ML19347D253
| ML19347D253 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 03/03/1981 |
| 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, SQRD-50-328-81, NUDOCS 8103110659 | |
| Download: ML19347D253 (3) | |
Text
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- 9cz'/ ALLEY Au".-;
- ,r-i 400 Chestnut Street Tower March 3, 1981 SQRD-50-328/81-02
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"b78 Mr. James P 0'Reilly, Director
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b-Cffice of Ins ection and Enforcement m
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- Id $ g U.S. Nuclear R latory Commission
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Region II - Suit 3100
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'9 Atlanta, Georgia 3 03
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Dear Mr. O'Reilly:
SEQUOYAH NUCLEAR PLANT UNIT 2 - FILLET WELDS MISSPECIFICATION -
SQRD-50-328/81 SECOND 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 SQN SWP 8025. A first interim report was submitted on January 9, 1981.
Enclosed is our second interim report. We expect to submit our next report by April 9, 1981.
If you have any questions, please get in touch with D. L. Lambert at FTS 857-2581.
Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, Manager Nuclear Regulation and Safety Enclosure
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cc:
Mr. Victor Stello, Director (Enclosure),V Office of Inspection and Enforcement U.S. Nucitar Regulatory Consission Washington, DC 20555 d
3103110 SI l
DCII)SURE SEX 7)OYAH NUCIZAR PIR7f UNIT 2 FILIST WEID MISSPECIFICATICN SQRD-50-328/81-02 10CFR50.5S (e)
SIMD I?TTERIM REPORT Description of Deficiency In a number of WA nuclear plant systems, fillet welds were specified in lieu of beveled groove welds to connect members wlose angle of intersection is outside the limits for fillet weld application as stipulated in the ATerican Institute of Steel Construction (AISC)
Standards. SeAISCStandardstagesthattheweldswhicharemade joining mmbers at an angle of 60 or less are to be defined as acute angic welds. Acute angle welds should be specified as beveled grcove welds according to AISC.
Interim Procress WA's investigation has fdentified that the 60 minian argie permitted for intersecting members of fillet-welded skewed tee joints has been exceeded. For Sequoyah, this requirenent is imoosed by the AISC specification and the ANS Dl.1 Structural Welding Code. Rese joints had not been qualified as required by AWS Dl.l.
h is condition was found to exist in miscellaneous Category I steel features and for Category I mechanical and electrical ccnoonent supports.
All drawings of the following steel features were reviewed for presence of the nonconforming geometry: cable tray supports, platforms, pipe-rupture protective devices, monorails, and tank and equipnent supports. Rese structures are located in the auxiliary, control,-reactor, and dir3el generator buildings. For all structures, over 75 representative nonconforming joints were selected for detailed structural analysis. In all cases evaluated, the joints were found to be stressed within allowable values. h is analysis was conservative in that it neglected the load-carrying capacity of the fillet weld in the acute angle portion of all joints, and on all but two joints the capacity _ of the fillet weld in the obtuse angle position could be ignored. WA's analysis was cwpleted with the conclusion that the structural integrity of these joints was not impaired by specification of acute angles less than allowed by the design codes.
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A sanpling program has been established for review of the approximately 7500 engineered pipe supports in the follcwing syster.s:
1.
Reactor Coolant Systen 2.
Residual Heat Re.w al System 3.
Safety Injection System 4.
Chemical and Volume Control System 5.
Auxiliary Feedwater System 6.
Main Steam System 7.
Ccrnponent Cooling System 8.
Main Feedwater System 9.
Upper Heat Injection System
- 10. Containment Spray System
- 11. Dnergency Raw Cooling Water System his program will also include a review of the aporo:<imately 1500 support drawings for conduit, instru:mntation, ducts, and alternately analyzed piping 2 inches and under.
Representative nonconforming joints will te selected for detailed structural analysis. W e review of these drawings is underway at the present tine.
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