IR 05000445/1978017

Forwards IE Inspec Repts 50-445/78-17 & 50-446/78-17 on 781004-12 During Which No Items of Noncompliance Were Noted

ML20148U254
Person / Time
Site:	Comanche Peak
Issue date:	10/26/1978
From:	Seidle W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:	Gary R TEXAS UTILITIES CO.
Shared Package
ML17195A414	List: IR 05000445/1978017
References
NUDOCS 7812060335
Download: ML20148U254 (2)

Text

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• 59 RE04 UNITED STATES o NUCLEAR REGULATORY COMMISSION

[ n REGION IV

• '. . .E 611 RYAN PLAZA DRIVE, SUITE 1000

'# AR Lf NGTON, TEXAS 76011

%*****/ October 26, 1978

In Reply Refer To: j RIV i Docket No. 50-445/Rpt. 78-17 50-446/Rpt. 78-17 l

l Texas Utilities Generating Company ATTN: Mr. R. J. Gary, Executive Vice President and General Manager 2001 Bryan Tower Dallas, Texas 75201 Gentlemen:

This refers to the investigation conducted by Messrs. J. J. Ward and R. G. Taylor of our staff on October 4-12, 1978, of activities authorized by NRC Construction Permit Nos. CPPR-126 and 127 for the Comanche Peak facility, Units No. 1 and 2, concerning the generic aspects of the failure of a Cadweld splice during fabrication operation The investigation and our findings are discussed in the enclosed investigation repor Within the scope of the investigation, no items of noncompliance were identifie In accordance with Section 2.790 of the NRC's " Rules of Practice," Part 2, Title 10, Code of Federal Regulations, a copy of this letter and the enclosed investigation report will be placed in the NRC's Public Document Roo If the report contains any information that you believe to be proprietary, it is necessary that you submit a written application to this office, within 20 days of the date of this letter requesting that such information be withheld from public disclosure. The application must include a full statement of the reasons why it is claimed that the information is proprietary. The application should be prepared so that any proprietary information identified is contained in an enclosure to the application, since the application without the enclosure will also be placed in the Public Document Room. If we do not hear from you in this regard within the specified period, the report will be placed in the Public Document Roo !

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Texas Utilities Generating Company -2- October 26, 1978 Should you have any questions concerning this investigation, we will be pleased to discuss them with yo

Sincerely,

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y I W. ' C. Seid14',) Chief ,

Reactor ConsYruction and-

' Engineering Support Branch

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Enclosure:

IE Investigation Report No. 50-445/78-17 50-446/78-17 .

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REGION IV==

Report No. 50-445/78-17; 50-446/78-17 Docket No. 50-445; 50-446 Category A2 Licensee: Texas Utilities Generating Company 2001 Bryan Tower Dallas, Texas 75201 Facility Name: Comanche Peak, Units 1 & 2 Investigation at: Comanche Peak Station and Off-Sita Investigation conducted: October 4-12, 1978 Inspector ? - /4/2.5'/7s R. G. Taylor, Resident Inspector, Projects Section Date

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/0f35'/7 y (/. J. Ward Investigation Specialist Date

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(Paragraph 4)

Approved: m /0/hf'/78 W. A. Crossman, Chief, Projects Section Date Inspection Summary:

Investigation on October 4-12, 1978 (Report No. 50-445/78-17;50-44S/78-17)

Areas Inspected: Special investigative inspection of generic aspects due to failure of a Cadweld splice during fabrication operations in Unit 1 Con-tainment Buildi.ng wall. The investigation involved sixteen inspector-hours by the CPSES Resident Inspector and the RIV Investigato Results: No generic aspects of the Cadweld splice failure were identifie AT[

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INTRODUCTION The Region IV Investigator and the IE Resident Inspector assigned to l Comanche Peak Steam Electric Station (CPSES) conducted an investigation !

related to generic aspects of poor workmanship in Cadweld splicing of the Unit 1 Containment wall reinforcing stee REASON FOR INVESTIGATION The licensee, on October 4, 1978, reported to the Resident Inspector an event that had occurred on October 2 and had the potential of being reportable under the requirements of 10 CFR 50.55(e). The licensee reported that a Cadweld splice in the Unit 1 Containment wall reinforc-ing steel had pulled apart upon application of a light force while pre- ;

paring the spliced bar for additional splicing. The mode of failure I was such that grossly poor workmanship had to be the cause, either by intent or by negligence. The Cadweld splicer, according to licensee ;

quality assurance records, had performed over six hundred (600) other !

splices throughout the various Category I buildings and involved both Units 1 and 2. The Cadweld splicer had been terminated in March 1978 for disciplinary reasons not related to his actual wor SUMMARY OF FACTS The following facts were established from licensee quality assurance records made available to the IE Resident Inspector: The failed Cadweld splice was made on the second shift during the evening hours of December 16, 1977, and was one of four (4)

sr Mces made that evening by the splice The splicer had made a total of six hundred eighty-seven (687)

splices over a period beginning January 21, 1977, and terminating March 27, 197 The splicer had been qualified initially and his work inspected and tested commensurate with the requirements of NRC Regulatory Guide 1.10 throughout his working perio a

. .. The licensee / contractor quality control organization had rejected a total of eight (8) splices made by the splicer for visual defects during the above working period, None of twenty-five (25) tensile tests conducted on the splicer's work evidenced failur All but twelve (12) splices made by the splicer were em-bedded in concrete and thus were not readily available for examination. Of the four made on the evening of December 16, only one splice in addition to the failed splice was avail-able for examinatio . The following facts were established by the licensee during the period from October 2 through October 11, 197 The IE Resident Inspector maintained an overview surveillance of these activities during the period: Each of twelve accessible Cadweld splices made by the person in question was radiographed to ascertain position of the bars within 1.he splice sleeve and visually reinspected for correct filler metal fil All splices were deemed acceptable by the license The licensee's Product Assurance Group, a component of the licensee's QA organization charged with special investigations, surevillances, etc., reinspected 3106 Cadwelds in Unit 1 Contain-ment not already embedded with following results:

(1) Nine (9) had visually detectable defects not meeting acceptance criteria. All were tension tested after being removed from the' structure and met acceptance criteri (2) Fifty-one (51) had witness mark problems making uncertain the sleeve centering over the bar ends. Twenty-six(26)

of these were radiographed where the highest degree of uncertainity existed. All were found acceptabl (3) Eight (8) vertical Cadwelds displayed some amount of end packing of asbestos remaining on the bottom end of the splice. Upon removal, all splices were visually acceptabl l l

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. ,, The following facts were established during an interview of the Cad-weld splicer in question at his home on October 7,1978. The inter-view was conducted by the IE Region IV Investigator with the Resident Inspector presen The individual denied any recollection of the specific splice involved although he was shown pictures of the failed elemen The' individual recollected having made a group of splices on the evening of December 16, 197 The individual stated that, in his opinion, he had been a good Cadweld splicer and has never knowingly made a poor splic The individual offered the possibility that' he may not have actually made the failed splice, but rather that another splicer may have used his identifier marking on the splice '

sleeve. The individual could not recall what other splicers may have been in the vicinity that evenin The splicer also offered the possibility that, during his absence, a helper may have improperly set up the Cadweld for him to fire on his return. The individual could not recall the name of the helpe . The following facts were obtained by the IE Resident Inspector during an on-site interview with the Brown & Root quality control inspector of record for the splices made on the evening of Dec-ember 16,1977: There were several other splicers in the general vicinity of the location of the failed splice on the evening of December 1 (The inspection record indicates three other splicers on the sameworksegment.)

, The B&R inspector stated that he recalled the particular work that evening because of the difficulties and hazards involve He stated that much of the splicer setup work was done under poor lighting conditions and that he had had to use a penlight to make his inspection The B&R inspector stated that he had inspected some of the preparatory setup work of each of the splices made that evening by each of the four splice crews involved, but had no recollection of what stage of work he had inspected on j any given splic ,

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CONCLUSIONS The defective splice reported to the IE Resident Inspector as having pulled apart was not representative of the splicer's work and is therefore considered to be an isolated cas . There is no reason to question the integrity of the Cadweld splices in the Containment based upon the licensee's reinspection and test effor : The Cadweld splicers are occasionally careless in proper marking of the spliced bars. The licensee has committed to certain pro-cedural revisions to make clearer the requirements and to retrain-ing'the splicers and their immediate supervision in this are ; The quality control personnel have been remiss in their inspections of Cadweld splices on occasion. The licensee has retrained these personnel during the course of their special inspectio .

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DETAIL 5-1.. ~ Persons Contacted Phincipal Licensee: Personnel '

R.'G. Tolson, TUGC0 Site QA Supervisor J. V.- nawkins, TUGC0/G&H Product: Assurance Superviso R. V. . Fleck, TUGC0/G&H Civil. Inspection Supervisor E. Holland, TUGC0 Product' Assurance Technician 0ther Personnel

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- Cadweld Splicer "CD," Brown & Root Ironworker (No longer employed)

Brown & Root QC~ Inspector

, Unit 1 Containment Wall Reinforcing Steel Cadweld Splice CDD-56 Identification of Incident The licsnsee on October 4,1978, reported a possible significant construction deficiency-to the IE Resident, Inspector. .The li-censee representatives indicated that: a Cadweld splice, identi-fied as.CDD-56.in the Containment wall diagonal reinforcing steel at approximately:the 955' foot level, had pulled apart-during preliminary work of preparing the bar. for additional splicing to continue the steel to the Containment springlin Examination of Cadweld Splice CDD-5 The IE Resident Inspector. examined the splice and found that-one bar, the lower one already embedded in concrete, extended 1 into the splice sleeve only about 1/2 inch rather than the' '

normal of 4-1/2 inches, while the other bar extended through the sleeve to meet the lower'ba The upper bar also had two witness file marks on the bar rib'

for locating the bar ends after splicing. cc.a positioned such as to indicate the actual bar end point and one 4-1/2 inches away indicating where the bar end point should have been, i.e., in the center of the sleeve. The concrete was subse-quently removed from the necessary area of. the lower bar on which two witness file marks were also reveale ,

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Further examination of the splice revealed that the bars had been properly located so as to be substantially concentric with the inside diameter of the splice sleeve and been properly filled with splice filler metal. The finished inplace splice would have met the visual quality control inspection criteria except for the presence of four witness marks instead of two, a point which apparently escaped the notice of the Brown & Root inspector who inspected the splice both before and after it was ,

completed as indicated by applicable inspection record l The IE Resident Inspector reviewed the background of the B&R inspector of record and determined that he had an educational ]

level conmensurate with current industry standards for the  ;

job and had received training (with attendant examination) in Cadweld splice inspectio . Interview with B&R QC Inspector On October 12, 1978, the IE Resident Inspector interviewed the B&R inspector for the puprose of ascertaining any peculiar conditions which might have prevailed when the splice was made on December 16, 1977, during the second shift. He was asked if he could give his understanding of the meaning of a check mark and initials on the i inspection record The B&R inspector appeared to very well recollect the particular evening, since it was somewhat unusual. The inspector related that he and several Cadwelders (the record indicates four) with their helpers were dispatched to Unit 1 Containment wall to add short bars to already installed diagonal bars in order to achieve the needed elevation for subsequent concrete placements. These personnel rode a construction elevator up the inside of Contain-ment, crawled over the top of the liner, down Nelson studs on the outside and into place in the reinforcing stee The work was to l take place about 150' above the ground with no scaffolding and only site area lighting availabl The inspector indicated the splice setups were done with the aid of flashlights and that he used a penlight to perform his inspections, a condition which might explain why the extra witness marks were misse l

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The B&R inspector also explained his understanding of the meaning of the check markt on the inspection record. He understood that he was to check the record form if he saw any part of the splice setup of any given splice whereas the related quality control procedure in effect at the time (now superceded and obsolete)

would imply that he observed the entire setup and found it accept-able. The B&R inspector could not recall what setup aspect he observed on any given one of the twelve (12) splices made that (

night although he saw some part of every one and so indicated on )

the recor . Interview with Identified Cadwelder The IE Region IV Investigator and the Resident Inspector jointly interviewed the identified Cadwelder of record involved in making the defective splice to ascertain if he could recall the particular splice or any others made by him or others that might be comparabl The interview took place at the home of the individual on October 7, 1978, rather than on the job site since he had been terminated for disciplinary reasci s not related to his work in March 1978. The l following is a summary of the results of the interview: l The individual denied having any recollection of setting up i a splice in the manner described to him and as illustrated with pictures, The individual could recall splicing the stub extension bars in December 1977 and that the lighting was bad, but did net relate other circumstances, The individual indicated that he thought he had made sixty or seventy diagonal splices for the two units. He further indicated that while the diagonal splices were sometimes more difficult than vertical or horizontal, they were not so difficult as to make him do his job improperly. (Note:

The site records reflect a total of sixty-one such splices, all but two of which have been embedded in concrete for a substantial period.) When asked to guess as to how this could have happened, the individual suggested the possibility that a helper could have done the entire splice setup and that the Cad-welder could have ignited it without first checking the alignmen He did not recall any time when a helper would have done this for hi He could not recall any of his helpers' name _ - _ _ _ _ _ _ _ _ _ _

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. The individual also stated that he might not have made the splice at al Sometimes a Cadwelder_will place another Cadwelder's identifier on a sleeve to' avoid the work in-volved in being tested. This might occue particularly when the splice has to be tested under adverse condition The individual claimed that he had been a good Cadwelder; had always tried to do a good job and never knowingly done improper wor The individual denied any knowledge relative to the double witness marks on the splic . Surveillance of Licensee Evaluation The IE Resident Ins ?ctor maintained general surveillance over the licensee's effort to resubstantiate the quality of Cadweld splicing in the Unit 1 Containment as well as in other building The licensee assigned a quality assurance component referred to as " Product Assurance" to the task. The group had no routine responsibility for making or inspecting Cadwelds but had the necessary expertise to accomplish a re-evaluation. The findings of the group were: The splicer identified as CD had worked in Unit 1 and 2 Containments, the Unit 1 Safeguard Building and the Common Auxiliary Building. Only one of his splices in Unit 1 Containment, other than the failed item, and eleven splices in the Auxiliary Building were not yet embedded in concret These twelve splices were radiographed with a technique suf-ficiently sensitive to reveal the bar positions within the splice sleeve. All were found to be satisfactory. The IE Resident Inspector reviewed selected radiographs including the one splice available in Containment and had no questions concerning this findin The group conducted a preliminary reinspection of other Cad-weld splices in the 955' concrete placement area of the Unit 1 Containment and found problems which caused them to ultimately reinspect all Cadwelds in the structure not yet embedded in concrete. The licensee's records indicate that 3106 such Cad-welds were reinspected by the group of five people over a period of four working day Nine (9) of the splices contained splicing defects which should have been initially rejected by either the craft or by quality control. Each of the nine were cut out and tension teste Each splice developed full bar strengt l

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.s Eight (8) vertical splices had some packi.ng still remaining on the bottom area.

l The balance of visually detectable Cadweld problems were either no witness marks, one witness mark or several marks; i.e., more than two. There were fifty-one splices in this category. The Product Assurance group had twenty-six (26)

of these splices radiographed where there was uncertainity as to correct bar positioning in the sleeve. All were acceptabl ,

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