV XES ,10.24 KEV)

BOAT l' CRACK MOUTH

,o 3 g .a ;.. , . ..y

.- o

.; p.:.gpy,,u r, ym w;m;,p"

.o r, li Jyn g ;,~, ,

e

, w, . .; @; . b...

)

. (J .ly e t pag,y ,.

, t,, t, ,y e

. 4 80ha hid . a 6:.! Aa u '4 +4  % i.. i 2;. to,lh k hI,%. MI.vk.

e4 J +N6 y

. I'd4.Sut a@

i$ed g,3.i d .1%. c.

HRH01010h.GWM Wi

/.anmaeu.a.sM@@esss$ Mf?TbVW;ix2!dh I Aih -

A n Mgst m:,,,a. u . m .u,uuawe W g g gdg d a mgo,iErgg w & mgAd @a cm . .

Smm[W.i@d@. l I @_n@w_$w$am$, a..$,, l%ma$d. SW h L.Ahm h[cm$hhhM(h:ib ude w aui,JbihhhhIhhhhhb

m. AeddcautL.,c.::

<: rw W mFw v .cznemyym MMMMMddd 6 0 6, 6; Y;R R% M u T N.m f r %

m W } d $ p p yb dMd D.f r M n gg w.n:.w ;.q p m eua g mw.;.w.  : w c, 4 %y n. p;.g Qq b gg w %n y.

dm un.a i a . u . w . w a w . w ....

' ?]lM@@$3W@$$ { $$QMQ _

< 0.00 KEV XES 10.24 KEV) 4 BOAT 1 CRACK TIP FIGURE 17 Energy dispersive X-ray analysis results of the crack deposits in Boat 1.

37

.a - .-- , _ _

. .+ ., '

te '

ROAT -I (RArk '1Jt;TH Clittil j f RY

1. .- ..

" ,$ ,? ..

~

f. _: a, - .

%*,a;-

jg ,..__ ,'

. ,. . y -- 1

  • f,.. - %y .. '

s .! f t.

"a ans w$ay..

~ .. A i; m '~' 274 .

00 005 1. .

S' r . a. ..

M PHOTO 5c iM3% PHOTO 5, ,

P. ; . u .,

SPOT 1 'et . SPOT 2 CU

, FE w PC.mi.

a" : a: m v.: g

, , t :_, , ,N!Fj ' .~

. ip1, b - ' .' ,,. ; .

. :g ;."

/

4$$ . i :. QJ

- fW}!jyt:t gt; Up.g ,

"** MW FE R,:

2 wns. f. A ;c  !"..

a-

  • i CU ll
t,p .

o.M!$,

/

4 + ,, t- ,1 g '

_ _ - _ _ ____; A _g '

_ _ . _ x 0 00KEU  ::E S 10 241EH n n it i FH lF lii J4FEH FIGURE 16 Energy dispersive X-ray analysis results of the crack deposits in Boat 1.

I l

1 l

l 1

SUMMARY

OF RESULTS i

GIRTH WELD / TRANSITION CONE CRACKS SURFACE PITTING AND OXIDE DEPOSITS WERE SEEN ATTHE I GIRTH WELD REGIONS '

MULTIPLE CRACK INITIATION WAS SEEN AT THE BOTTOM OF THE OXIDE FILLED PITS AND CRACKS WERE SEEN FORMED BY LINKAGE OF SURFACE PITS CRACKING WAS LOCATED AT EITHER THE WELD METAL,  !

WELD METAL TO BASE METAL INTERFACE OR IN THE HEAT AFFECTED REGIONS WHERE APPLIED AND RESIDUAL STRESSES ARE LIKELY TO BE HIGHER i

CRACKS WERE FILLED WITH HEAVY OX1DE DEPOSITS ALL THE WAY TO THE TIP OF THE CRACKS CRACKING WAS TRANSGRANULAR AND EXHIBITED MINOR BRANCHING IN LOCAL AREAS, BUT GENERALLY FOLLOWED STRAIGHT, RADIALLY OUTWARD DIRECTION OF THE STEAM GENERATORS l

COPPER DEPOSITS WAS CONSISTENTLY PRESENTLY IN THE CRACK '

FRACTOGRAPHIC EXAMINATIONS REVEALED TWO DISTINCTLY DIFFERENT MODES OF CRACK PROPAGATION DEPENDING ON THE SAMPLE EXAMINED THE FRACTURE MORPHOLOGY IN SOME BOATS SHob ED '

EVIDENCE OF EXTENSIVE BEACH MARKS AND FINE FATIGUE STRIATIONS SUGGESTING CRACK ,

EXTENSION UNDER CYCLIC LOADING CONDITIONS THE FRACTURE MORPHOLOGY IN THE OTHER BOATS FOLLOWED SMOOTH CONTINUOUS CRACK EXTENSION FLOW LINES CHARACTERISTIC OF STRESS CORROSION CRACKING UNDER STATIC LOADING CONDITIONS 39

CONCLUSIONS FROM SHELL SAMPLE EXAMINATIONS CRACK MECHANISMS ARE CORROSION FATIGUE AND STRESS CORROSION CRACKING IN THE SHELL REGIONS PITTING PLAYS A MAJOR ROLE IN THAT CRACKS INITIATE WITHIN THE PITS OXlDlZING ENVIRONMENT OF CU AND OXYGEN FOUND IN ALL SHELL SAMPLES l

CRACKING IS LOCATED IN THE WELD METAL, HEAT AFFECTED ZONE AND WELD TO BASE METAL INTERFACE  !

40

_,_______----------~--~-7

.N i

'{ YM 9

~ _

r- \ e

(

4 ,

t IL

,?

e \

l. \

41

_ , - - , - , - - - - - - _ , , _ _ - - _ - - __w, - _ - - - , - , - - - - , - - , - - - - _ _ - - - --

i i'  ;' ,  ;... .

~.''.~s&s . ,

Q- , 4f ;> :..

p - ,

.g.

[ .. _ -

O' .' .. n $7 .

l f.. y-:;l- y
{ . . ,,

M b= . jp .. . ;

g

,, .* ," d: -

t.) ,, .. , (*s.  :-

AA- g, h-iW g +2 . .

.r a ,-

a:

4 s. .N-, - #

6 4

. x,Y w ,

g

e.

,, r .

4 ~.- ...-'

H

,1 Y"'7 '

. di i . z . .  % y., . g.S ^

CY.

h a; O

z i'. ,

. . .' &. ' +'

.. pi g-[#

W , '

' ' : ' y . Q *'

n.. -

.a -_- 'yp* .

i (F - ,

N g% w: " ,d ,,g. g ,. . , ,

2, v

? k .

~

'* g .. ' . /*  ; ..~%

I . :e-

.g .. .

h5

?'<g . s hf ,,,

.& f.

. .p; -

,- .+ -,

e y ..- -

, c, .'v

~

" a:

1 l

l i

l 42

a.m4> u --- --- - - " " - ^ "' -

'#- ^# '

B .,

-r

~

'f

.n

,A g

~

~-'

. kyw'

~ v .-

(;.1 + -: - 9.4.f g y.

2 $ .

3, .r u --

~ -

., * ' ' Y h, $

,.n x m.N

_)f-hfg

.5

),,

4 g ,,

+. ,

.,,.,3,.

4 s

%s 9+- ,%9;gf..

4 -n ; . .:e :. . :.~

4,

'4- W

t. . u

- ~

4, +-

,3 7(n?fr:p*

..r p.y yg .;-

t c, .1

'";f'

^

~'

ff ehl. l?

. bYf' _ q: - RyQf en fI

'.. y

. , x

, ,-'.~p.

wwr '

u- -

. y .uy,_,y *n i

.. . p~ . .

=g ...; . .

qq .<. .

- ,4. . -

<4

. .e : .* . g.f&,. ' g

..', Y. 56 k

,,.'., ..'p(: ,

m, - - -

+4

,r  ! <0

,., f l-p *3 Ff. '. ,s . . .

g4

+44 p:' ~ '

e' Jne

  • If '

. ), I  ; d T <' =, '

) . w@. ,S.M.x'.).!%., E N.

.. h. e *m .

?

3 '.

eq

4. - .' . $q - ., t ug-w.. i

.O , ,

l "'* *

, ., .y Y',

y a 3; . .. > ; .2 9 . z, W., ,'

f . , .4, 's', ' '- . .  :,. ,ar4;v ,y .

]{ ' ;> ~' **:Q. Q ' N ,

'e

. ; 5.* '..',.

. .t - >'.O ,- gf.4i , .', t ' A 5,,{,), y{a -

, 3' {$ sf *'. ! Y q .',l.; ;&<

3.*,: c iC

. e . g,g .? . .g, :-p

.Q ' #.[ ,' Ifh.$'d,'MiQhIF I 4^eq%xd RM,25.S?

43

he _

a - - - - -- - - - -

l s . . ,

. ., y

,A ( ] Tr*,' +

p q . *

-[ ..,

y %.

4 .,

'I

'[- _

3/ ; T~

m

'1:~le

,y .q;

,~. , . ,

~

S

_.e. '

, s~

4

. .y) f

. .t.

.+

.. ; g> .3 . ,

g l 6 ,

f fjbh+ .

8 .3 .~. -

e. 3 %.

$j. " 'hh ,

I .; ,

=

g , . , .

?k" ..  :

. s

. #s, .

2  ;. ..

g -l , j o g -

, ; . / . gfh

~

' i.'* d .j. 41 n; k% l j/i -

J[3 g

,, , v . c

. 'lq. 'Q,* _
i. A T ' ;- \

.- .,.. ~.

g. 1

.- 4:

g

, 7.: ;. .;., t , 9 -

l l {l h '

f ; 1I

c. f,.
7. , " & . j#(;.. ,, . {x f..y l

+-

p'\& .

d -k N4k I 44

N % % *

,,A, s

/

/

/

/

/

/

e

- ( ; g
; ; e g ; n - :.: y;.; , ._. _ -y.g;+ - -

1 .* . *4L m A .yy.-

  • k,,

, - 9._',.. , _ .:.. , .

q m :/~'_'_'

< '- . . ' i ..  ?

,A p x ,%,5< w u s ,.;

7 ..

.,g 7.,,4_ *,

Y W

-f} ..., .- . t'

. ., + r. .

~-L _

e,, ;q
;.3

,\ ,

-u.

j.', L <* I ; j ? % . j ~~Le RW

,; .=-

  • ;;^ $ .

. .. ..gerf' .* v' -. . g ,s t;  ; .

- .- ..?

s '-r

~ g Y~

' ! * "g r' NT' M =

4,p '% ~ .

a +.m . _

g. y. ~, - -- ,.

.. n , : k.- ~

4 p. .. -; - .- -

A y t

^

(' .1 . - ..

.~

~,._f...

' ' j} _

' y  :

i i

Fracture Morphology of a Freshly Opened cnd Endoxed Fracture Face of a Crack in Boat - A (Sample M1)

SUMMARY

OF RESULTS FEEDWATER NOZZLE BORE CRACKING I

CRACKING WAS AXIAL TO THE NOZZLE CRACKING WAS INITIATED FROM OXIDE FILLED SURFACE PITS I

OXIDE DEPOSITS AND THE PRESENCE OF COPPER WAS SEEN IN THE CRACKS FRACTURE MORPHOLOGY SHOWED EVIDENCE OF BEACH MARKS AND FINE FATIGUE STRIATIONS INDICATING CRACK EXTENSION UNDER THE tt4 FLUENCE OF CYCLIC LOADS CRACK EXTENSION INVOLVED MULTITUDE OF LOAD CYCLE l

47

CONCLUSIONS FROM NOZZLE SAMPLE CRACK MECHANISM IS CORROSION FATIGUE

- i 'ECHANISM CONSISTENT WITH ALL PRIOR SAMPLES FROM COUNTER BORE REGION CRACKS FOUND TO INITIATE IN PITS ALTHOUGH PITTING GENERALLY LESS SEVERE THAN FOUND AT GIRTH WELD OXIDIZING ENVIRONMENT l

i I

l l

l l

l l

l j

48 i l

MECHANISTIC CONSIDERATIONS STAGE 1 SURFACE PITTING STRESSES (RESIDUALS AND APPLIED) CONTAMINANTS (C!,0) 2 HAZ MICROSTRUCTURE ilAQL2 CRACK INITIATION e CRITICAL PIT SIZE THE BOTTOM OF e (SURFACE ATTACK AND THE PIT. OXIDATION) e ADEQUATE LOADS TO ACHIEVE K ISCC, DELTA K n STAGE 3 CRACK PROGRESSION e CYCLIC LOADS e STATIC. LOADS e' PRESENCE OF CU AND 0 2

~

te a 49

4 7 / '

CRACKS WILL

,/ ylNITIATE

( )op t ,f I CT'oc I i

[A / .

\

zg Y -

(. s

(\ ,

=

Op i

l l l g2 ISCC  !

! a =

P 2 (

e3 1

I L

L 1

50

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

i f

5 e

['.

)

l) '

ul -

..?-

  • ' t *i

,/ ..

' , 'e ). ::* '

i e

( h,*, -

9 . l'? ,

,=

3 *

.,,s p.([

j t.  ?

c a ;.

6 a  :.u.

[ *' ,. t,i

.,se

Yk'( 3 *;*

I 5.9

> }i k., ~

g Q

t. ^'

K. . ' ~.

'~... ,

~~

., % C -- c,&

'**- . .si

~

. ..* MS.VQ g k.,yav, %.. .* s e <-

  • ' - ,.
  • i .". , 7 ;'.e] Prn :..s_

pm. e4.\. 3 jen.e

' ' 6,,*

  • q *== % m,, ,, ,- ... . , , , ,

51

a

  • O

- e, y . gy, , .

.e f , .

5, */ i

~s '".-<

. a *&

? *f .

n *: . . .R- '%

~

5  ; :- '

sg ~ - 'e-g  ;, _

a . . .

j 4 .-r-; , $. . -

'A ' ~ ?L g ,

. / ,4  :.  ;#g ,y' op y ;

g ., f , - .

  • 'R, r..

S

  1. , ,. .# .~

+~-

qvy y

~

  • ~

,1 2 f n a M

g G - * <

, .n, g e l s --

1 m _.

,- ". w .

e h g --

's 9 8l

, ,p .

'. . y, V; t * .-

- :- . sY;tyg;-

[

.,  ; . - *- y' l .. ; g.

g,

~

I . ,.

\ -
g. 4

.. y,fr . ><

,,t .h.  ;,5

{

,/" - -

  • ? M A, k g . {

._. Tr.?

e .

vk '

\

  • -w
  • 4 ,

p - ,

- . 5

. . . , t

+

1

'~

l 1

52

nP e

l r E

. . r,

- pc .. ,.

.t. .:. .w.

  • d T C.D.

. ~ e*.

,. T

.s e # g'$

4h.'g, ..

, $. gx* ? f

,y- ' >9: , ' Q -

3 -

~ r s-9 .,., .

.- ~

%,{',$t f

.. s . ..

v. .

_ ....\

~'

l, j[

~

3 Wl$4 %-(S M.. ~.2 W

e n, -

1 m .

1 ..; - >

2 ,

y.

8 ', +y i ;. - j y ;j . ,' A,i'

..,g y

. - t %. US .~ ~

- .;) , c- 3', - ;-9.-

s O

A.9;,

1. <

,. ,, 4 :, * -

..,3',

T 4$ ..."

'p ,C 1 . . .

's

[

.- e ,J

+. *

.l' . . . . '4 .R, Yn .'

[a,,

y igg"

.4 . " ,i , - , - - .. 'f;f.;

..,,1 ',. + n- . - g -. .

.. , , _ , t, 4-

$ * =; . .,;

,  :, s .. s

' _ ' ' , [.

a 444 M, '

' . - . . ' (- ' -m - $ 'j, "' , T *y *..{ J'_

j[y w ,y p A( .-

./ . - . 2- ,

. 4 Pg +? - - ,. g.

. ph.

t g

%.y. ,,. 1, s .tv.y . ? - N,-'~: ' ~ 4 ' .i

' G' hkY. ; y.*J- , g'. ._

}l

-p g ')

4. ' ./ :..

. . . ' . e' t' -3 '4. , j ' 5 - -1 l

r.

' . . n ~%-7 ,_ . *

+ .g s ,,

, s 3

y ~ 0' ' 7 _, .

i l"-.

~- , - l s.7.L'.

- fs T m. 6 . + . ; ' " .. p = ,i-[

}'- a '

M N M M N m

53 L _ .

1 4 4'

  • h I e 9 * .A/

3 ,,

g,"? .

+ -

4 w 44 .

,'6 '4 '

a hk',. '*

NI*e, %'f

  • .a r 4*? *"'}f . 8..'

e< ~

, .w;-

ad *-

~~

74 ,;t "; g,.** ,

-u ._g-y .

f4&: '

q e N

  • e e.

s < '&ws1

. ,* i f y. t , 3 .d. f,

~.

s ...

e :, ,

ag'

% cn ' 4.* .

,1 - L E n -r .

t 'f . . . .

x ,.

p ?' [ ,b.'.

' ~

0 '

t. ,

.. , ..W .

.I.d),'Y ~, ~

[; . N e5*'.!'

' f,

. s-

f. - " ,

3.p . ~

' . ,,s

's .

g v g ., : .

. z. -

. .4

i. t *.

e

.y

%i .. ' *: -

M', , .il e . .,

'.yr

. j,

" i s ' ; >r , N. -' *4 .

- . . .s ,

" 54 d.%t- c. ~:- .

, . . . . . . , . ^ . . . . .-

e ,. g-

' i f' _ ,

ing .+, , - e,

?

4

,& l -l ,

g

]. . "

i 8

~

C-

, - g)

. n:,. . .

' E~

g _ ,

% ,. f '%;.

ts 'i ,

  • - J
  • - l S .,

t

, 1_, ,

1 m -

^.- , , .'.

f e .

..jy 1 t

f . f+. ~

e f....

g

,' t

. ,a .

'{? .

f-

[ .:

.y

/>-

-y ,'j}ty g

3 E .

~

t. .

, ,' .c t- x . y;,; ,

,s '

55

Ama .m# a... --Gu' W a a

  • a _ . .. m e - a

.A

?if -

?

/, .

',v

, %y ,n u ,

,,%I q ,?'

Y?\f .-r.

-s 6

yQy~

%, ::t -

i

, w aZ m 4I5$

e,

/

a

~

^? .

~' s ' . . ~~'

f )EN-

, . s

  • l $ml?

, fj . a !~ .

wlf,ettok,gNfh J

~

l ~

3g*% 4 ..7

$ mlQ,  ? gg ; -

  • x

, 3f g" v: a: --

+ ,_

e g*%1 ~

kt- kg * = g'

~

g .,;_..

{g[ ' _.  %.

.. ,:: . , ty, I

"L t%g

  • lfif /

/

s

/

/

/

/

/

/

/

/

/

[

I  !

SUMMARY

OF RESULTS FEEDRING SUPPORTS CRACKING SEEN AT THE SHELF TO GUSSET WELD JOINTS THE CRACKS WERE BLUNT AND FILLED WITH HEAVY OXIDE DEPOSITS COPPER WAS SEEN IN THE CRACK DEPOSITS l

MAXIMUM CRACK DEPTH WAS 0.06 IN. i NO EVIDENCE OF FATIGUE STRIATIONS SEEN FRACTURE MORPHOLOGY WAS CONSISTENT WITH STRESS CORROSION MECHANISM i

57

CONCLUSION FROM FEEDRING SUPPORT BRACKETS ENVIRONMENTALLY AS$1STED CRACKING. MOST LIKELY MECHANISM IS SCC.

PITTING CONTROLLED INITIATION OXIDIZING ENVIRONMENT LONG TERM CRACK EXTENSION 58

CONCLUSIONS CRACKING IN THE GIRTH WELD AND TRANSirlON CONE IS CAUSED BY ' CORROSION FATIGUE' AND/OR ' STRESS CORROSION' DEPENDING ON THE LOADS, ENVIRONMENT AND LOCATION ---

CRACKING IN THE NOZZLE BORE IS CAUSED BY ' CORROSION FATIGUE' MECHANISM CR ACK INITIATION IS CONTROLLED BY SURFACE PITTING PITTING IS CAUSED BY THE PRESENCE OF OXYGEN, COPPER AND STRESS (RESIDUAL OR APollED)

NO MECHANICAL PROPERTY DEGRADATION IS SEEN FROM SERVICE AGING 59

l 6

MECHANICAL PROPERTY MEASUREMENTS 0 STEAM GENERATOR GIRTHWELD MATERIAL 0 FEEDRING SUPPORTS (SHELF) 60

ii ---

MECHANICAL PROPERTY MEASUREMENTS 0 HARDNESS MEASUREMENTS 0 TENSILE PROPERTY 0 CHARPY IMPACT TOUGHNESS 0 FATIGUE ENDURANCE 61

.N'; g.3 q ;- q :- y, ..

g. . ,

. :, - 4* $ 9 n, 6,[- 4: $ g yLQ:

.yc ce 1.,

y 9 g$4 _

- A , ,v.

i p ,.,"

bg g *y -~

5 fi-KHN

.tiY[

I' .1, '[

,r.'

b .h g f

%s s .g.,, , , yyg 4, J ,pF'

' ]N3

> s ga *,'F F* 6 l# Xin.q?' #f 380 KHN 4 'A : p " /j y 9,%,

4-

  • r ., [" -".;^(h j 370 KHN A w- I

.n g , r, .y , .

- . :, . f t -- AK i. * .

. i 7,. ,

.f . ", * $fGd$ I;. f/'

Y ' [ A[ . a ;. 4

~ ' ~.Q. }[.

\\,'(/ f, '-i -}$
  • , t, :,

g  ;,. ? ' -'

.- A h i ; ~ -l l 3 ; ^_ 2 QL % 4 7" :L  ?

. ! g.v.3?

fI':h}*

.,' :~j% ,,

,1 I C

.. a [f

) f, .

h'(

i

$ f { ,r

' ' !. . .k ( ,-

by?. ,. . .) Nl >

? s .

N?

~ :. e . .J -

^)?

$, 3r- yff,;.?Y!W'h. ,- e

$,fp..!?>,Yh ., ,,,;;

ys . .

p ,

  • x V.4 ., .

t , 4,g . ,

08 # i@: ,

lHAZ] -

(( ' / [, ,

q

-.}

.qv n .* b is@'

Y ,

& f figure 3.6 ,

.. ; h 'hh Optical Meta 11ography Results of the Boat Sample 'ip..". ' -

g-)N'Id- -

f' A^l N'te 1 Illustrating the Details of the "High Hardness rd '

i

-A .1s / '/ j. .p I Zone" Microstructure and Knoop Hardness Values Associated with the Second Weld Pass

$'$1.D[d '.{ .

'p'i Q 1W/i? h'  ?

M -

' *.'$f g?)'.,'N,N , - * .'[- Thj .5: )j . s'" ..e

  • , , p e :N ' 'y -#g j, i;t 94 f.J

(.c.'S,W Mhh. qt'['% ,, ,i yt M, ..[. } }

Sc4 $. -

.- .ou.;;6RQ .

AREA "A" lsooxl

Curve 75564 5- A 100 , ,

4 i i , , 100

^

o Charpy Energy ( ft-lbs) 90 -

. % Brittle Fracture -

90 80 -

80 70 - o .

/0 E 60 _ e o

A o. -

60 E b y h 50 - - - +- -

,g,

'****~Y...o~.. 50  :.

u o

1 l

, i e c

.5 l

/ \ LOWER BOUND 5 40 I g

i 2  ; c - 40 l

I 30 -

I f  : -

30 l l I

20 -

o j  :

20 1,o' 10 -

'l -

4 ,,, I 10 I

0 Fatt m-115

' ' \ F Ya *- ^' ^ ' ^ ' -

0

-300 -200 -100 0 100 200 300 400

. Temperature ( F)

Figure 3,53 Charpy Impact Test Results of the Gleeble Simulated HAZ High Hardness 2cne in SA302 Grade B Steel G3

MECHANICAL PROPERTY TEST RESULTS FEEDRING SUPPORT SHELF MATERIAL SG21

1. TENSILE TESTS -

0.2% YIELD TEN 51LE TOTAL REDUCT10N LInfMLIH LIADEIH ELONGATION IN AREA (K$1) (KSI) (%) (s)

$HELF MATERIAL 47.35 70.39 28.8 63.6 ASTM A 516 GR 70 MAT'L. 38 70 90 gg ,

2. CHARPY TOUGHNESS TESTS ,

UPPER $HELF: 98.5 FT L85 AT 50' F FATT  : 25'F

3. FATIGUE TESIS I

ENDURENCE LIMIT: - 33 K$1 (10 CYCLES )

7 CODE CURVE 13 K$1 (10 CYCLES) cause . 1

CONCLUSIONS t

CRACKING IN THE GIRTH WELD AND TRANSITION CONE IS  !

CAUSED BY ' CORROSION FATIGUE' AND/OR 'S?71ESS CORROSION' DEPENDING ON THE LOADS, ENVIRONMENT AND LOCATION

{

CRtCKfdG IN THE NO?7LE BORE IS CAUSED BY ' CORROSION .

FATIGUE' MECHANtSM l CRACK INITIATION IS CONTROLLED BY SURFACE PITTING I'

l- PITTING IS CAUSED BY THE PRESENCE OF OXYGEN, COPPER I

AND STRESS (RESIDUAL OR APPLIED) l NO MECHANICAL PROPERTY DEGRADATION IS SEEN FROM l-SERVICE AGING l

l I

l l

65

a a

!jt j E E 5! H a

Ei!

ga ig ig ilaa, I

ll5 a

g g

Ital m e - las - ,

a a

a a=ll aEI -

a is i

i 5 8 ll e

qs , , il i-0 i

a

@ N $

h

=

Ef. *

!b

  • N R a

X 2  % g. g 66

DONESTIC

FEEDWATER N0ZZLE/ PIPE INSPECTION '

St.gewty NUNBER # REPORTED S/G TYPE OF SGs INSPECTED TECWIOUE RESULTS i i

13 4 4 tK/RT 4 - COUNTERBORE/ PIPE CRACKS i t

27 7 7 IK/RT 4 - NO I MICATIONS i

3 - C0tNKERBORE/ PIPE CRACKS O 44 23 23 tK/RT 7 - NO IW ICATIONS 16- CetNKERBORE/ PIPE CRACK 5

51 75 50 LK/RT 12- NO IMICATIONS i 38- CetNITERBORE/ PIPE CRACK 5 t l

l .i

m.

v INTEGRITY EVALUATION GIRTH WELD, TRANSITION CONE, AND FEEDRING BRACKETS AND STRAPS.

e General Approach Allowable Fracture Toughness Crack. Growth Rates Reference Flaw Depth Determination Aspect Ratios Determination of Days of Allowable Service e

Results: Surface Flaws Girth Weld Transition Cone '

Feedring Brackets and Straps o

Results: Embedded Flaws Transition Cone None Found in Other Areas 68

OVERALL APPROACH Allowable Fracture Toughness = K i g + g 200 ksi/in +/f5 = 63.2 ksi/m Stress Intensity Factor Determination: Raju &

Newman

  • Flaw Shapes Considered:

Full Range of Flaw Shapes Shape Used in Analysis Was Based On Statistical Treatment Of AllIndications Found 69

- -.u4 ,.

8, C

- eem 0

4 0

0 ,

u

'M m

I I l

t .'1 e

i I

1 I ,-

l '1 i

i i

I 1

1 i

l i

l 1

1 70

CRACK GROWTH RATE DETERMINATION e Operating History Used

-e Previous Cycle Maximum Crack Growth (388 Days)

S/G 21 : 0.30 in.

22: 0.949 23 : 0.326 24:0.367 '

e Recent Part-Cycle Maximum Growth (212 Days)

S/G 21 : 0.360 in. (Zone 10, #37) 22 : 0.53 in. (Zone 6, #21)- '

23 : 0.28 in. (Zone 12, #5) 24: 0.34 in. (Zone 6, #8) '

-0 Maximum Crack Growth Per Day:

Previous Cycle Recent Part Cycle S/G 2f: 0.0008 in/ day S/G 21 : .0017 in/ day 22":'O.0024 22 : 0.0025 23:0.0008 23 : 0.0013 24: 0.0009 4

24 : 0.0016 71

TOTAL CRACK GROWTH = GROWTH PER DAY-OF X DAYS OF SERVICE BASIS OF CALCULATIONS = 300 DAYS  !

S/G TOTAL MAXIMUM GROWTH ESTIMATES FOR 300 21 : 0.51 IN.

22 : 0.75 IN.

23 : 0.39 IN.

24 : 0.48 IN. >

t 72

_- - - - _-- ----- - ------------ ~

a FEEDWATER RING SUPPORT BRACKETS AND STRAPS SG MINIMUM / MAXIMUM '

LOCATION DEPTH (INCH) 21 NozztE 0.09/0.44 SHER 22 O.12/0.45 Nozzle 0.20/0.40 HER 23 Nozzle 0.1/0.6 HE 0.05/0.70 24- NozztE 0.12/0.48 SHELL 0.14/0.7 0.12/0.43 i

73

n ASPECT RATIO DETERMINATION: GIRTH WELD o O ALL CRACK GROWTH RESULTS FOR 1987-199 BEEN STUDIED.

O CRACK SHAPE IS DIRECTLY RELATED TO GRO BEHAVIOR:

. . a, c

, - a, c 1

~

0 STATISTICAL EVALUATION 0F TNE 1990 DATA DONE.

-0 SMALLEST. CRACK EXTENSION.FOR 300 DAYS ;

OPERATION (0.39 INCH) WAS TAKEN FROM S/G

.23.

1 ALL OTHER CRACK EXTENSIONS WERE

~

LARGER,

. a, c 8, C  ;

O - '

~

_ _a,c.

0 f f L

l i-i 74

,P .

. . . . . ... .. . . , ,..s .-... . ,,...

_.W

'i U

o 1 l  !

s I

.i i

i

'l

-4 i

i k

I i-l 75  :{

(

=

_ . . i

REFERENCE CRACK DEFINITION If a surface crack of depth"a'is found at this outage in L

the girth weld, transition cone or at the brackets or straps, then a crack having a depth of(300/212)a is

' defined as the Reference Crack.

l t i

1 76

REFERENCE CRACKS (300 DAYS OF. OPERATION) FOR THE GIRTH WELD, TRANSITION CONES, BRACKETS AND STRAPS Crack Growth Crack Depth Steam Generator Location Rate (iniday) (in) Aspect Ratio 21 Girth Weld "

0.00170 0.51 22 Girth Weld 0.00250 0.75 23 Girth Weld 0.00130 0.39

24 Girth Weld 0.00160 0.48 All Transition Cone 0.00267 0.80 All All Bracketsa 0.00284 0.85-

& Straps .

a The brackets at the feedwater nozzle have been removed and new brackets installed away from the feedwater nozzle.

b This value is approximate.

DAYS OF SERVICE BASED ON THE INTEGRITY EVALUAT FOR THE GIRTH WELD, TRANSITION CONE, BRACKETS AND STRAPS e Days of ServlG Reference Based on i Steam Crack Aspect Kk = 63.2 Generator Location Depth (in.)b Ratio ksi v'in.

21 Girth weld (max. grind - -a,c depth of 0.78in.) 0.51 > 300 22 Girth weld (weld repaired to max. of 0.68 in.)a 0.75 '271 23 - Girth weld (max. grind I depth of 1.01 in.) i 0.39 > 300 j 74 Girth weld (max. grind depth of 0.80 in.) 0.48 > 300 All Transition cone 0.80 > 300 All Brackets and straps (areas weld repaired to original configuration) 0.85 > 300 t

a Weld repaired to return wall thickness to within 0.68 inch of original.

b -Does not include the affect of mitigating actions to i emove diss from the auxiliary feed water.

78

CONCLUSIONS: GIRTH WELD, CONE, BRACKETS AND STRAPS-o ALL INDICATIONS IN GIRTH WELD AND CONE HAVE BEEN REMOVED.

o ALL-INDICATIONS IN. BRACKETS AND STRAPS D N U 0 o

ALTHOUGH THE-AB0VE ACTIONS ARE SUFFICI TO SATISFY SECTION XI, FURTHER EVALUATIONS HAVE BEEN-CARRIED 0UT, ASSUMING THE CRACKS REINITIATE AND GRO o

THIS EVALUATION HAS-SHOWN THAT CRACKS INITIATING DURING THE NEXT PART CYCLE.

WILL ALWAYS REMAIN ACCEPTABLE TO SECT XI CRITERIA.

L 4

l l

l 79

a. c o.

FOR FEEDWATER N0ZZLE REGION:

1)

MODE OF CRACK EXTENSION IS .'

2)

ALL CRACKS HAVE BEEN WELD-REPAIRED TO THE ORIGINAL CONFIGURATION l

60 1

I Ih III g

\

\

i.. . v

~ _

q

.{

hi i

,cm ,

i;- ,l Q: .\. A rQ \

t i

t l

m- -_, q_ . m _ . )

1 Pipe Thermal Shield

_ _ Countertere pope ganggie

.1 .

~

81

N0Z2LE REGION EVALUATION L

I.

ALL INDICATIONS IN THE N0ZZLE L

REGION HAVE BEEN REMOVED BY GRINDING L

ALL GROUND REGIONS HAVE BEEN WELD-REPAIRED TO THE ORIGINAL

. CONFIGURATION, '

SATISFYING SECTION XI REQUIREMENTS COMPLETELY.

INTEGRITY EVALUATIONS HAVE BEEN CARRIED OUT TO CONSIDER POSSIBLE i CRACK GROWTH DURING THE NEXT PART-I CYCLE.

L u

G2

s j

e Source Of Cracks L.

  • Evaluation Of Hot Standby-

.. Crack Growth Rates At Hot Standby

  • The Fracture Criteria l'

Integrity Evaluation Of The Nozzle Region I

l-l l

'c

.nn.n. . . , w n B3

=-- _ _ _ . _ _ . _ .

CONCLUSION o THIS INTEGRITY EVALUATION INDICATES THAT THE REQUIREMENTS OF THE NEXT CYCLE ARE FULLY MET.

64

i MITIGATING MEASURES ,

ACCOMPLISHED-

1. MAIN FEEDWATER SHUT 0FF DELAY - DURING REACTOR TRIP HINIMIZE THERMAL SHOCK OF GIRTH WELD  !
2. REMOVAL OF DOWNCOMER RESISTANCE PLATE -

MINIMIZE DIRECT IMPINGEMENT ON GIRTH'  !

WELD AND POTENTIAL STRATIFICATION ACTION TO BE ACCOMPLISHED PRIOR TO RETURN TO SERVICE NITROGEN BLANIT.T IN CONDENSATE STORAGE TANK -

REDUCE OXYGEN INJECTION DURING STARTUP  ;

STANDBY AND. SHUTDOWN IMPROVE WET LAYUP PROGRAM TO MEET INDUSTRY GUIDELINES OUTAGE -8 85

FUTURE PLANS PERFORM AN EXTENSIVE EXAMINATION OF THE-GIRTH WELD AND OTHER AREAS DURING 1991 REFUELING OUTAGE.

SOME CORRECTIVE ACTIONS MAY BE NECESSARY BASED ON ABOVE EXAMINATION:

1. REPAIR TO PERMIT UNINTERUPTED OPERATION BETWEEN REFUELING OUTAGES.
2. REPAIR TO INSURE COMPLIANCE WITH APPLICABLE CODES.

CONDUCT CORROSION PRODUCT TRANSPORT DURING UPCOMING OPERATING PERIOD.

REPLACE ONE CONDENSOR WITH TITANIUM TUBING IN 1991.

REPLACE REMITTING CONDENSERS WITH TITANIUM TUBING IN 1993.

REPLACE REMAINING FEEDWATER HEATERS WITH STAINLESS

. STEEL TUBING IN 1993 86

_ __

Retrieved from "https://kanterella.com/w/index.php?title=ML20058K415&oldid=3079834"