ML20042F122

Forwards Preliminary Rept of IGSCC Insp Results.Flaw Indication Detected in Weld Overlay Matl of Weld 02J-S3 & Removed by Boat Sample & Std Weld Overlay Thickness Restored.Final Rept Will Be Forwarded within 30 Days

ML20042F122
Person / Time
Site:	Quad Cities
Issue date:	05/01/1990
From:	Stols R COMMONWEALTH EDISON CO.
To:	Murley T Office of Nuclear Reactor Regulation
References
NUDOCS 9005070244
Download: ML20042F122 (8)

Text

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s C;mmon=alth Edison 1400 Opus Placs

$' U Downers Grove, Illinois 60515

[ May 1, 1990

-Dr. Thomas E. Murley Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Quad Cities Nuclear Power Station Unit 2 Intergranular Stress Corrosion Cracking (IGSCC) Preliminary ,

Inspection Results .l' HRC Docket No. 50-265-l Dr. Murley: I The attached report provides the preliminary report of.the Intergranular Stress Corrosion Cracking (IGSCC) Inspection results. These inspections were performed during the Unit 2 Refueling Outage which began in February, 1990. The information contained in the report was discussed with your Staff on May 1, 1990. l A total of one hundred eighty three (183) weldments were i ultrasonically examined. No new IGSCC-like flaw indications were identified.

3 An indication, however, was detected in the weld overlay material of weld )'

02J-S3. The flaw indication was removed by a " boat sample" and the standard weld overlay thickness was restored.

A final IGSCC Inspection Report will be forwarded within thirty (30) i days following startup of Unit 2.

Please direct any question you may have to this office.

Very truly your I

Rita Stols Nuclear Licensing Administrator a

Attachment cc: A. Bert Davis - Regional Administrator, NRR Senior Resident Inspector, Quad Cities f L.N. 01shan - Project Manager, NRR W. Koo - Technical Staff, NRR

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9005070244 900501 k I' i PDR ADOCK 05000265 i Q PDC l

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ULTRASONIC EXAMINATION OF IGSCC SUSCEPTIBLE STAINLESS STEEL WELDMENTS  :

J QUAD CITIES UNIT 2 WINTER / SPRING 1990 REFUELING OUTAGE i

INTRODUCTION This enclosure provides a report of the ultrasonic. examinations-(UT) performed 0 on IGSCC susceptible stainless steel weldments during the Quad Cities Unit 2 1 Winter / Spring 1990 refueling outage.

In addition to the UT examinations results, this report.also provides:

1. A comparison ~of the current overlay UT resulta with those of'the 1988 refueling outage.  ;

2. A description of the repair activities to'the overlaid weld 02J-S3.- l

3. The Mechanical Stress Improvement activities during the 1990 '

refueling outage.

EXAMINATION SCOPE As shown in Table 1, a total'of.183 weldments were ultrasonically examined  ;

during the current Quad Cities Unit 2. 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 October 3, 1989 for Quad Cities Nuclear Power Station, Unit 2. The examination scope includes:-

1. Six (6) category "A" weldments.

2. All 100 category "C" weldments, including 1007,of the unrepaired L

IHSI welds.

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3. All 16 remaining category "D" weldments after the removal of.the l Head Spray and Control Rod Drive piping.

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4. All 31 category "E" weldments.

! 5. All 6 category "F" weldments after build-up or application of. q i~ standard overlay repair,-including welds 02AD-F12, 02AD-S6, 1 02AS-F14, 02AS-S12, 02BD-F8 and 02BS-S12.

6. All 24 remaining and accessible category "G"'weldments after'the-i 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.

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,76 n:w IGSCC-like ficv indicatitna.were idsntified this cutego. Howev3r, an '

.,- ,fndication w:s detsetsd in tha overley,catorici of weld everity 02J-S3. The.

flaw indication was removed by a " boat sample" and the standard weld overlay

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thickness was restored.

Because the scope of the examinations performed satisfies the Generic Letter.  !

88-01 inspection requirements of categories A, C, D,. and E welds for two (2) I refueling cycles and because no new IGSCC flaws were found this outage, no ,

ultrasonic. examination of the aforementioned welds will be performed during '

the next Unit 2 refueling outage currently scheduled for the Fall of 1991.

DISSUSSION

1. . Weld Overlay Repair on Weld Overlay 02J-S3 A standard weld overlay repair was applied to this weld.during the e 1988. outage. A post overlay UT detected.an axial indication with a

remaining ligament of 0.26".- The miminum standard overlay thickness is 0.21". f In 1990, weld overlay 02J-S3 was re-examined and an. indication was' -

noted with a remaining ligament of 0.12". This indication was-recorded in the same area as the original indications.

A boat sample was.taken in order to verify the UT indication. No r water leakage was observed during the removal of the boat sample.

The boat sample metallography has not been-completed at this time. -

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 Repair on Weld 02A-S10 Weld 02A-S10 has been identified in past outages as containing several indications related to IGSCC. In order to resolve station concerns, the end cap was removed and replaced by another with low carbon content. Materials and welding. techniques were designed to i minimize the possibility of future degradation'of the joint by IGSCC. Radiography and liquid penetrant testing was performed on the 3/8" thick partially finished weld and found acceptable.

Manual UT examination was performed on the finished weld and found acceptable. The new weld designation for ISI is 02A-F10R.

3. Mechanical Stress Improvement. ,

A total of 35 stainless steel welds were stress improved during this outage using the Mechanical Stress Improvement Process (MSIP). The original plan called for stress improvement of a total of 36 stainless steel welds. One (1) weld could not.be stress.

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improved because of weld geometry or interferences.

A post-treatment ultrasonic examination was performed on these.35 velds with no IGSCC-like indications reported.

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TABLE-1 ULTRASONIC EXAMINATION SCOPE QUAD CITIES UNIT 2 WINTER / SPRING 1990 REFUELING OUTAGR~

TOTAL NUREG-0313 WELD CATEGORY NEW

_, SYSTEM SIZE EXAM. A C D E F G FLAW

- RECIRCULATION Outlets 28" 30 0 18 0 6 6 0 0 Noz-SE 28" 1 1 0 0 0 0 0 0 Header 22" 14 0 10 2 2 0 0 0 Risers 12" 44 0 23 0 21 0 0 0 Noz-SE 12" 3 3 0 0 0 -0 0 0 Bypass 4" 8 0 0 4 0 0 4 0 RHR SDC. 20" 17' 0 2 5' 2 0 8 0 LPCI 26" 26 0 26 0 0 0 0 0 CORE SPRAY 10" 21 0 21 0 0 0 0 0 JPI 12" ,8" ,4 " 10 0 0 4 0 0 6 0 RWCU &

SPARE N0Z & 6" 6 2 0 1 0 0 3 0 HD SPRAY HD VENT & 4" 3 0 0 0 0 0 3 0 CRD TOTAL EXAMINATIONS: 183 6 100 16 31 6 24- 0 TOTAL NEW FLAWS 0 i

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TABLE 2 FLAW CHARACTERIZATION COMPARISONS STANDARD WELD OVERLAY (OL) REPAIRS QUAD CITIES UNIT 2 WINTER / SPRING 1990 REPUELING OUTAGE STANDARD YEAR OVERLAY WELD ID EXAMINED UT kESULTS THICKNESS RECIRC-28" 02BS-F2 1988 CIRC; NO TLAWS IN WOR 0.44" 1990 CIRC; NO FLAWS IN WOR 02BS-S3 1988 CIRCS3 NO FLAWS IN WOR, .44"RL 0.42" 1990 CIRCSI NO TLAWS IN WOR, 43"RL See Note 1 02BS-F7 1988 CIRC) NO FLAWS IN WOR 0.42"

, 1990 CIRC) NO PLAWS IN WOR 02BS-S12 1988 CIRCl ACCEPTED FOR CONTINUED SERVICE 1990 CIRCl NO REPORTABLE INDICATIONS AFTER 0.41" STANDARD OL APPLICATION 02BD-S6 1988 CIRC) NO FLAWS IN WOR, .58"RL 0.47" 1990 CIRCI NO FLAWS IN WOR 02BD-F8 1988 CIRCS; ACCEPTED FOR CONTINUED SERVICE 1990 CIRCS; NO REPORTABLE INDICATIONS APTER 0.46" STANDARD OL APPLICATION 02AS-S4 1988 CIRCS: NO FLAWS IN WOR 0.42" 1990 CIRCSI NO FLAWS IN WOR 02AS-S9 1988 AXIAL & CIRC; NO FLAWS IN VOR 0.42" 1990 AXIAL & CIRC; NO TLAWS IN WOR 02AS-S12 1988 CIRCS; ACCEPTED TOR CONTINUED SERVICE 1990 CIMCS; H0 REPORTAELE INDICATIONS APTER 0.41" STANDAR.D OL APPLICATION 02AS-F14 1988 CIR0; ACCEPTED TOR CONTINUED SERVICE 1990 CIRC) NO REPORTABLI lNDICATIONS AFTER 0.41" STANDARD OL APPLICATION 02AD-S6 1988 CIRC; ACCEPTED FOR CONTINUED SERVICE 1990 CIRCl NO REPDRTABLE INDICATIONS AFTER 0.46" STANDARD OL APPLICATION' 02AD-F12 1988- CIRC; ACCEPTED FOR CONTINU0D SERVICE 1990 CIRC; NO REPORTAEL3 INDICATIONS AFTER 0.46" STANDARD OL APPLICATION

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TABLE 2 (Continued)

PLAW CilARACTERIZATION COMPARISONS STANDARD WELD OVERLAY (OL) REPAIRS QUAD CITIFS UNIT 2 WINTER / SPRING 1990 REFUELING OUTAGE STANDARD YEAR OVERLAY WELD ID EXAMINED UT RESULTS TilICENESS RECIRC 22" 02B-S9 1988 AXIALS & CIRCS; NO FLAWS'IN WOR, 0.46" RL 0.38" See Note 2 1990 AXIALS & CIRCS; NO PLAWS IN WOR RECIRC 12" 020-S3 1986 AXIAL & CIRC; NO FLAWS IN WOR, 0.34" RL 0.28" 1990 AXIAL & CIRC; NO PLAWS IN WOR, 0.38" RL See Note 3 02C-S4 1988 NO FLAWS IN WOR 0.22" 2990 NO FLAWS IN WOR See Note 4 02D-S3 1988 AXIALS & CIRC;-NO FLAWS IN WOR; 0.29" RL 0.22" 1990 AXIALS & CIRC; NO FLAWS IN WOR; 0.30" RL 02D-F6 1988 AXIALS & CIRC; NO FLAWS IN WOR; 0.45" RL 0.25"  !

AXIALS & CIRC; NO FLAWS IN WOR; 0.52" RL 02E-S3 1988 AXIALS; NO FLAWS IN WOR, 0.42" RL 0.21" 1990 AXIALS; NO FLAWS IN WOR, 0.37" RL 02E-F6A 1988 AXIALS & CIkCSI NO PLAWS IN WOR 0.26" 1990 AXIALS.& CIRCSI NO FLAWS IN WOR ~

02F-S3 1988 AXIALS & CIRC; NO FLAWS IN WOR, 0.61" RL 0.21" 1990 AXIALS & CIRC) NO FLAWS IN WOR, 0.63" RL 02P-F6 1988 CIRC; NO FLAWS IN WOR 0.25"-

1990 CIRC; NO FLAWS IN WOR 02G-S3 1986 CIRCS; NO FLAWS IN WOR, 0.58"RL 0.25" 1990 CIRCS; NO FLAWS IN WOR, 0.60"RL 02G-84 1988 AXIALS: NO FLAWS IN WOR, 0.44" RL 0.21" 1990 AXIALS) NO FLAWS IN WOR, 0.44" RL

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TABLE 2 (Continued)

FLAW CHARACTERIZATION COMPARISONS STANDARD WELD OVERLAY (OL) REPAIRS QUAD CITIES UNIT 2 WINTER / SPRING 1990 REFUELING OUTAGE STANDARD YEAR OVERLAY WELD ID EXAMlHID UT_RESULTS THICKNESS 02H-53 1988 AXIALS; NO FLAWS IN W0k' O.21" 1990 AXIALS; NO FLAWS IN WOR, 0.67" RL 02H-S4 1988 NO FLAWS IN WOR 0.21" 1990 NO FLAWS IN WOR See Note 4 02J-F6 1988 CIRC; NO FLAWS IN WOR, 0.44" RL 0.25" 1990 CIRC) NO FLAWS IN WOR, 0.45" RL 02J-S3 1988 AXIAL; NO FLAWS IN WOR, 0.32" RL 0.21" 1990 AXIAL; NO REPORTABLE INDICATIONS AFTER REPAIR OF BOAT SAMPLE EXCAVATION, 0.47" RL 02J-S4 1988 CIRC; NO FLAWS IN WOR, 0.47"RL 0.21" 1990 CIRC; NO FLAWS IN WOR, 0.35"RL 02K-S3 1986 AXIALS; HO FLAWS IN WOR, 0.40" RL 0.26" 1990 AXIALS NO FLAWS IN WOR, 0.38" RL 02K-S4 1986 AXIALS NO FLAWS IN WOR, 0.50" RL 0.25" 1 1990 AXIALS) NO FLAWS IN WOR, 0.34" RL 02K-F6 1988 AXIAL & CIRC) NO FLAWS IN WOR 0.25" 1990 AXIAL & CIRC; NO FLAWS IN WOR, 0.56" RL 02L-SS 1988 AXIAL; NO FLAWS IN WOR, 0.41" RL 0.22" 1990 AXIAL; NO FLAWS IN WOR, 0.42" RL 02L-S4 1988 /XIAL; NO FLAWS IN WOR 0.22" 1990 AXIAL; NO FLAWS IN WOR 02M-S3 1988 AXIALS & CIRC) NO FLAWS IN WOR, 0.45" RL 0.25" 1990 AXIALS & CIRC; NO FLAWS IN WOR, 0.40" RL 02M-S4 1988 CIRCS; NO FLAWS IN WOR 0.22" 1990 CIRCS; NO FLAWS IN WOR i 1

02M-F7 1988 CIRC; NO FLAWS IN WOR, 0.68" RL 0.25" 1990 CIRC; NO FLAWS IN WOR 3

.' TABLE 2 (Continued)

TLAW CHARACTERIZATION COMPARISONS STANDARD WELD OVERLAY (OL) REPAIRS QUAD CITIES UNIT 2 WINTER / SPRING 1990 RETUELING OUTAGE STANDARD YEAR OVERLAY WELD ID EXAMINED UT RESULTS TEICKNESS RECIRC 20" 10S-F1 1986 CIRC; NO TLAWS IN WOR 0.45" 1990 CIRC; NO FLAWS IN WOR 10S-F5 1988 CIRCSg NO TLAWS IN WOR 0.45" CIRCSI NO TLAWS IN WOR Notes

1. Two (2) circumferential indications (L = 0.25" with RL = 0.48" and L =

0.35" with RL = 0.43"). The average thickness of-weld overlay 02BS-S3 is 0.492 inch. The required minimum design thickness is 0.42 inch.

2. Eight (8) axial and two (2) circumferential flaws observed in UT examination. The remaining ligaments of all flaws exceed the weld overlay thickness. One (1) axial flaw in low delta ferrite first layer not included in design thickness.

3. Two (2) axial and one (1) circumferential flaws observed in UT examination. The remaining ligament of the two (2) axial flaws exceed the weld overlay thickness.

4. Overlayed to reduce stresses on the risers and the ring header. This is an unflawed weld.

HQDikap10338M/47 i