ML20087K471
| ML20087K471 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 08/14/1995 |
| From: | Mccollum W DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9508230315 | |
| Download: ML20087K471 (9) | |
Text
'61
' flute (kwerCornpany:
LVn.u.utR McCow:n Jr
- Catan ha i%wicar Generatiott ikpartinent :
" ike hai&vt 4BlmConcordhbad (S03JS114X@ Olluce i
_ York, SC29745 '
(803)S31JL% Fax.
. DUKEPOWER
}
August 14,1995 U.S. Nuclear Regulatory Commission i
Attention: Document ControlDesk Washington, D.C. 20555 i
Subject:
Catawba Nuclear Station, Unit 2 Docket No. 50-414
'ReliefRequest 94-02 Reply to Request for AdditionalInformation
Reference:
Letter from Robert E. Martin, NRC to David L. Rehn, Catawba,
'i dated April 24,- 1995
' Gentlemen:
Please find attached Catawba's reply to your Request for Additional Information, as transmitted in the reference letter. For convenience, the questions in the request are reproduced, followed by our response. If there are any questions conceming this reply, please call L.J. Rudy at (803) 831-3084.
Very truly yours, i
.J
. W.R. McCollu i
a LJR/s i
-Attachment q
I 95082so325 950s24 0
{DR -ADOCK 05000414 9
eda
~
- J at -
C-t:
m
,e l
Document Control Desk
- Page 2 August 14,1995 5
- xc (with attachment):
S.D. Ebneter, Regional Administrator Region II i
R.J. Freudenberger, Senior Resident Inspector R.E. Martin, Senior Project Manager ONRR Mr. Boyd W. Brown EG&G Idaho, Inc.
INEL Research Center 2151 North Boulevard P.O. Box 1625 -
l Idaho Falls, Idaho 83415-2209 l
- I f
1 i
4 1
4
+
i i
l j
J i
i
, ;.s +.
J
^
cl.
D6cument ControlDesk Page 3 3-August 14,1995 lll bxc(with attachment):-
_ Z.L. Taylor L.J. Rudy J.E. Cherry NCMPA-1 '
NCEMC PMPA SREC Document Control File 801.01 Group File 501.01 ELL-EC050 t '
1 ATTACHMENT i
REPLY TO REQUEST FOR ADDITIONAL INFORMATION CONCERNING.
RELIEF REQUEST 94-02 L
- A.
' In the case of the steam generator shell-to-transition cone weld (Item -
C01.010.002), the licensee performed the ultrasonic examination with a 35 and a 45 degree angle. Article IV of Section V of the 1980 Edition with Addenda through the Winter 1981 of the ASME Code requires that two angle beams, having nominal angles of 45 and 60 degrees with respect to a perpendicular to the examination surface, shall generally be used. Other pairs of angle beams are permitted provided the measured difference between the angles is at least 10 degrees.
From a technical point of view, and as required by later Editions of the Code, t
the angles selected for the ultrasonic examination of welds in vessels should i
be 45 and 60 degrees or, alternatively, angles in the range of 45 to 60 degrees.
Because of the taper associated with the examination area, the 35 and 45 degree angles used by the licensee appear to intersect the inside surface of the vessel shell very close to perpendicular.
Provide technical justification for using the 35 and 45 degree angles, which have a low angle ofimpingement at the inside surface. Have these angles.
. been qualified as capable of flaw detection in the subject component? Based on the scanning surfaces available, estimate the percent of coverage that l
could be achieved by using an angle of 60 degrees or higher.
1
Response
A.
Steam generator shell-to-transition cone weld Item No. C01.010.002 was examined using 35 degree and 45 degree beam angles (refer to Figures I A-ID).
The 45 degree was performed by a full V-path calibration because of the single-1 sided access restriction. If a 60 degree beam angle is used, the coverage is calculated as follows:
Weld metal = 48.5%
Base metal = 62.8%
B.
For the upper head injection (UHI) cap welds (Items B09.011.076, B09.011.077, B09.011.078, and B09.011.079), it appean that the licensee
, -+:
- 3 w
~' ;.
,=
m
~
.l.
. :,a J
-2 i
- ' Af'
.y 1
'j,_
v i
_l N' 4.-
~
PERMANENTRESTRAINT RING 1
P
',],['
f s
~
V W
4
.:Q ye.
y s
g s
j
~..
l
~
d;
/
m.
SURFACE 1 - TRANS. CONE l
/
. SURFACE 2-LOWER SHELL
~
HEW..
g^'
s f
M Kiv,-
/
2
- M ^',
i
/
1g[g vg;. ^
. p; p
Figure 1A
'35 SCAN FIRST LEG STEAM GEN. C - UNIT 2 CATAWBA NUCLEAR STA.
LOWER SHELL TO TRANSITION CONE WELD # 2SGC-048-05 ITEM # C01.010.002 SCALE: 1/2" = 1"
o
< -.a
=-
=
4.
, a:
. h_
. -e ;'
~-
^
s s- -
y 4
+
4 y.
- P c.g
'~'4 g
J
~
..1 pgggggggyw gggg
- y:#
. s:
}
DN, w.
cm.
7
^
1
..r
~
- [.7 L c
v
_y m:
2..
~
u--
4 7
gg 3,,
y c
- q
.n=.
.- a
.c ll %.A 1 >
, -[,f
[
- ":. j,'L '
- y,-f l
- y:
?
', 3y
,~
o-r q
y,
,-1
. y, M
,o_
p2 '
j
~ %, &.,
l N
l j.se ig,
i4 h.,,,y-+j ;N2* ;
\\
SURFACE 1 - TRANS. CONE
.,. n
/
3@. m g
n,
_I..
Sh y.
I q.gp s#N's06
, w e' d y
^
s.
\\
j SURFACE 2-LOWER SHELL if;... if/g sis SEQ?
N l
- gnu
~, - - >
'I
. 3
- k Y.'>
I b
^.x
/
-:w.
xgp 1 '
Jh,m. R RD
.\\
TR ~
p.
. in.
g/-
t
- h
.+ :.9
- .x.-
....e
v Y
Q$:50-W ja
'I"^n,.,
'f e s
- p myg' g Figure IB 35 SCAN
.SECOND LEG STEAM GEN. C - UNIT 2 CATAWBA NUCLEAR STA.
LOWER SHELL TO TRANSITION CONE WELD # 2SGC-048-05 ITEM # C01.010.002 SCALE: 1/2" = 1"
____-,__.m_
2 m
.m e
- mv---
-w
---. --w-<i-+---
_+_.>__c_,
- t :-
4,
~
L.
~
-w r
^L 4-har nap,,,a 3
~
~4
+
- = =
N
.c--
~.
~
w
~
l'
.:: ;} 3
':!l ggy 4 ~
~
y.
/
m Y'/
i
?
f SURFACE 1 - TRANS. CONE
/
SURFACE 2-LOWER SHELL j
~ j Figure IC 45 SCAN FIRST LEG STEAM GEN. C - UNIT 2 CATAWBA NUCLEAR STA.
LOWER SHELL TO TRANSITION CONE WELD # 2SGC-048-05 ITEM # C01.010.002 SCALE: 1/2" = 1"
> ~
sp; p;-g r;-
3
.m
,A I.$
,cy r
-y..
46
~
.:-[j' :
.:. 2. ;
- a?
, :'f e',
s
-.4 :gg:e 3
a, r
.o.,
,u(
t
'f.
- .x PERMAIEffT RESTRABIT RN0G a
'" % i
+
[f,,
i t.;
~
.3-
~
32-
,a".
~
s 3 _.
/
-; + :.
E' -
. 'N x...
a3
~
. ~
/
,o W- ~
~
~~
~
' :?:y; a.
N
/
\\
- llf '
SUpFACE 1 - TRANS. CONE h
N i
SURFACE 2-LOWER SHELL
.\\
- ./
\\
\\
/
~\\
\\
ME
-.E
/
l'i f -
p g
+
\\
g/c-1:
g
- s - ;
.\\
- p;; [\\a-;
f.N
' 4:5 g
Figure ID 45 SCAN SECOND LEG STEAM GEN. C - UNIT 2 CATAWBA NUCLEAR STA.'
LOWER SHELL TO TRANSITION CONE WELD # 2SGC-048-05 ITEM # C01.010.002
. SCALE: 1/2" = 1"
y-cc y
s ultrasonically examined the pipe-to-cap circumferential welds with a' 45 degree shear wave from the pipe side, supplemented with a 60 degree L
refracted longitudinal beam scan from the pipe side scanning onto the weld -
crown. Is the licensee examining the entire Code-required volume with a -
refracted longitudinal angle? State of the art examinations are being performed on stainless materials with 45 degree refracted longitudinal techniques, which are recommended in NRC Information Notice No. 90-30.
Has this alternative been considered?
The percents of coverage stated to have been obtained for the subject welds are misleading because the coverages are based on a one-sided examination.
It appears that two-directional coverage could be achieved in some cases by scanning with the beam 180 degrees to the scan direction developed on the -
coverage plots. Provide a technical discussion of the basis for limiting the subject examinations to one-directional coverage and state the percentages of coverage obtained.
Response
A.
Upper head injection (UHI) cap welds are single-sided access welds examined with 45 degree shear waves for the near side and 60 degree refracted longitudinal waves for the weld metal and far side. These techniques have been qualified in blind testing at the EPRI NDE Center.
The examination volume coverage (86.44%) is based on the following:
l.
Axial scan from one side with the 60 degree RL covering the weld and far side base material in one beam path direction; 2.
Axial scan from one side with the 45 degree shear wave covering the near side base material in two beam path directions; j
3.
Circumferential scan with the 45 degree shear wave covering the full examination volume in two beam path directions.
>