ML20137G934
| ML20137G934 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 01/13/1986 |
| From: | Zimmerman S CAROLINA POWER & LIGHT CO. |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| References | |
| NLS-86-012, NLS-86-12, NUDOCS 8601210349 | |
| Download: ML20137G934 (25) | |
Text
-.
y Cp&L Carolina Power & Light Company SERIAL: NLS-86-012 I
J AN 131986 i
i Director of Nuclear Reactor Regulation Attention:
Mr. D. B. Vassallo, Chief Operating Reactors Branch No. 2 Division of Licensing United States Nuclear Regulatory Commission l-Washington, DC 20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NO.1 DOCKET NO. 50-325 / LICENSE NO. DPR-62 INTERGRANULAR STRESS CORROSION CRACKING
Dear Mr. Vassallo:
On November 7,
1985, your staff requested additional information concerning intergranular stress corrosion cracking (IGSCC) inspections performed on Brunswick-1.
l Design reports regarding these inspections were submitted on June 14, 1985 and September 25,1985. Enclosure I contains our responses to your staff's questions.
Please refer any further questions to Mr. Stephen D. Floyd at (919) 836-6901.
Yours very truly,
' fr S. R. Zim erman Manager l
Nuclear Licensing Section SRZ/ MAT /mf (3216 MAT)
Enclosure cc Mr. W. H. Rutand (NRC-BNP)
Dr. J. Nelson Grace (NRC-RII)
Mr. M. Grotenhuis (NRC) 9 r%4 3
l l
i 8601210349 360113 gSD',5b(L14)/
POR Apocn 03000325 e
PDR 411 Fayettevole street
- P O. Bos 1551
- Raleign. N C 27602
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ENCLOSUREI TO SERIAL NLS-86-012 RESPONSE TO NRC RAI REGARDING IGSCC INSPECTIONS BRUNSWICK-1 (3216 MAT /mf)
T (t
(
l Request for Additional Information Brunswick Unit 1 IGSCC Inspection I
i A.
With respect to the design report transmitted on September 25, 1985 please provide the following information:
1.
A detailed sample calculation for each kind of an overlay design used for the repair of cracked welds 2.
The overlay inspection of welds repaired prior to October 1984.
B.
With respect to the design report transmitted on June 14, 1985, please provide the following information:
1.
The "as built" overlay thickness, including the first layer, for the 4-17." and 1-4" repaired welds (see Table 2.1 page 9) 2.
The ultrasonic testing (UT) measured pipe wall thickness for the one unrepaired weld and the five repaired welds identified in B.1 above 3.
The method of calculating the shrinkage stress for weld 12-AR-B4A (page 26) 4.
The design menthod for the overlay for weld 1-RR-4A 10-A.
Due to the accessibility constraint, the flaws in the subject weld were not sized.
5.
A sample calculation for the overlay design for weld 12-13R-F4A 6.
The data of the ferrite measurements made on the first layer of the overlay for the repaired welds identified in B.1 'above 7.
The stress information for welds 28 (table 4.1, page 21).
u
RESPONSE TO A.1 The following provides: (a)a sample calculation for a circumferentially flawed weld (12-AR-A3) and (b) a sample calculation for an axially flawed weld (12-BR-K3).
(3216MAf/mf)
'l s
A.
With respect to the design report transmitted on September 24, 1985 (NUTECH Report CPL-30-100, Revision 2), please f
provide the following information l
1.
A detailed sample calculation for each kind of an overlay design used for the repair of cracked welds.
Typical weld overlay repair (WOR) design for a a.
circumferential1y flawed weld (12-AR-A3)
Wold Geometry / Configuration:
Ou tside Diamator = 12. 7 5"
= 0.75" Pipo Wall Thickness (tp)
Configuration = Elbow-to-Pipo 9
Measured Flaw Dimensions:
1.75" length x 35% depth circumferential flaw, elbow side.
Dosign Flaw Dimensions:
1.75" longth x 100% depth circumferential s
flaw, elbow side.
I A11owablo Material Stress Intensity (at 550* F):
S,= 16,950 poi a
0 g{
XCP-3303
Strossos (unropaired pipo):
(Deadweight + Pressure + Soismic P, + Pg
=
(OBE) Strossos)
= 8,493 psi Assumed WOR Thickness:
og = 0.25' t
Strces after WOR:
t{g X 8,493 psi = 6,370 psi g p ol Stross Ratio (SR):
SR = 6,370 psi /16,950 psi = 0.38 lion-Dimensional Flaw Longth (FL):
FL = 1.75"/(12" X :)
= 0.046 from ASME Section Allowablo Flaw Dopth Ratio (a/t)
XI, Tablo IWD-3641-1:
a/t = 0.75 Allowablo Flaw Dopth Ration nack Chuck Ascumod vs.
a/t = a/(tp+ tog)
= 0.7 5"/(0.75" + 0. 25")
= 0.75 = Allowablo a/tf 0.K.
XCP-3303 nutg9
WOR Design Length (L):
Rulo-of-Thumb 1.5 / Rt
<L<
2.0 /~Rt t = 0.75" (12.75* - 0.75")/2 = 6.0" R=
3" < L < 4 1/4" Typical WOR dcrign f or an axially flawod weld (12-b.
BR-K3)
Wold Geometry /Configuratlon:
Outsid. Diamotor = 12.75" Pipe Wall Thicknenu = 0.76" Configuration = Elbew-to-Pipo Measured /Dosign riaw Dimonaions 0.75" Longth x 1008 Dopth axial flaw, elbow sido 550'):
Allowablo Material Strono Intensity (at S,= 16,e50 psi s
Inte rnal P rounutv- (P):
P=
1,050 psi 9
9 0
3
- nutgg, 9
XCP-3303
Stress Ratio (SR):
l SR = PD/2tS,
= 1,050 psi (12.75")/[2(0.76")(16,950 psi))
l 0.52
=
Non-Dimensional Flaw Length (FL):
l FL = I //~ Rt g
0.75"// [(12.75" - 0.76")/21(0.76")
=
0.35
=
From Table 1, Leakage Ba rrior (2 Laye rs) Only Required.
WOR Design Longth (L):
Rule of Thumbs L > Butt Wold Root Width
+ 2(Flaw Length) + 2(1/2" Cover) 3.0"
=
e e
1 nutag XCP 3303
s s
i RESPONSE TO A.2 The 1983 overlays that were examined during the Unit 1 March 1985 outage are as follows:
i 12" B32 AR-E-2 12" B32 BR-H-4 28" B32 A-14 28" B32 A-15 28" B32 B-3 These welds were examined using the basic recommendations of the Electric Power Research Institute Interim Report dated Apri! 1985, " Examination of Weld Overlayed Pipe Joints." The overlay bond integrity was examined manually with a 2.25 MHz 0*
longitudinal transducer.
The overlay weld metal and base material underneath were examined manually and with the automated General Electric SMART UT system using 2.0 MHZ refracted longitudinal 45* and 60 dual transducers.
Calibration was accomplished utilizing " mock-up" overlayed pipe with a 1/16" side drilled hole and 75%
EDM notch. Calibration encompassed reflectors from the tip and corner reflectors of the EDM notch for the examination of base metal and the 1/16" side drilled hole at the base metal / overlay interface for the overlay weld metal and weld overlay bond to pipe integrity.
A minimum overlap of 50% search unit element size was utilized during manual examinations to assure complete examination coverage. The automated SMART system examination incorporated a minimum overlap of 25% search unit element size.
The manual and automated exams of the subject weld overlays did not yield IGSCC indications.
s 3
k 4
k
1 s
(3216 MAT /ljs)
~.
RESPONSE TO B.1 The "as-built" overlay thickness, including first layer, for the four 12" and one 4"
. repaired welds listed in Table 2.1 of our June 14,1985 submittal are as follows:
Weld ID Thickness (inches) 12-AR-A4A 0.439 12-AR-B2A 0.272 12-AR-B4A 0.432 12-BR-F4A 0.40 l
l-RR-4A10-A 0.525 (3216 MAT /ljs)
I RESPONSE TO B.2 The ultrasonic testing (UT) measured pipe wall thickness for the four 12" and one 4" repaired welds listed in Table 2.1 of our June 14, 1985 submittal and the unrepaired 28-A8 weld are as follows:
UT MEASURED PIPE WALL TillCKNESS (inches)
Location
' Weld ID 0*
90*
180*
270*
12-AR-A4A Upstream 0.638 0.608 0.684 0.639 Downstream 0.72l 0.712 0.724 0.708 12-AR-B2A Upstream 0.625 0.624 0.630 0.624 Downstream 0.789 0.778 0.790 0.793 12-AR-B4A Upstream 0.622 0.615 0.629 0.626 Downstream 0.709 0.688 0.717 0.702 12-BR-F4A Upstream NR 0.641 NR 0.639 Downstream NR 0.717 NR 0.724 1-RR-4A10-A Weld-O-Let Side 0.32 0.32 0.33 0.33 28-A8 Pipe Side 1.30*
NR NR NR Notes:
NR - Not Recorded 5
- Preservice Baseline UT Data (3216 MAT /ljs)
RESPONSE TO B.3 The following provides the method of calculating the shrinkage stress for weld 12-AR-B4A:
(3216 MAT /mf)
B.
With respect to the design report transmitted on June 14, 1985 (H.
.CH report CPL-21-103, Revision 1), please provide the following information:
'The method of calculating the shrinkage stress f or weld 3.
12-AR-B4A (page 26).
(from Axial Load and Moments due to Shrinkage Stress PISTAR computer output):
axial = 3,282 lb F
M
= 22,344 in-lb xx 21,988 in-lb
=
Myy M
= -1,468,701 in-lb zz Repaired Pipe Wall Thickness (t):
+ (overlay thickness) t=
(pipe wall thickness) 0.568 in
+
0.262 in
=
0.830 in
=
Area and Section Modulus:
A
=
(OD
- ID ) /4 13.774" OD = 12.75" + 2 x (0.262")
=
11.614" ID = 12.75" - 2 x (0.568")
=
2 A
= 32.4 in 4
4 ID )/(32 x OD) 2
=-s(OD 3
= 95.1 in D
nutg,q e
XCP-3303
1 Shrinkage Stress (o h)*
(F
/A) + (/ M 2+M 2+M 2 /2) o
=
sh axial xx yy zz 15,517 psi
=
nut.e. c.
XCP-3303
RESPONSE TO B.4 The following provides the design method for the overlay weld 1-RR-4A 10-A:
l (3215 MAT /mf)
B.
With respect to the design report transmitted on June 14, 1985 (NUTECH report CPL-21-103, Revision 1), please provide the following information:
The design method f or the overlay for weld 1-RR-4A10-A.
4.
the flaws in the Due to the accessibility constraint, subject weld were not sized.
Two Flaw Size Possibilities were Considered:
i.
Flaw is Axially Oriented, 0.5" Length x 100% Depth ii.
Flaw is Circumferentially Oriented, 2.0" Length x 100% Depth i.
Axial Flaw Weld Geometry / Configuration Outside Diameter = 4.5"
= 0.337" Pipe Wall Thickness (tp)
Configuration = Pipe-to-Weld-o-let
~
Stress Intensity / Internal Pressure 16,950 psi Allowable S,(at 550*F)
=
Internal Pressure (P) = 1,050 psi t
g nutgg 9
XCP'-3303
Stress Ratio (SR):
SR = PD/2t(S,)
( 1,0 50. ps i) ( 4. 5" ) / [2 ( 0. 3 37" ) ( 16,9 50 ] psi)
=
= 0.414 Non-Dimensional Flaw Length (FL):
FL = l //Rt g
= 0.5"/fl(4.5" - 0. 337 ")/ 2) (0. 337 ")
= 0.597
-From Table 1, Leakage Barrier (2 Laye r) Only Required.
WOR Design Length (L):
L>
(Butt Weld Crown Width)/2 + (1/2" Cover) &
from Weld Centerline to Weld-o-Let (Distance Transition) i i Circumferential Flaw available, maximum allowable Stress information was not stresses in.unrepaired pipe assumed:
Stress = 1.5 S,
e o
W nutggj XCP-3303
Assume a WOR thickness, reduce stress due to assumed WOR thickness, calculate stress ratio (SR):
oy = 0.125" t
0.337" 0.337"(
Reduced Stress =
0.125" +
m 1.09 S,
=
SR = 1.09 Non-Dimensional Flaw Length (FL):
PL = 2.0"/(4" X w)
= 0.16 Allowable Flaw Depth Ratio (a/t) from ASME Section XI Table INB-3641-1:
a/t = 0.74 Back check assumed vs. allowable flaw depth ratio:
a/t = a/(t
+tgy) p 0.337"/(0.337" + 0.125")
=
= 0.73 < 0.74; O.K.
~
nutgq 9
e 1
XCP-3303
- a..
I WOR Design Length (L):
i n
Rule-of-Thumb:
1.5 / Rt
< L<
2.0 / Rt
?.
t = 0.337" R= (4.5" - 0.337")/2
= 2.08" 1 1/4" < L< 1 5/8"
.i.
c WOR Design Assuming Circumf erential Flaw is Bounding.
Therefore, it is Used.
A 4
l 4
e a
4 i
6
?
4 1
e a
9 9
5 nuts XCP-3303
RESPON.iE TO B.5 The following is a sample calculation for the overlay design for weld 12-BR-F4A:
(3216 MAT /ljs)
F l
transmitted on June 14,
With respect to the design report B.
i 1985 (NUTECH report CPL-21-103, Revision 1), please provide f
the following information:
A sample calculation f or the Overlay Design for Weld 5.
12-BR-F4A.
Weld Geometry / Conf igu ration Outside Diameter = 12.75"
= 0.568" Pipe Wall Thickness (tp)
Configuration = Pipe-to-Safe end extension Measured Flaw Dimensions:
4.0" length x 9% depth and 0.5" length x 23%
depth circumferential flaws, pipe side Design Flaw Dimensions:
4.5" length x 100% depth circumferential flaw, pipe side Allowable Material Stress Intensity (at 550'F):
S
= 16,950 psi m
Stresses:
(Deadweight + Pressure + Seismic i
P, + PB
=
(OB,E ) Stresses)
= 8,872 psi
)
l nutgq[
l i.
XCP-3303 L.
1
Stress Ratio (SR):
0.52 SR
16,950 psi Non-Dimensional Flaw Length (FL):
FL = 4.5"/(12" x
)
= 0.12 Allowable Flaw Depth Ratio (a/t) from ASME Section XI Table IWB-3641-1:
a/t = 0.75 WOR thickness calculation:
0.19" 0.568"/0.75 - 0.568"
=
WOR Design Length (L):
Rule-of-Thumb:
1.5 / Rt
< L < 2.0 / Rt t = 0.568" R = (12.75" - 0.568")/2 = 6.1" 2 3/4" < L* < 3 3/4" WOR Length on Flawed Pipe Side of Weld =
L/2.
WOR Length on Unflawed Safe End Extension Side of Weld to Extend to t
within 1/4" of Inconel but liced not Exceed L/2.
e e
4 9
nutgqt XCP-3303
Table 1 REPAIR CRITERIA FOR AXIAL IGSCC NONOlMENSIONAL FLAW LENGTH 4/[RT STRESS RATIO 0.00 0.25 0.50 1.00 2.00 s
s 0.40
=
0.50
=
0.60 0.70
- IVe B-3640 020
=
0.90 0.95
=
1.00 s
sccam
- LEAK BARRIER ONLY REQUIRED ALL DEFINITIONS SAME AS IWB-3640 STRESS RATIO = PO / 2 T Sm P = MAXIMUM PRESSURE FOR NORMAL OPERATING CONDITIONS D = NOMINAL OUT3IDE DIAMETER OF THE PlPE T = NOMINAL THICKNESS y = END-OF. EVALUATION PERICO FLAW LENGTH R = NOMINAL RADIUS OF THE PIPE This table is contained in NUTECH Report COM-76-001, Note:
" Weld Overlay Design Criteria for Axial Cracks",
Revision 0.
nutg,q XCP-3303
RESPONSE TO B.6 The ferrite measurements for the first layer of the overlays for the four 12" and one 4" repaired welds listed in Table 2.1 of our June 14,1985 submittal are as follows:
Weld ID Delta Ferrite Measurement 12-AR-A4A 7.5 12-AR-B2A 7.5 / 10 / 7.5
- 12-AR-B4A 7.5 12-BR-F4A 7.5 / 10 / 7.5
- l-RR-4A10-A 7.5
- Measurements taken upstream / centerline / downstream (3216 MAT /ljs)
f;.. _
a
' RESPONSE TO B.7 t.
During a telephone conversation with members of your staff, it was determined that the stress information requested in B.7 pertains to weld 1-RR-4A10-A. This information can be found in our response to B.4.
l t
(3216 MAT /ljs)
.