ML20236N493
| ML20236N493 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 07/02/1998 |
| From: | Hernan R NRC (Affiliation Not Assigned) |
| To: | Scalice J TENNESSEE VALLEY AUTHORITY |
| References | |
| TAC-MA0630, TAC-MA630, NUDOCS 9807150146 | |
| Download: ML20236N493 (3) | |
Text
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i-fL July 2,1998 MriJ. A. Scalice
' Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street j
Chattanooga, Tennessee 37402-2801
SUBJECT:
SEQUOYAH UNIT 1: REQUEST FOR ADDITIONAL INFORMATION p
REGARDING THE REVIEW OF STEAM GENERATOR TURE INSPECTION
. SPECIAL REPORT (TAC NO. MA0630)
Dear Mr. Scalice:
By a letter dated August 8,1997, Tennessee Valley Authority (TVA) submitted for staff review the special report on steam generator activities completed during the Sequoyah Unit 1 Cycle 8 refueling outage. The report was submitted to satisfy a commitment as a part of implementing
. the voltage-based attemate repair criteria in the Sequoyah Unit 1 technical specifications. ' The l
altemate repair criteria were implemented based on Generic Letter 95-05, ' Voltage-Based l.
Repair Criteria for Westinghouse Steam Generator Tubes Affected By Outside Diameter Stress j
Corrosion Cracking."
In order to continue its review, the staff requests that TVA provide responses to the enclosed i-questions.
Sincerely,
[
Original signed by l
Ronald W. Heman, Senior Project Manager Project Directorate ll-3 j
Division of Reactor Projects - 1/ll l
Office of Nuclear Reactor Regulation Docket No. 50-327
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9807150146 900702 l-PDR ADOCK 05000327 P.
I REQUEST FOR ADDITIONAL INFORMATION
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REVIEW OF THE SPECIAL REPORT RELATED TO VOLTAGE-BASED ALTERNATE REPAIR CRITERIA FOR STEAM GENERATOR TUBING TENNESSEE VALLEY AUTHORITY SEQUOYAH UNIT 1 DOCKET NO. 50-327 l
l By a letter dated August 8,1997, Tennessee Valley Authority submitted for staff review the special report on steam generator activities completed during the Sequoyah Unit 1 Cycle 8 refueling outage. The licensee submitted the report to satisfy a commitment as a part of implementing the voltage-based attemate repair criteria in the Sequoyah Unit 1 technical specifications. The altemate repair criteria were implemented based on Generic Letter 95-05,
" Voltage-Based Repair Criteria for Westinghouse Steam Generator Tubes Affected By Outside Diameter Stress Corrosion Cracking."
l The staff has performed verification calculations; however, the staff has not been able to verify l
the licensee's results for the predicted tube burst probability and leakage. The staff believes l.
that the cause should be the differences in the input parameters that were used in the staff's and licensee's calculations. In order to compare the difference in calculations, the staff requests that the licensee provide the following information:
1.
For calculations to obtain the tube burst probability on page 74 of the submittal, provide the following input parameters: (1) the mean, standard deviation, and normalized value of material property distribution for steam generator tubing; (2) slope and intercept of the burst pressure vs. voltage correlation; (3) number of burst pressure data points; and (4) sum of (X-X-bar) **2, mean of X, and sum of X**2, where X is the log of the bobbin voltage of the burst pressure vs. voltage correlation.
2.
For calculations to obtain the tube leakage on page 7-4 of the submittal, provide the following input parameters: (1) intercept of the leak rate vs. voltage correlation; (2) total number of leak rate data points; (3) sum of (X - X-bar)"2, mean of X, and sum of X"2, where X is the log of individual bobbin voltage in the leak rate vs. voltage correlation; (4) slope, intercept, mean square error, and number of data points of probability of leak l
vs. voltage correlation; and (5) coefficients, V,,, V r, and V of the covariance matrix of i
22 the regression equation.
l 3.
For the burst probability and leakage calculations, provide the number of Monte Carlo simulations that were performed to obtain the results on page 7 ' 'f the submittal.
ENCLOSURE
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Mr.'J. A. Scalice SEQUOYAH NUCLEAR PLANT Tennessee Valley Authority cc:
SeniorVice President Mr. Pedro Salas, Manager Nuclear Operations Licensing and Industry Affairs Tennessee Valley Authority Sequoyah Nuclear Plant 6A Lookout Place Tennessee Valley Authority 1101 Market Street P.O. Box 2000 Chattanooga, TN 37402-2801 Soddy Daisy, TN 37379 Mr. Jack A. Bailey Mr. J. T. Herron, Plant Manager Vice President Sequoyah Nuclear Plant Engineering & Technical Services Tennessee Valley Authority Tennessee Valley Authority P.O. Box 2000 6A Lookout Place -
Soddy Daisy, TN 37379 1101 Market Street Chattanooga, TN 37402-2801 Regional Administrator
)
U.S. Nuclear Regulatory Commission Mr. Masoud Bajestani Region ll Site Vice President 61 Forsyth Street, SW.
i Sequoyah Nuclear Plant Suite 23T85 I
Tennessee Valley Authority Atlanta, GA 30303-3415 l
P.O. Box 2000 Soddy Daisy, TN 37379 Mr. Melvin C. Shannon Senior Resident inspector General Counsel Sequoyah Nuclear Plant Tennessee Valley Authority U.S. Nuclear Regulatory Commission ET 10H 2600 Igou Ferry Road
-400 West Summit Hill Drive Soddy Daisy, TN 37379 Knoxville,TN 37902 Mr. Michael H. Mobley, Director Mr. Raul R. Baron, General Manager TN Dept. of Er vironment & Conservation Nuclear Assurance Division of Radiological Health Tennessee Valley Authority 3rd Floor, L and C Annex
- SM Lookout Place 401 Church Street 1101 Market Street Nashville, TN 37243-1532 Chattanooga, TN 37402-2801 County Executive
. Mr. Mark J. Burzynski, Manager Hamilton County Courthouse Nuclear Licensing Chattanooga, TN 37402-2801
' Tennessee Valley Authority 4X Blue Ridge j
.1101 Market Street Chattanooga, TN 37402-2801 1
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