ML20244C531

Forwards Sequoyah Nuclear Plant,Unit 1,Cycle 3B Insp Steam Generator Tubing Insp Results, Per Tech Spec 4.4.5.5.b.None of Inspected Tubes Determined to Be Defective

ML20244C531
Person / Time
Site:	Sequoyah
Issue date:	06/08/1989
From:	Michael Ray TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20244C534	List: ML20244C531 ML20244C536
References
NUDOCS 8906150008
Download: ML20244C531 (2)

Text

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p m, k TENNESSEE VALLEY AUTHORITY u

CH ATTANOOGA. TENNESSEE 37401 i

5N 1578 Lookout Place 1 JUN 081989 l

U.S. Nuclear Regulatory Commission j ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:

In the Matter of ) Docket No. 50-327 l Tennessee Valley Authority SEQUOYAH NUCLEAR PLANT (SQN) UNIT 1 - INSERVICE INSPECTION (ISI) 0F UNIT 1 STEAM GENERATOR TUBES

Reference:

Letter from TVA to NRC dated. July 18, 1988, "Sequoyah Nuclear

, Plant (SQN) - Unit i Steam Generator Tube Plugging"-

As required by SQN Unit 1 Technical Specification 4.4.5.5.b, enclosed are the results of the steam generator tube ISI completed for Unit 1 on July 3,1988.

The referenced letter provided the tube plugging summary for this inspection.

An ISI was performed on 695 tubes'in steam generator 1 and 695 tubes in steam-generator 4. None of the inspected tubes were determined.to be defective.

The inspection result category was classified by TVA as C-1. An additional number of non-ISI examinations were performed, bringing the total' number of tubes examined in steam generators 1 and 4 to approximately 25 percent.

Independent of the ISI, TVA performed a self-imposed eddy current examination of all rows 1 and 2 tube U-bend regions in all four steam generators utilizing an optimized probe design (motorized rotating pancake coil probe). These examinations were performed for the detection of defects in close. radius U-bends. Rotating pancake coil examinations were performed in both steam generators 2 and 3 at the top of the tubesheet expansion / transition region.

Fifty-seven such examinations were performed in steam generator 2, and 73 in steam generator 3; no imperfections were discovered.

The enclosure provides a listing of steam generator-tubes that have recently been plugged based on the results of examinations. There were-50 Unit 1, row I tubes that were plugged because of imperfections greater than 40 percent of the tube wall thickness. An additional 12 tubes were deplugged and replugged with a permanently installed plug. Also, the steam generator 1, row 10, column 44 tube was stabilized and preventively plugged based on identification as being susceptible to rapidly propagating fatigue cracking.

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8906150008 890600 y1 PDR ADOCK 05000327 4 G PNU 1

- An Equal opportunity Employer

t 'a U.S. Nuclear Regulatory Commission AN.08 m.9 l No commitments are contained in this submittal. Please direct questions l- concerning this issue to K.' S. Whitaker at (615) 843-7748.

l Very truly yours, TENNESSEE VALLEY AUTHORITY l

[ L Mana$.(

ger, Nuc etr Licensing and Regulatory Affairs cc (Enclosure): -

Ms. S. C. Black, Assistant Director for Projects TVA Projects Division .

U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Mr. B. A. Wilson, Assistant Director l for Inspection Programs TVA Projects Division l U.S. Nuclear Regulatory Commission Region II 101 Marietta-Street, NH, Suite 2900 Atlanta, Georgia 30323 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379 l

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