ML20004E853

Deficiency Rept Re Defective Bahnson Svc Co Heating, Ventilation & Air Conditioning Supports,Initially Reported on 810324.Bahnson Procedures Have Been Revised to Include Documentation of Concrete Anchor Bolt Size

ML20004E853
Person / Time
Site:	Comanche Peak
Issue date:	06/08/1981
From:	Gary R TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	Madsen G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
10CFR-050.55E, 10CFR-50.55E, TXX-3329, NUDOCS 8106150401
Download: ML20004E853 (2)

Text

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CP TEXAS UTILITIt'S GENERATING COMIMNY June 8, 1981

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Mr. G. L. Madsen, Chief NED Reactor Projects Branch ~,

U. S. Nuclear Regulatory Commission 'y (

Office of Inspection & Enforcement 611 Ryan Plaza Dr., Suite 1000

$#@Qf Docket Nos. 50-445 S

Arlington, Texas 76012 50-446 COMANCHE PEAK STEAM ELECTRIC STATION BAHNSON HVAC SUPPORTS FILE NO: 10110

Dear Mr. Madsen:

In accordance with 10 CFR 50.55(e), we are submitting the attached report of actions taken to correct the identified deficiency regarding Bahnson HVAC supports. We previously made a verbal report to Mr. R. G. Taylor on March 24, 1981, with an interim report logged TXX-3306 and dated April 21, 1981.

Supporting documentation is available at the CPSES site for your Inspector's review.

If we can provide any additional information, please advice.

Very truly yours, i

t R ." Ga ry RJG:kh Attachment cc: NRC Region IV - (0 + 1 copy)

Director, Inspection & Enforcement - (15 copies) c/o Distribution Services Branch, DDC, ADM.

U. S. Nuclear Regulatory Commission Washington, D. C. 20555 i

010615n

TXX-3329 June 8, 1981 ATTACHMENT BAHNSON HVAC SUPPORTS DESCRIPTION OF DEFICIENCY

During a planned QA audit of the CPSES HVAC subcontractor, Bahnson Service Company, it was discovered that concrete anchor bolts (Hilti Kwik Bolts) shorter than intended or assumed in design analyses may have been installed for certain HVAC fan and duct supports. Subsequent ultrasonic investigations on a representative sample of installed supports confinned the use of Hilti bolts at "embedment" lengths less than minimum values recommended by tha bolt manufacturer, Hfiti Fastening Systems, as published in their " Architects and Engineers Anchor and Fastener Design Manu al" . Furthermore, fabrication and installation drawings did not clearly reflect bolt sizes or actual embedment lengths, thus causing post installation oesign verification activities to be indeterminate with respect to design base calculations.

Analysis of Safety Implications The described deficiency results in an indeterminate design base and attendant lack of assurance that the HVAC support eystems would perform as required under postulated seismic loading conditions.

Corrective Actions The following actions have been or will be taken to correct the described deficiency:

l 1. Bahnson procedures have been revised to include documentatica l of concrete anchor bolt size and embedment length for each I seismic support installation. Th4 information will be shown on the as-built support drawings.

2. Hilti bolts for supports installed prior to correction of the described deficiency are being reinspected and documentation will be consistent with Item 1 above.

3. Previous design verification efforts will be reviewed and reanalyzed (where necessary) to assure continuity between the as-built supports and the design base calculations. Any required rework will be accomplished in accordance with existing procedures.

Corrective actions were initiated on April 13, 1981 and will be completed on a system priority basis consistent with the turnover schedule.

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