ML18025A190

Letter Enclosing an Interim Report of Reportable Deficiency Regarding Unsatisfied Field Welding and Inspection of Shear Studs

ML18025A190
Person / Time
Site:	Susquehanna
Issue date:	06/22/1977
From:	Curtis N Pennsylvania Power & Light Co
To:	O'Reilly J NRC Region 1
References
Download: ML18025A190 (12)

Text

TWO NORTH NINTH STREET, ALLENTOWN, PA. 18101 PHONE( (215) 821-5151 Bicentennial Pennsylvania TL

.j Junn @, 1977 Sn pw diiilnnnn Hl thdr dnijnn.

Mr..J. P. O'Reilly Director-Region I U. S. Nuclear Regulatory CCIIission 931 Park Avenue King of Prussia, Pennsylvania 19406 SUSQUKBNNA STEM jKZCTRIC STATION (SSES)

INTERIM REPORT OF A REPORTAHEZ DEFIC~ REGARDING UNSATISFACTORY FIED WELDING AND INSPECTION OF SHEAR SXUDS DOCKET NOS: 50-387 & 50-388 LICENSE NOS: CPPR-101 & CPPR-102 ERs 100450/100508 FIrZ 840-4 PIA-182

Dear Mr. O'Rei1ly:

This relates to an occurrence which was reported to RepQatory Inspector, Mr..S. Folsom during the course of an unannounced inspection visit May 24-27, 1977. The inspector was inforIIIed that PP&L was evaluating the reportability of deficiencies in construction involving the installation of shear connectors.

It was deteemined that for concrete placements 183-S-02, 201-S-02 and.

714-S-03 there were several instances of the unsatisfactory resistance welding of shear studs and that the construction activities for the three (3) placements had progressed through final concrete preplacement inspection and acceptance by Bechtel QC personne1.

This is considered to be a significant deficiency in construction which is described in 10 CFR 50.55, (e), (iii).

An interim report, detailing the information available at this time, is attached for your information and review.

Although the attached report identifies early 1978 as the tentative time frame for a final definitive report, PP&L is making a deliberate effort PENNSYLVANIA POWER 8 L I GHT COMPANY

Mr. J. P. O'Reilly --2 JQI18 22'977

'I to id .' a specific and an earlier time for resolving this situation.

You wfFl be kept infarrneQ of progress or changes in status regarding our suhnittal of the final definitive report'of this deficiency.

Very truly yours, N.

4ACurtis W.

Vice President-Engineering and Construction Attachment ARS:mcb cc: Mr. Ernst Volgenau (15) Mr. G. McDonald, Director Director Office of Management Information Office of Inspection 6 Enforcement and Program Control U. S. Nuclear Regulatory Ccemission U. S. Nuclear Regulatory Ccmmission Washington, D.C. 20555 Washington, D.C. 20555

prepared Qy:

Checked Sy: .J>~:.~II, ~-

Approved By: (//pj's(

Project,.>" Engineer:

Project, QA >'ng sneer BSCHTBKr.PQKHQ CORPQHATXGN San Pzaneisca, Califoc'pic

INTERIN REPORT ON SHEAR STUDS

. TABLE OF CONTENTS A. Purpose B.. Background C. Discussion o Description of the Deficiency o Analysis of Safety Implications o Corrective Action

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SHEAR STUDS INTERIM REPORT SUSQUEHANNA STEAll ELECTRIC STATION UNITS 1 AND 2 PURPOSE The purpose of this interim report is to provide available infor-mation, pursuant to 10 CFR 50.55 (e) (3), concerning errors made in inspection and a siginificant deficiency in construction in-volving field welding and inspection of shear studs. These shear studs are used in reinforcing concrete construction to provide a shear anchor between concrete slabs and structural steel floor framing.

BACKGROUND Prior to placement of concrete for building floors in certain lo-

'cations, shear. studs are attached to structural steel members, primarily by resistance weldin'g (i.e. a large electric current is passed between the stua and the structural steel member causing local melting and fusion at the point of contact). The studs then become embedded in subsequently placed concrete and provide a shear connection between the steel and'he concrete.

The integrity of the weld between the stud and sturctural steel is inspected visually-and tested by selectively bending the studs after the welding process is completed. Such bending does not prevent the functioning of the stqd as a shear anchor. The bend tests, are performea on the first two studs welded to each struc-tural steel member, The materials, welding, inspection and testing of such studs is in accordance with American Welding Society Code AWS Dl.l-72, Section 4, Part IV.

DISCUSSION Subsequent to Bechtel Quality Control (QC) final pre-concrete place-ment inspection and acceptance on Nay 21, 197/ for concrete place-ments 283-S-02 and 201-S-02 in the reactor building and 714-S-03 in the control building, Pennsylvania Power and Light Company (PL)

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Quality Assurance (QA) personnel found studs which did not meet the requirements of project specification 8856-C-19, "Installation of Shear Connectors" in at least one of the above placements. This

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.Shear Studs Interim Report

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deficiency,was noted on May 24, 1977. Bechtel personnel performed another inspection of these three placements and rework was per-formed as required. Bechtel QC completed the second inspection and acceptance of these placements on May 26, 1977. On this same

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.date PG QA personnel again found studs in the above placements which did not meet specified requirements.

The basic cause of the inspection error was Bechtel QC personnel failure to carry out assigned responsibilities as defined in the quality control instructions for stud weld inspection. The follow-ing specifics are cited:

1. Responsible QC engineering personnel in 'the welding discipline signed inspection records signifying that 100'5 inspection had been performed. However, the inspections as defined by the program were not completely performed.

2. Responsible QC supervisi'on personnel at the jobsite failed to provide adequate, definitive directions to the responsible QC engineering personnel in the welding discipline and failed to detect the lack of acceptable performance of the QC engineer-ing personnel.

Major contributing elements to the unsatisfactory stud welding for concrete placements 183-S-02 and 201-S-U2, is known to include to following:

1. The installation of studs was performed out of normal construc-tion sequence, i.e. reinforcing steel and in some cases electric-al. conduit was installed prior to stud installation. This made it, difficult for craft personnel to properly clean steel surfaces prior to welding operation..

2. 'ome of the studs were welded through the metal decking later used to support the fresh concrete placement. Such studs had a greater, nonconforming rate then studs welded directly to.

'he top flange of the beams as has been the practice for all other concrete placements.

Evaluation of other factors which may have led to the unsatis-factory stud welding for placements 183-S-02 and 201-S-02 is continuing. Evaluation of factors which may have led to the unsatisfactory stud welding for placement 714-S-03 is similarly continuing.

Shear S tuds P d

Xnterim Report pa e 3 gelding of shear studs at the jobsite is limited to floors where it is desired to develop composite action of the concrete slab/

structural steel system. At the time the deficiency described

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above was discovered, stuas had been embedded in concrete in the following safety related buildings:

1. Containment Unit 1 and 2

2. Reactor Building Unit 1 hnd 2

3. Control Building

4. 'Diesel Generator Building Some areas containing studs which were welded prior to May 26, 1977 and which are to be part of other placements are available for inspection and testing as concrete has not yet been 'placed.

.Additional data will be gathered from these areas.

As noted above, the studs provide a shear anchor to permit com-posite concrete/steel action by the floors. A reduction in the ultimate integrity of the shear anchor has no effect where the margin in shear strength remains adequate for. the design loading for, previous concrete placements. Where it is determined that additional shear anchors should be included to ensure adequate margin is maintained, several alternative approaches will be de-.

veloped as required.

t Corrective Action Nonconformance reports (NCB's) were issued against the studs found to be in noncompliance with specified requirements for concrete placements 183-S-02, 201-S-02 and 714-S-03. These NCR's were evaluated and disposition provided to either "rework" or "use as is" depending upon engineering evaluation. In addition, Bechtel QA issued,a Management Corrective Action Report (MCAR-1-18) on Hay 26, 1977 and a Stop Work Report on Hay 27, 1977. These reports precluded further embedment of shear studs pending complete reinspection of studs in these placements to assure conformance to specification and design drawing require-ments.

l. Immediate, Corrective Action:

A complete reinspection of the three concrete placements with-in the scope of the HCAR has been carried out. The reinspection was accomplished in accordance with a specially prepared program, containing several provisions to maximize the effect-iveness of the inspection and to virtually. eliminate any in-spection error. The special provisions included the following:

a. 'A detailed training program specifically addressing the unique aspects of the special inspection program and the fundamental reguirem'ents for stud inspection was conducted.

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,Shear Studs Interim Report 4

Special 'emphasis was placed on the recent problems

. related to the studs.

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b. Each stud to be inspected was uniquely identified by num-ber, providing traceability to the inspection record for the particular stud.

c As-built drawings were made which identify the location

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of every stud by providing the direction sequence of the stud numbers.

d. A separate

'articular check list was completed and signed for each stud.

e. Each individual stud received a "general soundness test,"

consisting of striking the stud using a heavy =-hammer.

Each inspection for each individual stud was documented, and the resulting inspection records were independently reviewed for completeness and acceptability.

go NCR's were written identifying the general conditions de-scribed within the NCAR. These HCR's were dispositioned providing alternates of repair, retest or replacement thereby allotting the field engineer participating in the reinspection to provide direction for immediate rework, replacement or repair as necessary. Each occurence was documented.

All of the inspections are complete, and all required rework and repair has been accomplished with acceptable results.

2. Action to Prevent Recurrence The QC welding discipline has been relieved, of the re-sponsibility for inspection of the studs, except those installed during prefabrication of embeds. The QC ci-vil discipline has been directed to assume this respons-

'bility. This action results of the inspection program:

in the following upgrading

i. The inspection of studs is now more closely inte-grated with other related preplacement inspections, such as embeds, reinforcing steel, conduit, etc.

ii., The amount of QC engineering manpower which may be focused upon stud inspection is now increased.

iii. Inspection may now more 'often be carried out while stud installation is being performed, and while.

craft personnel are present to perform immediate rework or repair if necessary.

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C iv-;"'tud inspection .may now normally be completed before the studs are visually.,obscured by other installed items, such as curtains of reinforcing steel.

b., The inspection plan for stud inspection has been reviewed and strengthened in the following specific. areas:

i.'arking to physically identify both acceptable and unacceptable studs has been clearly defined in the

-inspection plan.

ii. Verification of proper stud welding 'cable length (i.e., less than 100 feet) has been added.

In addition, as further corrective action, a special jobsite training session on stud installation has been conducted for field engineering and craft supervision to guarantee improved quality of stud installation. The craftsmen were re-instructed on stud welding and requirements.

Based on the above, the stop work order was lifted during the.

week of June 6, 1977.

The disposition of embedded shear studs continues under review.

The absence of adequate evidence- of control over the welding of these studs requires that the, data referred to above under "De-scription of the Deficiency" be'utilized, along with other infor-mation such as design requirements for specific areas, to estab-lish the adequacy of the various floors or to identify corrective work which may be warranted. P Such'ata, which is currently. being gathered, shows variability-in inspection and test failure rates among various areas. This variability will= be accounted for and taken into consideration in the final disposition and report.

Until sufficient data is gathered and a preliminary assessment made based on this'ata, a firm date for submittal of a final report cannot be established. However, Bechtel expects that this report will be available in early .1978.

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