ML20038C915

Fourth Interim Deficiency Rept Re Fillet Weld Misspec, Initially Reported on 801210.Engineers & Designers Have Been Alerted to Aisc/Aws Requirements for Limiting Angles for Skewed Tee Joints.Next Rept Due 820302

ML20038C915
Person / Time
Site:	Yellow Creek
Issue date:	12/04/1981
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8112140259
Download: ML20038C915 (2)

Text

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TEffNEb NALLEY AUTHORITY

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' CH ATTANOOG A. TEN N ESSEE 37401 400 Chephnut treet Tower II er3 N December 4, 1981 ps \ mqwM/

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Mr. James P. O'Reilly, Director oh-Q[/p 3'

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Office of Inspection and Enforcement ,

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U.S. Nuclear Regulatory Commission ,,

Region II - Suite 3100 ,,

101 Marietta Street y */ / T [ &A 3, Atlanta, Georgia 30303 -

Dear Mr. O'Reilly:

YELLOW CREEK NUCLEAR PLANT UNITS 1 AND 2 - FILLET WELD MISSPECIFICATION -

YCRD-50-566/81-01 AND YCRD-50-567/81 FOURTH INTERIM REPORT The subject deficiency was initially reported to NRC-0IE Inspector R. W. Wright on December 10, 1980, in accordance with 10 CFR 50.55(e) as NCR YCN YCP 8006. This was followed by our interim reports dated January 9, April 8, and August 12, 1981. Enclosed is our fourth interim report. We expect to submit our next report by March 2, 1982. This deficiency has also been reported for every TVA nuclear plant.

If you have any questions concerning this matter, please get in touch with R. H. Shell at FTS 858-2688.

Very truly yours, TENNESSEE VALLEY AUTHORITY I

L. M. Mills, Manager Nuclear Regulation and Safety Enclosure cc: Mr. Victor Stello, Jr. , Director (Enclosure)

Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 U

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ENCLOSURE YELLOW CREEK NUCLEAR PLANT UNITS 1 AND 2 FILLET WELD MISSPECIFICATION

_t YCRD-566/81-01 AND YCRC-567/81-01 I 10 CFR 50.55(e)

FOURTH INTERIM REPORT

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Descritpion of Deficiency Our investigation has identified violations of the 135-degree maximum, 60-degree minimum angle permitted for intersecting members of prequalified fillet-welded skewed tee joints. For the Yellow Creek Nuclear Plant, this requirement is imposed by the American Institute of Steel Construction (AISC) specification and the American Welding Society (AWS) D1.1 structural welding code.

Interim Progress TVA has completed a review of all TVA and vendor designs which are governed by the AISC specification and AWS structural welding code.

Violations of the angle limitations were found to occur on TVA drawings of handrail and bracing connections in the Intake and Essential Raw Cooling Water Pumping Stations and on vendor furnished instrument racks. The instrument racks were seismically qualified by an actual test. In the other cases, the joints were evaluated and found to be stressed within allowable values. This analysis was conservative in that it either neglected the load-carrying capacity of the fillet weld in the acute and obtuse angle portions of all joints, or only considered a portion of the weld throat as structurally effective. TVA concludes that the structural integrity of these joints was not impaired by specification of acute angles other than allowed by the design codes.

Fillet weld misspecification was found to occur on one TVA civil drawing showing standard details for platform supports and on four TVA civil drawings involving stairs, platforms, and handrails in the Control

Building. These drawings were corrected and reissued in the time period between February 17, 1981, and May 11, 1981.

Fillet weld misspecification was identified on some AISC/AWS designs appearing on the design drawings prepared by CB&I under the containment design contract. These drawings had been issued but no welding had been performed . CB&I is revising these designs to comply with the applicable code requirements. We anticipate these changes will be completed, approved, and issued in approximately 3 months.

On all Combustion Engineering supplied equipment fabricated to the requirements of the AISC specification, the subject welds have either been qualified by analyses or are considered nonload carryi a welds.

Engineers and designers have been alerted to the AISC/AWS requirements for limiting angles for skewed tee joints.

Generic implications for other plants have been investigated and are being resolved with the disposition of NCR's SQN SWP 8025, WBN SWP 8008, WBN 2807R, BLN BLP 8007, HTA HPP 8003, HTB HPP 8003, and PBN HPP 8003, which were previously reported under the requirements of 10 CFR 50.55(e).