ML20235T059

Responds to NRC Bulletin 88-009, Thimble Tube Thinning in Westinghouse Reactors. Insp Frequency Established as Refueling Outage Until Wear Data Base Established & Insps Will Be Accomplished by Eddy Current Testing

ML20235T059
Person / Time
Site:	Sequoyah
Issue date:	02/28/1989
From:	Gridley R TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
IEB-88-009, IEB-88-9, NUDOCS 8903080128
Download: ML20235T059 (3)

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i TENNESSEE' VALLEY AUTHORITY :

CHATTANOOGA, TENNESSEE 37401 SN 157B Lookout Place

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FEB 281989 i

4 V'.S. Nuclear-Regulatory' Commission

-ATTN: Document Control' Desk Nashington, D.C.-

20555 Gentlemen:

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.In.the Matter of,

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Docket No. 50-328.

. Tennessee Valley Authority-

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x SEQUOYAH NUCLEAR PLANT- (SQN)' UNIT.2 - NRC BULLETIN 88-09, THIMBLE TUBE

-THINNING IN WESTINGHOUSE ELECTRIC CORPORATION REACTORS

'As: required inLthe subject bulletin, TVA has developed'a thimble tube.

Inspection program for SQN unit 2.

Near acceptance criteria have.been established, and appropriate. corrective actions identified.

The criteria and corresponding disposition are as follows:

1.

Equal to'or greater than 60-percent.through-wall loss requires-thimble

. tube plugging' 2'

. Equal to or greater than 30-percent and less.than 60-percent.through-wall' Lloss requires? repositioning the thimble tube by a minimum of one and one half inches 3.- Less-than 30-percentrthrough-wall loss requires no corrective action for the next fuel cycle The inspection frequency has been established as each refueling. outage until a wear data base is established and the inspections w11.1 be accomplished by eddy ~ current testing.

Eddy _ current testing and analysis were completed for unit 2 on February 7, 1989. 1Three of.the 58 thimble tubes have equal to or greater.than 60-percent through-wall lossi Thirteen tubes'.have equal to or greater than.30-percent and less than 60-percent through-w'll loss. Thirty-two tubes have less than a

30-percent and greater than 0-percent through-wall loss. Ten tubes have no L

identifiable loss. The enclosure provides a listing.of the 16 tubes with k

equal.'to or greater than 30-percent.through-wall loss, their location, and their'most severe through-wall loss. percentage.

These 16 tubes will be dispositioned in accordance with the thimble tube program described above.

s90308012e'89022e

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PfliB 28;1989 U.S. Nuclear Regulatory Commission l

There are no commitments contained in this submittal. Please direct questions concerning this issue to K. S. Whitaker at (615) 843-7748.

Very truly yours, TENNESSEE VALLEY AUTHORITY R. Gr1 ley, Ma a er Nuclear Licensing and

. Regulatory Affairs Enclosure 3

cc (Enclosure):

Ms. S. C. Black, Assistant Director

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for Projects' TVA Projects Division U.S.. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike i

Rockville, Maryland' 20852 Mr. F. R. McCoy., Assistant Director for Inspection Programs

/A Projects Division J.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379 l

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s-ENCLOSURE.

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- Thimble. Tub'es with Equal ~to or Greater Than 30-Percent Through-Hall Loss.

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. Tube Core.

Most Severe-

' jl Number Location Loss Percentage 13 L-10.

32' i

16 M-7 39'

^ j 19 L-5 40

.l 20 E-5 41 i

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K-12 37 d

24-H-13 46 30 F-3 35-l 37"

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P-9 43 F-14 56 40 44'

'R-8 75 i

45 N-131 36-i 47, A-9 56 48.

P 47 49 D-14 55 l

50 R 81 52 L-15 62 1

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