ML19326B692

AO 50-313/74-12A:on 741109,PDT-1035,PDT-1037 & PDT-1039 Reactor Protection Sys Instrument Line Socket Welds Failed. Caused by Interdendritic Shrinkage Imperfections, Supplementing AO 50-313/74-12.Micrographs Encl

ML19326B692
Person / Time
Site:	Arkansas Nuclear
Issue date:	03/04/1975
From:	ARKANSAS POWER & LIGHT CO.
To:
Shared Package
ML19326B689	List: ML19326B688 ML19326B692 ML19326B695 ML19326B699 ML19326B704
References
NUDOCS 8004170531
Download: ML19326B692 (7)

Text

. ,. - . - .. , . . . - - . ..

r J. * , p , .

,4j

, f .

(/ -1.: TAbnormal= Occurrence Repo'rt No. ~-50-313/74-12A-

?2. . Report Dato: '3. Occurrence Date: 11/9/74

4.- Facility

Arkansas Nuclear One-Unit 1 i

Russellville,' Arkansas S.- Identification'of Occurrence: -

. PDT-103S,' PDT-1037, and PT 1039 Reactor Protection System (RPS) instrument'line. socket-weld failure.

M 6.. Conditions Prior to' Occurrence: -

Steady-State Power Reactor Power 'O FlWth -

llot Standby Not Output 0 h!Ne

. Cold Shutdown- X Percent of Full Power 0  %

Refueling Shut'down Load Changes During Routine.

. Power Operation

,Routinc Startup Operation-Routine Shutdown -'

} Operation

.' Other '(specify) s-s-

f

7. Description of Occurrence:

4

See Abnormal Occurrence Report 50-313/74-12.

1 i ::

? *

p. .

L u

(~'N ' s o 04170[3[ .

. A+-

~ Mareh 4,.1975 1NSP-10, Rev.r2'.  : Page 2 of 4

\'

o

. ,a : .. ... z -

__-m..-.._.._..- _.~_-.m..- .- . _ . . - - - . -

3

• y; ~ - .-

. s,

~

( t 5 (~Nt

~~

5 Abnormal Occurrence Report .No. 50-313/74-12A

- 8. - -Designation of Apparent Cause of Occurrence:

Desi~ng Procedure bhndfacture Unusual Service Condition

_ Installation / X Construction- Component Failure Operator Other ;(specify) -

9. Analysis of Occurrence:

Two instrument line samples each containing a weld which showed liquid penetrant: indications were subjected to metallurgical examination.

Photographs of the samplesL are attached -(Figures 1 and 2). -Both samples Jwere~ sectioned to explore the cause of the examinations. Visual exam-ination of longitudinal sections prepared from the samples disclosed crsvices- open to the external surface at the locations of the liquid penetrant indications. An over-all view of the longitudinal section --

- sm

.from PDT-1039 is provided_in the attached Figure 3. The crevices of both samples are in the same relative position, that is, at the center of the weld face.

Examination at a higher magnification of the surface crevices (as shown 2

.in Figure 4). indicate that they are interdendritic shrinkage imperfec- ,

tions. These are limited in_depty to 0.009 and 0.034 inch for sample PDT-1037 and PDT-1039 respectively. ,

L I).

.bbrsh 4,1975 NSP-10, Rev._2 Page 3Of4 -

u '

t 4 q - w '

" ^ ' ' '

}-'b gTl

1. i 4 ,Q'3., .a

m -

g

,  !

~

y; ,

, , , 3s. .-

n -

6 g . ,

z;D , - , -

_ ..j w.

l:L - -

~ Alniorma~1: Occurrence Rcport No. 313/7_4-12A-I

. 210.1 Corrective ' Action:

- i

!?  :- !

1_ . . i W -

'[

- See 'AOR :50-313/74-12.c -!

m; .

a ':N -

l 1

;i

~

je ,

e. -

t. .

6-E..

~

-l

(' :,. .

1 .

tt<-

.~ .,

i

?

4 a ~

1 j;

~

! l t

l ' ._.

11. ;Fabure Data: . I

.. 1 s-- cNo;pr'iorJ failures of_this type, o

4-- ,

I >

t i

}; -

']

1, . .

t -

l' .,

s q t ,

..d;

. 4

( i i, ^

f s -f

, ^ . ,

t g ,

E , - -

e i 4-  ;

g. -

i. .,

1>  ;

-'\

L:

y -

1: . a' :1 b

r

.}

r' . .s

. -k,

!=

7 l1

c. .. March'4 (11375 . !NSP_-10,:Rev. 2: Page 4 of _4_-

t>  :;  %' ~

. ;_

c-

, r u - 1 R g. q -

i .. +

,. k') *.

i-

• I n- ,

%,.,a---s.w..+-,:..-.L.14.----~..-,-.L+.'~,~~,--:i,+----.--------:--.-L~-- L------ - ~ ~ ~ ' ~ ~ ~

l l

s

. +-- . ,

l. - ..

1 , , .

Jh ' s:  %']ty 4

, fu .%.8 <

,n t' , ; :i L1 ,

lk Ee. j --

$$$n 3;;Vi

.?(Y

).

c e.$

3 : .!

4.'

.^* -

t,q.;; ..

, (([f/,t

': .. ::t 3 h.b L,27 i . 3. . . ., . r . . . ,3 .y

- Figure 1 Instrument Line Sampics -

A) PDT-1039 -

B) PDT 1037 -

• O e

49 -

9

-. . - . , , - . , , , . _ . _ , . - _ _ _ _ . _ . . _ , ,,,,,_,,_.,_.........,-m,.-ww..-w..,-.--.- ,,-.m.,..,-,

.s -

1, . ..

II. .

il t

i r

[ 9 . -

(* J.

kh

' t. . l

'6. '..m '. #

6,h_ ..

.x:rg;;.. . .

4) , ,

1 ,

S,jfhy.;>

, b -- (..5 , l7.1

, T . nz.i s Y  %[ u*

{L s , l{lET

'r , f,gl,,. .'b, a

.' ".~. jiy ,:... .._ ,

d k' *, '

.%.t f.

y,:.w s w_ ".0.tn ,c;v1: n (;.

'. G ; '. c%. 91.

. I -

s . a4.

..y... ,,

(@f.y 4

?. i*0f..; h -

t

'P

?! 4[(',f, - h' ..

,>, I- b:

.? . 'i ,

c.

hi

r. ..

s e3 9 '; f.;,

. i } '

] Q.

I, . *- d.

a k'a?!hY,'q .1 l&

.W

?4 g ,. e;.

PD T-1037 PDT- 1039

~

Figure 2 Close-up view of welds which showed liquid penetrant indications.

'l l

l l

l r-wn-y - .,-,w-. , . , . - . . ~ . - . . . - , -.,----w,--.- . . - ,,-,e- , , - . -_ _ _ - . . , - - . . , _ . _ _ _ _ ._,.ewm-m_ memtwe

r~

-j,.

0

l l'

l l

l

\

s ni l

l . .

I s

~

l. 4 f:04[4

.. gg j _

.s

,' .  ?

y .

,t .

!  ! . .I . .,.

_,_ i.

i Electrolytic Oxalic Etch 5X Figure 3 A longitudinal section of Instrument Line PDT-1039 i

6 b

4 r-

- sem

., - ..f.- - , .- , -,m,,y. - . . ,m ,sw.g, .rm . , . , .,,%w. , yy,ym.,,,w ,,.g, . . . . , . . . - ._gy,,.y_,,..- , -.,- en n_. w-

,, .. m. ,

~

l H!?s

. i@45Qa: .

$WE.D,?p.tFM

- :: . t;* .,)3 yjs 4,.:.'

i .a,$# yh$/ 'iq,!h'.My$l.i"h0?

?}%':1 ,5)

J  ; ,

.. *s* u q,'m. . gi! L

'S'.fh.fi,jf!l*py.,%g.cS."'1 P0"f, b" I

' - 'w$6g{$v.egwg[p M e .r.:

f w, si. y

^

' ... fi W t-T .5 M y $'?2kh {$y h1p6ip ' 3' '3'i6p h G)j l 4.h$Q,'d..kshfr.k.,,fgQ3%.7 4x

~

.s Q.'i.9$lJi l

M.'w. h $-.vn. .h

-l '(.h):-)N%.

..n

%; 'P) .y}p;gg;;byw!

'r W'gg',

m:

. f' . y,Ngt;y.q- y H 'kh.h \

-i ffsikN kAl I

/  % E s sii845bsh Electrolytic Oxalic Etch 100 X W M[ $55ffh ll t

I (a) PDT-1037

.l

4. '7, g.f::: ~ ' .b '

w,Qt., 41.Jh4"'$ .x % . .;. . ' ..,

.,,t L/;1; SE h :*: i Th@y.[. is W h(,$.?-@%7}!$.. ,

. jQ. W . l,-

.p; .

- 'I

~

Wi"hJ ;. u rs. . .

if4N, ? -

..s.:

f ti,,g%cc b.,c(Db y@'? a f.,( d,N.Y.q"!

gy.

d?, .! [h'j 3

$5'

, 'I Electrolytic Oxalic Etch 100 X (b) PDT-1039

( -

Figure 4 Micrographs of the weld sections through the *

\

indications shown in figure 2.

b e - e. ,-

- - - - , , _ , - ,.-,,e- - ,,-,,.--.we-o. .ny..wr,-.- --,.r.-.rweww.--mew