ML20010C456

Third Interim Deficiency Rept Re Fillet Weld Misspec Initially Reported 801210.Util Is Reviewing All TVA & Vendor Designs Governed by AISC Spec & Aws Structural Welding Code. Structural Integrity of Joints Not Impaired by Misspec

ML20010C456
Person / Time
Site:	Yellow Creek
Issue date:	08/12/1981
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 8108200099
Download: ML20010C456 (2)

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TENNESSEE VALLEY AUTHORITY- k['N!*'O p c . ,.

CHATTANOOGA. TENNESSEE 374o1 6, ~'+N .-

400 Chestnut Street Tower II-August 12,-1981 Ol/;Ifpj7 4 ,

YCRD-50-566/81-01

', YCRD-50-567/81-01

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Mr. James P. O'Reilly, Director Office of Inspection and Enforcement d le 19W '

U.S. Nuclear. Regulatory Commission D .v.u.maa;

'* g"C Region II - Suite 3100 101 Marietta Street %x YP Atlanta, Georgia 30303 W/ 'g ,

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 THIRD INTERIM REPORT

.The subject deficiency was initially reported to NRC-OIE 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 and April 8, 1981. Enclosed is our third interim report. We expect to submit Lour next report by December 8,1981. This deficiency has also been reported for every TVA nuclear plant.

If you have any questions concerning this matter, please get in touch with D. L. Lambert at FTS 857-2581.

Very truly yours, TENNESSEE VALLEY AUTHORITY L. M' Mi Is,l4anager Nuclear Regulation and Safety Enclosure oc: Mr. Victor Stello, Jr., Director (Enclosure)

Office of Inspr,ction and Enforcement U.S.' Nuclear Regulatory Commission Washington, DC 20553

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$ An Equal Opportunity Employer

, .'s ENCLOSURE YELLOW CREEK NUCLEAR PLANT UNITS 1 ~ AND 2 FILLU2 WELD MISSPECIFICATION YCRD-566/81-01' AND YCRD-567/81-01 D

10 CFR 50.55(e)

THIRD INTERIM REPORT t

. Description of Deficiency l

. Our investigation h&s 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 (specification for the

. design, fabrication, and erection of structural steel for buildings) and.the American Welding Society (AWS) D1.1 structural welding code.

Interim Progress TVA is in the process of reviewing all TVA and vendor designs which ,

are governed by the AISC specification-and AWS structural welding c ode.

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-furniahsd 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 cnd 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

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joints was not impaired by specification-of acute angles other than allowed by the design codes.

Regarding the joints not yet reviewed, any nonconforming skewed tee joint designs.will- either be redesigned, have their adequacy -

established by structural analysis or other methods, or will be

-repaired.

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

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