ML20133N416

Forwards RAI Re SG Tube Voltage Based Repair Criteria 90 Day Rept Submitted IAW GL 95-05

ML20133N416
Person / Time
Site:	South Texas
Issue date:	01/22/1997
From:	Alexion T NRC (Affiliation Not Assigned)
To:	Cottle W HOUSTON LIGHTING & POWER CO.
References
GL-95-05, GL-95-5, TAC-M97305, NUDOCS 9701230283
Download: ML20133N416 (4)

Text

, 1 1

Mr. William T. Cottle January 22, 1997 l Executive Vice-President & 1 General Manager, Nuclear {

Houston Lighting & Power Company 1 South Texas Project Electric  ;

Generating Station  !

P. O. Box 289  ;

Wadsworth, TX 77483 '

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING STEAM GENERATOR TUBE VOLTAGE BASED REPAIR CRITERIA 90-DAY REPORT, SOUTH TEXAS  :

PROJECT, UNIT 1 (TAC N0. M97305) i

Dear Mr. Cottle:

The Nuclear Regulatory Commission staff is reviewing the subject report, dated September 5, 1996. This 90-day report was submitted in accordance with Generic letter 95-05, " Voltage-Based Repair Criteria for Westinghouse Steam Generator Tubes Affected by Outside Diameter Stress Corrosion Cracking."

l Based on its review, the staff has determined that additional information is needed. It is requested that you provide the additional information requested in the enclosure within 30 days from the date of this letter.

Sincerely, ORIGINAL SIGNED BY:

Thomas W. Alexion, Project Manager Project Directorate IV-1 ,

Division of Reactor Projects III/IV  !

Office of Nuclear Reactor Regulation Docket No. 50-498

Enclosure:

RAI l

cc w/ encl: See next page DISTRIBUTION:

EDocket File..

PUBLIC PD4-1 r/f T. Alexion W. Beckner C. Hawes J. Roe J. Dyer, RIV E. Adensam (EGA1)

ACRS OGC Document Name: STP97305.RAI *See previous concurrence OFC PM/PD4-l' b - (A)LA/PD4-1 SL/EMCB* \

NAME TAlexion/v CHawesCNN ETSullivan DATE k/21/97 i /Jd/97 01/16/97 5)1 COPY !YES/N0 YES/N0 YES/NO j hh 9701230283 970122 PDR ADOCK 05000498 P PDR

. . _ _ __ m.. _ . = -

$ RCE?u g 11 UNITED STATES j

5 NUCLEAR RE2ULATORY COMMISSION 2 WASHINGTON, D.C. - anni

%*****/ January 22, 1997 Mr. William T. Cottle Executive Vice-President &

General, Manager, Nuclear Houston Lighting & Power Company South Texas Project Electric Generating Station P. O. Box 289 Wadsworth, TX 77483

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING STEAM GENERATOR TUBE VOLTAGE BASED REPAIR CRITERIA 90-DAY REPORT, SOUTH TEXAS PROJECT, UNIT 1 (TAC NO. M97305)

Dear Mr. Cottle:

The Nuclear Regulatory Commission staff is reviewing the subject report, dated September 5, 1996. This 90-day report was submitted in accordance with Generic Letter 95-05, " Voltage-Based Repair Criteria for Westinghouse Steam Generator Tubes Affected by Outside Diameter Stress Corrosion Cracking."

Pased on its review, the staff has determined that additional information is l aeeded. It is requested that you provide the additional information requested I in the enclosure within 30 days from the date of this letter. <

Sincerely, ,

v Ql -

YTJ Thomas W. Alexion, Project Manager Project Directorate IV-1 Division of Reactor Projects III/IV l Office of Nuclear Reactor Regulation !

Docket No. 50-498

Enclosure:

RAI cc w/ enc 1: See next page

Mr. William T. Cottle Houston Lighting & Power Company South Texas, Units 1 & 2 cc:

Mr. David P. Loveless Jack R. Newman, Esq.

Senior Resident Inspector Morgan, Lewis & Bockius U.S. Nuclear Regulatory Commission 1800 M Street, N.W.

P. O. Box 910 Washington, DC 20036-5869 Bay City, TX 77414 Mr. Lawrence E. Martin Mr. J. C. Lanier/M. B. Lee General Manager, Nuclear Assurance Licensing City of Austin Houston Lighting and Power Company Electric Utility Department P. O. Box 289 721 Barton Springs Road Wadsworth, TX 77483 Austin, TX 78704 Rufus S. Scott Mr. M. T. Hardt Associate General Counsel Mr. W. C. Gunst Houston Lighting and Power Company City Public Service Board P. O. Box 61867 P. O. Box 1771 Houston, TX 77208 San Antonio, TX 78296 Joseph R. Egan, Esq. ,

Mr. G. E. Vaughn/C. A. Johnson Egan & Associates, P.C.  !

Central Power and Light Company 2300 N Street, N.W.

P. O. Box 289 Washington, DC 20037 Mail Code: N5012 Wadsworth, TX 74483 Office of the Governor i ATTN: Andy Barrett, Director 1 INP0 Environmental Policy Records Center P. O. Box 12428 700 Galleria Parkway Austin, TX 78711 Atlanta, GA 30339-3064 l

Arthur C. Tate, Director Regional Administrator, Region IV Division of Compliance & Inspection U.S. Nuclear Regulatory Commission Bureau of Radiation Control 611 Ryan Plaza Drive, Suite 400 Texas Department of Health Arlington, TX 76011 1100 West 49th Street Austin, TX 78756 Dr. Bertram Wolfe 15453 Via Vaquero Texas Public Utility Commission Monte Sereno, CA 95030 ATTN: Mr. Glenn W. Dishong 7800 Shoal Creek Blvd.

Judge, Matagorda County Suite 400N Matagorda County Courthouse Austin, TX 78757-1024 1700 Seventh Street Bay City, TX 77414 J. W. Beck Little Harbor Consultants, Inc.

44 Nichols Road Cohasset, MA 02025-1166

~^

l i

l REQUEST FOR ADDITIONAL INFORMATION STEAM GENERATOR TUBE VOLTAGE BASED REPAIR CRITERIA 90-DAY REPORT l

SOUTH TEXAS PROJECT. UNIT 1 l DOCKET NO. 50-498 I

l By letter dated September 5, 1996, " Steam Generator Tube Voltage Based Repair i Criteria 90-Day Report," information was provided pertaining to the licensee's i assessment of the structural and leakage integrity of the steam generator i tubes. As a result of a review of this document, the staff requests that the j licensee provide responses to the following questions and comments in order i for the staff to assess differenro between the results provided by the

! licensee and results generated by the staff.

i i 1. For the projected end-of-cycle (E0C) voltage distributions provided in i the report, discuss the key assumptions in the methodology (e.g., is

interpolation between voltage bins performed, is WCAP-14277 Equation 3.5

• or 3.6 used, how are values of probe wear that exceed the probe wear cutoff handled, is the non-destructive examination uncertainty i adjustment applied to the beginning-of-cycle (B0C) voltage only or to 1

the sum of the BOC voltage and the growth rate, what method is used to 2 account for the fractional indications, how are the probe wear 4 adjustment and analyst variability adjustment determined).

2. For the projected E0C voltage distributions contained in Table 4-8, it i appears that when the number of indications was less than 0.1, the

values were not reported. If this is the case, provide an updated EOC voltage distribution which shows all E0C voltages observed regardless of the frequency of occurrence (e.g., 0.003 indications).

3. In the determination of the probability of burst and the primary-to-secondary leakage under postulated accident conditions, discuss how fractional indications were accounted (e.g., 7.3 indications, 0.002 '

indications).

4. Provide the mean probability of burst associated with the 95% upper confidence limit values provided in Table 5-1. Provide the number of trials used in determining the probability of burst (e.g., 100,000).

Since one of the purposes of the information requested in Questions 1 and 2 is .

to assess differences between the licensee's EOC projections and projections i made by the staff, it would be acceptable to provide additional calculations of the EOC voltage distribution using assumptions that are different than those made in the September 5, 1996, letter provided the assumptions and the input data are provided.

ENCLOSURE