NL-10-0967, Pressurizer Nozzle Full Structural Weld Overlays, Nondestructive Examination Results -Spring 2010 Outage (2R20)

Pressurizer Nozzle Full Structural Weld Overlays, Nondestructive Examination Results -Spring 2010 Outage (2R20)

ML101390422
Person / Time
Site:	Farley
Issue date:	05/18/2010
From:	Ajluni M Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-10-0967
Download: ML101390422 (13)

Text

Southern Nucle,,;

Operating Company Inc May 18, 2010 SOUTHERN'\\

COMPANY F!]!*) (Ii' fl'....-(".l*( [(H/r \\f/J}ld Docket Nos.: 50-364 NL.:"10-0967 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Joseph M. Farley Nuclear Plant - Unit 2 Pressurizer Nozzle Full Structural Weld Overlays Nondestructive Examination Results - Spring 2010 Outage (2R20)

Ladies and Gentlemen:

Southern Nuclear Operating Company (SNC) completed the Performance Demonstration Initiative (POI) qualified ultrasonic examination (UT) of pressurizer nozzle full structural weld overlays on May 7,2010 during the 2R20 outage. The 2R20 examination scope consisted of the four pressurizer safety/relief nozzle to safe-end weld overlays and the pressurizer spray nozzle to safe-end weld overlay. The pressurizer surge nozzle to safe-end weld was previously overlayed and examined during the 2R18 (Spring 2007) outage.

The examination of the five overlays was accomplished in accordance with SNC's alternative ISI-GEN-ALT-07-01, Version 2, which was approved per NRC safety evaluation report (SER) dated March 10, 2008 (NRC Accession Number:

ML080580291). The SER states, liThe licensee will provide to the NRC, within 14 days after the completion of the ultrasonic examination of the weld overlay installations, (a) the examination results of the weld overlays, and (b) a discussion of any repairs to the overlay material and/or base metal and the reason for repair". The following is a summary of the examination results and a discussion of required repairs. See Enclosure 1 for additional details.

Liquid penetrant (PT) indications were recorded during the examination of the base metal and the final weld overlays. No PT indications were recorded during the examination of the sacrificial layers. All unacceptable PT indications were removed.

• During the POI ultrasonic examination of the 4502 nozzle overlay there were no recordable planar indications; however, there were eight laminar indications. Six of the eight indications were unacceptable and were removed by grinding and re-welded. Two acceptable laminar indications were left in place.

U. S. Nuclear Regulatory Commission Log: NL-10-0967 Page 2 During the POI ultrasonic examination of the 4503 nozzle overlay there were no recordable planar indications; however, there were six laminar indications. Five of the six indications were unacceptable and were removed by grinding and re-welded. One acceptable laminar indication was left in place.

During the POI ultrasonic examination of the 4501,4504, and 4205 nozzle overlays there were no recordable planar or laminar indications.

For the acceptable laminar indications left in the 4502 and 4503 nozzle overlays, the SER requires that:

"The licensee will provide to the NRC, within 90 calendar days of the completion of the refueling outage, the IWB-3640 evaluation performed for any assumed flaw in any uninspectable volume in the weld overlay beneath a laminar flaw, if that assumed flaw failed to meet the preservice acceptance criteria of Table IWB-3514-2."

Assumed (planar) flaws were postulated for Indications No.2 and NO.6 (see Figure 1 of Enclosure 1) in the 4502 nozzle overlay and for Indication No.1 (see Figure 2 of Enclosure 1) in the 4503 nozzle overlay. These postulated flaws did not meet the preservice acceptance criteria of Table IWB-3514-2; therefore, they were evaluated per IWB-3640 and determined to be acceptable. Enclosure 2 contains the IWB-3640 evaluations.

Additionally, the March 6, 2007 letter from SNC to the NRC (NL-07-0483) states, "SNC will report to the NRC, within 60 days of restart, details of examination results of any unmitigated weld examinations and any corrective or mitigative action taken. SNC will report bare metal visual examination results to the NRC within 60 days of restart".

With the completion of the five overlays during the 2R20 outage and the one overlay during the 2R18 outage, all six pressurizer nozzle Alloy 82/182 welds have been mitigated and no future 60-day reports will be made to the NRC. Bare metal examinations of the pressurizer nozzle to safe-end welds were not performed (and will not be performed in the future) because of the application of the weld overlays.

In summary, this letter completes the 14-day and gO-day reporting requirements of the SER and the 60-day reporting requirements of the March 6, 2007 letter for Joseph M. Farley Nuclear Plant - Unit 2.

U. S. Nuclear Regulatory Commission Log: NL-10-0967 Page 3 This letter contains no NRC commitments. If you have any questions, please contact Jack Stringfellow at (205)992-7037.

Sincerely,

'fYLJ-So:r-:

M. J. Ajluni Manager - Nuclear Licensing MJAIT AHfphr

Enclosures:

1.

Weld Overlay Examination Results and Repairs

2.

ASME Section XI, IWB-3640 Evaluations cc:

Southern Nuclear Operating Company Mr. J. T. Gasser, Executive Vice President Mr. J. R. Johnson, Vice President - Farley Ms. P. M. Marino, Vice President - Engineering RTYPE: CFA04.054 U. S. Nuclear Regulatory Commission Mr. L. A. Reyes, Regional Administrator Mr. R. E. Martin, NRR Project Manager Farley Mr. E. L. Crowe, Senior Resident Inspector - Farley Mr. P. Boyle, NRR Project Manager

Joseph M. Farley Nuclear Plant - Unit 2 Pressurizer Nozzle Full Structural Weld Overlays Weld Overlay Examination Results and Repairs

Weld Overlay Examination Results and Repairs Farley Unit 2 Weld Overlay Examination Results and Repairs Nozzle Base Metal PT Results/Repairs Sacrificial Layer PT Results Completed Overlay PT Results/Repairs POI UT Exam Results/Repairs Post-Repair Exams Masked Flaw Evaluations 4501 Safety IRel ief Surface conditioning was performed to remove indications found during the initial PT of the base metal. The followup PT had no recordable indications.

NRI One acceptable indication was detected during PT exams of the completed overlay and left in place.

NRI NA NA 4502 SafetylRelief Surface conditioning was performed to remove indications found during the initial PT of the base metal. The followup PT had no recordable indications.

NRI Five unacceptable indications were detected during PT exams of the completed overlay and were removed by surface conditioning. The followup PT had no recordable indications.

No recordable planar indications were detected by angle beam exams of the overlay and the required volume beneath the overlay. However, there were six unacceptable laminar indications (Indications 1,3,4, 5, 7, and 8) and two acceptable laminar indications (Indications 2 and 6) detected in the overlay by zero-degree exams. See Figure 1 for layout and sizes. The six unacceptable laminar indications were removed by controlled grinding. Because of the close proximity of indications, only three cavities were ground to remove the unacceptable indications. The three cavities were then re-welded.

PT exams were performed of the welded repair areas and there were no recordable indications. PDI UT exams were performed of the welded repair volumes and there were no recordable planar or laminar indications.

Per ISI-GEN-AL T-07-01 the largest planar flaws that could be masked by laminar indication 2 and by laminar indication 6 during ultrasonic angle-beam examinations is required to be postulated. A planar flaw for each lamination was postulated and then evaluated per the preservice acceptance criteria of Table IW8-3514-2. The postulated flaws did not meet the preservice acceptance criteria; therefore, each postulated flaw was subsequently evaluated per IW8-3640 and found to be acceptable. See Enclosure 2 for the IW8-3640 evaluations.

E1-1

Weld Overlay Examination Results and Repairs Nozzle 4503 Safety/Relief Base Metal PT Results/Repairs Surface conditioning was performed to remove indications found during the initial PT of the base metal. The followup PT had no recordable indications.

Sacrificial Layer PT Results NRI Farley Unit 2 Weld Overlay Examination Results and Repairs Completed Overlay POI UTExam Post-Repair PT Results/Repairs Exams Results/Repairs Five unacceptable indications were There were no recordable planar PT exams were detected during PT exams of the indications detected by angle beam performed of the completed overlay exams of the overlay and the required welded repair and were removed volume beneath the overlay. However, areas and there by surface there were five unacceptable laminar were no indications (Indications 2, 3, 4, 5, and recordable conditioning. The

6) and one acceptable laminar indications. POI followup PT had indication (Indication 1) detected in the UT exams were no recordable ind ications.

overlay by zero-degree exams. The performed of the unacceptable laminar indications were welded repair Two acceptable removed by controlled grinding. See volumes and indications were Figure 2 for layout and sizes. Because there were no also detected of the close proximity of indications, recordable during PT exams only two cavities were ground to planar or remove the unacceptable indications.

laminar of the completed The two cavities were then re-welded.

indications.

overlay and left in place.

Masked Flaw Evaluations Per ISI-GEN-AL T-07-01 the largest planar flaw that could be masked by laminar indication 1 during ultrasonic angle-beam examinations is required to be postulated. A planar flaw for the indication was postulated and then evaluated per the preservice acceptance criteria of Table IWB-3514-2. The postulated flaw did not meet the preservice acceptance criteria; therefore, the postulated flaw was subsequently evaluated per IWB-3640 and found to be acceptable. See Enclosure 2 for the IWB-3640 evaluation.

I 4504 Safety/Relief Surface conditioning was performed to remove indications found during the initial PT of the base metal. The followup PT had no recordable indications.

NRI NRI NRI NA NA E1-2

Weld Overlay Examination Results and Repairs Farley Unit 2 Weld Overlay Examination Results and Repairs Nozzle Base Metal PT ResultslRepairs Sacrificial LayerPT Results Completed Overlay PT Results/Repairs POI UT Exam ResultslRepairs Post-Repair Exams Masked Flaw Evaluations Surface conditioning was performed to remove indications 4205 Spray found during the initial PT of the NRI NRI NRI NA NA base metal. The followup PT had no recordable indications.

NRI - No Recordable Indications E1-3

Weld Overlay Examination Results and Repairs 1"

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Joseph M. Farley Nuclear Plant - Unit 2 Pressurizer Nozzle Full Structural Weld Overlays ASME Section XI, IW8-3640 Evaluation

Westinghouse Electric Company

.)Westinghouse Nuclear Services P.O. Box 355 Pittsburgh, Pennsylvania 15230-0355 USA May 13, 2010 ALA-l 0-77 Mr. J. R. Johnson Vice President Farley Project Southern Nuclear Operating Company Farley Nuclear Plant P. O. Box 470 Ashford, AL 36312 SOUTHERN NUCLEAR OPERATING COMPANY JOSEPH M. FARLEY NUCLEAR PLANT UNIT 2 Transmittal ofSWOL Masked Flaw Evaluation (Post WOL Repair)

Dear Mr. Johnson:

Attached is LTR-PAFM-I0-91-NP summarizing the results ofthe masked axial flaw evaluation performed in accordance with the evaluation procedure and acceptance criteria.

Should you have any questions, please feel free to contact Chris Ng at 412-374-4521 or me at (412)374-3093.

Very truly yours, John M. Robinson, Manager Southern Nuclear Projects

/jag This document is the property of and contains Proprietary Information owned by Westinghouse Electric Company LLC and/or its subcontractors and suppliers. II is transmitted 10 you in confidence and trust, and you agree to treat this documenl in strict accordance with the terms and conditions of the agreement under which it was provided to you.

Electronically Approved Records arc Authenticated in

©2010 Westinghouse Electric Company LLC The Electronic Document Management System All Rights Reserved

Westinghouse Non-Proprietary Class 3 8)Westinghouse To: Robert Vestovich Date: May 10,2010 cc:

From: Chris Ng Your ref:

Ext: 412-374-4521 Our ref:

LTR-PAFM-IO-91-NP Fax:

Subject:

Farley Unit 2 SWOL Masked Flaw Evaluation (Post WOL Repair)

References:

1. ASME Boiler and Pressure Vessel Code,Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components." 2001 Edition including 2003 Addenda.

2. WesDyne Evaluation Number APR-2R20-4503-021, Final Report dated May 8, 20lO.

3. WesDyne Evaluation Number APR-2R20-4502-024, Final Report dated May 8, 2010.

4. Westinghouse Letter LTR-PAFM-lO-79, "Farley Unit 2 SWOL Masked Flaw Evaluation,"

dated April 28, 20 I O.

Table I summarizes the results of the masked axial flaw evaluation performed in accordance with the evaluation procedure and acceptance criteria in paragraph IWB-3640 of Reference I.

The evaluation was performed based on the masked flaw parameters provided in the WesDyne reports of References 2 and 3 resulting from the laminar indications detected in the structural weld overlay of the pressurizer safety nozzles at Farley Unit 2. The masked flaw parameters were obtained after the completion of repairs made to the weld overlay at pressurizer safety nozzles 4502 and 4503. The results of the evaluation provided in this letter supersede those in Reference 4.

Based on the results from Table 1, all the masked axial flaws can be shown to be acceptable in accordance with the acceptance criteria in paragraph IWB-3640 of Reference 1.

Author"': C. K. Ng, Piping Analysis and Fracture Mechanics Verifier"': A. Udyawar, Piping Analysis and Fracture Mechanics

"'Electronically Approved Records Are Authenticated in the Electronic Document Management System

Page 2 of2 Our ref: LTR-PAFM-IO-91-NP May 10,2010 Table 1 ASME Section XI IWB-3640 Masked Flaw Evaluation Results Pressurizer Nozzle Safety 4503=

Safety 4502 Safety 4502 Indication No.

1 (Reference 2) 2 (Reference 3) 6 (Reference 3)

Flaw Orientation Axial Axial Axial Distance From Nozzle Outer Diameter S (in) 0.260 0.290 0.560 As-found Full Flaw Depth 2a (in) 0.280 0.260 0.230 As-found Half Flaw Depth a (in) 0.140 0.130 0.115 As-found Flaw Length I (in) 0.200 0.250 0.500 Weld Overlay Thickness tswol (in) 0.680 0.770 0.870 Outside Diameter Do (in) 8.000 8.000[1]

8.000 Mean Radius Rm (in) 4.340

,+.385 4.435 Pressure P (ksi) 2.50 2.50 2.50 Safety Factor (Paragraph C-2622)

SFm 2.70 2.70 2.70 Hoop Stress (Table C-54 10-1 )

(Jh (ksi) 15.956 14.237 12.744 Yield Strength Sy(ksi) 27.50 27.50 27.50 Ultimate Strength

~u (ksi) 80.00 80.00==t= 80.00 Flow Stress (Jf (ksi) 53.75 53.75 53.75 Stress Ratio (Table C-541O~1) 0.802 0.715 0.640 Nondimensional Flaw Length (Table C-5410-1) 0.116 0.136 0.255 As-Found Flaw Depth to Wall Thickness Ratio 2aJt 0.41 0.34 0.26 Allowable End-of-Evaluation Period Flaw Depth to Wall Thickness Ratio (Table C-541O-1) 0.75 0.75 0.75 As-Found End-of-Evaluation Period Flaw Length[2j If (in) 0.20 0.25 0.50 Maximum End-of-Evaluation Period Flaw Length lallowahle (Table C-541 0-1)

(in) 8.73 10.57 12.72 Flaw Acceptability Per Section XI Paragraph Acceptable Acceptable Acceptable IWB-3640 I

I I

i Note:

1.

2.

Conservatively used 8.0 inch as the outer diameter in the evaluation resulting in higher stress ratio and lower allowable flaw length As found end-of-evaluation period flaw length is the same as the as-found flaw length since fatigue crack growth of the postulated masked axial flaw is negligible for the remaining plant operation duration.