ML19332D171
| ML19332D171 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 11/17/1989 |
| From: | Stols R COMMONWEALTH EDISON CO. |
| To: | Murley T Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8911300110 | |
| Download: ML19332D171 (8) | |
Text
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\\ Commonwealth Edison
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_ / AddiisslipiiloIPoit OTficbno. Illinois 72 West Actms Street. Chica 5
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's Chicago,Ilknois 60690 0767 l
.3 November 17, 1989
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i Dr.. Thomas E. Murley, Director i
Office of-Nuclear Reactor Regulation
' U.S. Nuclear: Regulatory Commission
.Hashington, DC 20555-Su'oject: Quad Cities Nuclear Power Station Unit 1
[
Intergranular Stress Corrosion Cracking (IGSCC) Preliminary Inspection Results H
NRC. Docket No. 50-254 i
f Dr. Murley:
The attached report provides the preliminary report of the Intergranular Stress Corrosion Cracking (IGSCC) Inspection Results.
During the-Unit 1 examination, no growth or new IGSCC-like flow l
indications were identified; however, indications were detected in-three weld overlay repairs.
Flaw indication on Held 02G-S4 were removed and repaired.
Flaw indications on Helds 02D-S3 and 02C-S3 were found acceptable for continued operation.
A final IGSCC Inspection will be forwarded within thirty (30) days following startup of Unit l'.-
Please direct any questions you may have regarding this matter to this j.
office.
I Very truly yours, L
Nuclear Licensing Administrator
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Attachment:
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A.B. Davis - Regional Administrator, RIII R.L. Higgins - Senior Resident Inspector, Quad Cities T.H. Ross - Project Manager, Quad Cities H. Koo ht2 l
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ENCLOSURE 1 ULTRASONIC EXAMINATION OF IGSCC SUSCEPTIBLE STAINLESS STEEL WELDMENTS 1
QUAD CITIES UNIT 1 - FALL 1989 REFUELING OUTAGE
-INTRODUCTION This enclosure provides a report of the ultrasonic examinations-(UT) performed on IGSCC susceptible stainless steel weldments during the Quad Cities Unit 1-Fall 1989 refueling outage.
In addition to the UT examinations results, this report also provides:
o a comparison of the current overlay UT results with
~r those of the 1987 refueling outage.
o a description of the repair activities to the overlaid weld 02G-S4.
a' description of the repair activities to the o
overlaid weld 02M-S3 which had a pipe lock.
o the Mechanical Stress Improvement activities during the 1989 refueling outage.
EXAMINATION SCOPE As shown in Table 1, a total of 182 weldments were ultrasonically examined during the current Quad Cities Unit 1 refueling outage.
This examination scope meets or exceeds the requirements of Generic Letter 88-01.
It also addresses the requirements of the Safety Evaluation dated June 6, 1989 for Quad Cities Nuclear Power Station, Unit 1.
The l
examination scope includes:
o Six (6) category "A" weldments.
L o All 105 category "C" weldments, including 100% of the L
l o All 25 remaining category "D" weldments after the L
remuval of the Head Spray and Control Rod Drive i
Pi ing.
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o All 15 category "E" weldmente.
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o All 16 category "F" weldments after build up or application of standard overlay repair, including welds 02G-S3, 02BS-SS, 02BS-S9, 02M-S3, and-10BD-S13.
o All 15 remaining and accessible category "G" f
weldments after the Reactor Water Clean Up piping modification.
Lambert, MacGill, and Thomas, Inc. (LMT) performed the ultrasonic examinations using level II and III examiners qualified by-EPRI after September 10, 1985.
Both manual and automated UT techniques were utilized.
.o new IGSCC-like flaw indications were identified this N
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outage.
However, indications were detected in the overlay material of three' weld overlay repairs; 02G-S4, 02D-S3, and 02C-S3.
For weld 02G-S4, flaw indications were removed and the weld overlay was repaired.
The flaws indications in the weld overlay repairs on welds 02D-S3 and 02C-S3 were judged l
to be welding defects and found accentable for continued
_ operation without additional repairs'.
L Because the scope of the axaminations performed satisfies the Generic Letter 88-01 inspection requirements of categories A, C,
D, and E welds for two (2)~ refueling cycles and because no new flaws are found this outage, no ultrasonic examination of the aforementioned welds will be performed during the next Unit 1. refueling outage currently scheduled 3
in the Fall of 1990.
l.
DISCUSSION r
- 1. Wald Overlay-Repair On Wald 02G-84.
l ll A standard weld repair was applied to this weld in 1987.
Steam blow-out's were experienced during the repair. The overlay repair was ultrasonic examined in 1987 after the application of the overlay repair.
Several axials indications were detected with the deepest flaw at 0.38" remaining ligament.
In 1989, this weld overlay repair was re-examined ultrasonically.
Three linear indications were detected at low amplitude in the weld overlay material at 0.14",
j 0.17",
and 0.19" remaining ligament; however, the indications could not be followed into the base material.
These indications were located in the general location of l.
the deepest flaw found in 1987 at 0.38" remaining ligament. This was also the location of a steam blow-out repair.
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1 A boat sample was taken in order to determine if IGSCC had grown into the overlay material.
The results of the destructive examination of the boat sample indicated that the linear indicat1ons were stringer slag inclusions possibly introduced:into the weld overlay during-the repair of the steam blow-out's.
No water leakage was j
observed during the removal of the boat sample.
The boat sample cavity was filled with welding material and an additional layer of welding material was applied.
A new baseline examination was then performed on the~
repaired weld overlay with no indications reported in the overlay material.
- 2. Weld overlay Repair on Wald 02M-83.
A leak barrier overlay repair was applied to weld 02M-S3 l
in 1984.
Only a bonding examination was performed after l
the overlay application.
In addition, a pipe lock was
-installed on this leak barrier weld overlay repair.
In 1989, the pipe lock was removed from this weld.
As previously committed, a best effort ultrasonic examination was performed on the leak barrier overlay repair. It was determined that the pre-existing flaws had not propagated.
l The leak barrier overlay repair was built up to a standard overlay design.
An ultrasonic examination was performed after the standard overlay build-up and no indications were reported.
Since a standard overlay has been applied to this weld, the pipe lock was not reinstalled.
- 3. Mechanical stress Improvement.
i A total of 29 stainless steel welds were stress improved during this outage using the Mechanical Stress Improvement i
Process (MSIP).
The original plan called for stress improvement of a total of 36 stainless steel welds.
Seven (7) welds could not be stress improved because'of weld geometry or interferences.
A post treatment ultrasonic examination was performed on these 29 welds with no IGSCC-like indications reported.
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ky TABLE 1 Ultrasonic Examination Scope Quad Cities Unit 1 - Fall 1989 Refueling Outage TOTAL NUREG-0313 WELD CATEGORY New SYSTEM SIZE EXAM.
A C.
D E
F G
Flaw RECIRCULATION Outlets 28" 30 0
28 0
0 2
0 0
Noz-SE 28" 1
1 0
0 0
0 0
0 Header 22" 12 0
7 2
2 1
0 0-Risers 12" 41 0
22 0
13 6
0 0
Noz-SE 12" 4
4~
0 0
0 0
0 0
Bypass 4"
8 0
0 5
0 0
3 0
3 10 0
0.
3 0
LPCI 16" 26 0
25 0
0 1
0 0
i CORE SPRAY 10" 26 0
20 0
0 6
0 0
t
'JPI 12",8",4" 10 0
0 3
0 0
7 0
RWCU &
SPARE N05 &
6" 5
1 0
4 0
0 0
0 L
.HD SPRAY 1-1' L
HD VENT &
4" 3
0 0
1 0
0 2
0 CRD TOTAL _ EXAMINATIONS 182 6
105 25 15 16 15 TOTAL NEW FLAWS 0
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TABLE 2 Flaw Characterization Comparisons Standard Weld Overlay (OL) Repairs Quad-Cities Unit 1 - Fall 1989 Refueling Outage Standard Year Overlay Weld ID Examined UT Results Thickness RECIRC - 12" 02C-S3 (1) 1987 OL not examined,due to Leak O.23" Barrier Overlay (LBOL).
1989 Axial; 0.19" Remaining Ligament (RL).
Axial; 0.73" RL.
.1987 Axials; 0.40" Min RL.
0.265" 1989 Axials; 0.36" Min RL.
02D-S3 (1) 1987 OL not examined due to LBOL.
0.23"
>1989 Circ.; 0.16" RL (No measurable depth).
02D-S4 1987 Axials; 0.38" Min RL.
0.25" 1989 Axials; 0.38" Min RL.
l.
02E-S3 (1) 1987 OL not examined due to LBOL.
0.24" 1989 No reportable indications l
after standard OL application.
02E-S4 1987 Axials; 0.36" Min RL.
0.24" i
1989 Axials; 0.30"' Min RL.
i L
02F-S3 1987 No indications in OL.
0.21" l
1989 Axial; 0.41" RL.
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02F-S4 1987 Axial; 0.41" RL.
0.24" i
1989 Axial; 0.38" RL.
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02G-S3 1987 Axials; 0.38" Min RL.
0.26" I
l 1989 Axials; 0.35" Min RL.
l 02G-S4 1987 Axials; 0.35" Min RL.
0.24" I
Laminar at 0.32" RL.
1989 No reportable indications after repair of boat sample excavation.
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'Wc-r 02H-S3 1987 Axials; 0.43" Min RL.
0.25" 1989 Axials; 0.44" Min RL.
02H-S4 1987 Axials; 0.35" Min RL.
0.24" 1989 Axials; 0.35" Min RL.
-1987 Axials; 0.26" Min RL.
0.21" 1989 Avials; 0.25" Min RL.
02J-S3 1987-
\\xials; 0.37" Min RL.
0.24" 1989 Axials; 0.37" Min RL.
02J-S4 1987 Axials; 0.33" Min RL.
0.235"
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1989 Axials; 0.33" Min RL.
i 02K-F6 1989 No reportable indications 0.24" After standard OL application to balance system shrinkage stresses.
02K-S3 1987 Axials; 0.35" Min RL.
0.235" Circ.; 0.50" RL.
1989 Axials; 0.35" Min RL.
02K-S4 1987 Axials; 0.37" Min RL.
0.24" 1989 Axials; 0.37" Min RL.
02L-S4 1989 No reportable indications 0.24" After standard OL application to balance system 'hrinkage stresses.
02M-S3 (1) 1987 OL not examined due to LBOL.
0.24" 1989 No reportable indications after standard OL application.
l 02M-S4 (1) 1987 OL not examined due to LBOL.
0.25" l
1989 No reportable indications after L
standard OL application.
RECIRC - 22" l^
02B-F1 (1) 1987 OL not examined due to LBOL.
0.37" 1989 No reportable indications after standard OL application.
i 02B-S7 1987 Axial; 0.56" RL.
0.37" 1989 Circs.;
0.6" Min RL.
02B-S10 1987 Axials; 0.45" Min RL.
0.37" 1989 Axials; 0.32" Min RL.
(Evaluated in 1989 by NUTECH and found acceptable for continued operation).
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RECIRC - 28" 02BS-SS (1) 1987 OL not examined due to LBOL.
0.46" 1989 No reportable-indications after standard OL application.
02BS-S9 (1) 1987 OL not examined due to LBOL.
0.49" 1989 No reportable indications after i
standard OL application.
CORE SPRAY - 10H 14A-F2 (1)
'1987 OL not examined due to LBOL.
0.22" 1989 No reportable indications after standard OL application.
14A-F11 (1) 1987 OL not examined due to LBOL.
0.22" 1989 No reportable indications after standard OL application.
14A-S8 1987 Not Examined.
0.21" 1989 No Reportable Indications.
14A-S9 (1) 1987 OL not examined due to LBOL.
0.21" 1989 No reportable indications after standard OL application.
14B-F2 (1) 1987 OL.not examined due to LBOL.-
0.27" 1989 No reportable indications after standard OL application.
14B-S8 (1) 1987 OL not examined due to LBOL.
0.21" 1989 No reportable indications after standard OL application.
RER LPCI - 16" 10BD-S13 1987 MSIP Treated.
0.27" 1989 No reportable indications after standard OL application.
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NOTE (1)
Leak barrier overlay built up to standard overlay repair in 1989.
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