ML20093D437

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Forwards Typeset Version of Suppl to Rept on QC Insp/Reinsp Program,Errata & Addenda to Orignial Rept,Per 840628 Commitment.Related Correspondence
ML20093D437
Person / Time
Site: Byron  
Issue date: 07/11/1984
From: Furse M
COMMONWEALTH EDISON CO., ISHAM, LINCOLN & BEALE
To: Callihan A, Cole R, Smith I
Atomic Safety and Licensing Board Panel
References
OL, NUDOCS 8407160306
Download: ML20093D437 (78)
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COUNSELORS AT LAW P THREE FIRST NATIONAL PLAZA CHICAGO. ILUNotS 60002 , EC EDWUtD S. lSHAM. 1872-1902 WASHINGTON OFFICE RO8fRT T. UNCOLN. 1872 1939 1120 CONNECTICUT AVENUE.N W ,84 JUL g,gg = 5==. ~'= a n.m July 11, 1984 rr. : Ohi,pg~g g. R4t:CM Ivan W. Smith, Esquire Dr. Richard F. Cole Administrative Judge and Administrative Judge Chairman Atomic Safety and Atomic Safety and Licensing Licensing Board Board U.S. Nuclear Regulatory U.S. Nuclear Regulatory Commission Commission Washington, D.C. 20555 7 Washington, D.C. 20555 Dr. A. Dixon Callihan Administrative Judge Atomic Safety and Licensing Board c/o Union Carbide Corporation P.O. Box Y Oak Ridge, Tennessee 37830 Re: In the Matter of Commonwealth Edison Company ~ - - -

{ Byron-liuclear Power _S ta. tion,_ _ Uni.ts _ l. and. 2)_. __..

Docket Nos. 50-454 and 50-455 o C__ Gentlemen: As promised in my letter of June 28, Common-wealth Edison Company is providing the Board and the parties with the typeset version of The Supplement to the Report on the Byron QC Inspector Reinspection Program, plus errata and addenda to the original report. Please excuse our delay in providing this version, as it has only very recently become available. Very truly yours, W-Mark C. Furse One of the Attorneys for Commonwealth Edison Company MCF: reg l Enclosure cc: Service List 8407160306 840711 PDR ADOCK 05000454 .\\ Q PDR

O3 C:mm:nw:rith Edison one First National Plaza. Chicago Ilhnois Address Reply to: Post Office Box 767 Chicago. flhnois 60690 RELATEDCcy,,,_gggg July 3, 1984 ,avUg rr. Unnt ~ Mr. James G. Keppler 0*33 Regional Administrator en U.S. Nuclear Regulatory Commission 00cq)g %p' 799 Roosevelt Road BRIM;f Glen Ellyn, IL 60137

Subject:

Byron Generating Station Units 1 and 2 Byron QC Inspector Reinspection Program I&E Inspection Report Nos. 50-454/82-05 and 50-455/82-04 References (a): L. O. DelGeorge letter to J. G. Keppler dated February 24, 1984 (b): L. O. DelGeorge letter to J. G. Keppler dated June 27, 1984.

Dear Mr. Keppler:

Attached is the bound version of the supplement dated June, 1984 to the report on the Byron QC inspector reinspection program which was submitted in reference (a). This document provides the results of the supplemental inspections and evaluations to which we committed in the February final report. Aside from the printing and binding, it is identical to the version provided in reference (b). Errata and addenda to the February report are also included. The errata and addenda are printed in a form suitable for replacement of pages in the February reinspection program report. They are otherwise identical to the version provided in reference (b). These changes are necessary to correct typographic'al errors and clerical errors introduced during the preparation of computerized weld inspection tabulations for l the February report. These clerical errors resulted in the omission of l reinspection results for a number of welds and overstatement of the number of weld discrepancies. Our review of the corrected data does not alter any of our conclusions regarding either the adequacy of QC. inspections or the quality of construction at Byron. Minor additions to Appendix C are also being made to more accurately report the findings and conclusions regarding the Category Y engineering evaluations of Hatfield Electric and Pittsburgh Testing. Chapter VII is being revised to incorporate the results of the supplemental inspections and evaluations reported in the supplement. Any line which has been revised is marked eith an "Rl" in the margin.

%N J. G. Keppler July 3, 1984 One signed original and nineteen copies of this letter and the attachments are provided for NRC review. Please direct any questions regarding this matter to this of fice. Very truly yours, < <"Z 4.~ L. O. De1 George Assistant Vice President im Attachment cc: Mr. H. R. Denton (NRR) w/20 copies Mr. R. C. DeYoung (IE Headquarters) w/20 copies I 8788N M

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.M SUPPLEMENT .[ TO REPORT ON THE BYRON QC INSPECTOR REINSPECTION PROGRAM DOCKET NOS. 50-454 AND 50-455 I b. ~ 4-i 4 j i T a P b i r i 1 1 June,1984 P w ? k g P 4'. 9 ~

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= _. - e SUPPLEMENT TO REPORT ON THE BYRON QC INSPECTOR REINSPECTION PROGRAM CONTENTS Page I. INTRODUCTION SI-l s II. SUPPLEMENTAL INSPECTIONS AND EVALUATIONS S!!-l FOR SUBJECTIVE WELD ATTRIBUTES FOR HATFIELD ELECTRIC AND PITTSBURGH TESTING 111. SUPPLEMENTAL INSPECTIONS AND EVALUATIONS FOR Sill-1 OBJECTIVE ATTRIBUTES FOR HATFIELD ELECTRIC 1 i e \\ + a 0 0 l t 4 e.

51-1 I. INTRODUCTION L The Byron QC Inspector Reinspection Program was established to verify the effectiveness of former certification practices and QC Inspector Qualification programs by reexamining, on a sampling basis, inspections performed by QC Inspectors certified prior to September,1982. The Reinspection Program was completed and confirmed the adequacy of inspector activities at the Byron Station. Although the Reinspection Program focused on an assessment of individual inspector qualifications and contractor certification practices, a significant amount of work quality data was accumulated. Observed discrepancies were evaluated for their significance to the design and the quality of construction work at Byron was determined to be adequatei This supplement provides the results of supplemental inspections and evaluations which Commonwealth Edison committed to in the Report on the Byron QC Inspector Reinspection Program, Feburary 1984 (hereinaf ter referred to as the Reinspection Program Report). These supplemental inspections and evaluations covered subjective weld attributes for Hatfield Electric Company and Pittsburgh Testing Laboratory and objective attributes for flatfield Electric Company, s 6

o S 11-1 1 SUPPLEMENTAL INSPECTIONS AND EVALUATIONS FOR SUBJECTIVE WELD ATTRIBUTES FOR liATFIELD ELECTRIC AND PITTSBURGli TESTING A. INTRODUCTION Appendix C to the Reinspection Program Report included commitments to perform supplemental inspections and evaluations (see Exhibit C-2, pages 10 and 13). These supplemental inspections included highly stressed welds for Hatfield Electric and Pittsburgh Testing and welds with overlap for welds inspected by Pittsburgh Testing. The engineering evaluation of weld discrepancies noted in these supplemental inspections and evaluations followed the same process described in Exhibit C-2 of Appendix C in the Reinspection Program Report. B. HATFIELD ELECTRIC 1 Two sets of supplementalinspections were performed. One set of evaluations involved identifying highly stressed welds from the population of Hatfield Electric subjective weld discrepancies identified in the Reinspection Program. The other set of inspections involved highly stressed welds inspected by inspectors whose work was not reinspected in the Reinspection Program. The supplemental inspections and evaluations completed for Hatfield Electric show that the highly stressed welds are capable of carrying the design loads even with the presence of weld discrepancies. 1. liighly Stressed Welds Within Reinspection Program This evaluation considered the highly stressed connection welds from the entire population of Hatfield Electric weld discrepancies in the Reinspection Program. The type of supports which have the highest stressed welds are cable tray supports. Cable tray support connections fall into four basic - groups: i l l

R i 6 S 11-2 'l t! i l I auxiliary steel connectidos to in-place building steel, j o 2 top connections for supports to auxiliary or in-place building steel, o internal connections for support members to vertical members, and o cable tray hold down connections to horizontal support members. o The cable tray supports associatet! with the discrepant welds shown in Table C-1 of Appendix C to the Reinspection Program Report were identified. The design margins for the connections in sad group were then tabulated. Then at least 15 supports having highly stressed connections from each of the four groups were selected for weld mapping and endvation.,The wcId maps were used to determine the reduction in weld strength based on the mapped weld discrepancy. The results of the engineering evaluation are shown in Table SCE-9. T s e %e I to - i m e O $

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S 11-3 Table SCE >I Results of AWS Weld Discrepancy livaluation for flighly Stressed Cable Tray Welds - ifatfield Electric 2 Weld Discrepancy Category A Bt B2 _ C Weld Weld No Strength StrenSth Weld No. of Weld Structural Reduced Reduced Rejected Weld Type Discrepancies impact by < 10% by 210% (Cracks) Auxiliary steel connections 21 0 4 17 0 Top connections for supports 16 0 3 13 0 Internal connec-tions for supports 17 0 4 13 0 Cable tray hold-down 15 0 8 7 0 TOTAL 69 0 19 50 0 Notes for Table SCE-9 k 1. The format of Table SCE-9 corresponds to Table CE-9 in Exhibit C-2 of Appendix C of the Reinspection Program Report. 2. For definition, refer to page 1 in Exhibit C-2 of Appendix C of the Reinspection Program Report. s 4 ) t mm.

c. \\. 011-4 i s The results of the engineering evaluation showed that each. weld is capable of carrying the design loads; thus, str0ctural integrity is not impaired. This evaluation demonstrates that 69 highly stressed cable tray connections with weld discrepancies are capable of carrying the design loads. 2. liighly Stressed Welds Outside the Reinspection Program l This inspection addressed highly stressed welds for the 10 flatfield weld inspectors whose work was not reinspected during the Reinspection Program. Approximately 60 highly stressed welded connections from the four groups of cable tray support welds were reinspected for the 10 liatfield l Inspectors' work. A total of 187 welds were mapped. The types of weld f discrepancies identified were similar to the discrepancies in the welds identified in the Reinspection Program. The results of the engineering evaluation of these connections are shown in Table SCE-9A. T s f I

S11-5 Table SCE-9A i Results of_AWS Weld Discrepan_cy Evaluation for liighly Stressed Cable Tray Welds outside the Reinspection Prograrn - Hatfield Electric Weld Discrepancy Category A B1 B2 C - Weld Weld No. No - Strength Strength Weld of Weld Structural Reduced Reduced Rejected Weld Type Discrepancies impact by < 10% by 210% (Cracks) Auxiliary steel connections 40 0 19 21 0 Top connections for supports' 29 0 11 18' 0 Internal connect-tions for supports 30 0 12 18 0 Cable tray hold-down 88 0 48 39 1 TOTAL 187 0 90 96 1 in the case where a cracked cable tray hold-down weld was found during these additional inspections, the other welds in the connection were capable of carrying the load. The engineering evaluation of these highly stressed welds showed tliat each weldment is capable of carrying the design loads even with the presence of weld discrepancies. 3. Conclusion The results of.the supplementary evaluations complement the results of the Reinspection Program and give a total of 356 weld maps of discrepant - welds which have been evaluated (50 randomly selected weld maps and 50 o

= = -. Sil-6 weld maps containing the most weld discrepancies f,- the Reinspection Program; 69 weld maps from highly stressed cable tray support welds; and 187 weld maps for highly stressed welds for weld inspectors not included in the Reinspection Program). These evaluations, which revealed no design significance, result in a reliability of better than 99% which is consistent with the previous conclusions reached concerning the quality of Hatfield Electric's work. 4. Additional Inspections and Evaluations As noted previously, none of the weld discrepancies in the Reinspection Program or in the supplemental inspections and evaluations described herein impair the structural integrity of any structure or component. However, there were three types of discrepancies which resulted in a considerable reduction in load-carrying capacity. Even though these conditions were found to be acceptable for the highly stressed elements reviewed in the program, additional inspections and evaluations were performed to provide assurance of the adequacy of the entire plant. The-three types of discrepancies for which additional inspections were undertaken are categorized as follows: o Conduit support weldments o Cable tray support connec.tions with fit-up gap s o Cable tray support internal diagonal member connection a. Conduit Support Weldment The Reinspection Program identified two' cases where a portion'of the - weld was omitted from a weldment for a conduit support connection. The weldment consisted of four individual welds of which two welds-were omitted, in order to assess the effect of such ~an omission

1 5 11-7 ~ l i anywhere in the plant, a sampling plan was developed to inspect this type of weldment.. A randomly selected sample of 489 of these weldments out of an approximate total population of 3,000 were

examined to determine if all required welds had been made. In this examination, two supports were identified where the specified welds had been omitted. Based on the as-built conditions of these supports,.

an evaluation was made and it was determined that the conduit loads could be accommodated by the discrepant supports or by redistribution of loading to adjacent supports. Therefore, it has been demonstrated, with greater than 99% reliability at a 95% confidence Icvel, that the structural integrity of the conduit system is adequate. These favorable engineering evaluation results are due to the fact that the original conduit and conduit support design have design margins. Conduit supports are generally spaced closer than the maximum conduit span requirements because of physical limitations in the plant. Furthermore, the supports are initially selected from typical details. The typical details are designed using peak seismic responses for a given area of the plant. Support selection is also based on loads which assume maximum cable loads-in each conduit. When individual supports are reviewed using actual cable loads and more exact seismic analysis, there is sufficient design margin available to accommodate the weld discrepancy. b. Cable Tray Support Connections with Fit-Up Gap The supplemental Hatfield. Electric'. inspections-identified recurring - cases of welds with a fit-up gap. The engineering evaluations of these - discrepancies conservatively assumed a considerable' reduction in the - load-carrying capacities of these connections. To assess the actual eifect on ' weld capacity due' to a fit-up' gap,.a supplemental ' test program was established.- Ten. fillei welded' specimens 1with

representative fit-up gap were prepared using the app!'icable'Hatfield

(1l' 5 11-8 t-h ll i i' Electric weld procedure. These specimens were strength tested, and l the test results indicated that there was no reduction in strength of l the weld due to the fit-up gap. Therefore, it was concluded that the l fit-up gap that was identified in the Reinspection Program had no effect on the capacity of similar cable tray connections in the plant. l 1 l c. Cable Tray Support Internal Diagonal Member Connection i In the Reinspection Program and the supplemental Hatfield inspections, some of the connections for cable tray support diagonal member connections did not conform to the design configuration, in the worst ' case, a partial penetration weld was used instead of the l specified fillet weld. The engineering evaluation of this case assumed that this diagonal did not carry any load and demonstrated that the support _ could still accommodate the design loads. Although the support was adequate, in order to address the-effect of this type of discrepancy on the entire plant, the actual strength of this weld was investigated. The diagonal member with the welds in question was removed from the cable tray support and cross-sections of the welds were macroetched to determine the depth of weld penetration. Based on the results of this supplemental test, it was determined that the as-built welds had less than a 10% reduction in capacity from that calculated for the original fillet welds. Therefore, this type of discrepancy has no design significance and can be accepted for other such cases in the plant. C. PITTSBURGil TESTING The-supplemental evaluations and inspections completed for Pittsburgh Testing show that:- (1) highly stressed welds inspected by Pittsburgh Testing are capable of carrying the design loads and (2) weld discrepancies involving overlap do not mask other discontinuities or reduce the weld capacity. L

Sil-9 1. liighly Stressed Welds This evaluation considered the highly stressed connection welds from the j entire population of welds inspected by Pittsburgh Testing with weld discrepancies in the Reinspection Program. The design margin for each of the 905 welds shown in Table C-1 of Appendix C of the Reinspection Program Report was determined using the design loads and weld properties. Forty-three highly stressed welds were identified, and detailed weld map were prepared showing all weld discrepancies. The results of the evaluations for the discrepant welds in the highly stressed connections are shown in Table SCE-II. Table SCE-II Results of AWS Weld Discrepancy Evaluation for Highly Stressed Welds inspected by Pittsburgh Testing Weld Discrepancy Category A Bl B2 C Weld Weld No Strength Strength Weld c No. of Weld Structural Reduced Reduced Rejected Discrepancies impact by < 10% by3 10% (Cracks) 43 0 28 15-0 s

  • Note:

The format of this table corresponds to Table CE ll in Exhibit C-2 of Appendix C of the Reinspection Program Report. The results of the engineering evaluation showed that each weld is capable of carrying its design load.. The results of this evaluation complement the results of the Reinspection Program and give a total of 107 weld maps of discrepant welds inspected by Pittsburgh Testing which have been

$11 10 evaluated (14 randomly' selected weld maps and 50 weld maps containing the most weld discrepancies and 43 highly stressed welds). None of the discrepancies had design significance. 2. Welds with Overlap These supplemental inspections were initiated to address Pittsburgh Testing's failure rate for the inspection of welds v7ith overlap. The presence of overlap may make visual weld quality inspection more dif ficult since overlap can mask other discontinuities. The third-party inspector identified the 51 welds from the 905 weld discrepancies which had the most severe cases of overlap.. The overlapped portion of these-welds was removed by grinding and the weld was then reinspected. In all cases, the remaining weld was at least the size specified by the design. These welds revealed no other discrepancies. Because it was found after grinding that no other discontinuities were masked by overlap and that the weld size remained within the specified limit, it is concluded that the amount of overlap present on welds inspected by Pittsburgh Testing has no' impact on the capacity of the welds. I 1 a k y

5 111-1 111. SUPPLEMENTAL INSPECTIONS AND EVALUAT.lONS FOR OBJECTIVE ATTRIBUTES FOR flATFIELD ELECTRIC A. INTRODUCTION Appendix D to the Reinspection Program Report included commitments to do ' additional inspections for Hatfield Electric objective attributes where the sample size was not statistically significant. These supplemental inspections are described in Note 5 to Table DE-5, in Exhibit D-1 of Appendix D cf the-Reinspection Program Report, and include equipment setting, equipment modifications, A325 botting, and conduit support bolting. B. EQUIPMENT SETTING The work reinspected as part of the Rein 3pection Program did not include any reinspection of equipment setting. In order to complete the data base, the setting of 50 randomly selected pieces of safety-related electrical equipment from a total population of approximately 250 have been reinspected. A total of 778 items were inspected and 34 discrepancies were identified. An evaluation was made to determine whether or not the observed discrepancies have any design s significance. The result of this evaluation is that none of the observed discrepancies has design significance. The majority of the discrepancies consist of equipment anchoring details with weld length and weld spacing deviations. The equipment anchoring details were determined to be adequate because of the conservatism which was used in the determination of design anchorage loads. The only deviation which resulted in a significant reduction of strength was a hold-down weld detail for 4160 volt switchgear. In this detail, welds on the two short sides of a four-sided weld were omitted. In order to evaluate the overall effect of this discrepancy it was assumed that all of the 4160 volt switchgear had this discrepancy. Because of the conservatism in the original equipment ~ anchorage loads, it was determined that the as-built condition was adequate to support the required loads.

A Sill-2 A few discrepancies involved discontinuities in the equipment grounding - connection. The discontinuities were determined to be acceptable because of the pr'esence of an alternate grounding connection in each case. C. EQUIPMENT MODIFICATION The work reinspected as part of the Reinspection Program included reinspection of 27 iterns associated with equipment modification. This sarnple was too small to permit meaningful reliability calculations. In order to expand the data base, an additional random sample of 50 pieces of safety-related electrical equipment out of a total population of 250 have been reinspected. Equipment modification work is, in large part, not recreatable.J Several modifications may be made to the same L equipment. A subsequent modification rnay alter a previous modification. Modifications may be made by the electrical contractor, the equipment supp!!er, Commonwealth Edison Operational Analysis Department, or Conunonwea:th Edison Byron Station personnel. To accomplish the supplemental reinspection of equipment modification, a 100% wiring inspection was made. A total of 1,850 items covering a considerably larger number of inspection points were inspected.md 44 discrep.mcies were identified. An evaluation was made to determine whether or not the observed discrepancies had any design significance. The result of the evaluation is that none of the observed discrepancies has design significance. The discrepancies are primarily minor wiring variations that do net affect the functioning of the equipment. ] D. A325 BOLTING In the Reinspection Program only eight cases of A325 bolting in electrical supports were reinspected. In order to expand this data base, an additional random sample of 51 supports out of a total population of 169 supports using A325 bolted connections were reinspected. The engineering evaluation established an acceptance criteria taking into account bolt relaxation and measurement accuracy. Of the 293 bolts which were reinspected on these supports,46 bolts did 9 tir

~ Sill-3 not meet this acceptance criteria. The design of the associated connections was i reviewed, and it was deterrnined that these connections are adequate as bearing rather than friction type connections. Although these discrepancies have no design significance, because of the number of discrepancies found, a retorquing of I all Hatfield A325 bolting installation has been initiated. Any discrepant conditions will be corrected. / E. CONDUIT SUPPORT BOLTING e The work reinspected as part of the Reinspection Prograrn did not include l checking the torque level of conduit support bolting. Conduit support bolt torque was deemed not recreatable because it could not be associated with an individual inspector. In order to resolve questions concerning conduit support bolting, 305 randomly sciected supports were reinspetted from a total of approximately '23,000. A total of 1,00S bolts were inspected. Torque values were recorded for i any bolt with torque less than the minimum installation criteria. The engineering evaluation established an acceptance criteria taking into account bolt relaxation and measurement accuracy. Thirty-four bolts did not meet this acceptance criteria. These conditions were evaluated and found to have no design - significance because the loads would be carried by the adjacent supports. in this process of inspecting conduit support bolt torques, two clamps with four bolts were found missing. Based on our concern for missing clamps and bolts,'a walkdown of the critical clamps was undertaken. A critical clamp is typically - located where a conduit terminates. There were 3,532 cases included in this ' initial walkdown and ten cases were found with missing bolts or clamps. The walkdown of the remaining accessible conduit is continuing to ensure that conduit 7 clamps and bolts are in place. Any missing bolts or clamps will be restored. l. ( i j .j +,,

Sill-4 F. CONCLUSION The supplemental inspections and evaluations which have been conducted for flatfield lifectric objective attributes confirm the adequacy of the quality of work. O

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n -gdg. . ERRATA AND ADDENDA.TO THE REPORT ON THE~ BYRON QC r INSPECTOR REINSPECTION PROGRAM J t I: l-i [ 5 - i I-Insert the following page behind the first title page. - 6 4 4 0 1 b ' s b e 9 e 5-Y

s, .. = e-ERRATA AND ADDENDA n TO hli REPORT ON THE BYRON l QC INSPECTOR. ll H REINSPECTION PROGRAM .The following pages contain errata and/or addenda: Page Numbers [. ES-4, 6 VI-5, 6 VII-2, 9,10,11,12,13 Exhibit VII-l page 3,5 A-6 B-6 C-1,2,4, Exhibit C-1 page 3,4 Exhibit C-2 page 2,7,8, 9,1I F-6 f /. June,1984 b

.? ERRATA AND ADDENDA TO TIIE REPORT ON TIIE BYRON QC INSPECTOR REINSPECTION PROGRAM Page ES-4 Table ES-1 Reinspection Program Summary Line Indicating Revision Change 26,660 to 27,538 Change 92.0% to 92.8% Change 86,905 to 87,783 Line Indicating Revision Change 44,980 to 45,858 Change 201,906 to 202,784 1 i 1 (The revised page for the Reinspection Program Report follows.) t 9

m ES-4 D. BYRON RiilNSPECTION PROCkAM RESULTS The results of the Reinspection Program are summarized by contractor in Table ES-1. This-table also delineates the number of reinspections performed as part of the Program. Table ES-1 ReinspectioiiProgram Summary Total Objective. Subjective Objective No. of Inspection No.of Inspection and Objective Results Subjective Results Subjective Contractor inspections

  • Acceptable ! Inspections' d Acceptable,3 Inspections 2

Blount Brothers 2,390 98.8% NA NA 2,390 4 4 Johnson Controls 7,812 99.4 % 1,459 x 95.5% 9,271 Hunter 69,624 99.0 % 3,725 97.0 % 73,349 NISCo 2,792 99.6 % 229 100.0 % 3,021 Hatfield Electric 60,245 96.5% 27,538 92.8 % 87,783 R1 4 N Powers-Azco-Pope 8,047 96.3 % 6,607 86.2% 14,654 Pittsburgh Testing 6,016 98.9 % 6,137 85.3%" 12,153 Peabody Testing 0 NA 163 75.5%) 163 TOTAL 156,926 45,858 202,784 R1 From Appendix D, Table D-1.

  • From Appendix C, Table C-1.

Notes for Table ES-1:

1. Program acceptance criterion is 95%.
2. Program acceptance criterion is 90%.

i

3. Includes concurrence by third-party inspector.

100% of inspectors samp!cd; 100% of accessible work for inspectors rot meeting 4t acceptance criterion reinspected.

5. 100% of inspectors sampled; 100% of accessible work reinspected.

As can be seen from Table ES-1, over 200,000 reinspections were performed as part of the Byron Reinspection Program. All seven contractors performing objective - inspections exceeded the acceptance criterion. Four of seven 5 e s

ERRATA AND ADDENDA TO TI!E REPORT ON TIIE BYRON QC INSPECTOR REINSPECTION PROGRAM Page ES-6 Section 3. - Plant Quality inferred From the Reinspection Program Line Indicating Revision Change 4t,930 to 45,858 Change 4,132 to 4,001 l (The revised page for the Reinspection Program Report follows.)- 1 w-.._ ., ~ --,.+ +

o ES-6 j l surveillances, and evaluations implemented as part of this quality program j. further assure us that the results of the Reinspection Program are l representative of the overall plant quality. 2. Plant Quality inferred From Inspector Qualification The Reinspection Program validates the adequacy of the inspector training and certification programs in use prior to September 1982 for six out of I eight contractors reviewed. These contractors are responsible for 38% of the total work at Byron. This ensures that all work performed by these contractors was adequately inspected, from which it can be inferred that the contractors' construction work is of good quality. j l 3. Plant Quality Inferred From the Reinspection Program -For the objective inspections, a total of 156,926 items were reinspected, and 3,247 discrepancies were noted. For the subjective inspections, a total of 45,853 items were reinspected, and 4,001 discrepancies wcre noted. The R1 evaluation of these subjective and objective discrepancies showed that many of the discrepancies are insignificant or do not affect the design (e.g., chipped paint, documentation, measured dimensions different than those of the, original inspector but still within design tolerance, etc.). The remaining discrepancies which had potential for affecting the design were evaluated further. Thiscengineering evaluation showed that these discrepancies had no design significance. This provides direct evidence of the quality work at the Byron Station. F. CONCLUSIONS 1. The Byron Reinspection Program has been completed in accordance with the agreement reached with the NRC staff. 2. The Program verified that the vast majority of inspectors whose work was reinspected passed the established acceptance criteria and were qualified (see Table ES-2). l i n l l .o

~ _. ERRATA AND ADDENDA TO Tile REPORT ON TIIE BYRON QC INSPECTOR REINSPECTION PROGRAM Page VI-5 Line Indicating Revision Change 2,117 to 1,986 Change 11 to 8 Change 2,064 to 1,936 Line indicating Revision Change I to 10 Change 887 to 878 Line Indicating Revisior. Change 4,132 to 4,001 Change 253 to 259 Change 3074 to 2937 Line Indicating Revision Change 253 to 259 4 i i (The revised page for the Reinspection Program Report follows.)

VI-5 C. RESULTS Olt ENGINEERING EVAltJATION 1. Subjective Discrepancy Evaluation The results of the subjective discrepancy evaluations for each contractor are summarized in Table VI-1. Tabic VI-l Summary of Subjective Discrepancy Evaluation Results No.of Category X Category Y Category Z No. with Discrepancy No. Within No. Acceptable No. Acceptable Design Contractor Evaluations Parameters by Judgment by Calculation Significance Blount Brothers

  • 0 N/A N/A N/A N/A Johnson Controls 65 15 12 38 0

Hunter 109 25 23 61 0 NISCo 0 N/A N/A N/A N/A Hatfield Electric 1,986 8 1,936 42 0 R1 Posvers-Azco-Pope 914 201 7' 636 0 Pittsburgh Testing 905 10 878 17 0 R1 Peabody Testing 22 0 11 11 0 TOTAL 4,001 259 2,937 805 0 R1

  • Inspection of Blount Brothers was performed by Pittsburgh Testing.

Inspection results are reported under Pittsburgh Testing. Table VI-l shows that 259 of the discrepancies (6%) identified in the R1 Reinspection Program are not " valid" discrepancies and represent work that is within current design parameters. The Category X discrepancies result primarily from design parameters that have been expanded since the time of the original inspection. Therefore, the observed discrepancies are actually within current design limits. 5 e

ERRATA AND ADDENDA TO TIIE REPORT ON Tile BYRON ' QC INSPECTOR REINSPECTION PROGRAM j l Page VI-6 Line Indicating Revision Change 3,074 to 2,937 ~ Line Indicating Revision Change 19% to 20% r e a f - (The revised page for the Reinspection Program Report follows.) ? i e 4 ,,p 3 ,.,n 3w.--,- ,,w-y g

VI-6 The Category Y evaluation covered 2,937 of the weld discrepancies (74%) R1 wherein weld capacity was reduced by approximately 10% after accounting for the weld discrepancy. In all cases the margin remained within the specified design limits. The Category Z evaluation covered 805 of the weld discrepancies (20%). RI The reduction in weld capacity varied after accounting for the weld discrepancy. However, in all cases the design margin remained within the specified design limits. The engineering evaluation of subjective discrepancies has shown that none have design significance. A detailed presentation of subjective discrepancy evaluation is contained in Appendix C. 2. Objective Discrepancy Evaluation The results of *he objective discrepancy evaluations for each contractor are summarized in Table VI-2. l 4 P e 0 0 4

ERRATA AND ADDENDA TO Tile REPORT ON Tilti BYRON QC INSPECTOR REINSPECTION PROGRAM Page Vll-2 Line Indicating Revision Added phrase and changed 156,926 to 160,857 Line Indicating Revision Change 44,980 to 47,676 Line Indicating Revision Added word " objective" Line Indicating Revision Added sentence Line Indicating Revision Added footnote Add Page VII-2A (The reviwd pages for the Reinspection Program Report follow.)

VII-2 uniformly effective, performed most of his work af ter September l982. The vast majority of the work performed prior to September 1982 was reinspectable, and 100% of that reinspectable work for all inspectors failing to pass the Program acceptance criteria was reinspected. Because no discrepancy of design significance was identified, the quality of work was shown to be good. Peabody Testing had too little reinspectable work from which conclusions on certification program effectiveness could be drawn. However, this contractor had a very limited scope of work (0.2% of the site total), most of which was overinspection of other contractors or inspections overseen by Commonwealth Edison personnel. Inasmuch as 100% of this contractor's reinspectable work was reinspected and no discrepancy with design significance was found, the good quality of this contractor's work can be inferred. 1 3. The Reinspection Program and supplemental inspections" subsequent to R1 the Reinspection Program resulted in a total of 160,857 objective inspections and a total of 47,676 subjective inspections being repeated by R1 currently qualified inspectors. These reinspections ranged over a wide variety of plant work items. Engineering evaluation of all observed I objective discrepancies showed that none had design significance. R1 Engineering evaluation of all subjective discrepancies for six contractors R1 and a representative sample of discrepancies for Hatfield Electric and j Pittsburgh Testing Laboratories showed that none had design significance. i This data supports the inference that the quality of work for all eight contractors in the Reinspection Program was good. The remainder of this chapter elaborates upon and substantiates these points. 1 B. MANAGEMENT APPROACH TO ENSURE QUALITY OF CONSTRUCTION l Commonwealth Edison has implemented a comprehensive quality program to assure that the Byron Station is constructed properly and is of high quality. The program begins prior to award of contracts by requiring that procurement documents include commitments to specific quality requirements and it continues a These supplemental inspections were performed as a result of commi - a to the Rt NRC staff. )

VII-2A throughout the construction phase. The essence of the approach is the provision of many independent layers of inspection and review of field installations to assure compliance with requirements and, thereby, to ensure quality construc-tion. s O s t 1

l =o ERRATA AND ADDENDA TO Tile REPORT ON Tile BYRON QC INSPECTOR REINSPECTION PROGRAM i Page Vil-9 i i Lines Indicating Revision Added and inodified sentences 1 t 4 I i i n d l' I i 1 b i 1 4-i } i i j - 3 L 4 I i . (The revised page for the Reinspection Program Report follows.) a h i

p m

1 1

~ VII-9 acceptance criteria, and no observed discrepancies were determined to have design significance. The quality of their work is inferred from the reliability calcualtion presented in Section D below, i D. INFERENCE OF WORK QUALITY FROM Tile REINSPECTION RESULTS R1 In this section, the detailed reinspection data given in Appendix B and, the engineering evaluation data given in Appendixes C and D ana the supp!cmental RI inspections and evaluations presented in Section !! and III of the Supplement to the Reinspection Program are combined to obtain reliability estimates for each of the eight contractors' work. These re!!abilitics are intended to address the quality levels for work that was not reinspected. 1. App,licability of Data to Plant Quality inferences R1 The data from the Reinspection Program and the supplemental data R1 provide a reasonable basis for estimating plant quality when samples are adequate in size and scope, and the entire Reinspection Program is of sufficient technical scope. The question of sample size and adequacy of representation for sampled inspectors in the overall inspector population is discussed in section C above. The sampling of inspectors' work was not entirely random in that it concentrates entirely on cach inspector's first 3 months of work. tiowever, i R1 l the selection of the inspectors was random, and thus the work reinspected I was largely random from a plant quality viewpoint. It should be noted l that the calculation of the reliabilitics presented below is based on a formal statistical methodology which assumes random selection of R1

sampics, llowever, the biases introduced by the sample selection procedure are conservative and the results of the formal calculation are thus justified in that they are underestimates of the true reliabilitics.

The sufficiency of technical scope is an engineering judgment that relates to the relevance of inspected attributes to work quality. Based on the QC procedures and their associated checklists used in the Reinspecion Program, it is our conclusion that the Reinspection Program did have suf ficcient technical scope to yield information, on construction quality. e e

ERRATA AND ADDl!NDA TO Tile REPORT ON Tile BYRON QC INSPECTOR REINSPECTION PROGRAM Page VII-10 Evaluation of Reliabilities Line Indicating Revision 4 Change Sentence Line Indicating Revision Change 44,980 to 45,853 Line Indicating Revision t Change 4,132 to 4,001 Change Paragraph Add Page VII-10A 1 1 I l \\ (The revised pages for the Reinspection Program Report follow) e

vil-lg. 2. Evaluation of Reliabilities in the Reinspection Program, for objective inspections, a total of 1%,926 R1 items were reinspected and 3,247 discrepancies were noted (Appendix D). For the subjective inspections, a total of 45,858 iterns were reinspected, R1 and 4,001 discrepancies were noted (Appendix C). All the objective Rt discrepancies which had potential for affecting the design were evaluated. This engineering evaluation showed that none of these discrepancies had design significance. Engineering evaluation of all subjective discrepancies for six contractors and a representative sample of discrepailcies for Hatfield Electric and Pittsburgh Testing 14 i Laboratory showed that none had design significance. Subsequent to the Reinspection Program, objective inspections for an additional 3,931 items and subjective inspections for an additional 1818 welds were performed. All the discrepancies which had a potential for affecting design were evaluated. This evaluation showed that none of these discrepancies had design significance. These evaluations demonstrate the good quality of the work performed by the contractors reviewed at tne Byron Station. Tables Vile-1 through Vile-8 of Exhibit Vil-1 list the number of inspected items, the number of discrepancies of design significance, and calculated reliabilities for each of the eight contractors. Objective and subjective attributes are listed separately. The reliability for each attribute can be defined as the proportion of work items in the total population of work for that attribute which have no discrepancies with design significance. Statistical estimates of the reliability can be made from inspections and engineering analyses of, random samples from the population. The precision of ther,e estimates, of course, increases with the sample size. - _ _ _ - = - _ _ _ - _ _ _ _ _ - _ _ _ _ - _ _ - _ _. _ - _.

i i I Yll-10A '1 A generally accepted statistical method for calculating such reliabilities is to compute reliabilities at 95% confidence level from the samp!cd data. Such a reliability represents a con <.crvative estimate of the true reli-ability. It is conservative in the sense that there is a 95% chance that the true reliability is greater than the estimate. In the case where no l discrepant items are observed in a random sample from a large population, the reliability at 95% confidence level can be calculated from the formula' i ilTJfeieininT Miller. I.,.mifl7eiiiid,3.1:., " Probability and statistics fcr Engineers " Prentire llall, Inc.,19/7, Chapter 9. m

j. !l ERRATA AND ADDl!!4DA TO Tile Rl! PORT ON Tilli1)YRON QC INSPECTOR REINSPECTION PROGRAM Page Vll-11 Line Indicate Revision Change 25 to 29 Line Indicating Revision i Change 30 to 31 l: Change 21 to 2h l Line Indicating Revision l. Change four to five i Line Indicating Revision Change five to two Line Indicating Revision Change five to two Page VII-12 i Line Indicating Revision Change 5 to 6 Deletes part of a sentence i i Page Vil-13 i Line Indicating Revision l' Change sentence l i l I (The revised pages for the Reinspection Program' Report follow.) , f, 1 J 9 D I. c c

VII-I1 R = 1 23951 Eq. VII-l n ~ where R = Reliability at 95% confidence level - n = number of inspections in the random sample In Exhibit Vil-1 and Tables Vile-1 (Blount), Vile-2 (Johnson Controls), VIIE-3 (Hunter), VIIE-4 (NISCo), Vile-5 (Hatfield), Vile 36 (Powers-Azco-Pope), Vile-7 (Pittsburgh Testing), Vile-3 (Peabody Tcsting), which follow, the reliabilities presented are based on Eq. VI!-1,. i.e., they represent reliabilities at 95% confidence level based on samples which contained no discrepancies of design significance. It should be emphasized that, when a. sample size is small, the true reliability is likely to be much greater than indicated. Tables Vile-1 through Vile-8 show better than 95% reliability for 29 of the R1 31 attributes reinspected. In 24 of these cases, the calculated reliabilities R1 are better than 99%. For five cases, the reliabilities are computed in the R1 96% to 99% range. For the remaining two cases, in these tables no R1 reliability estimate at 95% confidence level is projected because Equation VII-l requires at least 60 observations to provide 95% reliability. For these two cases,' the sample sizes were too small to obtain meaningful R1 reliabilities based on Equation VII-1. This does. not prevent us from concluding, on the basis of calculated reliabilities, that all contractors performed good work. This conclusion remains valid because all inpectors within a contractor organization were qualified under the same program and good reliability demonstrated in one objective attribute provides a valid basis for inferring the reliability in another objective attribute where e G

Vil-12 sampling was limited. In Table Vile-6, three out of five attributes have R1 better than 95% reliability, therefore it is inferred that the reliabilitics not listed in the tables would also be better than 95E Note that for attributes where the nurnber of items reinspected is large (>300), the computed reliabilities are better than 99E This is indicative of good quality work. The above discussion of reliabilities indicates that better than 95% reliability is expected for the work of all eight contractors. This component !cvel reliability is considered to be high enough to conclude that work quality is good. E. CONCLUSIONS The evaluation of Commonwealth Edison management approach to ensure quality of construction and the successful completion of the Reinspection Program ! cads us to conclude that: 1. The good quality of construction at Byron is ensured because of the comprehensive quality program implemented by Commonwealth Edison management. The many layers of inspections, overinspections, audits, surveillances, and evaluations implemented as part of this quality program further assure us that the results of the Reinspection Program are. representative of the overall plant quality. 2. With limited exceptions, the Reinspection Program verified the effectiveness of QC inspector certification programs prior to September 1982. This ensures that work performed by the contractors whose programs were effective was _ adequately inspected, from which it can be inferred that the contractor's construction work is of good quality.. The _ quality of work for the contractors whose QC inspector programs were not verified has been confirmed through additional reinspection and evaluation. 1 5 + 3 0 AA t-9

ti

1 l

Vil-13 1 ) 3. The adequacy of construction quality for all eight contractors is supported by the Reinspection Prop, ram results, the results of the supplemental R1 inspections subsequent to the Reinspection Program, and by inferences drawn from these results. e i 4 0 O

l ERRATA AND ADDEN11A TO Tile REPORT ON Tilh BYRON l QC INSPECTOR REINSPECTION PROGRAM l I Exhibit Vil-1 Page 3 of 5 I' ltem A. - Objective Attributes Line Indicating flevision. Change O to 778 and add 99.6 Line Indicating Revision Chan;c 3 to 295 and add 93.9 Line Indicating Revision i Change 27 to 1850 and add 99.8 Line Indicating Revision Added item 9 Line Indicating Revision Change footnote Item B. - Subjective Attributes l Line Indicating Revision 3 Change 26,660 to 27,538 and 99.9 to >99 Line Indicating Revision Added Footnote e (The revised page for the Reinspection Prograin Report follows.) -W, s-.- .+ -e- , r .~

Exhibit Vll-l Page 3 of 5 Table Vile-5 Calculated Reliabilities for Work of Hatfield No.of Reliability No.of Discrepancies % at 95% Inspected with Design Confider.cc Items Significance Level A. Objective Attributes 1. Conduit 2,793 0 99.9 2. Terminations 7,784 0 >99.9 3. Equipment setting" 778 0 99.6 R1 4. A325 bolting" 295 0 98.9 R1 5. Equipment modification

  • 1850 0

99.8 R1 6. Conduits as-built 44,777 0 >99.9. 7. Pan hangers 4,776 0 >99.9 8. Pan 80 0 96.3 9. Conduit support bolting

  • 1,008 0

99.7 'R1 B. Subjective Attributes 1. VisuaI welds - 27,538 0** >99** R1 Supplementalinspections subsequent to the Reinspection Program. R1 Inferred from the engineering evaluation presented in Appendix C. R1 I-4

l jL ERRATA AND ADDiiNDA TO Tl111 RiiPORT ON Tilli15YitON QC INSPIICTOR REINSPliCTION PROGRAM 1 Exhibit Vil-1 Page 5 of 5 Line Indicating Revision 4 Added " Work inspected By" Lir.e Indicating Revision Changed 99.9 to >99"

  • Line Indicating Revision Added Footnote i

i -'(The revised page for the Reinspection Program Report follows I

l

.l

~ [ Exhibit Vil-1 Page5of5 i L 1: Table VIIE-7 Calculated Reliabilitics for Work Inspected by R1 Pittsburgh Testing 1 No.of Reliability No.of Discrepancies % at 95% inspected with Design Confidence Items Significance Level A.. Objective Attributes 1. Concrete expansion anchor 6,016 0 >99.9 B. Subjective Attributes 1. Visual welding 6,137 0** >99** R1 Inferred from the engineering evaluation presented in Appendix C. R1 Table Vile-8 Calculated Reliabilities for Work of

Peabody, No.of Reliabilty No.of Discrepancies

% at 95% Inspected with Design Confidence A. Objective Attributes items Significance Level None B. Subjective Attributes 'l. Visual welding

  • 163 0

98.2 5 100% of accessible and recreatab!c work was reinspected. 4

i ERRATA AND ADDENDA TO Tile REPORT ON Tile BYRON QC INSPECTOR Rii!NSPliCTION PROGRAM Page A-6 - Item A. - Results brInspection Type Line Indicating Revision Change 89.9% to 88.6% Change 92.1% to 92.8% Line Indicating Revision Change (23,978/26,660) to (24,402/27,533) ~ Change (24,543/26,660) to (25,552/27,538) Under Item B. - Results by Inspection Attribute Line Indicating fievision Change 92.1% to 92.8% ' ine Indicating Revision Change 2,682 to 3,136 (The revised page for the Reinspection Program Report follows.) t

l[ ERRATA AND ADDENDA TO TIIE REPORT ON Tile BYRON QC INSPECTOR Rl!!NSPliCTION PROGRAM L it. i Page A-6 Item A. - Results by inspection Type Line Indicating Revision Change 89.9% to 88.6% Change 92.1% to 92.8% Line Indicating Revision Change (23,978/26,660) to (24,402/27,538) Change (24,343/26,660) to (25,552/27,538) Under item B. - Results by Inspection Attribute Line Indicating Revision Change 92.1% to 92.8% Line Indicating Revision Change 2,682 to 3,136 l (The revised page for the Reinspection Program Report follows.) 5

q 0 ERRATA AND ADDENDA TO Ti!E REPORT ON TIIE BYRON l QC INSPECTOR RlilNSPliCTION PROGRAM i Page A-6 Item A. - Results brinspection Type Line Indicating Revision Change 89.9% to 88.6% Change 92.1% to 92.8% Line Indicating Revision Change (23,978/26,660) to (24,402/27,538) Change (24,543/26,660) to (25,552/27,538) Under item B. - Results by inspection Attribute ' Line Indicating ({evision Change 92.1% to 92.8% Line Indicating Revision Change 2,682 to 3,136 (The revised page for _the Reliispection Prograni Report follows.) - S-

i ERRATA AND ' ADDENDA TO TIIE REPORT ON TIIE BYRON l QC INSPECTOR RlilNSPECTION PROGRAM i' i Page A-6 Item A. - Results by Inspection Type Line Indicating Revision Change 89.9% to 88.6% Change 92.1% to 92.8% Line Indicating Revision Change (23,978/26,660) to (24,402/27,538) Change (24,543/26,660) to (25,552/27,538) Under Item B. - Results by Inspection Attribute Line Indicating Revision Change 92.1% to 92.8% Line Indicating Revision Change 2,682 to 3,136 1 J . (The revised page for the Reinspection Program Report follows.)- S

A-6 Table A-5 Reinsisction Results flatfield Electric A. Results by Inspection Type Reinspection Results (Acceptable / Total) Type Level Il Reinspection Third-Party Review Subjective 88.6 % 92.8 % R1 (24,402/27,538) (25,552/27,538) R1 Objective 96.5% (2) B. Results by Inspection Attribute Initial Samole Period Expansion Sample Period No.' oft)cople Final % No. of People Final % Attribute Reinspected Acceptable Reinspected Acceptable

1. Visual weld (Subjective) 8 92.8 %

(1) (1) Rl'

2. Conduit 6

97.6 % (1) (1) ~ 3. Terminations (Objective) 5 99.9 % (1) (1)

4. Equipment setting 0

0% (1) (1) (Objective)

5. A325 botting i

100.0 % (1) (1) (Objective)

6. Equipment modification 3

100.0 % (1) (1) l (Objective)

7. Conduit as-bull-3 95.9 %

(1) -(1) (Objective)

8. Cable Pan hangers 2

95.5% (1) - (1) (Objective)

9. Cable Pan 1

100.0 % (1) (1) (Objective) Notes for Table A-5:

  • Results are cumulative. 3,136 observed discrepancies were reinspected by R1 third-party inspectors.

- (1) Not required (2) Not applicable 4 g. w-

ERRATA AND ADDENDA TO Tile REPORT ON Tile BYRON QC INSPECTOR REINSPECTION PROGRAM Page B All entries under Table B-5 Detailed Inspector Results Ifatfield Electric - Attributes All items under Attribute No. I have been revised. Change Item A 828/365 to 833/863 Change Item C 60S/693 to 630/712 Change item E 10221/11312 to 10554/11501 Change item G '724/771,to 1132/1211 Change item I 4233/4439 to 4462/4701 Change item N 3309/3404 to 3331/3489 Change Item O 31/51 to 50/50 Change Item W 4369/5070(3) to 4510/5011(3) Change total 24543/26660 to 25552/27538 i (The revised page for the Reinspection Program Report follows.)- ..z

= ll \\l B-6 1l i -Table B-5 Detailed liiigiector Results t ~ II5tIicId'Iliect7Ic~ Attributes Inspector No. I No.2 No.3 No.4 No. 5 No.6 No.7 No.8 No.9 A 833/863 R1 B 4795/4974 t C 630/712 R1 D 80/80 638/638 (1) 8/8 E 10554/11501 187/188 48/48 R1 F 178/179 72/72 2/2 G 1132/1211 386/401 544/546 1/1 R1 H 3985/4112 1 4462/4701 R1 J 639/661 K 1256/1284 L 705/742 M 10952/11457 N 3381/3489 R1 0 50/50 R1 -P 2001/2081 Q 4818/5055 R 11734/12205 S 2753/2879 T . 1917/2014 U 6473/6480 (2)- -.24/24(2) V 3854/4034 80/80 W 4510/5011(3) R1 TOTAL 23552/27538 2726/2793 7775/7784 8/8 27/27 42955/44777 4559/4776 80/80 R1 Notes for Table B-5: No expanded sampling was required; a substitution (W) was made for (C) in Attribute No. I because (C) failed the first 3-month period but had no further inspections to reinspect. Attribute 1 - Visual weld Attribute 2 - Conduit Attribute 3 - Terminations Attribute 4 - Equipment setting Attribu.c.5 - A3?5 bolting. Attribt t6 6 - Equipment modification Attribute 7 - Conduit as-built Attribute 8 - Pan hangers Attribute 9 - Pan (. Notes for Table B-5: Continued on the following page) L 2 e T

ERRATA AND ADDENDA TO TiiE REPORT ON Tile BYRON QC INSPECTOR REINSPECTION PROGR AM bgeC-1 Appendix C Engineering Evaluation of Subjective Discrepancies Item B. - Quantity of Subjective (Weld) Inspection Discrepancies Line Indicating Revision Change 4,132 to 4,001 Line Indicating Revision { Change 44,980 to 45,858 Table C Summary of Weld Discrepancies by Contractor Line Indicating Revision 4< Change 26,660 to 27,338 1 Change 2,117 to 1,986 Line Indicating Revision Change 44,980 to 45,858 Change 4,132 to 4,001 k u 1 I 4

(The revised page'for the Reinspection Program Report'followi) 6d

]

C-1 APPENDIX C ENGINiililllNTl1VeiEUATION OF ~SUBJIiCTIVE DISCREPANCIES A'. -INTRODUCTION Thi.s appendix has been reformatted from the Appendix C submitted with the January 12, 198t, Interim Report. A sample of the subjective (weld) dis-l crepancies was evaluated for the Interim Report. All weld discrepancies have been evaluated and tabulated for this report. The tables which form part of this appendix tabulate discrepancies by type and by method of engineering evaluation. B. QUANTITY OF SUBJECTIVE (WELD) INSPliCTION DISCREPANCIES The Reinspection Program identified 4,001 weld discrepancies associated with R1 visual weld quality inspection out of 45,858 welds inspected. Table C-1 R1 summarizes the number of welds inspected and weld discrepancies for each contractor.. ' Table C-1 Summary of Weld Discrepancies by Contractor No. of Welds - No. of Weld Contractor Inspected -Discrepancies Blount Brothers 0*- N/A Johnson Controls 1,459 65 Hunter 3,725 109 N15Co - 229 0 Hatfield Electric 27,538 1,986 R l -' Powers-Azco-Pope 6,607' 914 Pittsburgh Testing 6,137 L905

Peabody Testing 163 22**

TOTALS _'45,858 4,001 R1 Inspection of Blount Brothers was performed.by Pittsburgh Testing. The. -inspection results are reported under Pittsburgh Testing.

    • 40 discrepancies v" re identified; 13 were-located in non-safety related structures.

b n

liRRATA AND ADnliNDA TO Tl111 Rl! PORT ON Tilli BYRON QC INSPl!CTOR Rl!INSPliCTION PROGRAM Page C-2 Category Y Delete last seri:ence in paragraph l (The revised page for the Reinspection Program Report follows.) L_

C-2 C. CATEGORIZATION OF SUBJECTIVE DISC'lEPANCIES 4 An engineering evaluation has been performed for each observed subjective (weld) discrepancy. The evaluation methods used can be divided into three categories. These three categories are related to the acceptance criteria for visual weld inspection. The acceptance criteria consists of inspecting welds for arc strike, j spatter, convexity, crater, incomplete fusion, overlup, porosity, undercut, underrun, and cracks. The presence of these weld inspection items are considered as weld discrepancies. These weld discrepancies. vary in degree as to their effect on weld capacity. j Category X - Evaluation by comparison with current design parameters and tolerances. j Category X contains weld discrepancies that do not reduce the weld capacity. Arc strikes and spatter are cosmetic indications that relate only to appearance. Convexity relates to weld metal on the faca of a weld in excess of the weld metal-2 necessary for the required weld size. Convexity has no effect on weld capacity (see Exhibit C-2 Section C.1). i_ i Category Y - Evaluation based on engineering judgment by comparison of the i discrepancy with design margins. i Category Y contains some of the following weld dis-crepancies: crater, incomplete fusion, overlap, - porosity, i undercut, or underrun. Portions of the weld with these discrepancies are considered ineffective, and wc!d capacity is ' based on a reduced weld length. Engineering judgment is used to evaluate. the weld discrepancies based on the availabic design margin in the weld and the reduced weld length,.which accounts for the assumed inef fective portions. R1 7 y 9

ERRATA AND ADDENDA TO Tile D.EPORT ON illE BYRON QC INSPEC1OR REINSPECTION PROGRAM i. Page C-4 - Table C Summary of Subjective Discrepancy Evaluation Results Line Indicating Revision ^ Change 2,117 to 1,936 Change 11 to 8 Change 2064 to 1936 Line Indicating Revision ' Change 1. to 10 . Change 887 to 878 Line Indicating Revision Change 4,132 to 4,001 Change 253 to 259 Change 3074 to 2937 Lines Indicating Revision - This paragraph has been revised.~ Add Page C-4A Line Indicating Revision Change 19% to 20% J' (The revised pag. for the Reinspection' Program Report follows.) i ,s O = t % f 7 N* F'

m C-4 3 Table C-2 Summary of Subjective Discrepancy Evaluation Results No. with Category Z Category Y Design No of Category X No. Acceptable No. Acceptable Significance No. Within by Calco_lation Discrepancy by Judgment Evaluations Parameters 0 Contractor N/A Blount Brothers

  • N/A N/A N/A 0

38 12 65 15 0 61 Johnson Controls 23 25 0 109 0

Hunter 0

0 0 R1 0 42 NISCo 8 1,936 0 Hatfield Electric 1,986 '33 6 - i 77 201 0 R1 914 17 Powers-Azco-Pope 878 10 0 905 11 Pittsburgh Testing 11 0 22 Peabody Testing 0 'R1 805 259 2,937 4,001 TOTAL h Testing. Insp'ection

  • Inspection of Blount Brothers was performed by Pittsburg 1

results are reported under Pittsburgh Testing. i tion Table C-2 shows that 6% of the discrepancies identified in the Re k that is Program as Category X are not '. valid" discrepancies and re design parameters. i the time of within current primarily from design parameters that have been expanded s nce design limits. the originalinspection and therefore are within current b d The Category Y evaluation in Table C-2. indicates that 74% of t I Powers-Azco-Pope - weld discrepancies, wherein for Johnson Controls, Hunter, l 10%' after and Peabody, the weld capacity was reduced by approximate y.In all ~ accounting for the weld discrepancy, are acceptable. i d Pittsburgh margin remained within design limits..For Hatfield Electr c an ld discrepancies Testing, the remaining weld discrepancies, beyond the 100 we j dged to be mapped for Hatfield Electric and 64 for Pittsburgh Testing,~were u R1 f ld discrepancies. It acceptable by comparison v' the number and types o we of welds are the weld discrepancies 'in the mapped set i f flatfield Electric was found that representative of the entire group of weld discrepanc es or I i and Pittsbut gh Test ng.. J '1 o m

C-4A The Category Z evaluation in Table C-2 indicates that 20% of the observed weld R1

j discrepancies are acceptable.

The reduction in weld capacity varied af ter H accounting for the weld discrepancy. However, in all cases, the design margin remained within the specified design limits. e 0 e

Exhibit C-1 Page 3 of 4 Table CE-3 Summary _of Subjectint)iscrepancy Evaluation llatiield Electric Type of Category X Category Y Category Z No. with Discrepancy Total No. Within No. Acceptable No. Acceptable Design By Attribute Quantity Parame_ters by Judgment by Calculation Significance Visual weld 1986 8 1936 42 0 RI Note for Table CE-3: 1. Categories X, Y, and Z are defined in Section C of Appendix C. Table CE-4 Summary of Subjective Discrepancy Evaluation i Powers-Azco-Pope 4 Type of Category X Category Y Category Z No. with Discrepancy Total No. Within No. Acceptable No. Acceptable Design By Attribute Quantity Parameters by Judgment by Calculation Significance Visual weld 1. Instrument 608. 167 77 364 0 tubing supports 2. Socket welds 44 1 0 43 0 (NC) 3. Socket welds 24 11 0 13 0 (ND) 4. Support -34 0 0 34 0-welds (NF) 5. Socket welds 204' 22 0 182 0 ' (B31.1) TOTAL 914. 201-77 636 0 Note for Table CE-4: 1. . Categories X, Y, and Z are' defined in Section C of Appendix C.. 4 i l ~! L

~,.. .. -. -.. ~ - ~ - - - - - 4-ERRATA AND ADDENDA TO Tile REPORT ON Tile BYRON QC INSPECTOR REINSPECTION PROGRAM EXHIBIT C-1,' Page 3 of 4 i Line Indicating Revision Change 2117 to 1986 Change 1i to 3 Change 2046 to 1936 4 4 i J 4 i. j i .i t i I ( L e j' (The revised page for the Reinspection Program Report follows.). .n r {.. e. p t N . f. -.. L c,, y

' EltitATA AND ADDiiNDA TOTilli IlliPORI' ON Tilli BYRON QC INSPliCTOR ltlilNSI'liCTION 12ROGilAM EXHIBIT C-1, Page 4 of 4 Line Indicating Revision Change I to 10 Change 837 to 873 (The revised page for the Reinspection Program Report follows.) t

Exhibit C-1 i Page 4 of 4 1 Table CE-5 Sinnmary of Subjective Discrepancy Evaluation Pittsburgh Testing Type of Category X, No. Acceptable No. Acceptable Category Y No. Within Category Z. No. with Discrepancy Total Design By Attribute Quantity Parameters by Judgment by Calculation Significance Visual weld 905 10 878 17 0 R ! L l . Note for Table CE-5: 1. Categories X, Y, and Z are defined in Section C of Appendix C. Table CE-6 Summary of Subjective Discrepancy Evaluation Peabody Testing Type of Category X Category Y Category Z No. with Discrepancy Total No. Within No. Acceptable No. Acceptable Design By Attribute Quantity Parameters by Judgment 'by Calculation Sig,nificance Visual weld 22 0 11 11 0 Note for Table CE-6: 1. Categories X, Y, and Z are defined in Section C of Appendix C. s I s' f e l. 1-I }

I!RRATA AND ADDliNI)A TO Tile RiiPORT ON Tile BY t QC INSPECTOR REINSPl!CTION PROGRAM EX111 BIT C-2, Page 2 of 15 Paragraph Indicating Revision This paragraph has been revised Add Exhibit C-2, Page 2A of l5 ( (The revised page for the Reinspection Program Report follows ) 4

ll t - r1 lixhibit C-2 Page 2 of 15 therefore have no design significance. These are limited to arc strike, j convexity, and spat ter. 1 Category B Weld discrepancies that result in a reduction of the size, length, or capacity of the weld. These include craters, incomplete fusion, l overlap, porosity, undercut, and underrun. Category B weld dis-crepancies are further subdivided into Categories B1 and B2 to qualify the significance of these weld discrepancies as follows: Category BI Weld discrepancies that have capacity reductions of less than 10E Category B2 Weld discrepancies that have capacity reductions of equal to or i greater than 10% Category C Weld discrepancies that are assumed unsuitable for load. transfer and result in total weld rejection. Cracks are the only case for this category. According to the American Welding Society, a weld discrepancy is defined as "An interruption of the typical structure of a weldment, such as a lack of homogeneity in i the mechanical, metallurgical or physical characteristics of the material or weldment. A discontinuity is not necessarily a defect" (Reference C2). !r The terms Category X, Category Y, and Category Z have been used to categorize the evaluation methods used for the AWS weld discrepancies in Chapter VI and in this appendix.. Categories A, B, and C have been used to categorize the significance of the weld discrepancy. The. evaluation methods and weld discrepancy significance are

  • {i related. Category X is equivalent to Category A, and Category Z is equivalent to i

Categories B2 and C. Category Y is equivalent to Category B1 for Johnson Controls, R1h flunter, Powers-Azco-Pope, and Peabody. For flatfield Electric and Pittsburgh - Testing, the results of the engineering evaluation of 100 mapped weld discrepancies' for Hatfic!d Electric and 64 for Pittsburgh Testing indicated no design significance. l-The mapped welds' for ifatfield Electric and Pitt'sburgh Testing were biased by -j including at least 50 welds that the third-party inspector identified as having the most j ~ weld-quality discrepancies. This was done by reviewing all the reinspection records I-q- for discrepant welds which were previously examined in the field by the same third-1

m Exhibit C-2 Page 2 of 15 therefore have no design significance. These are limited to arc strike, convexity, and spatter. ' Category B Weld discrepancies that result in a reduction of the size, length, or capacity of the weld. These include craters, incomplete fusion, overlap, porosity, undercut, and underrun. Category B weld dis-crepancies are further subdivided into Categories B1 and B2 to qualify the significance of these weld discrepancies as follows: Category B1 Weld discrepancies that have capacity reductions of less than 10% Category B2 Weld discrepancies that have capacity reductions of equal to or greater than 10E Category C Weld discrepancies that are assumed unsuitable for load transfer and result in total weld rejection. Cracks are the only case for. thb l category. According to the American Welding Society, a weld discrepancy is defined as "An interruption.of the typical structure of a weldment, such as a lack 'of homogeneity in : the mechanical, - metallurgical or physical characteristics of the material or-weldment. - A discontinuity is not necessarily a defect" (Reference C2). - The terms Category X, Category Y, and Category Z havs been used to categorize the evaluation. methods used for _the AWS weld discq v;ios in Chapter VI and in this appendix. Categories A, B, and C have been mw< tegorize the' significance of the weld. discrepancy.. The evaluation methoe; x.a, d ' discrepancy significance are. related. Category X is equivalent to Catcgory A, and Category Z is equivalent 'to ' Categories B2 and C. Category Y is equivalent to Category B1 for Johnson Controls, I-liunter, Powers-Azco-Pope, and ' Peabody. For _11atfield-Electric. and Pittsburgh Testing, the results of the engineering evaluation of 100 me, id weld discrepancies for Hatfield Electric and;64 for Pittsburgh Testing indicated no design significance. The mapped welds. for liatfield Electric and Pittsburgh. Testing were biased by. inchidityg at least 30 ~ weld, that the thirri-party inspector. identified as having the. nnst weld-quali.ty; discrepancies. This was done by reviewing all the reinspection records - for disciepant wehls which 'were previously examined in~ tije field.by the same third-- ~ a

Exhibit C-2 Page 2A of 15 l party inspectors. For the remainder of the weld discrepancies for flatfield Electric and Pittsburgh Testing, a detailed review of the reinspection records was made to assure that the number and types of discrepancies in the inapped welds were representative of the entire group. Based upon the results of the engineering calculations for the mapped wc!ds, the review of the reinspection records including discussions with the third-party inspectors, and the knowledge of the conservative design process, it was inferred that the remaining population of weld discrepancies is acceptable. On this basis, the remaining ilatfield Electric and Pittsburgh Testing weld discrepancies were placed in Category Y. 1 o' e s 4 e f v m g

ERRATA AND ADh!!NDA TO Tilli RliPORT ON Tile BYRON QC INSPliCTOR lililNSI'liC~ LION PitOGilAM .~ EXHIBIT C-2, Page 7 of 15 Paragraph 3 - Hatfield Electric Evaluation Results - AWS Weld Discrepancies-Line Indicating itevision Change 26,660 to 27,533 Change 2,117 to 1,936 Line Indicating Revision Change 2,117 to 1,986 ~ (The revised page for the Reinspection Prograin Report follows.) N g ,,g- -ip--- W -e -r v-t-H-m-' g +1

1 Exhibit C-2 Page 7 of 15 Table CE-8 Results of AWS Weld I iscrepancy Evaluation lionter Weld Discrepancy Category A BI B2 C Weld Weld No Strength Strength Weld No. of Weld Structural Reduced Reduced Rejected Weld Type Discrepancies Impact by < 10% by >_10% (Cracks) Pipe supports and pipe whip restraints 60 19 18 23 0 The results of the engineering evaluation of Hunter AWS welds indicate that each of the compcnents are adequate to carry the design loads with the obrerved discrepancies present. Based on the small number of discrepancies and the evaluation which determined that no discrepancy had design significance, the AWS welding performed by Hunter has been determined to be of good quality. 3. Ilatfield Ele tric Evaluation Results - AWS Weld Discrepancies The inspection work performed by Hatfic!d included cor.duit supports, junction-box supports, cable tray supports, cable tray hold-down welds and auxiliary steel for electrical supports. A total of 27,538 welds were reinspected and 1,986 weld R discrepancies were identified. A detailed review of the reinspection records for all 1,986 discrepancies was R made. This review indicated that there were only two cracked welds. In order to achieve 95% reliability with 92% confiderce, a statistical sampling plan was chosen in accordance with Military Standa:d 105D. The resulting sample size for the engineering evaluation was 100 welds. The sample was conservatively biased' ~ by. including.the 50 welds' that the third-party inspector identified as having the. ~ most weld quality discrepancies.' The two welds with cracks were part of that. . group. -The remaining 50 wc!ds were randomly selected. .q-L

ERRATA AND ADDENDA TO Tile REPORT ON TIIE BYRON QC INSPECTOR REINSPECTION PROGRAM EXHIBIT C-2, Page 8 of g Line Indicating Revision Change 35 to 36 Change 15 to 16 Line Indicating Revision Change 36 to 34 Change 17 to 16 Change 18 to 17 Line Indicating Revision Change 29 to 30 Change 19 to 20 l f. r 4' (The revised page for the Reinspection Program Report follows.) F

r EXillBIT C-2 Page 8 OF 15 The results of the engineering evaluation for the sample of 100 Hatfield welds are shown in Table CE-9. Table Cli-9 ~ Results of AWS Weld lliscrepancy livaluation llatfield ElectrTc~~ ~ i Weld Discrepancy Category A B1 B2 C Weld Weld No Strength Strength No. of Weld Structural Reduced Reduced Rejected Weld Type Discrepancies Impact by < 10% by 2 10% (Cracks) a. Conduit / junction box supports and associated auxiliary steel 36 2 17 16 1** R1 b. Cable tray supports and associated auxiliary steci 34 1 16 17 0 R1 c. Cable tray hold-down 30 2 20 7 1* R1 -TOTAL 100 5 53 40 25** One of the two hold-down welds attaching the cable tray to its support was cracked. It was found that, after subtracting the entire length of the cracked weld, the other weld was sufficient to transfer the design loading. Temporary tack weld used to aid construction was cracked. The tack weld is not required by design. There is no crack in the design weld.. The potential of crack propagation into the base metal was evaluated. For the two reported cases, based on the fracture toughness of the materials, it was determined that the cracks will not propagate into the base metal under the maximum design loading and minimum plant operating temperatures. Design margins exist in conduit and junction box supports and associated auxiliary steel because the initial design conservatively assumed maximum (

=. =,_. 4 ERRATA AND ADDliNI)A TO Tile IREPORT ON Tile BYRON QC-ji ' INSPECTOR REINSPliCTION PROGRAM - rl Exhibit C-2, Page 9 of 15 f.ine Indicating Revision [ Change 36 to 34 I Line Indicating Revision Change 13% to 14% Line Indicating Rev,ision p Change 29 to 30 ei: r i i 1 r 4 - (The revised page for'the Reinspection Program Report follows.)$ ~ / r y

EXillBIT C-2 Page 9 cf 15 cable weight in each conduit. In addition, the supports and auxiliary steel are conservatively designed for peak seismic acceleration. When a more exact calculation was performed using actual cable loads and actual seismic acceleration, the design margin exceeded a 1.5 factor. This design margin it representative of the highly stressed conduit and junction bo, supports and associated auxiliary steel in the plant. The weld strength reduction for all but the two lowest quality welds was applied to all of the ' components with weld discrepancies and the weld stresses remained within design basis allowables. The two lowest quality welds were evaluated and those supports have a design margin greater than one. A design margin exists in welded connections for cab!c tray supports and cable tray support auxiliary steel because the initial design was conservatively based on a maximum uniform cable load. In addition, the components are generally designed using simplified, yet conservative, techniques. By using actual cable tray loadings and more exacting methods of analysis, it was shown that the actual stresses are lower than the stresses from the original design. For the 34 cases where a detailed R1 engineering evaluation of the weld discrepancy was performed, the welds are adequate to carry the loads. The average value of the weld strength reduction for cable tray supports and auxiliary steel is approximately 14% This reduction is not significant to the overall behavior of the R1 support system. s A design margin exists for cable tray he'd-down welds because the initial design conservatively assumed maximum cable weight, maximum cable tray span and peak seismic acceleration. When a more detailed calculation is performed for any particular cable tray hold-down weld using the seismic values for that particular location, actual cable tray loads and actual cable tray spans', there is aditional design margin. There is additional design margin for the 30 cases where a detailed engineering R1 evaluation was performed, and the welds are adequate to carry the design loads.. ~

- ERRATA AND ADDENDUM TO Tile REPORT ON TilB BYRON QC INSPECTOR REINSPECTION PROGRAM EXillBIT C-2, Page 11 of 15 s Line Indicating Revision Change Twenty-eight to Thirty-one 4 !~ i I I i. (The revised page for the Reinspection Program Report follows.) P ~. ,_..e-. ,,,--w-- -,m,p,p. n,.

Exhibit C-2 Page 11 of 15 An engineering evaluation of all 608 AWS weld discrepancies was completed. In all cases, the design of the component was acceptable with the observed discrepancy present. The results are categorized in the Table CE-10. Table CE-10 Results of AWS Weld Discrepancy Evaluation Powers-Azco-Pope Weld Discrepancy Category A Bt B2 C Weld Weld No Strength Strength No. of Weld Structural Reduced Reduced Rejected Weld type Discrepancies Impact by < 10% by 110% (Cracks) Instrument tubing supports 608 167 77 364 0 i The supports installed by Powers-Azco-Pope typically have a large design margin. The supports are designed for peak seismic accelerations. These supports are selected from generic design tables which envelope the various design considera-tions and use standard member sizes. Thirty-one of the supports associated with R. the 608 discrepancies had a design margin of 1.1 or less. This is representative of - the highly stressed supports installed by Powers-Azco-Pope. The maximum weld strength reduction based on the lowest quality weld was applied to all of the supports associated with the 608 discrepancies.. In all cases, af ter performing a more exact analysis, the design margin remained greater than one and had no design significance. The results of the engineering evaluation of Powers-Azco-Pope AWS weld discrepancies indicate that the Reinspection Program has captured a representative sampic of highly stressed c!cments with lowest quality welds and that there is no design significance. O 9

] ~ ERRATA AND ADDENDUM TO Tile REPORT ON TIIE BYRON QC

INSPECTOR REINSPECTION PROGRAM Page F-6 Paragraph deleted i

f J (The revised page for the Reinspection Program Report follows.) 4 L

F-6 Evaluation of fif ty welds from the entire population of discrepant welds with the lowest factor of safety.~ Another method would be to select the worst weld in each category and the weld with the lowest factor of safety in each category. Then perform a detailed engineering evaluation to determine if the worst weld would meet the design intent for the weld with the lowest factor of safety."

Response

As stated in the response to Q4, all weld discrepancies have been evaluated. Refer to Exhibit C-2, Sections D.1 through D.6, for the engineering evaluation of highly stressed wc!ds and their compliance with design criteria. Q8. " Provide a summary regarding the number and type code (ASME) and AWS) rejectable items'found during the reinspection for each contractor. Further, with regard to the number of rejectab!c ASME Code items, please explain how you are going'to assure that the items that have not been repaired are acceptable. This includes both items that have and have not been reinspected." R1 l 9 O e _.m____ __.___.__i_.___._.______..______ .}}

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