ML20094D413

Special Rept:On 951006,notified NRC of SG Tube Insps That Fall Into Category C-3 Due to Detection of Circumferential crack-like Indications During ISI at TSP Intersections Associated W/Dents

ML20094D413
Person / Time
Site:	Sequoyah
Issue date:	10/26/1995
From:	Shell R TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9511030362
Download: ML20094D413 (2)

Text

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E Ienne5See Vaney Autho,ity Post Off.ce Box 2000. Soddy-Da sy Tennessee 37379 l October 26,1995 l

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

In the Matter of ) Docket No. 50-327 Tennessee Valley Authority )

SEQUOYAH NUCLEAR PLANT (SON)- SPECIAL REPORT ON STEAM GENERATOR (SG) TUBE INSPECTIONS THAT FALL INTO CATEGORY C UNIT 1 Pursuant to the reporting requirements of Technical Specification (TS) 4.4.5.5.c, this submittal provides notification of the classification as Category C-3 as a result of SON's in-service inspection (ISI) of SG Nos. 2,3, and 4. The initial hot-leg top of tubesheet rotating pancake coil sample in SG Nos. 2,3, and 4, were 1644,1622, and 1611 tubes, respectively. There were 46,18, and 23 tubes in SG Nos. 2, 3, and 4, respectively, that were determined to have primary water stress corrosion cracking.

In accordance with SON TS 3/4.4.5, SG Nos. 2,3, and 4 were classified as Category C-3. NRC was initially notified of these results during a telephone conference call on October 6,1995. The remaining nonplugged tubes in SG Nos. 2,3, and 4 were subsequently examined as required by TSs.

TS 4.4.5.5.c also requires a written follow-up report. This report will be sent in conjunction with the 90-day alternate plugging report discussed in TVA's TS Change 95-15 and Generic Letter 95-05.

l In accordance with TS 4.4.5.5.d, implementation of the voltage-based repair criteria to tube support plate (TSP) intersections requires that the staff be notified before returning the SGs to service should certain conditions arise. Circumferential crack-like indications were detected during SON's ISI at TSP intersections associated with dents. NRC was notified of these results during a telephone conference call on October 6,1995.

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October 26,1995 Please direct questions concerning this issue to D. V. Goodin at (423) 843-7734.

l l ' Sincerely, l

i e R. H. Shell Manager l SON Site Licensing l

cc: Mr. D. E. LaBarge, Project Manager Nuclear Regulatory Commission l

One White Flint, North j 11555 Rockville Pike l Rockville, Maryland 20852-2739 NRC Resident inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy-Daisy, Tennessee 37379-3624 l

Regional Administrator U.S. Nuclear Regulatory Commission Region 11 101 Marietta Street, NW, Suite 2900 i Atlanta, Georgia 30323-2711 f

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