ML20236N472

Forwards Rept of Results of Steam Generator Tube Inservice Insp,Per Tech Spec 4.4.5.5 Requirements.Quantity & Extent of Tube Exams Exceeded Requirements of Tech Specs.Tubes Plugged Due to Nonquantifiable Percentage Wall Loss

ML20236N472
Person / Time
Site:	Sequoyah
Issue date:	08/04/1987
From:	Gridley R TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20236N476	List: ML20236N472 ML20236N995
References
NUDOCS 8708110513
Download: ML20236N472 (2)

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l TENNESSEE VALLEY AUTHORITY SN 157B Lookout Place to cra so 7t=

lillG 041981F l l

1 U.S. Nuclear Regulatory Commission l

ATIN: Document Control Desk j l Washington, D.C. 20555 .

! Gentlemen:

l In the Matter of ) Docket Nos. 50-327 i Tennessee Valley Authority ) 50-328 i

SEQUOYAH NUCLEAR PLANT (SQN) - IN-SERVICE INSPECTION OF UNIT 2 STEAM GENERATOR TUBES - REPORT OF RESULTS

References:

1. Letter from R. Gridley to B. Youngblood dated August 22, 1986

2. Letter from R. Gridley to Stewart Ebneter dated i March 16, 1987, "Sequoyah Nuclear Plant - Additional Information Regarding Steam Generator Tube Stress Relief - U-Bend Heat Treatment" l As required by SQN unit 2 technical specification 4.4.5.5, enclosed are the results of the steam generator tube in-service inspection completed on unit 2 August 10, 1986.

The selection of tubes for examination was based on past SQN and industry .

experience. The quantity and extent of tube examinations exceed the I requirements of SQN unit 2 technical specification 4.4.5.0. Self-imposed {

eugmentative examinations of over three times the required quantity were performed. Of these, over twice the number required by technical specification had full-length examinations. The inner radius U-bend examinations used a special state-of-the-art probe that was developed through TVA sponsorship and funding. In addition, independent data analysis was performed to minimize the potential for human error associated with the analysis of examination data. l As reported in reference 1, 24 row 1 tubes were preventively plugged because of nonquantifiable percentage wall loss. In the future, TVA plans to reclaim the preventively plugged tubes by removing the plugs, heat treating the U-bend area of the tubes, and performing post-heat-treatment eddy current tests. A description of the heat treatment methods was provided in reference 2.

8708110513 870804 PDR G

ADDCK 05000323 PDR 0 bk' I I An Equal Opportumty Employer

r U.S. Nuclear Regulatory Commission 2 0 041987 If you have any questions concerning this matter, clease telephone Kathy S. Whitaker at (615) 870-7748.

Very truly yours, TENNESSEE V LEY AUTHORITY R. idley, ' rector Nuclear Safe y and Licensing Enclosure cc (Enclosure):  !

Mr. G. G. Zech, Assistant Director  !

for Inspection Programs 1 Office of Special Projects U.S. Nuclear Regulatory Commission i 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. J. A. Zwolinski, Assistant Director for Projects .

Division of TVA Projects l Office of Special Projects U.S. Nuclear Regulatory Commission 4350 East West Highway EWW 322 Bethesda, Maryland 20814 Sequoynh hesident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379 l

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