ML20212H145

Rev 1 to Welding Project:Improper Weld Repair

ML20212H145
Person / Time
Site:	Sequoyah
Issue date:	01/13/1987
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20212G828	List: ML20212G824 ML20212G859 ML20212G962 ML20212G991 ML20212H051 ML20212H072 ML20212H095 ML20212H103 ML20212H128 ML20212H145
References
WP-25-SQN, WP-25-SQN-R01, WP-25-SQN-R1, NUDOCS 8701210290
Download: ML20212H145 (7)

Text

- _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _

TVA EMPLOYEE CONCERNS REPORT NUMBER: WP-25-SQN SPECIAL PROGRAM REPORT TYPE: Welding Project REVISION NUMBER: 1 TITLE: Improper Weld Repair REASON FOR REVISION: MADE THE FOLLOWING EDITORAL CHANGES:

Added revision note on cover sheet, numbered pages, and corrected operations report number for SRP consaants SWEC

SUMMARY

STATEMENT: N/A PREPARATION PREPARED BY:

Original signed by G. L. Pitz1 12-16-86 SIGNATURE DATE REVIEWS PEER:

Original signed by J. E. Rose 12-16-86 SIGNATURE DATE TAS: TECHNICAL REVIEW ONLY a *U- / '

l* U~hW__

DATE

/' M SIGNATURE CONCURRENCES Original signed by CEG-H: J. F. Lewis 12-29-86 n SRP: \) w N. (d. and/ l= l3 -87 n@$ SIGNATURE DATE f SIGNATURE

• DATE 08' oo APPROVED BY:

/

/-/3[7 N/A DATE Ob ECSP MA)(AGER DATE MANAGER OF NUCLEAR POWER CONCURRENCE (FINAL REPORT ONLY) s'

- *SRP Secretary's signature denotes SRP concurrences are in files, b$m a.n.

2242T l

t.

WELDING PROJECT EMPLOYEE CONCERN EVALUATION REPORT REPORT NUMBER: WP-25-SON, R1 DATE: 12-04-86

SUBJECT:

EFFECT OF WELD REPAIRS NOT MEETING ASME CODES CONCERN (S) CONSIDERED: 2850162005 PREPARED BT A A' AsuzM t . b. T2t /2//<f[ OC, WP o' /

REVIEWED BY \ iG.. . 17.,[fu / & Q , OC , WP REVIEWED BY '

4eal=4 / f[/ 'T!85

, QA, WP O C REVIEWED BY $ rims id Y , .>>M

> 17

• 1 9

• f (s , CEG-R, WELDING

, PROGRAM MANAGER APPROVED BY Revision 1, Reviend Report Format 2830T l 07870 l

r.

EMPLOYEE CONCERN

SUMMARY

SHEET Report Number: WP-25-SQN uR 1, Report

Title:

EFFECT OF WELD REPAIRS NOT MEETING ASME CODES I. CONCERN CONSIDERED: 2850162005 II. ISSUES INVOLVED.

1. Repairs by welding using overlays and patches. (The portion of this concern addressing repairs using furmanite has been addressed by Operations Report Number 308.03-SQN).

III. STATEMENT ON CONCERN / ISSUE VALIDITY Validity: Y X ,N , Substantiated: Y ,N X IV. EFFECT ON HARDWARE AND/OR PROGRAM Nons V. JUSTIFICATION:

Wold overlay repairs at Browns Ferry and patch repairs at Sequoyah were performed in accordance with TVA's ASME Section XI Repair and Replacement Program using detail weld procedures and welders qualified in accordance with 6SME Section IX.

VI. RECOMMENDATION AND/OR CORRECTIVE ACTION NEEDED None VII. REINSPECTION NEEDED: Y ,N X VIII. ISSUE CLOSURE Closure is based on this report.

IX. ATTACHMENTS

1. Text of Employee Concern - 2850162005 2830T Page 1 of 1

, o EMPLOYEE CONCERN Report Number: WP-25-SQN, R1 Report

Title:

EFFECT OF WELD REPAIRS _NOT MEETING ASME CODES I. SCOPE OF EVALUATION This engineering ovaluation relatos to the potentially generic employee concern 2850162005, which states the following:

"TVA makes repairs to their nuclear plants which are not in accordance with ASME Codos, such as overlays, patchos, and even furmanito (sophisticated glue)."

II. ISSUES ADDRESSED BY CONCERN The concern regarding temporary repairs is a shared concern with the Operations Employee Concerns Task Group. This report only addresses repairs by welding using overlays and patches. The portion of this concern addressing repairs using furmanite has been addressed by Operations Report Number 308.03-SQN.

III. CONCERN VALIDITY OR SUBSTANTIATION A. Weld Overlays Wold overlay repairs to Intorgranular Stress Corrosion Cracking (IGSCC) flaws in Boiling Water Reactor stainless steel piping were first applied on Quad Cities unit 2 Reactor Water Cleanup piping in oarly 1982. Since that timo, over 300 of these repairs have boon applied worldwide. This includes 42 overlays on Drowns Ferry unit 1 primary piping, one overlay on Drouns Ferry unit 2 primary piping, and two overlays on Browns Ferry unit 3 jot pump instrument nozzlo safo ends. The overlays on tho Browns Ferry units are designed to provide safety margins required by the ASME Codo using Subarticle IWD-3640 of the ASME Section XI Codo as a guido. Tho wolding  ;

aquipment, personnel, and detail weld procedures utilized for these overlays wore qualified in accordance with ASME Section IX Codo requirements and additional requirements recommended by the '

industry. The overlays were applied in accordance with the Section XI Repair and Replacement Program which includos ANI and ANII hold points and final sign off in compliance Section XI Articlo IWA-4000, Repair Procedures. The use of overlays is widely accepted by the industry and N7C. The published documents which contain the NRC position for overlay repairs to IGSCC degraded piping in operating plants include NRC Genoric Lottor 84-11 and NUREG-1061 (Volumes 1 and 3). In addition, publication of Revision 2 of NUREG-0313 is currently ponding and its technical provisions havo boon prosonted to the ACRS. This document will consolidate the regulatory position reprosantad by the previous documents and updato it to includo recent regulatory actions and ruscarch results. 1ho results of the ovorlay repair proceduros for Browns Forry unit I woro reported to i

pago 1 of 3 4

f.

i*,

• Wp-25-SQN, R1 NRC in late 1983. The NRC then issued a Confirmatory Order and Safety Evaluation (Docket No. 50-259) which granted approval for unit 1 to be returned to power and operated in its repaired configuration. The results of the overlay repair procedures for Browns Ferry units 2 and 3 were also reported to NRC. The NRC has not yet granted approval for unit 2 to be returned to power; however, the NRC did issue a Safety Evaluation report (Docket No.

50-296) which granted approval for unit 3 to be returned to power and operated in its repaired configuration.

In summary, this portion of the employee concern is valid but not substantiated for the following reasons.

1. Overlays are designed to provide safety margins required by the ASME Code using Subarticle IWB-3640 of ASME Section XI pa a guide.

2. Personnel and procedures are qualified in accordance with ASME Section IX and additional requirements rocommandod by the industry.

3. All weld overlays are applied in accordance with the TVA Section XI Repair and Replacement Program.

4. Weld overlays are widely used and accepted by the industry and NRC.

5. The NRC has issued two Safety Evaluation Reports (Docket Numbers 50-259 and 50-296) which granted approval for Browns Ferry units 1 and 3 to be returned to power and operated in their repaired configurations.

B. Patches ,

TVA has utilized reinforcement patches as temporary repairs to ASME Code Class 3 and ANSI 031.1 raw water piping systems whore pipe wall thinning below acceptable thicknossos due to corrosion and/or cavitation has occurred. Piping subject to wall thinning is monitored ultrasonically on a continuing basis by plant Survoillance Instructions. Wall thickness values that are below minimum wall thickness established by Division of Nuclear Engincoring (DNE) are ropaired on a temporary basis by the installation of a rainforcement patch.

For SQN, acceptable wal.1 thickness values for the various piping diameters of the ERCW system have been generically addressed by DNE calculation N2-67, Essential Raw Cooling Water Corroded Piping Qualification. Patchos were installed using woldors and dotail wold proceduros qualified in accordanco with ASME Section IX and documented in accordance with the ASME Soction XI Ropair and Replacement Program for SQN. DNE performed an Unroviewod Safety Question Determination (USQD) on the structural intogrity of the reinforcement patch installations and their offect on the ERCW system. DNE concludod that the addition of temporary patchos does Pago 2 of 3

m t

z. ,

e ,

s. .

WP-25-SQN, R1 not significantly affect the ERCW piping analysis and provides adequate structural integrity based on the following:

1. The patch does not significantly change the piping cross-sectional stiffness or weight.

2. The patches are of the same thickness as the original pipe wall thickness.

3, The installation welds are sized such that the process pipe will not fail during any plant condition.

In summary, this portion of the employee concern is valid but not substantiated for the following reasons:

1. Reinforcement patches are designed with adequate safety margins such-that the piping will not fail during any plant condition.

2. The impact of the patch installations has been reconciled with the ERCW piping analysis.

3. The patches are installed using welders and detail weld procedures qualified in accordance with ASME Section IX, and documented in accordance with TVA's ASME Section XI Repair and  ;

Replacement Program.

IV. . CONCLUSIONS To date, TVA has performed weld overlay repairs at Browns Ferry and reinforcement patch repairs to raw water piping at Soquoyah. In all cases, design verification of the repairs was well documented and structural integrity of the affected systems demonstrated. The repairs were performed in accordance.with TVA's ASMC Soction XI Repair and Replacement Program using detail weld procodures and woldors qualified in accordance with ASME Section IX. Therefore, no corrective action is

, roquired and the subject concern is closed, i

i 4

i Pago 3 of 3

{

l

T Ue Attachment 1

,. .. . .. . ..~.-- -

~-

.a . : -\ .

.. . . .. . - . , .T 5 ..cb .

+& -.a.=.,w~: T. , :.mi.m.#MW$?4?h-7.QYk.Y=4%.w:ro.hu. . : . .-crty.5 cM%t.%EMM4%'.w.W.*?4:?h*W. . ...+ t~=..m .& tk & M :...q.

. . .i'*.5

- .= -

I I

REFERENCE - ECPS120J-ECPS121C TENNESSEE VALLEY AUTHORITY ' PAGE -

FREQUEf!CY - REQUEST OFFICE OF NUCLEAR P0HER RUN TIME - I6:

CNP - ISSS - RUM EMPLOYEE C0riCERN PROGRAM SYSTEM (ECPS) RUN DATE - 11/

LIST OF EMPLOYEE CONCERN INFORMATION CATEGCRY: HE NON CA/QC HELDING SUBCATEGORY: 50805 IMPROPER HELD REPAIR S GENERIC  :. KEYWORD A H APPL QTC/NSRS P KEYHORD B CONCERN SUB R PLT B B.S W INVESTIGATION S CONCERN KEYHORD C g NUMBER CAT CAT D LOC FLQB REPORT R DESCRIPTION KEYHORD D XX 1c0-001 HE 50805 N SQN NNNN SR SEQUDYAH: AN UNDETERMINED NUMBER OF HELDING .

T50153 K-FORM HELDS MAY HAVE BEEN IMPROPERLY REPAI REHORK

'l RED. DETAILS KNGHN TO QTC, HITHHELD OPERATIONS

$ .

• DUE TO CONFIDENTIALITY. CONSTR. DE HELDS PT. CONCERN. CI HAS NO FURTHER INFO RMATION. NO FOLLOHUP REQUIRED.

30303 S NPS YYYY SS TVA MAKES REPAIRS TO THEIR NUCLEAR P k 2350162005 OP HE 50505 REPORT LANTS HHICH ARE NOT IN ACCORDANCE HI TH ASME CODES, SUCH AS OVERLAYS, PAT

~

CHES, AND EVEN FURMATITE (SOPHISTICA '

TED GLUE).

2 CONCERNS FOR CATEGORY HE SUBCATEGORY 50805

. .: .