ML20151Y996
| ML20151Y996 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry, Sequoyah, 05000000 |
| Issue date: | 02/07/1986 |
| From: | TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML082340155 | List: |
| References | |
| PROC-860207-02, NUDOCS 8602130241 | |
| Download: ML20151Y996 (54) | |
Text
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YOLUME 3 TVA WELDING PROJECT SEQUOYAH PHASE II REVIEW AND PROGRAMS RESULTS TABLE OF CONTENTS 1.
INTRODUCTION LATER 2.
APTECH ENGINEERING REPORT I
3.
BECHTEL AUDIT REPORT LATER y
4.
SEQUOYAH WELDING REINSPECTION REPORT LATER 5.
SEQUOYAH PROGRAM RESULTS REPORT LATER L
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SUMMARY
OF APTECH REVIEW OF SEQUOYAH WELDS w/
TVA and its contractor APTECH Engineering Services has performed a review of welding and subsequent preservice and inservice inspection activities at Sequoyah Nuclear Plant for the purpose of determining the suitability for continuing service of welds currently installed at Sequoyah. The basis for this determination is derived from historical records and activities related to the production of quality welds (via an appropriate welding and inspection program) and historical perfcrmance of welds during the operating phase of the plant. This review is an adjunct to other TVA activities focused on weld quality determination, weld reinspection, and welding program assessment, problem identification and resolution. The criteria used for determination of suitability for service in this review are:
1.
Did the welding and weld-related quality assurance programs contain the control features that are necessary and appropriate for the production of quality welds?
2.
To what extent have Sequoyah Section XI welds been inservice and preservice examined?
3 What are the results of the prservice and inservice examinations that indicate weld quality (i.e., indication rate)?
(
4.
To what extent has operation of the plant indicated weld quality N--
(Licensee Event Reports relating to weld quality)?
5.
Are the quality indicators or indication rates determined above (3 and
- 4) acceptable for continued operation and commensurate with accepted industry standards?
This review has been completed and is attached. The results of this review are positive and indicate suitability for service of Sequoyah welds.
With respect to the above criteria the APTECH review indicates the following:
1.
The Sequoyah welding and weld related quality assurance program did contain the necessary and appropriate control features for production of quality welds.
2.
42.1 percent of Sequoyah ASME Section XI field welds have been examined; 88.4 percent of integrally welded attachments have been examined; 100 percent of Class 1, 2, and 3 hangers have been examined.
3 Indication rates calculated are:
0.95 percent, piping 4.79 percent, integrally welded attachments 0.31 percent, hangers O
-- As) 14.
No Licensee Event Reports relating to weld quality have been reported.
5.
The above meets or exceeds accepted industry standards.
To support the applicability of this review and for additional information TVA is providing here a discussion of the applicability of preservice and inservice inspection to weld quality determination, and additional detail on all notification of indication documents referenced in the APTECH report including dispositions and supplementary comments. These notification of indication documents are attached at the end of this summary.
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Applicability of Inservice Inspection Results to Weld Quality Determination There are essential differences between the purposes, techniques and criteria for inservice inspections and welding inspection at the time of construction.. These differences modify and limit the applicability of the inservice results as weld quality indicators. In the case of ASME pressure retaining welds where volometric techniques are employed for post fabrication inspection and subsequent inservice inspection, the ability of inservice to determine' weld quality is excellent, especially in the case of radiography and subsequent ultrasonic inspection where the two techniques compliment each other. On ASME welds and integral attachments where only surface examinations are required the techniques and methods are the same for PSI /ISI although the acceptance criteria are different. Both address signifient flaws.
The largest differences in purpose, technique and criteria exist in the case of structural support welds and as such imposes some limits _on the applicability of inservice inspection results as weld quality indicators for the construction phase. However, from the review of the attached notification of indication documents generated t'y preservice and inservice inspection of units 1 and 2, it is apparent that this process does, in fact, identify conditions that are quality indicators of welds as originally installed. The reasons the NOI system identifies defects that are not service induced are:
1.
Inspectors are responsible to report conditions adverse to quality even when performing inspection for other expressed purposes.
2.
Many inspectors have certification in visual inservice end welding inspection.
3.
As a practical matter it is difficult or impossible to create inservice inspection criteria which will only identify defects which are service induced.
Since an extensive number of Notification of Indication reports have been examined in conjunction with the APTECH study it is possible to derive other information concerning weld quality which was not in the scope of the APTECH study. There have been several supports which deformed under operating transient conditions which did not result in failure of the welds. In these cases base materials were obviously loaded in excess of yield, sometimes to the point of releasing anchors without causing failures of related welds. Although these are indirect indicators of weld quality they provide some assurance in a practical sense of the adequacy of hanger welding at Sequoyah.
Therefore, in context of all quality indicators examined in the APTECH study and in spite of a possible lack of conservatism of the indication rate for structural welds, the fundamental conclusions are sound.
O
-2 It is TVA's position that since:
(a)Section XI and safety-related pipe welds were originally welded and inspected to the same program; (b)Section XI structurally significant and safety-related structural welds were welded to the same program; (c) a large number of pipe welds have been PSI and ISI examined; and (d) essentially all structural welds in the ISI program have been inspected, then the PSI and ISI results are effective quality indicators of Sequoyah welds, and if systematic, widespread and/or chronic deficiencies existed in Sequoyah welds / welding, this would produce unfavorable PSI /ISI results.
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O NOI DESCRIPTIONS - SEQUOYAH NUCLEAR PLANT UNIT 1 Page 1_ of 7
-Systems.
Report Disposition and NOT Number (Weld Number)
Type Weld Size Number Discrepancy Additional Comments R0082 FDF-4 Field 18" R3082 Linear Indication Removed by grinding.
1/2" Long Minimum wall thickness verified Reexamined. MR# A-038177 R0081 RHRS-2 Shop
'18" R0081 2 Arc Strikes Removed by grinding.
R0039 Reexamined to verify removal.
MR# A-036818 Reinspection report R-166 RO124
-SIF-127 Field 10" RO124 Unacceptable Surface Removed by grinding.
R0221 Condition for PT Examination Reexamined to verify removal.
MRf A-036818 Reinspection Report R-221 R0125 SIF-148 Field 10" R0125 1 Arc Strike Removed by grinding.
l R0220 Reexaminted to verify removal, MRf A-036818 i
Reinspection Report R-220 3
l R0192 SIS-337 Shop 2.5" R0192 Unacceptable Surface Removed by grinding.
R0225 Condition for Examination Reexamined to verify removal.
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MR# A-036818 j
Reinspection Report R-225 j
R0193 SIS-333 Shop 2.5" R1064 Unacceptable Surface Removed by grinding.
R0226 Condition for Examination Reexamined to verify removal.
6 MRd A-036818 I
Rainspection Report R-226 l
R0219 UPIF-19 Field 12" R0219 Linear Indication, 5/8 Lorg Removed by grinding.
j RS20 Reexamined to verify removal 2
and minimum wall thickness.
MR# A-037009 Reports R-425 and B-520 R3232 SIH-453 Hanger CIA) 8" R0232 Linear Indication, 5/32" Long Removed by grinding.
I R0334 (Appears to be are strike)
Reexamined to varify removal and minimum wall thickness.
Report R-334 MR# A-037002
Pago 2 cf 7 Systems Report Disposition and j
NOI Number (Weld Number)~
Type Weld Size Number Discrepancy Additional Comments S00178 RHRF-109A Field R2540 Linear Indication, 1/4" Long Removed by grinding.
Reexamined to verify removal and minimum wall thickness.
Report R-3095 MRf A-520395 SQO201 FDH-203 Hanger R2714 Weld Missing per Disposition open as of 1-15-86.
as constructed drawing Instructions to weld pipe to 1-H4-203 support per OT-11-01A, clean weld area per SQM-17, paint and reexamine. MRf A-520902 SIH-17 Hanger MR550488 Weld Missing per Left as is.
Disposition per as constructed drawing FCR 3987: revise dwgs 1-SIN-17, 1-SIH-17 and 1-SIH-462 to reflect as built configuration.
S00213 SIH-21 Hanger (IA) ---
R2813 Two 3/4" Long Linear Linear indication due to weld Indications irregularities. Not service induced. Disposition by USQD.
MRf A-548376 1
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SQO212 SIH-20 Hanger (IA) ---
R2812 Two 3/4" Long Linear Linear indication due to weld Indications irregularities. Not service
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induced. Disposition by USQD.
MRd A-548376 I
SQ0154 MSH-289 Hanger (IA) ---
R2374 Linear Indication, S/16"Long Disposition open as of 1-15-86.
Instruction to remove i
d indication per MRd A-543180
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i SQO179 RHRH-460 Hanger R2541 Crack-Like Indications on Removed by grinding.
Tack Welds Reinspected to verify removal.
4 Reinspection Report R-2773 l
MRf A-550460. Are currently
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inspecting all similar configurations. One indication.
found on unit 2.
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Systems Report Dicp:clition and' NOI Number (Weld Number)
Type Weld Size Number Discrepancy Additional Comments R235 Stm. Gen.
Shop R235 3/4" Linear Indication Removed by grinding.
Reinspected to verify removal and minimum wall thicknees.
Reinspection Reports R-496 and R-519 MR# A-038179 and A-037007 R279 RCF-31 Field R279 Arc Strike Removed by grinding.
Reinspected to verify removal.
Reinspection Report R-499 MR# A-036818 R00A SIS-274 Shop R00A Arc Strike Removed by grinding.
Reexamined to verify removal.
Reinspection Report R-426.
R404 RCH-231 Hanger R404 Arc Strike Removed by grinding.
Reexamined to verify removal.
Reinspection Report R-428 MR# A-036818 R506 CVCH-291 Hanger R506 Arc Strike Removed by grinding.
Reexamined to verify removal.
Reinspection Report R-713 MR# A-036818 R844 RCH-29 Hanger R844 Cracked Weld-2" linear Weld repaired to comply with indication in weld design specification. Welded connecting I beam to per procedure SM-P-1.
steel plate on wall-MR# A-037876 confirmed as crack by Reexamined to verify repair.
liquid penetrant eram.
Reinspection Report R-1146.
Could not be determined whether constniction defect or serviced induced.
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~ Pagg-77 Systems Rrport Digpsoition and
_NOI Number (Weld Number)
Type Weld Size Number Discrepancy Additional Comments R846 Lack of Fusion Weld repaired to comply with R846 CVCH-44
. Hanger design specification. Welded per procedure SM-P-1.
MRf A-037021.
Reexamined to verify repair.
Reinspection Report R-1145 FD = Feedwater System UHI = Upper Head Injection System RHR = Residual Heat Removal System MR = Maintenance Request SI = Safety Injection System CVC = Chemical and Volume Control MS = Main Steam System RC = Reactor Coolant
NOI DESCRIPTIONS - SEQU NUCLEAR PLANT UNIT 2 Pa LT 7 Disposition and NOI Number Syste=3 Type Weld Size Report Number Discrepancy Additional Comments SQ0007 CVC-1045 Socket 2.0" R0077 Linear Indication x 3/16" Reducted to acceptable P0527 Long, 14 Rounded indication size by grinding. Rein-2 in a 6 in Area spection to verify acceptability.
Reinspection Report R-0527 MRf A-112052 SQ0008 CVC-1253 Socket 2.0" R0078 Linear Indication 1" Long Removed by grinding per R0528 MRf A-112053 Reexamined to verify removal.
Reinspection Report R-0528 SQ0025 SIH-219 Hanger Rigid 1.5" R0308 Separated Weld Weld repaired per detail Support R1177 Previously described weld procedure SM-P-1.
as " missing" during Reexamination to verify meeting with NRC repair. Reinspection on 1-7-86.
Report R-1177 MRP A-112057 SQO126 AFDH-308 Hanger Rigid 6"
R1293 Arc Strikes, Undercut Repaired by grinding and Support R1855 and Porosity rewelding per MRf A-244588 and detail weld procedure SM-P-1.
Reinspected to verify repair. Reinspection Report R-1855 SQO103 ERCWH-84 Hanager Rigid 30" R1334 Weld deposit on Removed per MR# A-295568 Support R1833 supporting non-welded Reinspection to verify area.
removal. Reinspection Report R-1833 CVC = Chemical and Volume Control System SI
= Safety Injection System IFD = Auxiliary Feedwater System ERDd = Essential Raw Cooling Water System t
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O Page 6 of 7 SEQUOYAH NUCLEAR PLANT UNIT 1 NOI'S PRESERVICE INSPECTIONS Disposition and/or Report Number System Type Weld Discrepancy Additional Comments R153/153A RHRS-119 Shop Linear Indication 0.5" in Length Reinspection Reports R-1294 and R-1395 find weld acceptable.
MR not located.
R885 RCW-25(SE)
Shop Linear Indication 0.5" Long Removed by grinding.
Reinspected to verify removal.
R1094 TE-68-83 Field Unacceptable Tack Welds Removed by grinding.
Reinspected to verify removal.
Reinspection Report R-1094A
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u Paga 7 of 7 SEQUOYAH NUCLEAR PLANT UNIT 2 NOI'S PRESERVICE INSPECTIONS Disposition and/or Report Number System Type Weld Discrepancy Additional Comments R-540 RHR-15 Shop Linear Indication in Fusion Weld removed and replaced with Walls of Long Seam E11 welds RHRF-19B & RHRF-19X.
Inspection of new welds. to establish baseline. Reports R-2259, R-2257, R-2258, R-2256.
R-743 RHRS-60 Shop Incomplete Penetration in "T"
Tee removed and replaced.
Longitudinal Weld New weld RHRF-388 reinspected to establish baseline. Reports R-2179 and R-2189 R-1666 RHR-105LS Shop Linear Indication in "T,"
Tee replaced. New welds RHRF-61A, 2-1/2" Long RHRF-61X, and RHRF-61B inspected to establish baseline. Reports R-2181, R-2190, R-2180, R-2192, R-2178, and R-2191.
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l AES 8511598AQ-1 Y
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I EVALUATION OF QUALITY OF WELDS AT
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SEQUOYAH NUCLEAR PLANT I
Prepared by L
Jeffrey L. Grover Erwin L. Capener L
Aptech Engineering Services Inc.
795 San Antonio Road Palo Alto, California 94303 Prepared for Tennessee Valley Authority Chattanooga Office Complex Chattanooga, Tennessee 37401 d
January 1986
/
795 SAN ANTONIO ROAO O PALO ALTO C CALIFORNIA 94303 O (4is)858-2863 L
VERIFICATION RECORD SHEET REPORT NO.:
8511598A0-1 I.
TITLE.
Evaluation of Quality of Welds at Sequoyah Nuclear Plant DATE:
January 6, 1986 l
/d4 lv Originated By:
gpject Engineer
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Approved By:
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Verified By:
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L EE APTECH ENGINEERING SERVICES
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ABSTRACT I
Aptech Engineering Services has perf ormed a review of the welding progran at Sequoyah Nuclear Plant, Units 1 and 2 in order to verify that the quality of welds at the plant is suf ficient for their intended use.
This review consisted of three parts: a review of the welding and quellty assurance program to determine whether the necessary controls were in place to ensure quality weles, a revlew of preservice and inservice inspection results to determine the rate of indications in welds, and a review of the operational I.
history to determine the f ail ure rate due to initial weld quality. Based on this review, there is no evidence that the quality of welds at Sequoyah is less than required for its intended service.
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CONTENTS
-v Section Pace ABSTRACT 1
INTRODUCTION 1-1 2
REVIEW 0F WELDING AND QUALITY ASSURANCE PROGRAM 2-1 3
REVIEW 0F PRESERVICE AND INSERVICE INSPECTION RESULTS Preservice Inspection Results 3-1 Inservice Inspection Results, -
3-1 Indication Rates 3-7 3-12 f
4 REVIEW 0F OPERATIONAL EXPERIENCE 4-1 5
SUMMARY
AND CONCLUSIONS
'5-1 i
REFERENCES z.
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APPENDIX A A-1 APPENDIX B
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Section 1 INTRODUCTION I
As a result of employee concerns regarding the quellty of the welding progem at Tennessee Valley Authority's (TVA) Watts Bar Nuclear Plant, the quality of welds made at the Sequoyah Nuclear Plant (SNP) also came into questlen.
The Sequoyah Plant is an operating plant which is currently of fline for environmental qualification testing.
TVA management decided to take this I
opportunity to evaluate the welding program at Sequoyah and to reat firm the quality of the welds. Aptech Encineering Serv ices, Inc. (APTECH) was asked by TVA to review the quality of welds at the SNP Units 1 and 2 to ensure that structurally significant and saf ety related welds are adequate for their intended serv ice.
AFTECH developed a progre plan to evaluate the quality of welds based upon a three-pronged approach. That approach is illustrated in Figure 1-1 and is described below.
The first aspect of this evaluation is a review of the overall welding and quality assurance (QA) progra at Sequoyah.
This includes a review of welding, construction, and Inspection procedures, control of materials and weld consumables, and quellfication of welders and inspectors.
A properly designed and Implemented welding /QA progrm acts as a series of checks and balances that ensure that high quality welds are being produced.
The proof of the quellty of the welds lies in the welds themselves, not in the quellty of paperwork that accompanies the welds.
In order to independently evaluate the quality of the welds, two parallel paths were pursued.
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The first apprcach toward determining the quality of the welds was to evaluate the preserv ice and inservice inspection (PSI and ISI) results.
If the initial quellty of the welds were pocr, it would be anticipated that the inspection results would Indicate an abnormally high rate of detection of weld g
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y Evaluate
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Review ISI and)
Evaluate Q
As ur-PSI Program Sucessful ante Prooram and Results Operating l
Experience u
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Quality Indication 1r-Es ta bl ished Rate and Weld Related Confidence Incidents Level Set 1
Quality Established 7-s and Service Suitability l
Reaffirmed (Indication Rate and Confidence 1.evel Established)
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Repo rt Yes Indication and N Rate Presentation N Acceptable?
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N0 And/or 1P Augment Y
ISI Consequence Program Analysis
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Figure 1 Sequoyah Weld Review Flow Chart
L 1-3 t
4 Indications.
As the inspection techniques involved in the PSI and ISI progres are typically dif ferent than the construction inspection techniques, these inspectlons represent an independent measure of the quality of the welds.
The second approach in validating the quality of the welds was to review the successf ul operating experience of the two units. As both units have over 20,000 reactor hours of operating experience, any initially def ective welds should have already been screened out by the natural "Inf ant rnortality" period associated with the Initial operation of any component.
Review of licensee event reports (LER's) would show whether there has been any f ailures due to I
poor initial quality of the welds.
The lower hal f of Figure 1-1 Illustrates the process that would be followed af ter the three st.parate reviews have been completed and the overall quality of the welds has been determined.
If the quality of the welds is cetermined to be good enough to warrant restart of SNP, then no additional work would be C
required.
However, if the review were to. indicate that the welds were not satisf actory for their Intended service, then several options would exist, including augmenting the existing 151 progra and determining the consequence g
of f ail ure of specif ic components.
The results of the reviews did show that L
the welds were satisf actory and theref ore no f urther discussion of consequence analyses or augmentation of the ISI progre is included in this report.
The scope of this review was limited to wolds made by TVA only.The quality of shop welds made by certif ied vendors has not been questioned and theref ore has not been evaluated.
The scope of the review was f urther limited to structurally significant or saf ety related welds, sucn as piping welds, component supports and piping hangers.
The basis for the determination of whether a weld was structurally significant or saf ety related is whether the
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weld is included in the preservice and inserv ice inspection pl ans.
The total population of field welds considered was subdiviced into two categories:
piping welds and structural wolds.
The basis f or this delineation is that piping and structural welds are built to dif ferent procedures and acceptance
1-4 criteria and theref ore represent dif ferent populations which could have dif ferent measures of weld quality. A third population was def ined which f alls scrnewhere between the other two categories:
Integrat attachment weldments. The welds on Integral attachinents are typically perf ormed to structural standards, but as the weld is made to the pressure boundary, Inspection criteria are usually similar.to those for pressure bouncary welds.
Section 2 of this report summarizes the review of the welding and quality assurance prograns.
Section 3 summarizes tne preservice and inservice inspection prograns and presents the rate of Indications detected to date.
This rate is compared with typical reinspection data for simil ar structures.
Section 4 presents the revlew of the operating experience and any weld related licensee event reports.
The results and conclusions of this review are summarized in Section 5.
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v Section 2 REVIEW OF WELDING #4D QUALITY ASSURANCE PROGRAM I
The construction of SNP was carried out in accordance with an Integrated system of corporate level construction specif ications and procedures designed to assure that all regulatory requirments were satisfied and to ensure that the necessary welding quality was achieved. These speci f ications were implemented at the plant by the use of a series of construction specif ications, inspection Instructions, and standard operating procedures governing specific aspects of f abrication.
This integrated progr m assured that each phase of work in the welding progrm was properly controlled.
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Those components that were covered by the quality assurance progem were 1
g delineated on TVA Division of Engineering Design approved drawings and in TVA SNP Construction Speci f Ication N2-G-877 "Identi f Ication of Structurcs, Systems, and Ccrnponents Covered by the SNP Quality Assurance Progrm".
Fabrication of specific ccmponents (e.g., structural steel, or seismic supports) was governed by construction procedures, which prescribed additional construction procedures for detailed steps in the f abrication process (e.g.,
weld procedure assignment). Table 2-1 lists the SNP construction procedures rolated to welding.
These procedures also cover the qualIf Ication, certification, and QA training of personnel.
These construction procedures also include by ref erence the AISC, AWS, N4SI, and ASME Codes (1-A) as well as TVA's general construction specifications, such as G-29 (" Process Spect fIcations f or Welding,' Heat Treatment, Nondestructive Examination, and Allied field Fabrication Operations").
The G-29 specification is broken into several sections, such as G-29C (structural), G-29M (piping), and G-29E (electrical). The G-29M specif ication is written to be consistent with the ASPE aac ANSI Codes for piping, whereas j
the G-29C specification is written to be in accordance with the AISC and AWS
2-2 o
Table 2-1
_ WELD RELATED CONSTRUCTION PROCEDURES
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C2 Erection & Inspection of Structural Steel E3 Installation & Inspection of Seismic Supports for Conduit
& Lighting Fixtures G1 Fabrication & Installation of Seismic Supports I
Erection of Piping & Instrument Lines G3 G4 Surveillance of Site Contractors
-15 Fabrication, Installation,J& Inspection of Seisinic Instrument 2
. Line Supports & Wall Mounted Panels M1 Procurement, Storage, Issue, and Control of Welding Materials M2 Welder & Welding Operator Perfomance Qualification M3 Welding Surveillance & Weld Procedure Assignment M5 Certification of Nondestructive Examination Personnel M7
" Erection & Documentation Requirements for QA Piping Systems M15 Post Weld Heat Treatment M19 1
Cleanliness of Fluid System Piping and Components M20 -
Pipe Support' Installation & Documentation M23 Fabrication, Installation, & Inspection of HVAC Duct Supports p
M28
., P2
_ Arc Strike Removal t
Handling Nonconformances C
CP3 Procurement, Storage, Issue, & Control of Welding Materials P3 Reporting and Documenting Conditions Adverse to Quality 1
- CP4 Welder & Welding Operator Performance Qualification L
P8 Preparation, Review, Handling & Storage of QA Records P9 Responding to NRC Inspection Items & QA Audit Findings
~P10 Control of QA Documents '
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'P12
~ Control & Documentation of Permanent Material Field Fabrications Storage of 0A Material
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P13 Release for Drilling, Chipping, Cutting, Welding, Sandblasting,
& Rework of Permanent Structures P14 Installation & Inspection of Embedded Material & Equipment P16
'~P30 Certification of Nondestructive Testing Personnel Fabrication and Installation of Seismic Supports P33 Certification of Inspectors P34 Heat Number Validation P41 Handling Allegations P48 Personnel QA Training P50 Stop Work & Pestart W1 Frocurement, Storage, Issue, & Control of Welding Material W2 Welder & Welding Operator Performance Qualification W3 Weld Prccedure Assignment & Welding Surveillance
. W4 Base Metal Repair W5 Arc Strike Removal W6 Post Weld Heat Treatment W7 Repair of Welds
2-3 Codes. As a result, the acceptance criterla are slightly different for structural welds than for piping welds.
This fact, plus the f act that structural welds are typically made using dif f erent techniques than piping welcs indicates that the quality of structural welds is likely different than the quality of piping welds. As a result, they will be treated as two separate populations in the statistical evaluation of the Inspection results in Section 3.
I in order to ensure that the construction procedures were followed properly, a series of Inspection instructions were utilized.
These govern prewelding inspections as well as post weld Inspection.
Table 2-2 lists the SNP inspection instructions related to welding.
Standard operating procedures are also'def ined to prescribe procedures not specif ical ly covered by construction procedures or inspection Instructions.
Weld related standard operating procedures are listed in Table 2-3.
Brief ly, the construction procedures imposed the f ol icwing controls over the v
welding prograrn: bese metals and welding materials were controlled f rom procuranent through t Inal use incl uding reccl pt, storage, issue and in process f abrication.
two requiroments were placed on traceability of a heat number of an electrode to a particular joint, as all of the electrodes were purchase'd, stored, and issued to the same quality standards. Welders were tralned, g
tested, certified, and had their continuity (recent experience) maintained as L
required.
Welds were made by quellf led welders whose certif ications were verified on a continuous basis.
Welding was perf ormed to quellfled welding procedures which were assigned by knowledgeable personnel.
Welding inspections were assigned, conducted, evaluated, and documented as dictated by the procedures.
The welding and QA progrtm described above has all of the characteristics of a good program.
It provides for personnel quellfication and training, procurtrnent and control of welding materials, and written procedures for welding and Inspecting the quality of the welds.
The progrtin has been audited 9
and approved by both Internal
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J and external audi ting and regulatory bodies.
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f' 2-4 Tat.le 2-2 f
WELD RELATED INSPECTION INSTRUCTIONS.
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.t 11 05 Piping 8. Supports Walkdown Procedure l
11 34 Surveillance of Contractor Site Activities.
II 38 Inspection of Site Fabricated Assemblies II 39 Heat Code Transfer I
II 41 Hydrostatic Test of Piping Systems II 63 II 66 Piping Inspection Inspection of Supports I
'.II 67 Vacuum Box Testing II 70 Inspection of Base Metal Repairs II 71 Inspection of Post Weld Heat Treatment 11 72 Ferrite Content l
11 73 Arc Strike Removal 11 74 Fitup & Cleanliness Inspection II 75 II 76
. -Visual Examination of Weld Joints Liquid Penetrant Examination i
11 77 II 78
.. Magnetic Particle Examination Ultrasonic Examination
/
11 79 Radiography Examination II 85 Installation Verification & Pressure Test of Instrument C
Lines II 91 Pneumatic Test of Piping Systems l6 O
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I f-2-5 Tabic 2-3 WELD RELATED STANDARD OPERATING PROCEDURES 50P 102 Conduit Hanger Installations
[
50P 300 Reporting of Field Discrepancies I
S0P 301 Qualification of Inspectors SOP 302 Releases to Drill, Chip, Cut, Weld, or Sandblast SOP 318 Resolving & Documenting items Identified in NRC Exit Meetings or Inspection Reports S0P 319 Work Suspension & Restart Procedure 50P 321 Weld Map Status Program Operation & Maintenance 50P 400 Mechanical Hanger Installation, Inspection, &
Documentation S0P 401 Weld Maps I
SOP 405 Requirements for Pipe Bends, Threaded Pipe Connecti.'ns, Weld Location, Piping Bolted Connections,& Valves 50P 550 Review of QA Records SOP 601 I
Receipt Inspection of Permanent Plant Material SOP 650 Walkdown of Permanent Plant Features 50P 700 Weld Surveillance 50P 703 Welding Inspection Unit Weekly Report 50P 704 Procurement of Welding Inspection Unit Materials 50P 901 Supplementary Welding Instructions for Heavy Membera L
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2-6 This implies that the progran, if properly implemented, is capable of producing quality welcs.
However, an early audit by the Atanic Energy Canmision (AEC) Directorate of Regulatory Operations discovered several T
l' violations in SNP's welding progran (3).
As a result of this audit, several changes were made to the welding ;progran, including revising construction I
procedures, increasing the QA training, and addl'tional weld surveillance.
Standard operating procedure Number 700 " weld Surveillance" was impleme subsequent to this cucit as a check on.the quality of welding.
This progran requires a minimum of two complete survelilance tours of each inspection area each shif t to ensure that correct procedures are being f ollened.
The survelllance inspections served as a mejor control fearuru for the Sequoyah construction welding progran, although other controls, including internal and I
external audits, were also utilized.
As a check on the implementation of the progran, ~APTECH selected at random welcs for detailed exemination of the documentation supporting those welds
()
An integral welded attachment f rom Ung I '(SlH-21)
L from Unit 2 (UHIF-55) and a field piping weld
' Complete cocumentation was provided by were selected.
TVA for both welcs, incluc J. piping draw ings, construction procedures, wel d history records, material certif ications, welder qualif ications and continuity, inspection procedures, inspector qualif ications and certi f ication, PSI and ISI results, and NDE equipment calibration.
The PSI examination of the structural weld was perf ormed by outside contractors (Lanbert, MacGil l and Thomas, Inc.),
theref ore providing an independent assessment of the quellty of ttle weld.
All other NDE was performed by TVA personnel.
This review did not address the technical edequacy of the construction procedures in detall, as they relled heavily on existing codes and standards
~
In sone cases the acceptance criteria for SNP were more stringent than
~
V comparable codes, and in sane cases, they were more lenient.
However, those cases that we observed to be more lenient than the Code of record were consistent with current codes and technical justification existed for deviations from the Code of Record (6).
9
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2-7 f
1 In summary, APTECH has reviewed the welding /QA progrem at Sequoyah and has found that subsequent to the 1974 AEC audit, the prog an contains the necessary checks and balances to ensure high quality welding. As a result of a
the 1974 audit, steps were taken to evaluate the quality of welds made prior to the audit, and it Is felt that there is no reason to question the quality of thess welds further.
A spot check of the implementation of the progran uncovered no def Iclencies in documentation of the progran.
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I 3-1 1
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- REYlEW OF_ PRESERVICE AND INSERVICE,1NSPECT10N RESULTS Section 3 u.
~
The best way to measure the quell +y of field welds at Sequoyah Nuclear Plant is to reinspect the welds using some form cf sampling plan to ensure high conf idence in the inspection results, shor t of Inspecting 100% of the welds, which may be impossibs e to do because of problems of accessibility.The preservice and inservice inspections required by Section XI of the ASME Code represent independent reinspections of the quality of the welds.
The PSI and 151 examinations are perf ormed by dif ferent personnel (in scate cases outside c
contractors) than those involved in the f abricaticn of the wulds, and the technicues and procedures are different, ensuring an evaluation which is independent of 1he original construction inspections.
Thus, the PSI and ISI results will-be used as quality indicators for the welds at SNP.
If chronic detIclencies existed in the welding program at SNP, it would be expected that an unusually high number of def ective welds would be detected in the PSI and ISI programs.
The rate of generation of Notices of Indications (N0l's) will be used here as a measure of weld gaality, Preserv i ce inscection Results The results of the PSI progran were taken f rom the PSI summaries (1, 8 The type of weld was determined fran the weld identi fication number Field piping welds were identified by an "F" suf f ix af ter the system number.
Socket wel ds
~
were Icentifled by four digit weld numbers, it is possible that additional socket welds exist that are not designated by four digit numbers.
The result of these unknown welds would be to increase the population size, theref ore decreasing the indication rate for a known number of Indicottons.
Thus, the ef feet of not counting these unknown socket welds in the total population i conserv ati ve.
s Hengers were identi f ied by an "H" suf fix, and those hangers that are Integrally welded attachments were subsequentl y indentified by the L
3-2 hanger type "l A".-
The numcer of PSI examinations for each category 6ce summarized in Table 3-1.
There were 1101 Class 1 and 2 field welds examined during the PSI progrm (including socket welds). Most of the subsequent ISI examinations represented reinspection of those wolds examined in the PSI progra and thus this aumber represents the total number of piping welds a
in spected.
The total number of Class 1 and 2 field.welas (representing the entire population) determined by TVA from a review of construction ecwings is 2618, thus the PSI's on Units 1 and 2 covered 42.1'% of the tota! fleid weld pop ul ati ons. Tnese counts are used in another section of this report to estimate the N01 rate.
The only hangers inspected in the PSI progrm were integral attachments.
The number of integrally welded attachments (I A's) Inspected during the PSI progran (61) 1 represents less than half of the total population (146). Some of the I A's inspected in the PSI progre were subsecuently reinspected during the ISI progrm. The values shown in Table 3-1 represent only those I A's which (3
were not subsequently ~1nspected during the ISI progrm. This number (39) will
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be added to the number of 1A's inspected during the ISI examinations to
~
provide the tctal number of Integral attachments inspected during PSl/ISI.
A summary of notices of indications reported as a result of the PSI,on Unit 1 and 2 is given in Table 3-2.
Only one significant N01 was reported for all the categories of field welds inspected.
There were five N0l's on shop welds.
"Significant N01's" In this case ref ers to indications which were unacceptable per ASME Section XI and required repair and re-inspection.
The N0l's generated as a result of the PSI ex minations are described in more detail in Tables 3-3 and 3-4.
The only field weld containing an Indication was Weld Number TE-68-83, which is a reactor coolant main loop temperature element weld.,
Sightly under 10% of the field welds were inspected by penetrant (PT).
The rmaining 90% were inspected ultrasonically (UT), which is a more rigorous
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3-3 l
d Table 3-1
SUMMARY
OF PRE-SERVICE INSPECTIONS (PSI's)
~
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Unit 1 Unit 2 Field Piping Welds 473 484 Field Socket 1.' elds
..., 2 0 124.....
l Integrally Welded Attachments 25 14 l
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Table 3-2 PRE-SERVICE N01's ON FIELD WELDS f
Unit 1 Unit 2 Field Piping Welds 1
0 Field Socket Welds 0
0 Integrally Weided Attachrents 0
0 I
Note: 2 NOI's or. Shop Welds Unit 1 3 N0l's on Shop Welds Unit 2 I
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3-6
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Table 3-4 SEQUOYAH UNIT 2 NOI's - PRE-SERVICE INSPECTIONS Report Number System Type Weld Discrepancy R-540 RHR-15 Shop Linear Indication in Fusion Walls of Long Seam Ell R-743 RHRS-60 Shop Incomplete Penetration ir "T" Longitudinal Weld R-1666 RHR-105LS Shop Lir: ear Indication in "T",
2-1/2" Long i
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Table 3-3 SEQUOYAH UNIT.1 N0!'s - PRE-SERVICE INSPECTI0ris Recart Numbcr ~ System -
7ype Weld '-"~ ~ ~ ~71screpinc_y R153/153A.--.- -RHRS-119 -.-. Shop-- -- - L-inear Indication-0.5" in Length R885 RCW-25(SE)
Shop Linear Indication 0.5" Long R1094 TE-68-83 Field Unacceptable Tack Welds I
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volumetric examination tnan PT, which is primarily a surf ace examination.
The lack of significant numbers of N0l's from the PSI is a strong Indicator that the quality of the welcs is high.
~
inserv ice inspection Results Althougn Inservice Inspection is directed at finding defects caused by operating f actors, the inspection findings are also a measure of the initial weld qua:lty.
This will become apparent balow as some of the Indications detected during 151 are construction related detects.
The number of ISI's performed on Unit 1 through three f uel cycles and on Unit 2 through two f uel I
cycles are listed in Tabl e 3-5.
This table also includes the number of Class 1, 2 and 3 hangers which were visually inspected.
Field welds and I A's were alI inspected by UT, PT, RT or MT, or a combination of two inspections by these methods.
The total number of ISl's on field welds (piping and socket welcs) for both units is 456.
As these are mostly repeats of the welds
)
inspected in the PSI progem, these welds are not included in the total number b
of inspections used to establish an Indication rate below.
Ninety henger IA's have been perf ormed to date In'ine Inservice inspection progrm The total population of Class 1, 2, and 3 hangers according to a TVA count is 2,580 and al l were inspected at least once during a total of 3,150 ISI examinations.
As a result of the 151 progran a total of 22 N0l's were written on welds (including shop welds) on Units 1 and 2.
These are summarized in Table 3-6 under the appropriate category. Not at i of these N0l's were considered to be significant N01's.
Notices of Indications for Unit 1 are listed in Table 3-7 Only linear Indications, missing welds and cracks are considered significant I
def ects.
There were three signif icant N0l's on f ield welds (FDF-4,' UPif-19
~
and RHRF-109A);
f our N0l's were written on hanger I A's (SlH-453, SlH-20, SlH-21 and MSH-289); f Ive N0l's were written on hangers (FDH-203, SlH-17 and RHPH-460, RCH-29 and CVCH-44).
All were adequately repaired as determined by re-Inspection.
Table 3-8 shows the five significant N0l's for Unit 2 af ter two f uel cycl es.
Two were associated with fleid socket welds (CYC-1045 and CVC-1253 ) and are considered significant.
The other three which were written f
d
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Table 3-5
SUMMARY
Unit One Unit Two
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Cycle 1 Cycle 2 Cycle 3 Cycle 1 Cycle 2 Field Piping Welds 90 1/
85 65 3
Field Socket Welds 63 0
60 76 0
Integrally Ided Attachments 29 0
26 9
26 Hangers
- 683 752 463 710 544 4
- Class 1, 2, and 3 y
Table 3-6 i
SUMMARY
OF WELD ff01's Unit One Unit Two Cycle 1 Cycle 2 Cycle 3 Cycle 1 Cycle 2 Piping Field Welds 7
1 Field Socket Welds 2
Integrally Helded Attachments 1
3 3
1 2
Ilangers
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Tabl!. 0 7,
N01 DESCRIPTI0flS - SEQUOYAH UtilT 1 f101 fiumber Systems Type Weld Size Report flumber Discrepancy (Weldtio.)
i R0082 FDF-4 Field k8" lR0082 linear Indication 1/2" Long i
R0081 RHRS-2 Shop 18"
, R0081 2 Arc Strikes
- R0039 f
I R0124 SIF-127 Field 10" l R0124 Unacceptable Surfalce Condition i R0221 For PT Examinatfori R0125 SIF-148 Field 10" R0125.
1, Arc Strike i
I R0220 ',
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I R0192 515-337 Shop 2.5" e R0192 Unacceptable Surface..
R0225 Condition For Examination R0193 SIS-338 Shop 2.5" R1064 Unacceptable Surface R0226 Condition for Examination u
is lo R0219 UPIF-19 Field 12" R0219 Linear Indication, 5/8" Long RS20 i.
R0232 S111-453 Hanger (I A) 8" R0232 Linear Indication, 5/32" Long R0334 (Appears to be arc strike)
SQ0178 RilRF-109A Field R2540 Linear Indication,1/4" Long j
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SQ0201 FDil -203 Hanger R2714 Weld flissing Sill-17 Ifanger MR550188 Weld Missing l
500213 5111-21 Ilanger (IA)
R2813 Two 3/4" Long Linear Indications SQ0212 SIH-20 Hanger (IA)
--- i jR2812 Two 3/4" Long Linear Indications SQ0154 MSH-289 Hanger (IA)
R2374 L'inear Indicationj 5/16" Long 500179 RilR!l-460 Hanger
- R2541 Crack-Like Indications on Tack Welds
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S jg yl' Type Weld Size Report flumber Discrepancy NOI Number R235 Stm. Gen.
Shop R235 3/4" Linear Indication R279 RCF-31 Field R279 Arc Strike R00A SIS-274 Shop R00A Arc Strike R104 RCil-231 Hanger R404 Arc Strike R506 CVCil-291 Ilanger R506 Arc Strike R844 RCil-29 Ilanger P.844 Cracked Weld R846 CVCil-44 Hanger R346 Lack of Fusion i'
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=
RilR Residual ifeat Removal System
=
SI Safety Injection System
=
itS Main Steam System
=
UHI Upper Head Injection System
=
ItR Haintenance Request
=
CVC = Chemical and Volume Control RC Reactor Coolant
=
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Table 3-8 NOI DESCRIPTIONS - SEQUOYAH UNIT 2 flui flumtier Systems Type Weld Size Report Number Discrepancy 540007 CVC-1045 Socket 2.0" R0077 Linear Indication > 3/16" Logg,14 R0527 Rounded Indication in a 6 in Area SQ0008 CVC-1253 Socket 2.0" R0078 Linear Indication I" Long R0528 5Q0025 5111-219 Ilanger Rigid 1.5" R0308 Hissing Weld Support Ril77 SQ0126 AFDil.308 llanger Rigid 6"
R1293 Arc Strikes, Undercut and Support RIBSS Porosity ye 500103 ERCH;l-84 Ilanqer Rigid 30,
R1384 Unacceptable Weld Depositiot d
Support R1833 CVC Cliemical and Volume Control System
=
SI Safety injection System
=
AfD Auxiliary feedwater System
=
i ERCW = Essential Raw Cooling Water System e
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3-12 on hangers (SlH-219, AF0H-308 anc ERCWH-84) are also consicered significant because of their linear Indications, missing weld, undercut, porosity and unacceptable weld ceposition.
The ISI progran plan requires only 25% of the piping welds and 100% of the hangers to be inspected in the fIrst ten year inspection interval
- However, SNP has inspected in four years f ar more welds than required to be inspe in ten years.
This is a good Indication that SNP personnel are concerned about the quality of their welds.
I Indication Rates The PSI and ISI results are summarized are in Table 3-9.
Since the ISI's on field welds were essentially a repeat of those in the PSI's, the latter numbe is taken as the sample size.
This makes the resulting Indication rate conservative since the addition of any ISI's to this sample number will increase the sample number above 1101 and decrease the cef ect rate For the integral attachments, the PSI's_are added to ISI's to give the total sample size of 129.
All duplicate inspections were deleted (this is conservative as described above).
For hangers, 3044 ISI examinations were perf ormed on a -
total of 2689 dif ferent hangers.
However, only 2588 hangers were included in the 151 progran plan.
This means that all of the hangers in the ISI progran plus many otners have been Inspected.
Since all hangers in the ISI population were inspected once, we are 100% confident that the N01 rate is:
8 X 100 0.3M
=
2588 For field welds and integral attachments, the Indication rate for a p
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sampling progran was calculated using the hypergecnetric distribution theor artial This Is used for the same situations as the bincm!al distribution y.
2 when the proportion of OK's cannot be assumed to be constant af t except that Is drawn, the hypergeonetric distribution is used.
er the sample A more detailed description of this theory is in Appendix B.
The estimated rate of significant-Indications for the field weld population is 0 95% with a conf idence/probabil ity level greater than 95%/95%.
The estimated rate of
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Table 3*9 l
SIGNIFICA?!T IflDICAT!0ft RATE I
Total Population S
PSI AI.
% Examine'd N01's fl01 R' ate (%)***
Field Pining Welds 2618 1101
' 456 42.1 6-0.95 (includes Sockct Welds)
Integrally Welded 146 39 90 88.4 4
4.79 At t achmen ts.'
i, llangers 2588 0
.2689 100-8' O.31 (Class 1. 2. and 3) t u,
ISI Examination liostly Repeated PSI. [ Tot' l !! umber of Welds Examined is 1101 b
a Includes IA's not Subsequently Reinspect in,hSli
- Prabability Level at Greater,Than 95%, Confidence..
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4 significant indications for the hanger I A's is 4.79% which is h so gremter than the 95% confidence /95i probability levels.
Another way of describing the I A indication rate is, "we are more than 95% conf ident ther the estimated Indication rate wil l not exceed 4.79%".
All of the Indivicual incication rates (and thereto a the cumulative incication rate) provide greater conf idence in the quality of the welds than the 95% contIcence/95% probability level tnat l', common In the nuclear industry.
Use of a statistical confidence i Wit is necessary because no inspection technique is capable of detect ing 100% of the detects with 100%
confidence.
Theref ore there will be a finite probability that cef ects will be I
detected in a component esen if it has already been inspectcd and no kncwn detects were left Ir. the component. For comparison purposes, a complete re-evaluation of 254 radiographs of Class 1 piping at Millstone Unit 3 thet had previously been interpreted as being f ree from def ects revealed a 1 6%
reinspection Indication rate (S).
The 0.95% Indication rate for field piping
(
at Sequoyah compares f avorably with this value.
d For structural welds, there is very little data avail able f or comparison, however, limited reinspection data of structural welcs in of fshore platforms Indicate a reinspection Indication rate of nearly 5i (10, U, g). Thus, the rate of Indications in the reinspections at Sequoyah are comparable with similar data for similar types of welds.
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4-1 6
'r Section 4 REYlEW OF OPERATIONAL EXPERIEN T z
Sequoyah Nuclear Plant Units 1 and 2 have seen a comolned service life o 46,430 critical-hours of operation.
This amount of service should be enough to identify any welas which are not of suf ficient quellty for thei r intended serv ice.
Once a plant is in operation, any failures would be reported to the Nuclear Regulatory Commissi' n (NRC) o as Licensee Event Reports (LER's).
LER's associatec with SNP were reviewed looking for any events related t The wc!ds or welding.
o The results of that review are summarized below.
Sequoyeh Unit 1 startco commercial operation on July 1,1981~ and to d fm system has 24,445 critical reactor hours.
e
)
These critical reactor hours
/
represent a total of 2.79 years of continuous operation.
V During this period only five LER's related to welds were sent to the NRC.
summarized in Table 4-1.
These LER's are field welds.
No f ailures can be attributed to poor quality of L
Sequoyah Unit 2 went into commercial operation on June 1,1982 When shut cown on August 21, 1985, the reactor had achieved 21,985 critical hours of L
operation representing 2.51 years of continuous operation.
There were no LERLs relating to welds sent to the NRC (Teble 4-2).Theref ore, these two Sequoyah units have 5.3 years of critical operatior with no f ailure poor quality of field welds.
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I Table 4-1 SEQUOYAll VillT OllE OPERATI0ff EXPERIEf1CE Date of Connercial Operation: July 1, 1981 flours Reactor Critical:
24.445 Capacity Factor (Cumulative):
59.5%
LER's Concerned With Welds:
LER flumber Date Event 80-156 10-5-80 fiozzle Failure on CVC Seal Water Injection Line - Vibration or Physical Damage A,80-141 08-29-80 Seal Weld Failure on CRDfi - Westinghouse Defect 80-150 09-27-80 Check Valve Stuck Open - Tack Weld Interferred With Disc and Valve Body (Vendor Defect) 81-17 02-12-81 Welder Blew Pin llole in Pipe - Restricted Access 82-97 08-03-82 Door Latch Connecting - Rod Broken at Weld - Fatigue Weld Record:
e fio Failures Due to Poor Quality of Field Welds
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I Tddle 4-2 SEQUOYAll UNIT 2 OPERATION EXPERIEllCE Date of Commerical Operation:
8 June 1, 1982 Ilours Reactor Critical:
21,985 Capacity Factor:
69.2%
LER's Concerned with Welds:
LER Number Date Event i
tione a
i s
I-Weld Record:
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s s No failures Due to Poor Quality of Field Welds
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5-1 t
-Section 5
SUMMARY
AND CONCLUSIONS I
I APTECH has perf ormed _a revlew of the welding /QA progran at Sequoyah Nuclcar plant and has evalunted the quality of welds through a revlew of the preservice and inservice inspection results and Licensee Event Reports related to welding.
The following conclusions have been developed based upon these rev iews:
I e The welding progran contains the necessary controls to ensure high quality welds (af ter the 1974 AEC audit).
e SNP evaluated the quality of welds made prior-to the 1974 audit through reinspection and repair where requirea.
Those welds made v
prior to the 1974 audit can now be considered to be satisf actory despite a breakdown in the QA progran.
e The rate of significant Indications detected during the preservice and inservice inspections is less than 5% with greater than 955 confidence.
[
e No Licensee Event Reports have been generated which relate to poor i
quality fleid welos.
Based upon these conclusions, there is no evidence that the quality of welds at Sequoyah Nuclear Plant are not f it f or their Intended serv ice.
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R-1 4
1 REFERENCES 1.
American Institute of Steel Construction " Specification for the Design, Fabrication, and Erection of Structural Steel for Buildings".
2.
Araerican Welding Soclety, " Structural Welding Code - Steel", AWS 01.1.
3.
American National Standaras institute, " Power Piping", ANSI.831.1.
4 American Society of Mechanical Engineers, "Boller and Pressure Vessel Coce", Sections 1.
lit, and Vill.
5.
" Corrective Action Report f or Welding at SNP", NovemDer 4,1974 (ECD-11).*
I Menorandum f rom G.H. Kirrrnons, to H.N. Cul ver, " Watts Bar Nuclear Pl ant -
6.
Technical Justif ication of Contrasts of AWS 01.1 and General Construction Specif ication G-29C", December 15, 1982 (ECD-23).
7.
Summary of Preservice inspection at Sequoyah Nuclear Plant Unit 1 (ECD-2).
8.
(
)
Summary cf Preservice inspection at Sequoyah Nuclear Plant Unit 2 (ECD-3).
-~
G 9.
Felereisen, Thomas J., Peter D..Heegecock, and Geof frey R. Egan, ->
" Radiographic Rev iew of Piping Welcs, at, Mil l sti ne 3_Nucl ear Pcwer Plant",
APTECH report AES 8501521AQ-1.
10.
Rocrigues, Pedro E.L.B., W. Kheen Wong, and John H. Rogerson, " Weld Def ect distributions in Of fshore Platf orms and Their Relevance to Rellaniiity Studies, Quality Control and in-Service inspection", Of f shore Technology Conference,.0TC 3693,1980.
]
11.
Taylcr, 8.0. and J.H. Rogerson, " Weld Def ect Levels in Site Construction L
and the Effectiveness of Conventional NDT Techniques,
Welding institute a
Conference on Non-Destructive Testing in the Fitness-f or-Purpose Assessment of Welcec Conriructions", November 1984.
12.
Groves, 0, and D. Connell, "Of f shore Structure Fabrication Experience with Magnetic Particle inspection", Welding Institute Conference on Non-Destructive Testing in the Fitness-for-Purpose Assessment of Welced Constructions", November 1984.
Externally generated controlled documents are conoted by (ECD-n).
i
A-1 8y I
I Appendix A PRE-SERVICE INSPECT 10N I
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J Table A-1 UNIT ONE PSI FIELD WELD INSPECTIONS RCF RCF UPlF SlF SIF RHRF RHRF RC f
13 63 19 2
147B 4A 88 1
14 63A 20 3
148 6A 89 2
I 15 64 21 4
149 10A 90 3
16 65 22 7
150 12 90A 4
17 66 23 8
150A 14 91 5
1 18 66B 24 10
,160
}5 92 6
19 67 25 12 162 16 93 7
20 68 26 14 163 17 1 06 8
21 69 27 19 166 18 1 07 9
22 70 28 36 167 19 107A 10 22A 70A 29 87 168 20 108 11 23 71 30 88 169 23 109 12 1
24 72 31 89 170 25 109A 13 24A 73 32 118 170A 26 1098 15 248 74 33 119 170B 29 109C 16
/
)
24C 75 34 120 171 31 1090 17
/
240 76 35 1 21 175 34 109E 18 D'
24E 77 36 121A 176 38 109F 19 24F 77A 37 122.
177 39 110 20 24G 78 38 125 178 40 111 21 24H 79 39 125A 179 41 111A 22 24P 80 40 126 182 42 112 23 25 81 41 1 27 183 43 122 24 26 82 44 128 184 44 1 23 25 26A 83 45 128A 185 45 124 26 26B 84 46 129 186 46 124A 27 l-26C 47 130 186A 48 124B 28 260 48 130A 1868 50 125 29 22.
49 130B 187 51 30
{
29-X1 50 131 193 52 31 30 51 132 194 53 32 30A 52 133 194A 54 33 l
308 53 135 195 55 34 L
30C 54 137 196 58 35 3 00 55 138 197 f,9 1 (SE) 31 56 138A 198 60 2 (SE) l 36 57 139 201 61 3 (SE) 42 58 142 202 63 8 (SE) 45 59 143 202A 64 9 (SE) 49 60 144 203 65 10 (SE) 49A 61 145 204 66 11 (SE) 50 62 145A 205 67 16 (SE) 17 (SE) i_
6
I (TABLE 1 - Continuec)
RCF UPIF SIF SIF RHRF RC 51 63 146 206 65 18 (SE)
[
51A 64 147 86 19 (SE) 1 52 65 147A 87 24 (SE) 53 r
54 25 (SE) l 55 26-(SE) 27 (SE) 32 (SE) 1-TE-68-1 1-TE-68-1C 1-TE-68-18 1-TE-68-24 1-TE-68-24C 1-TE-68-41 1-TE-68-43 1-TE-68-43C 1-TE-68-60 1-TE-(8-65 1-TE-68-65C 1-TE-68-83 1-TE-68-318
)
CVCF Si RCW FDF SIW SWIW UPlw MSF SlH RCH v
163 1575 1
4 1
'1968A 9
3 2
15 163A 1588 2
10 2
19688 10 11 7
27 164 1631 3
11 3
2040A 11 31 20 70 165 1643A 4
18 4
20408 13 38 21
'125 l
166 1664 5
21 5
2098A 14 39 22 126 L
167 1669 6
22 7
2098BX 16 46 24 140 158 1681 A 7
128 8
2158A 17 71 188 g
169 1719 8
130 9
2158B 19 79 232
[
170 1732 9
131 10 20 164 288 171 1734A 10 140 1734 22 318 172 12 141 1772A 209B 13 320 210 14 210A 22 l
210B L
211 211A y
211B 212
~
213 214 2428 243 243A 2438
1 (TABLE 1 - Continuec) y C.
244 f
244A
~~
s 245 246
[
246A 3
246B 247 UU MM MW CVCW UHlH E
UHi
~
l
'~
s 3
1 1
34 1
1 uHi Oo30x2 i
37 2
2 UHI 0039 32 5
3
~
106 7
183C 4
34 I
136 15 296 302 1
=..
.S.
O L
i 9
up y
9 1
x Table A-2 UNIT TWO PSI FIELD WELD INSPECTIONS RHRF RHRF SIF SIF RCF RCF UPlF UPlF CVCF 4A 60 1
168 13 66 17 62 163 5A 61A 2
169 13A 67 17A 63 164 6A 61B 3
170 14 68 178 64 165 6C 61X 5
171 15 69 18 65 166 7
62 11 176 16 70 19 167 1
10A 64 12 177 16A 70A 20 168 12 65 13 178 168 71 21 169 13 66 18 179 17 71B 22 170 14 67 36 182 18 72 23 171 1
16 85 87 182A 19 73 24 172 16A 86 88 183 20 74 25 2098 17 87 90 184 21 75 26 210 1
18 88 118 185 22 76 27 210A 19 89 1 21 186 23 77 28 2108 19B 90 121A 187 24 78 29 211 19X 90A 121B 193 24A 79 30 211A f
i, j
20 91 122 194 24C 80 31 212 C
22 92 125 194A 240 81 32 213 23 93 125A 1948 25
-~ 82 33 214 24 94 1 26 195 26 83 34 242B 25 104 1 27 196 26A 84 35 243 26 105 128 197 26B 36 243 A -
l 27 1 06 129 198 26C 37 244 L
28A 106A 130 201 260 38 244A 288 1 07 131 202 27 40 2448 3
30 107A 132 202A 29 41 245
(
32 108 135 202B 30 42 246 33 109 136 203 30A 43 246A 3A 110 137 204 30B 44 247 35 111 138 205 30C 45 36 111A 139 205A 30U 46 37 111C 142 206 31 47 l
38B 112 143 206A 36 48 L
40 113 144 206B 42 49 41 114 145 45 50 42 120 145A 56 51 43 121 146 568 52
~
44 122 147 57 53 45 1 23 148 58 54 46 124 149 59 55 47 124A 150 60 56 49 125 161 (g!
53 61 57 162
'd 56 62 58 163 63 59
6 (TABLE 2 - Continued)
']{
RHRF s SIF RCF UPlf 57 166 63A 60 58 167 64 "2i '61
~
65
- .~
~
. ~. '
SI CVC RC RC FDF CSF RCW MSF CVCW UPlh Siw 1129 1017 1
1234 2
1 1
2 1
- 10 1
1130 1031 2
1250 5
2
-2 5
2 11 2
1136 1039 3
1268 6
3
- 3 10 3
13 3
1142 1040 4
1269' 10 14 14 14 4
14 4
1 1148 1049 5
^ 1284 ~
11 15 5
17 1057A 16 5
1161 1056 6
1348 15 16 6
18 10578 17 7
1162 1057 7
1368 16 7
20 - 1069 19 8
1822 1069 8
1379 20
~ 8 24 10918 20 9
1 1829 1072 9
1386 '
21 9
30 11698 10 1830 1086 10 1412 22 10 32 1236 1848 1087 11 1413 125 12 35 12368 1
1856 1094-12 1430 1 27 13 39 1864 1103 13 1449 128 14 41 1865 1104 14 1450 130 22 43A
' _ ')
1866 1116 15 1460 131 44 K '
1670 1128 16 1466 134
\\-/
1876 1129 17
- 1477 140 1890 1139 18 1495 141 1897 1143F 19 1510
~
1898 1148 20 1511 19068 1149 21 1523
~
1915 1164 -
22 1542 1916 1169-23 1543 1921 1177 24 1561
[
1926 1188 25 1585
(
1940 1189 26 1586 1950 1200 27 1592 1951 1207 28 1607 1984A 1 213 20 1618 1993 1225 30 1626 2057 1237 31 1644 2098 1241 32 1651 2115 1251 33 1652 2187 1252 34 1661 2193 1259A 35 1671 2255 1272 1 (SE) 1672 2256 2 (SE) 1675 2270 3 (SE) 1729 8 (SE) 1745 9 (SE) 1761 10 (SE) 1762
/
=
(TABLE 2 - Continuec)
R RC 11 (SE) 1767 I'
16 (SE) 1772 17 (SE) 18 (SE) 19 (SE) 24 (SE) 25 (SE) 26 (SE) 27 (SE) 32 (SE) 2-TE-68-1 1
2-TE-68-1C 2-TE-68-18 2-TE-68-24 I
2-TE-68-24C 2-TE-68-41 2-TE-68-43 2-TE-68-43C 1
2-TE-68-60 2-TE-68-65 2-TE-68-65C
(^')
2-TE-68-83 v
2-TE-68-318 L
UHI SlH ROi RHRH UHlH CVCH RHRW 1261 2
15 2
34 296 1 -
1265 7
91 3
302 2
1272 20 125 4
3 21 126 5
]
22 140 7
L 24 188 71 232 79 288
(
161 l
m 1
B-1 r
t 4x t i..
Appendix 8 THE HYPERGE04ETRIC PROBABILITY DISTRIBUTION
-~
ge 6
b
- O I~
W L_
i.-
t L
~
O m
0 6
Appendix 8 THE HYPERGEOMETRIC PR08 ABILITY DISTRIBUTION I
Th~e hypergecmetric probability distribution is used to calculate the probability of finding i def ects in a sample size of Q, when thero is a finite population of N Items and there are R def ects in the total populatio~n.
The f
equation for this distribution is:
K P( ) = I (R}(N-R)
I (0-1 I=0 N -
(1)
~
- Where, P() = Probability that a sample of Q ltens will contalri i def ective items R =
Number of def ects in total population (m)
I Number of defects in sample
=
d N
Total popluation
=
Q Sample size
=
The pertinent terms in the above equation are:
R!
(h = 11 (R-1)!
N!
( ) = Qi (N-QJ !
N-R (N-R)!
~
Q-I (Q-I)! ((N-R - (Q-I))!
In order to calculate the probability of finding i defects in the sample and relating this to conficence limits the above equation is set equal to 1-C where C is the confidence level as a decimal:
p.
'qJ
l-2 i
f=0 P
=
t (2)
Ine use of tnis equation requires an iterative process assumed and the conf idence as computed.
A value for R is Our normal conf idence level nuclear work is 95%. Theref ore R. values are assumed u In i
i = 0 to i =.K def ects is es near equel to the 95% conf idence level as e summation from i
posslDie.
Note that only whole numbers are possible for R defects In the total population.
, the numcer of The justification for equation (2) comes from a similar development fcr the binomial distribution (B 1)
B-1.
Amstedter, Bertram L., Rallability Mathematics Company, Page 247.
, McGraw-Hil l Book A
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