ML20214D856
| ML20214D856 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 11/14/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20214D842 | List: |
| References | |
| NUDOCS 8611240275 | |
| Download: ML20214D856 (18) | |
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ENCLOSURE 1 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO ASSESSMENT OF TVA'S UCLDING PROGRAM SE000YAH UNITS 1 & 2 DCCKET NOS. 50-327/328 I.
INTRODUCTION During the Tennessee Valley Authority (TVA) preparation of the Watts Bar Unit 1 to load fuel, the Director of the Office of Nuclear Reactor Peguleticn (NRR) received direct telephone calls from concerneo TVA employees alleging sericus problems in many areas of construction at the TVA's Watts Bar site. With tine, more concerns by TVA enployees were expressed, some of them expressing their concerns directly to the Ccngressional staff. As a result, the TVA Employee Concern Program was established and an independent centractor was hired by TVA to interview approximately 5880 employees. Approximately 2000 of those inter-viewed raised a total of about 5200 concerns, of which about 2000 were cetermined to be safety-related. Arrrcximately 30" of the safety-related concerns pertain to various aspects of the TVA welding program. TVA deciced to address these concerns on a programmatic basis and established the Welding Project Revieu Plan, aimed at a reassessment of the quality of welds at various TVA plants.
Although the TVA Employee Concern Program with Quality Technology Corcoration (0TC) was initiated at the Watts Bar site, many concerns (26) were expressed specifically pertaining to the Sequoyah plant, and accrcximately 94 were judged to be generic; i.e., that they may be applicable to the Sequoyah plant. As both units at the Sequoyah site are operating plants and Unit 2 would probably be the first of TVA's nuclear units to restart, TVA's effort to resolve welding issues was directed first to the Sequoyah site.
The NRC staff categori:cd all of the concerns related to welding to identify the issues that may affect the quality of welds at the Secuoyah plant. The categories represent elercnts that the staff believes to be essential for a successful welding program. The categories are:
1.
Welding Procedures 2.
Welder Cualification/ Training 3.
Welding Inspection and Inspector Training /0ualificaticn 4.
Weld Design and Ccnfiguration 5.
Filler Material Control 6.
Miscellaneous aspects such as good engineering practice in the field.
8611240275 061114 PDR ADOCK 05000327 P
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Each individual employee concern was assigned to one of these cateperies.
Pithin each category, the concerns were evaluated as to whether they a+fected hardware quality or were a programmatic aeficiency. The staff review was concentrated on infonaation pertaining to these elen:ents. TFe information was provided by TVA, es the result of their contractors' progranratic reviews and by their sample reinspections of the plant hardware, and by independent inspections conducted by NRC insrectors. This infonnation was then evaluated against either TVA's licensirs ccrrmitrrents or industry standards in each of the above six essentiel elements of an effectively implemented welding program.
The NRC staff was assisted by the Brookhaven National Laboratory (BNL), and supported by an Expert Consultant Team in conducting this review and evaluation.
The Technical Evaluation Repcrt (TER) prcvioeo by BNL is incorporated as part of this evaluation.
II.
DISCUSSION Because sorre of the concerns expressed were vague, almost all aspects of welding in all structures and systems were affected.
These structures and systems are generally designed and constructed to the trajor welding fabrication ccdes normally used in nuclear pcwer plant construction; i.e., ASPE, M'SI, AISC, and AWS Codes or Standards.
Cn January 7,1986, TVA presented in a treeting with the NRC staff a program plan to address employee concerns ever their welding program and hcw the program was implemented during ccnstruction of various TVA nuclear power plants. By letter dated January 17, 1986, TVA forr: ally submitted this program plan for staff review.
In essence, TVA formulated their program for addressing this issue in two phases: Fhase I is to determine whether the vritten welding program (design docurrents, policies, and proceoures) in place correctly reflects TVA's comraitments and regulatory requirements, and to identify and categorize concerns / deficiencies in the program. The Phase II effort is te evaluete the implen:entation of the written welding program, to verify thet weldments made by TVA in the field meet requirements or are cdeccate for service, to correct any problems, and to irrolerrent changes tn prevent recur-rence.
II.1. Phase I Program The Phase I orogram consists of the following subtasks:
Peview TVA corritrrents to NRC.
Verify that the written program reflects various ccnraitments:
a.
te determine that weld-related contaitments are reflected in desicr rutcut; and b.
to determine that the programs implemented by the C" ices cf Construction and Nuclear Oceraticts, as applicable, reflect dcsico output and quality docurents.
t
, Assemble empicyce concerns by type ano plant.
Analyze and evaluate quality indicators that may have irracted on the programs.
Issue adecuacy statement regarding writtcn programs to implement / control weloing activities.
II.2. Phase II Procram The Phase II pecgram consists of the folicwing stbtasks:
Contract with an outside consultant, APTECH Engineering, to assess plant fitness for service.
Perform independent audits by Ecchtel Power Corporation of welding program implementation:
a.
for the historic Office of Construction program which was used to build Sequoyah; and b.
for Nuclear Operations program in place.
Evaluate the need for reinspections based on the result of an evaluation of quality indicaters.
Irrplement any additional reinspections and deficiency resciutiens.
II.3. Secucyth Reevaluation Program Many of the employee concerns from the Watts Bar site have possible generic implications to the Sequoyah plant. These general concerns relate to the adequacy of welder qualification / training, welding inspection, weld design and configuration, and filler metal control.
There were some employee ccncerns which were very specific; e.g., that a certain component had a hd weld in it. These concerns were addressed specifically with its own investigation effort and report. For the vague, general type employee concerns, a reinspec-tion of many components was performed to design requirercents and compared to the record packages. This approach cuts across these and other issues to dddress the general concerns about the welding orograrr adecuacy, and provides a basis to make a judgerrent as to the capability of the plant to operate safely.
During the meeting with the URC staff on January 7,1986, the FPC sta#f corrented on TVA's proposed approach and recomended that, regardless of the outccre of the Phase 11 program review, TVA consider a supplementary orceram on a samoling basis to reinspect the physical condition of hardware at tFe plant. TVA accepted on January 10, 1986 the staff reccrrendation and responded with a draft reinspection plan. This draf t plan was ccwented on by the NRC staff, modified to irecrpcrate the staff coments, anc ccocurred in by the NRC staff. The reinspection plan was then ferralized ard submitted on February 17, 1986 to the staff as part of the Sequoyah program plan.
t 4_
l As a result of the Phase I effort for the Sequoyah plant, TVA ccncluded that:
1.
The engineering work of the Office of Engirrerire was cenducted under a valid 10CFR50 Apperdix B program and the output accurents (drawings and specifications) produced under that program properly reflect welding reltted cor.vitments to the user organization with the exception of specifying a preweld fitup inspection by certified personnel in accordance with ANSI Standards to which TVA committed to in their FSAR.
2.
The Sequoyah plant was constructed in accordance with a functioning welding quality assurance program.
3.
Prograrrcatic requirements were found to be addressed in procedures and instructions and the operating program has rret cermitrcents in all areas except as ncted above.
4 There are communication and procedural improver 4ents to be rede which are viewed as not affecting quality but will enhance / improve the welding orogram.
As a result of the evaluation of the Sequoyah related erroloyee concerns, TVA concluded that there were five prcblem areas of a programmatic nature which are to be addressed. These five areas cercerned (1) box anchor design deficiencies (2) Nuclear Operations (h0) prograrmatic deficiencies regarding compliance with ANSI N45.2.5 where a required inspection was perfern.ed by someone other than the OC inspectors, (3) inadequacies in the inservice inspection (ISI) program, /ll a specific case of poor welder performance, and (5) minor iraplcrentation defi-ciencies in the NO welder qualification continuity program. Ncne of these prob-lens involvec hardware deficiencies. The r.: cst sienificant recommendation is to stop the practice that allows welders to update their welder performance qualifications by running a bead on plate rather than making a full penetration weld.
The results of the Phase IT efforts of TVA's Welding Project are discussed as follows:
The APTECH Engineering review consisted of a review of (1) historical reccrds and activities related to the production of welds under Sequoyah's weldino ard welds, and (3) gram, and (2) preservice and inservice inspecticn records of inspection pro Licensee Event Reports (LER) relating to weld quality. APTECH concluded that (1) the welding program containcd the recessary controls to ensure high quality welds, (2) the rcte of significant indicaticrs detected during the preservice and inservice intrections is low, and (3) no LEPs were generated that are related to poor cuality field welds.
In summary, there is no evidence that the quality of welds at the Sequoyah plant are nct fit for their intended service.
The Rechtel audit concluded that TVA hed an ef fective program related tc weld-irg erd fide at the Sequoyah site. However, the auditors noted that sorre of the program documents were ccnfusing, overlapping, repetitive, erd unclear.
The entity and euthcrity changes for upper tier quality program manuals did not provide for consistent and uniform guidelinct.
Tre rurrber of quality
O
, centrol progranis implemented during the course of construction activities rade it unclear as to who ultimately had prograr. control and responsibility. The Bechtel audit team recocrended that the cuality control program be centralized to one level of authority for uniformity and consistency. Those employee concerns within the sccpe of this audit were not substantiated by the audit.
By letters dated February 7,1986 and April 25, 1986, TVA sutritted a report that sunriarizes the results of their efforts on the reassessment of the weld quality at the Sequoyah plant. Subsequent to a review by the f:RC staff and it's consultants, the NRC staff requested, by letter dated June 10, 1986, additicnal information to clarify sente discrepancies in the report. By letter dated August 1,1986, TVA responded to staff questions.
The Sequoyah Welding) Reinspection Plan specified, among other elerrents, a scope that consisted of (1 333pipingweldsinseven(7) systems,(2)15weldsin I
spiral welded duct, and (3) 403 joints (1394 welds) in 50 structures.
This reinspection scope was purposely skewed toward areas where less strincent criteria and, thus, feuer QC checks were normally applied during construction.
The philosophy behino this approach is that, if there were problems, these are areas where the orablems vculd most likely be reflected by the hardware conditions. The results of the TVA reinspecticn effort are sunnarized as follows:
11.3.1. Piping Welds:
Table I presents the results of reinspections of piping welds.
In terrrs of components, the rejection rate is about 55*.(184/333).
In terms of deficient weld attributes containec per weld, the rate of deficient velds is about 4*,
(184/4662). Obviously, both nurabers are misleading in that the first number tends to magnify the severity of the problemt, perticularly when one considers that 104 out of 184 are in the arc strike / spatter category. The weld scatter / arc strike indications should have been reportable, but not cause fcr rejection. The visual observations by the fmC inspectors found arc strikes to be mostly superficial. The seccrd nurrber (4*. rejection rate) is also misleading; it tends to obfuscate the fact that these indications are generally indicative of pccr quality and should have been properly addressed if they were detected during construction. The superficial arc strikes or spatters should have been removed by light grinding, as requireo by TVA's internal prcccdures.
Crackire is an in;portant attribute for inspection and no cracks were fourd.
For piping welds with f;DE indications, filing or grinding were used to eliminate indications.
It should te noted that the paint removing techniques used (rotary wire brushes and flapper wheels) also cFarred the original inspection surface and presented an altered surface for reinspection. These slightly altered surf aces will provide differert reinspection results. Only five (5) welos requireo acottional surface rework to remove surface indications. Grinding encroached upcn the ranufacturer's minimum wall thickness in one of these five welds; however, the remaining wall thickness was more than twice the design ucll thickress.
Visual discrepancies cther than size, shape,1ccation, undercut, and contour /
transition were accepted based upon NDE results; i.e., by flT or PT. The engineering evaluations showed that all of the visuelly detected indications for all attributes were acceptable; i.e., reeting the applicable design stress limits.
e 6-TABLE I - PIPING WELDS No. of Ueld flo. of Welds Attributes Weld Attribute Attribute Reinsoected Acceptable / Rejectable Acceptable /Pejectable Centcur/ Transition 333 317 16 95.2 a.R Cffset/ Alignment 333 331 2
99.4 0.6 Undercut 333 331 2
99.4 0.6 Reinforcement 333 326 7
97.9 2.1 Weld spatter /
Arc strike 333 229 104 68.8 31.2 Weld Location 333 333 0
100.0 0.0 Weld Size 333 320 13 96.1 3.9 Meld fietal/
Base Metal 333 333 0
100.0 0.0 Weld convexity 333 333 0
100.0 0.0 Inccrrplete Fusion 333 328 5
98.5 1.5 Weld Overlap 333 325 8
97.6 2.4 Underfilled 333 P21 17 96.4 3.6 Surface Porosity 333 318 15 95.5 4.5 Surface Slag 333 333 0_
_100.0 0.0 4,662 4,382 184 96.0 4.0 I
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, Table IA is a rearrangement of the same data provided in Table I.
The table shows that c' cst of the welds reinspected were rcade by the Office of Construction (OC), and that the reportable indication rate was significantly higFer for OC-made welds.
TABLE 1A - PIPE WELDS N0. OF WELDS NO. OF WELDS WITH NO. OF WELDS TYPE OF WELD REINSPECTED REPORTABLE INDICATIONS ret 1ECTED BY CODE
-Socket Welds Office of Const.
204 78 0
Nuclear Ops.
34 6
0
-Butt Welds Office of Const.
68 46 0
Nuclear Ops.
22 6
0
-Attachrent'to Pice Wall Office of Const.
5 3
0 Nuclear Ops.
0 0
0
-Total Welds Office of Const.
277 127 0
Nuclear Ops.
56 12 0
4 II.3.2. Structural Welds:
The reinspection results of structural welds are summarized in Table II. Table IIA is a recompilation of the same data in Table II, as provided in TVA's August 1,1986 letter response to a staff recuest for additional information.
The rejection rate on the basis of deficiencies per inch of weld is about 16%
(1194/7369), even thcugh the ccmconents containing these deficiencies are suit-dble for service by engineerin The rejection rate on the component basis is about 15% (g Calculations.
211/1394). On ceficient attributes per linear inch basis, the rejection rate is cbout 2.3%.
Again, these numbers cculd be misleading.
For welds made by the Office of Construction, these rejectables i
should have been detected and disposeo of either by analysis or repair durirg the original construction.
Lo crack or reportable porosity indiretions were found. The reinspecticn results also showed nine (9) missirg welds. No underlength welds were identified. The number of reported attributes for size and profile are rather high for the nunber of welds inspected; however, tFe er.gineering evaluations demonstrated that es corstructed none of the structural welds, including the structures with inissing welds, reouired veld repair.
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TABLE II STRUCTURAL WELDS Inches of Wela Weld Attribute Inches Percent (O Attributes Fxamined Accepteble T< ejectable Acceptable Rejectable Size 7%9 6604 765 89.62 10.38 Incomplete Fusion 7369 7351 18 99.76 0.24 overlap 7369 7266 3
99.96 0.04 Craters 7369 7302 7
99.91 0.09 Profile 7369 6999 37C 94.cP F.02 Undercut 7369 7338 31 99.58 0.42 Correct Filler fletal 7369 7369 0
100.00 0.00 Type SW3 SQ9 134 Table IIA - STRUCTURAL WELDS NO. OF UELDS NO. OF WELD JOINTS NO. OF WELDS WITH REPORTABLE NOT ltEETING TYPE OF WELD REINSPECTED INDICATIONS DESIGN RE0VIREMENTS
-Fillet Welds Office of Const.
1080 160 0
Nuclear Ops.
148 21 0
-Butt Welds Office of Const.
50 4
0 Nuclear Ops.
0 0
0
-Other (specify) - Flare Office of Const.
92 24 0
Nuclear Ops 24 2
0 T3M YIT T
- Weld joints were evaluated, not individual wclt secrrents..
. III. EVALUATION III.1. Employee Concerns The categorizing of a concern generated at the Watts Bar site as being screric was importtnt in that the issue represented by the concern could possibly be applicable to all TVA's nuclear plants. An analysis to detect cessible bias of the selection of employee concerns was made when approximately half of the concerns related to welding had been identified. The enalysis indicated that, in terms of issues, those issues thet had a relatively large number of concerns at the katts Bar site also had a prcccrtionate number of concerns categorized as generic. Accordingly, the issues of importance to the Watts Bar plant are generally the same issues eoplicable to the Sequoyah plant and, similarly, the other TVA nuclear plants.
The patterns of the histograms (plots of issue vs. number of cencerns raised) are very similar; i.e., the cost frequently raisec issues are very similar for both Watts Bor ano Sequoyah sites.
On the basis of above analysis, the staff believes that the TVA program for determining the generic applicability of a given concern to other TVA plants has tcen conducted effectively. The stcff's monitoring of TVA's employee ccncern program is still continuing. To date, the staff has not identifit.d any cutliers, at least in the area related to various aspects of the wc! ding program.
III.2. NRC Tean Inspections Between January 20 and July 11, 1986, the NRC staff conducted three tean inspections of TVA's activities related to the welding at the Seouoyah site.
These team inspections have been conducted in accordance with established procedures and with predetermined areas for inspection. The second team inspection, conducted during the period ketween February IP-PP.1986 also included indererc'ent examinations, by tk Region I hCE Van, of welds randomly selected by the NRC inspectors.
The results of the staff inspection are contained in Inspection Report Nos.
50-327/86-09 and 50-328/86-C9; Report Nos. 50-327/86-12 ard 50-328/86-13; and Repcrt Nos. 50-327/86-33 and 50-328/86-33. These reports indicate thtt no violaticns were identified in TVA's current efforts under the Program Pier, but there were some Inspector Follow-up Items and reconrendatices.
III.2.1. Inspection Recor ts Hos. 50-327/86-09 and 50-328/86-09:
The c4.alifications of the personnel performing the Bechtel audit, organi cticr.
t internal preccdures, and policies were reviewed and were found satisfactory.
The selection of the populations, and the means for detenrininc the specimen's to be included in the samples, and other procedures were reviewed. The selec-tion of populations to be sampled was based oper engineering judgement and the
. ' availability cf recoros. The actual selection of specicens to be in the sample
'from a given populatien was rar.dco, and performed by the aucit teco rcembers.
The Cechtel audit determined only if the rccords were present and correct.
This eudit did not address the tecFnicci suitability of the documents which were aucited. The documents were cnly to be checked for completeness of information for the organization or 1rdividuals who must use the document to make sure they can continue forward with the program.
IR 86-09 also summarizes the staff's review and evaluation of the following elements in the TVA Reinspection Progrcn:
TVA inspectors qualificatiens/ certifications and nondestructive evaluation procedures;
- performance of TVA reinspections;
- records of reinscections that TVA had alreacy performed; checked for the possible bias of the samole by determining the time of original fabrication of tFe items selected for reinspection and com-pared them to the level of effort of ccnstruction in the past; distribution of welds reinspected between Units 1 and 2; and TVA had reinspected at least the minimum number of welds in each group as specified in the Welding Project progran Plan.
TVA's reinsrection effort identified undersized fillet welds as being the major problem for structures that required engineering calculations.
In terms of the essential elements of a successful welding program, the results of the reinspec-tion were judged by the NRC inspectors to he rather typical for the same vintage construction. Mcwever, the deficiencies fcund during the reinspection should have been identified during construction and disposed of through engineer-ing evaluations. There are no records to indicate that, during censtruction, these urdersized welds were identified and disposed of in accordonce with the due prccess provided in the Codes.
For ASME sccpe piping welds, most deficien-cies are of a surface nature; 1.e., crc strikes and spatters that should have been removed by licht grinding during construction. An argument could be made that the arc strike /welo spatter indications occurred after the acceptance inspection, but the inciderce rate is too high to have credence for such an l
a rgument.
In addition, NRC inspectors noted that TVA used the terms " suitable-for-service" and " meeting licensing commitments" interchangeably.
III.2.2. Inspection Reports fcs. 50-327/86-13 and 50-328/P6-13:
In order to further assess the overcil TVA welding program and tc evaluate the results of the TVA reinspecticn effort at the Secuoyah plant, the NRC staff reviewed a sample of the TVA reinspection weld data packages, and indepenoently examined a selected raiter of welds. There were some minor problems in the
s
. reinspecticn wcid data cackages which required action by TVA to resolve and are being tracked as Inspector Follow-up Iters. The NRC staff selectec v.eles from those reinspected by TVA's Reinspecticn Team and additional welds th6t vere not in the TVA's reinspection scope. The selection of welds in one of the groups in TVA's reinspection scope was done on a random basis, considering factors such as accessibility, tire tc perform the examinations, NDE cethod required, pipe size, material type, time of fabricaticn, erd whether the fabrication was done by the Office of Constructicn or Office of fiuclear Operations.
For the group of welds not reinspected by TVA, the selection of piping welds was trace randomly from a walk-through in the auxiliary building. Additional piping welds were randomly selected frcm welds that TVA had selected for reinspection, but had excluded for sorte reason.
For non-piping welds which t.ere not rein-spected by TVA and were inspected by the NRC Region I NCE team, the selection was made randomly, considering Iccation, accessibility, and other factors rentioned above. The NRC Region I f;0E Team Report is attached to Inspecticr Report 86-13. fio violations or deviations were identified during these insper-tions for the TVA current activities. The overall conclusien ccnfirms the results of the TVA reinspection results.
111.2.3. Inscecticn Recort Nos. 50-327/86-33 and 50-328/86-33: -
The subject report summarizes the NRC Team Insrecticns conducted during the periods June 2-6, June 16-20, and July 7-11, 1986 at the Sequoyah site. The NRC welding team reviewed eight follow up items which were identified by previous liRC inspections; the team was able tn clcse seven of those items. The licensee should address and resolve the remaining open item befcre startup of the plant.
The team found that TVA had not cortpleted its review of employee ccocerns; thereferc, the team could not review this area during its inspection. The hardware and decurrentation that were reviewed for the inscccted welding activities were generally in accordance with requirerrents and licensee commit-ments. The teani noteo a number of weld discrepcncies ard rrost of these discrepancies had been identified and evaluated as a result of the TVA reinspec-tion effort, which indicated that the current TVA welding project reassessn.ent program was effective in identifying weld deficiencies. However, the welding team did identify a nunter of irregularities which in trost cases related to the accuracy of welo accurrentation. These irregularities are surcarized as follows:
- The guidance was confusing for support inspection requirements provided in drawings and specifications for instrun.entation installation; eler-trical installations; heating, ventilating, and air conditioning irstal-lations; and pipe supports. The team coula not clearly identify which supports required Quality Level 1 inspection and which required Ouality Level 2 inspection. Quality Level 1 inspections require documentation for each weld while Quality Level 2 inspections only require deccrren-tation for the completed support.
A number of welds were fcurd to deviate from the requirerents of the applicable design drawings. The drawing required one type of weld t
{
f
o
. when, in fact, the actual weld was found to be some other type of weld; e.g., drawings required full-penetration weld while the hardware was installed usirg flare bevel weld.
Section 3 of Volume II of TVA's revised nuclear performance plan for Sequoyah provides an action plan that will improve the design control program for the Sequoyah nuclear plant when implecented. This plan includes the reconcilietion of "as constructed" and "as designed" drawings to achieve a single set of plant drawings. This plan should address the irregularities identifiea above to ensure that the welds and welding requirements stated cn the "as designed" drawings match the installed hardware.
III.3. Secunyah Phase I Results The approach taken by TVA for this effort can be characterized as a " paper chase" exercise; starting with a review of the requirenents and commitments, and then searching for a TVA document (specification, procedure, instruction, etc.) that provided for implementaticn of the comitments or requiren:ents.
However, the Phase I effort failed to cddress the situation that there are so many tiers of documents with overlappino requircrents, produced by different organizatiuns with little direct authority. With many duplicating implemen-tation documents, it is inevitable that there would be conflicting requirements or instructions that make it almost irapossible to understand and ircolerent all of TVA's cwn requirements.
In sumary, the Sequoyah Phase I results do not convincingly support the conclusions (see Discussion Sectioni. On the contrary, the Phase I effort oroduced evidence to indicate that, in sone instances, TVA's quality control program did not treet Apcerdix B to 10 CFR 50. For example, TVA committed in the FSAR that structural steel welding be conducted in accordarice with the requirements of Arerican Velding Society's (AWS) D1.0-69,
" Code for Welding Building Construction", or later versions, up to AWS D1.1 - Rev. 2-74, " Structural Helding Code". All of these codes specify in Section 6, that "The inspector shall examire the work to make certain that it meets the requirements of Section 3...."
In Section 3, the requirements for fitup are specified. TVA's Process Specifications G-?oc ard the raodifications to the AUS Ccde reouirements were not made applicable until Amendment 47 to the FSAR was submitted in January 1983. This was after construction ard rucicar generating operations had begun.
The staff recognizes that fitup inscections for non-safety-related fabrica-tions may be waived, but for safety-related fabrications, the compliance of fitup requirements in these codes is viewed as necessary to n.eet Appenoix B to 10 CFR 50.
If an unacceptable fitup is incorporated in a welded fabrication, the effective veld size may not be adequate for structural integrity. The results of the TVA Welding Project investigation revealed that fitup irs g ctions were not performed as a quality control function because they had nct been incorporated into the drawings. This does not meet Criteria III and X of 10 CFR Part 50, Appendix B.
Criterion III requires, in part, that "Peasures shall be established to assure that applicable regulatory requirements and the design basis...specifiea in the license applicatter...are correctly translated into specifications, drawings, crocedures, and instructions. These measures shall include provisions to assure that appropriate quality standaros are specified and included in design documents...." Critcrion X requires, in part
i o
o i
. that A program for inspection of activities affecting quality shall be established.and executed by er for the organization perfonalng the activity to verify conforn:ance with the documented instructicns, procedures, and drawings for acccmplishing the activity. Such inspection shall be performed by individuals other than those who performed the activity being inspected."
In addition, the G29c Process Specification 0.C.1.1 as exists now cn the creweld fitup inspection procedures does not meet Criterion X of Aptendix B which states, in part, "... inspection shall be performed by individuels other than those who performed the activity being inspected."
III.a. Secuoyah Phase II Results The APTECH Engineering review of preservice and inservice inspection results dces not appear gennane to the employee concerns.
In addition, because the visual inspection attributes specitled, and the operating stresses being so small compared to the seismically induced stresses or stresses induced by postulated design events, the staff does not see any significance to the study except to indicate that defects ar.d deficiencies great enough to have resulted in failure during normal plant operation prebably do not exist.
The Bechtel audit of records cccurred af ter TVA's reviews of their records in Phase I.
TVA's review and resolutions of discrepancies are reported in the L'elding Project Generic Employee Concern Evaluation Reports kP-03-SCH, UP-06-SON, and WP-C7-SGN. That the Dechtel audit did not find any discre-pancies of significance regarding welder and inspector qualifications /certifi-cations after TVA's review and correcting of deficiencies is uncerstandable.
Therefore, the Bechtel audit does not address conditiers that might have existed durirg ccnstruction.
The Bechtel audit dio provide an outside evaluation of TVA's approach to meeting their FSAR ccroitments. For systems selected by TVA, the audit followed the ficw chart of Sequoyah's Quality Assurarce Program for the Office of Construction and Nuclear Operaticns to the documentations proviced for the piping weld joint or welded structural assembly. Of the systems selected by TVA, the auditors selected the weld joint erd cudited its chain of documen-tations. The audit team reviewed each weld document package for the following 17 key elements:
1.
Implementation of technical and welding program requirements Adequacy)of design cutput document (not in terms of technical 2.
ddequaCy 3.
Initial welder or welding operator qualifications 4.
Maintenance of welder or welding opereter qualifications 5.
Renewal of welder or belding crerator cualifications
. 6.
Initial welding inspection personnel qualificatior.s 7.
Maintenance of welding inspector personnel quclifications P,. Penewal of welding inspector perscr.nel qualifications 0
Use of appropriate welding procecures
- 10. Use of apprcpriate inspection procedures
- 11. Use of apprcpriately trained and qualified perscorel
- 12. Use ano cor. trol of welding filler materials 13.
In-process control of welding
- 14. Documentation of the above activities
- 15. f.'onconferrance and corrective actions
- 16. Training programs adequccy
- 17. Additieral areas of concern as determined by a review of employee concerns as specified (54 ccncerns)
As a result of the Bechtel audit, one audit findirg ard fcur observations were documented by the audit team. The cr.c audit finding concernea procecural errors regarding the use and control of filler materials by the Office of Construction. The impact on the produced harcuare of the errors (the post weld heat treatment teciperature ard tirre were less than specified, and yield strength not recorded as specified) was minimal. The Code requirements (FSAR corritments) were ret, but this indicated that TVA dio not follow its own procedures.
The r.ust significant reconnendation trade by the Bechtel audit is that TVA, whcrever possible, should centralize the quality assurance prcgram to cre level of authority for uniformity and consistercy.
The TVA reinspecticn effort provides probably the most direct measure of the degree of control exercised by the welding program at the Seoucyah site. The rejection rates cited in TVA's letter of August 1,1986 illustrate a ger.eral lack of ccntrol or sloppiness during implementation of the weldina prcgram in seme instances during plant construction. This statement is trade en tFe basis of high rejecticn rates in piping welds for contour /transitien, weld size, underfilling and surface porosity and, in structural relds, for size, under-cut, incomplete fusion, and profile.
111.5. Surmary As mentioned earlier, the staff evaluates a welding prcgra.m on the basis of the elements we believe are essential for a successful welding progran. For the first element regarding Welding Procedurcs, there were no employee concerns expressed for the Sequoyah site. and the staff team inspections aid not find any problems in this area.
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. Fcr the second element regarding Welcer Cualification/ Training, there tre 27 employee concerns, fbst had to do with irregularities in the dctire of welder certifications. A welder is requireo to renew his qualification every 90 days, and this may be done by the welder's use of the welding prccess certified by his cmployer. The time between taking the test and the handling of his paperwork and actual signing by the respcnsible authority often gives the appearance of the 90-day rcquirerrent being violated, and that backdating or upasting occurred. TVA imposes two week suspension without pay for the first violation of the 90-day requirement and dismissal for the second violaticn. As a result, backdating or updating in violation of the 90-day requirement might have occurred to avoid punishrrent to a welder, especially in circumstances where this may have occurred because of events ~beyond the welders' control.
In instances where it occurred, the safety significance is rather minirrel tccause the welders' skill would not be that touch different between not welding fcr 90 days versus 100 days.
It would be a cause of concern when someone like a fore-man who had not done any welding on the job, or maintained his qualification by falsification, and for lengthy periods. However, its safety significance would be rather minimal as long as the individuals in cuestion did not make actual pro-cuction welds; and there is no evidence, nor erployee concerns, to indicate that this was practiced at the Segeoyah site.
The results of the TVA reinspection, the Bechtel aucit, and the staff's independent examinations inoicate that the level of workranship was adequate for the structures and systems involved. No instances of unsatisfactory workmanship significant to the degree that required weld repair were iden-tified. Workmanship type flaws / defects bere found, but upon removal by filing and grinding or engineering evaluations, the systems or structures were demon-strated to meet applicable code requirements. Perever, the type of defects /
flaws should have been fcund and disposed of during construction by the QC inspectors under an effectively implemented QA program. The everall quality of welds showed that the welders at the Sequoyah site had the capability to make scund welds and, by definition, were qualified. The impact on the produced plant hardware by welders' updating / backdating qualification rcccrds was found insignificant.
The third eierent regarding Welding Inscection and Inspector Training /Oualifi-cation had the largest number (48) of errplcyee concerns. The results of the reinspections and audits indicate that the welding inspectors performed their duties in a generally acceptable manner, although they may ret htyc Leen fully qualified to perform visual inspections. The adherence to code requirements for addressing held discrepancies should have been more stringently applied.
The high rejection rates for the reinspections of welds (see Sectico II.3) that were accepted by the original TVA inspections derrenstrate that TVA had not perfon ed the original acceptance inspections in accordance with their licensing cccmitments. As no repairs are recessary to meet the code requirements that TVA had corrmited to in their licensirp application, the significance of these viulations is small.
The fcurth element, Weld Design and Configuration, had only seven (7) employee concerns for the Sequoyah site. Five of the concerns related to a particular box anchor design for piping. These concerns are adequately cddressed for
. the Sequoyah plant because of the special care and drcuire changes for these installations. The other twc concerns were individually irnestigated by TVA and the responses are adequate for closecut. Accordingly, the staff does not believe there are major problems under this element.
The fifth element regarding the Filler Material Ccntrol had 26 concerns. Many of the concerns related to no portable rod ovens ano the lack of material accountability. These issues were adequately addressed by TVA. One concern dlleges that welders kept unused electrodes and used them later for welding without baking to remove moisture. Hewever, the reinspections shculo have oetected some cracking in weldments if this was a cunmon occurrence. The employee concerns regarding the peor cuality electrodes were investigated by TVA and the responses are reasonable. The two instances of incorrect elec-trodes being usec were investigated by TVA and the responses are adequate. The results of the reinspections and audits found no signs of inadequate filler material centrol. Even if there were deficiencies in the filler material con-trol, they did not appear to have impacted the produced hardware.
For the miscellaneous category, the issues concerned unpainted welds, incdequate welding machines, and that the results of the TVA interrel repnrt 0AE-80-2, " Review and Evaluation of the GEDC Welding and NDE program" were ret epplied to the Sequoyah site.
The uncoated welds are being addressed by TVA under a Corrective Action Report.
Although the welcing machines might not have all features and aides a welder would like, the machines were adequate to perform the weld when used by a qualified welder. The OAE-80-2 Report was completed after the construction of the Sequcyah plant was completed and, therefore, is not really pertinent.
III.6. Expert Consultant Teara Evaluation The attached Technical Evaluation Report evaluates specific er..plcree cercerns in detail, and is incorporated as part of this staff safety evaluation. The principal finding of the Expert Consultant Team is thct, although there were discrepancies, these discrepercies were not significant or extensive enough to conclude that the plant was not ready cr ursafe to startup. This statement is bounced by the concerns expressed by employees and no welding problems signifi-cant to safety were found during their evaluations.
IV.
FINDINGS / CONCLUSIONS On the basis of the staff evaluation of information provided by TVA, obtained by independent inspections conducted by itRC staff, end evaluated by the NRC Expert Consultant Team, the staff has reached the fcilewino conclusions:
(1) During the construction of both Sequoyah units, TVA's implemen-tation of the CA/CC program in the area of welding, while cenerally effective cserall, was ineffective in certain instances. The basis of this finding is as follcws: a significant number of deficient welds have been found that requireo engineering calculations to cemenstrate their suitability for service, and that these calcule-tions had not been performed during construction. Alsc, weld configuraticr discrepancies between the design drawings and the actual hardware installed were identified.
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. Notwithstanding these findings, the fact that no welds requirce repair to treet Code requirements indicates an everall effective irrplerentation of the QA/QC program in the area of welding.
(2) The effectiveness of TVA's process for QC inspector trainirg erd cualification/ certification auring plant construction and after
- cperation was questionable in the area of visual inspecticn cf welds. The weld oeficiencies discussed in (1) above shculd Fave been detected and corrective actions taken.
(3)
In spite of the deficiercics fcund in the implementaticn of the OA/CC program for welding activities, including some that were of a programatic ratere, the staff finds that these oeficiencies have not impacted significantly on the suitability for service of the plant tardware. The basis for this finding is principally due to the fact that all hardware oeficiencies found during TVA's reirsrec-tien and fiRC'S independent examinations are relatively minor and recuired no weld repair after engineering calculations that cemen-strated suitability for service. The design criteria applied are thc sare as TVA originally comitted to in the FSAR.
(4) Other than the element related to the OC inspectors training and qualification / certification, the staff finds that other essential elements (i.e., welding procedures, welder c,uclification and training, weld design and configuration, and filler metal control) of a sound welding program were functioning and the resultant hardware was suitable for service.
In sunmary, the staff concludes that TVA's welding reevaluation program has bcen carried out adequately ano that TVA has demonstrated that the hardware as constructed is suitable for service. The staff further concludes that the restart for operation of both Sequoyah units will not endanger the public health and safety.
V.
REC 0tGENDATIONS Because the staff conclusions are made en the basis of information generated by a limited, sample reinspection program, there is still a finite probability that there are deficient welds that have not been identified. The staff concern relates particularly to ASME scope safety-related welds (e.g., piping and pipe support weids and major component support welds). Therefore, the staff reconinends that the Sec;Uoyah plant's first 10-year inservice inspection prograin be augtrented and accelerated; i.e., TVA be required to complete inspec-tions of 100% of ASME Classes 1 & 2 piping ard pipe support field welos anc; major component (reactor vessel, steam generators, pressurizers, ano reactor ccolant pumps) support welos voce in the field that are already in the first 10-year program in two (2) consecutne refueling outages follcwing the restart.
The revised first 10-year inservice inspection program should be submitted for staff review and approval in six (6) months after the restart.
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, For an overall improvement of the welding program, the staff endorses TVA's expressico of intent to make the following changes in their fluclear Performance Plan:
tutting into a single docun:ent the requirements for the welding program for all organizations; indoctrination of personnel to use this docun.ent; and review and revision of present welding and nerdestructive examination specifications, further, the staff recommends that TVA consicer the following:
- use industry generated standards where possible, particularly the use of Alls /0CI standards for certifying the AWS sccpe weld inspectors; amend relevant FSAR sections to reflect changes in corrittents and to formalize their intent as stated above; and
- training of personnel in the application of standards adopted.
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