ML20214G420
| ML20214G420 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 04/09/1975 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | Thornburg H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| CON-WNP-0041, CON-WNP-41 NUDOCS 8605220096 | |
| Download: ML20214G420 (6) | |
Text
DR MtJ C4 I
EE
- 11. D. Thornburg. Chit.f. Field Support & Enforcement Branch. IE WASH!iiGTO I PUl;LIC POWER 5tiPPLY SYSTEM < L%P-2 (DOCrIT tt0. 50-3'A);
WELtXui blFFICULTIES I;UOLY!!G STEEL COUA!httENT YESSEL (AITS H00604111) inis refers to your request concerning the reported lameller decohesion crackier) experience with the relief valve support ring attachment to the cor.tainment vessel at the suaject facility.
We have discussed the problas with General Electric and were advised that their enginscring staff is working with Burns & Roe (A-E) on possibic modifications of the weldsent to minimize effects of welding ami restraint parameters on tne bases metal (transverse thickness stresses) which are believed to have promoted the conditions observed.
Regarding the gencric aspects. GE informed us that no similar experience with the advanced GE. containment design elsewhere has been reported and attrfbute this to differences in other A-E designed component support structures. Accordingly, we believe that aside from follow-on review of the failure acde analysis, related weldment modifications, repair and 4A messorst by WPPSS. no futher action is warranted at this time.
It hay be notcd t'at decohesion cracking (lanellar tearing) of under-weld base suterial in weld operations is a well recosuized anaooly, particularly among carbon steels due to their variant anistrSpic prop-erties and plate quality. Because:of this, the ASME subgroup on Fabrication and Examination has proposed revisions to Subsectica 17 and Appendix XVII of ASttE Code section III relative to this matter.
These changes are discussed in Enclosure (1). This information is subaltted to provide functional 2nidance only in Region V developecnt of their r4 view ard evaluation of the licensee's proposed repair program t
within the context of applicable code rules. It should be emphasized that the remedial welding modifications stated are not mutually exclusive and that QA/QC measures relating to electrode control, weldiry operations and post.eid IRE (Ili supp1wenteW by UT) arc essential to reasonably l
I assure welcacnt integrity.
' Ddg!nal.Irned by
(
E.V. Seyfrit Karl V. Seyfrit. Chief Technical Assistsnce Brarnb. IE l
Enclosure:
Led:!!ngs In the Stort Transvarse Direction 7
cc:
G. S.C4$tsdi4h)0H1W1(w/cnclosure)
IE: TAD IE: TAB WJCollins:sgh KYSeyfrit e60522o096 790409
{DH ADOCK 05000397 PDR
Enciosure (1)
~
/.;; ends I ten Ft.E-74-35 N-73-4
^
LOADINGS IN THE SHORT TRANSVERSE DIRECTION Proposed Revision of Subsection NF and Appendix XVII j
1.
Delete the following:
NF-3226.5 g
NF-3321.1(c)
',,) l ',' f 'a
/.
NF-3391.1(b)
,, e '
Fig. NF-3226.5-1 kg-9 4",(l',,'
.NF-339 2.1(b) b,.r -
2
@g p
g q<'
, p,. / #.< >
3." ',
Fig. NF-3321.1(c)-1
< XVII-2211(c) f.e
, I'. r. '4 Fig. XVII-2211(c)-1
,la "
W(',
g V
2.
Add a new NF-3294 as follows':
NF-3294 SPECIAL WELD JOINT LIMITATIONS g
[Y direction of material over 5/8 inch thick shall meet the requirements AWeld joints which transmit tension stresses in the through thickness
\\('t f af W
- - (a,)(a) > (h) 3 g (c) bele.
g,Ag The weld joint shall be designed to minimize through thickness b
't stresses caused by weld solidification during f abrication. The P
t' p
weld contact surface shall not be perpendi*cular to the through 6
Y
'0I#s' thickness direction (Fig. 3294(a)-1). The weld shall develop the g
required strength with a minimum volume of weld metal.'
\\
lt pa.., o rp...
s.
k nW.' %..:-. ~. t... ; * -
.W Th is [ *,. f (b) The material shall have through thickness properties meeting the O[r 3'
materials specification mechanical properties requirements.
- ' f, c.
sufficient data to indicate that{da'ca for the heat of material or Z requirement may be met by eitheF
(/>0 [..
i',3
' *?
the type of steel and steelmakin k'
practice consistently provide material meeting the requirement.
t-
.s p
t ) N
{, '[ (c) f The veld joint shall be designed and fabricated in accordance with NF-4430.
3.
Add a new XVII-2455 as follows:
XVII-2455 SPECIAL WELD JOINT LIMITATIONS Weld joints which transmit tension stresses in the through thickness direction of material over 5/8 inch thick shall meet the requirements of (a), (b),_or (c) below.
f) n.n A e.,/ 3 pre. k 5 v2 s<." ytn:n-o '.', E/., e a s. s ~ /c..s e.w < ^ * /
,,,4
?' r p a.,.., & s. 1 u.,,i.ne >hr m s (es '< M-JJm a r. A r.- s /-
5<<> Ls/r arre4arae's d,,mpa e ste d, ?. }, yre *,a.s-r ! / s n f. e, 6 s J'*l y
A do n ). /c n he,o,
/()s'/r '=e 5s */f O
- b' o
(c) The weld joint.shall be desinned to ninini::e through thickness stresses caused by weld solidification during fabrication. The weld contact surface shall not be perpendicular to the through thickness direction (Fig. XVII-2455(a)-1). The veld shall develop the required strength with a minimum volume of weld metal.
(b) The material shall have through thickness properties meeting the materials specifiction mechanical properties requirements. This 4
requirement may be met by either data for the heat of material or U
sufficient data to indicate that the type of steel and steelmaking practice consistently provide naterial meeting the requirement.
(c) The weld joint shall be designed and fabricated in accordance with NF-4430.
~
l 4.
Add a new paragraph NF-4430:
NF-4430 Special Weld Joints NF-4431 The requirements of NF-4430 apply only to welded joints which transmit tensile stresses in the through thickness direction and do not meet the requirements of NF-3294(a) or (b) or XVII-2455(a) or (b).
Filler Metal (t/.r%,fr -l (4.4.'c c,-. A / el cer:,, ) %er 2. V NF-4432 A.,g
& % A2 < % Me m e.' o4 M'. e e oe. ist.
a., ge., g ~ c, b <. ct: ~ c~r )
F111cr metal shall 1,6 6616ct=J tu match, as closely as possible, the tensile strength of the materials being joined. When two materials of different strength level are joined, the filler metal shall be selected to match the 1,ower tensile strength base material. Care should be exercised during fabrication to prevent over welding.
NF-4433 Preheat - {Ur !~ M. /c; /?,s ruv./ a /m1 <r.u.c,1.ss..,u' k 4.n../c c} %
Nu irr. a.m e -t.*,~$ c'r,y a g o src.)
A Preheating, except for electroslag or electrogas welding processes, shall be in accordance with Appendix D and shall be mandatory.
NF-4434 Buttering Techniques i
Weld metal shall be deposited on plate surfaces at the point of i
attachment and shall extend the width of the completed weld plus 1/2 inch ininimum on either side and full length plus 1/2 inch on Y
either end.
Buttering may be deposited in a groove cut into the plate or may be deposited on the plate surface. The depth of the buttering shall be shown by demonstration, for each welding process N
used, to extend 1/4 inch beyond the depth of fusion of the initial weld passes for joint welding. This requirement shall not apply to electroslag or electrogas welding processes. (Figure 4434-1) l NF-4435 Welding Sequence t
Double welded " tee" joints shall be welded by alternate passes l
or layers on each side of the joint in order to balance weld
\\/
shrinkage stresses on both sides of the weld joint.
.... _.. ~ ~.
I
I
(
1
. ~.
f
'l/.
1 1
i i
ll
..i}_
-s\\.-.
k ---
UAAC C5.or/93,L E
..-. 3,
. ~ ~
i I
i
'd
%--(
s I
0 CCif?~r^ d,L E E/G. 32 Y'Y{d-) ~ l
.j_~s.t. a : T/ltW/.> <J $ o f 'J~b ie> 7S
~~
s.
f~ot 7t'r'IIStilTTItXr " W R J. H il T h's C.< < & 'i 5 7DJS/M 57tll*SSE S
)
l 1
e i
(-
g
)
)
i i
I 8
'\\-
,.j\\-
U N A C C 3 9 7,9 g,i g e
s i
-~1
.. \\,.
f
/
s t
t a l-t Lp.:
OCCiM~r16LE
[/G.E'/55(ob~l
- a f 2..O S~1?'0 7/>rJS ot~ ~3b i< ' 7 5
. s.
f o A 7 X i i15 h l T TI N 3r THR J.N :: Th', C Ks ' S G
~7"itJS/JJ S7tlCSSES a
4 i.L
- ' * ; * ', e;,.~.h
.. a.~,
_,Q.,Ty 3, --
- s.'\\ (
M *.*..'*.:.
- c-
- ~
=,s N *.
f N -
/iar f yd
\\i
<;. \\
, r, p
, r
, i.,
yj\\
Tve
--+
-4
.W
. /6) e
'v
- l' f ' "
s u - w-....,
.,w.
m.r....,..
... =., m.
.w.
..c ;/
acrc
+
~
++-s l M_%25-7i'-%
/
~.
e,./
b s
- p N
e s
u n - sorru,os c ~ a n,s.~ s M
u (a s g. na,e
- s. s.
?is. VY3'l Exen nc5 of 6 07TiR'1JG Ti C!!!)! 9s C C
_ - * *. -.