ML20090K526

Interim Significant Deficiency Rept Re Incorrectly Drilled & Tapped End Blocks for Itt Grinnel Figure 307 Mechanical Snubber Extension Pieces.Initially Reported on 840405. Unacceptable Threads Will Be Replaced by 840511

ML20090K526
Person / Time
Site:	Catawba
Issue date:	05/04/1984
From:	Tucker H DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
NUDOCS 8405240239
Download: ML20090K526 (3)

Text

r Dume POWEM GDIPANY P.O. HOE WHHH CHAltfAYITtt. M.C. 98949

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]419y;y ,$Na$),1984 Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission Region !!

101 Marietta Street. NW, Suite 2900 Atlanta, Georgia 30303 Re: Catawba Nuclear Station Units I and 2 Docket Nos. 50-413 and 50-414

Dear Mr. O'Reilly:

Pursuant to 10 CFR 50.55e, please find attached Significant Deficiency Report No. SD 413-414/84-07.

I Very truly yours, 1

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Hal 8. Tucker

! LTP/php Attachment cc: Director INPO Records Center Office of Inspection & Enforcement Suite 1500 i U. S. Nuclear Regulatory Commission 1100 Circle 75 Parkway Washington, D. C. 20555 Atlanta, Georgia 30339 NRC Resident Inspector Mr. Robert Guild, Esq.

Catawba Nuclear Station -

Attorney-at-Law i P. O. Box 12097 I

Palmetto Alliance Charicston, South Carolina 29412 21356 Devine Street

Columbia, South Carolina 29205 E

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Duka Power Company Catawba Nuclear Station l

REPORT NUNBER: SD 413-414/84-07 REPORT DATE: May 4, 1984 i

FACILITY: Catawba Nuclear Station Units 1 and 2 i

IDENTIFICATION OF DEFICIENCY: l End Blocks for ITT Grinnell Figure 307 mechanical snubber extension pieces.  :

modified by Duke Power Company's Con:truction Department, were found to be incorrectly drilled and tapped. This discrepancy was identified by Noncon- (

forming item 18167.

j INITIAL REPORT: j On April 5, 1984, Virgil Brownlee. NRC Region !!, Atlanta, Georgia was i notified of the deficiency by J L Ritchie, W 0 Henry, and T L Utterback of Duke Power Company, Charlotte, North Carolina. ,

COWONENf AN0/0R SUPPLIER _

Fabricated by Duke Power Company, Catawba Nuclear Station.

DESCRIPTION Of DEFICIENCY:

On August 10, 1983, the Construction Department at Catawba.NucIcar Station began drilling and tapping end blocks for extension pieces of ITT Grinnell Figure 307 mechanical snubbers. During a support / restraint inspection, excessive play between the rod end threads and the end block threads was identified by the QA inspector as a discrepancy. This aroblem was identified March 14,1984 on Nonconforming Item Report 18167. Su) sequent investigation by Construction Technical Support revealed that 315 supports with extension pieces had been fabricated since August 10, 1983. Of the 315, 104 were found to have extension pieces with oversized holes. The threads were checked with "go-no go" gauges for the specified class fit.

ANALYSIS OF SAFETY IPFLICATIONS:

l Had this situation not been detected, it is possible that some of these mechanical snubbers could have failed during a design basis event. This possibly could have led to an overstressed condition of the restrained component.

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CORRECTIVE ACTION:

The Construction Procedure (CP-353) used to perform the modification of extension pieces has been revised to include a check of all threads with "go-no go" gauges as a part of the fabrication process.

All extension pieces modified since August 10 1983 have been checked with "go-no go" gauges. Those found to have unacceptable threads will be replaced by May 11, 1984.

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