ML20086Q589

Suppls 891102 Response to NRC Bulletin 89-008, Thimble Tube Thinning in Westinghouse Reactors. Detected Wear for Thimble Tube Locations J-14 & L-10 Below 20% (First Action Level for Thimble Tube Wear)

ML20086Q589
Person / Time
Site:	Comanche Peak
Issue date:	12/20/1991
From:	William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
IEB-89-008, IEB-89-8, TXX-91455, NUDOCS 9112300258
Download: ML20086Q589 (3)

Text

. ,

""O Log # TXX-91455

.i 2 File # 10119

~~ ~~

904.4 Ref # NRCL 03 01; illELECTRIC December 20, 1991 William J. Cahill, Jr.

Group Yice Presi. Ire U. S. Nuclear Regulatory Commission Attu: Document Control Desk Washington, DC 20555

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES) UNIT 1 DOCKET NOS. 50-445 THlMBLE TUBE THINNING IN WESTINGHOUSE REACTOPS REF: TV Electric Letter logged TXX-89781, from Willitm J. Cahill. Jr. to the NRC, dated November 2, 1989.

Gentlemen:

The NRC Bulletin 88-09, ' Thimble Tube Thinning in Westinghouse Reactors,"

discusses thimble tube wear resulting from flow-indu;ed vibration for Westinghouse reactors with bottom mounted instrumettation. As a resalt of this bulletin, TV Electric established an inspection program to monitor thimble tube performance. Thimble tube inspections were compleud at CPSES Unit 1 on November 26, 1991. This letter reports the results of the inspection as described in the referenced correspondence.

Each of the 58 thimble tubes was subjected to a multi-frequency eddy-current examination over its entire length. Only two tubes exhibited detectable wear.

The thimble tube at core location J-14 had an indicated thru-wall wear of 17%

and the tube at core location L-10 had indicated thru wall wear of 11%, The wear on both tubes was determined to occur at the lower core support.

The detected wear for both thimble tube locations was below 20% (the first action level for thimble tube wear). Each thimble tube will be re-examined at its next pericdic inspection interval, i

l 6

ean1 t, C t) U $ e r ..

9112300258 DR 911220 -

1. //f

{d ADOCK 05000445 400 N. Othe sutet LB,81 Dallas, Texas 75201 f h FDR

?

1XX 91455 Page 2 of 2 If t here are any questions, please contact Mr. Jimmy Seawright at (214's 812 4375.

Sincerely,

/

William J. Cahil.1, r.

.1DS/grp Attachment c - Mr. R. D. Martin, Region IV Resident inspectors CPSES (2)

Mr. T. A. Bergman, NRR

/'.

Attachment to TXX 91455 Page 1 of 1 UNITED STATES OF AMEklCA NUCLEAR REGULATORY COMMISSION in the Matter of )

)

Texas Utilities Electric Company ) Docket No, 50-445

)

(Comanche Peak Steam Electric )

Station, Unit 1) )

AFFIDAVIT William J. Cahill, Jr. being duly sworn, hereby deposes and says that he is Group Vice President, Nuclear af TV Electric, the lead-Applicant herein: that he is dui) authorized to sign and file with the Nuclear Regulatory _ Commission this response to NRC Bulletin 88-09 for the captioned facility: that he is familiar with the content thereof: and that the matters set forth therein are true and correct to the best of his knowledge, information and belief.

, /

/

fl J WilliamJ.Cah%,Jr.

Group Vice President. Nu/ clear STATE OF TEXAS )

)

COUNTY OF DALLAS )

Subscribed and sworn to before me, on this 19th day of December , 1991, b

~

Notary F ublic

.) Y J

L L