ML20248M106
| ML20248M106 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 06/10/1998 |
| From: | De Agazio A NRC (Affiliation Not Assigned) |
| To: | Zeringue O TENNESSEE VALLEY AUTHORITY |
| References | |
| GL-92-01, GL-92-1, TAC-MA1179, TAC-MA1180, TAC-MA1181, NUDOCS 9806120406 | |
| Download: ML20248M106 (6) | |
Text
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UNITED STATES y
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NUCLEAR REGULATORY COMMISSION o
WASHINGTON, D.c. 20066 4001 p!
June 10, 1998 Mr. O. J. Zeringue Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority SA LWA Place 1101 Market Street Chattanooga, Tennessee 37402-2801
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION REGARDING REACTOR PRESSURE VESSEL INTEGRITY AT BROWNS FERRY NUCLEAR PLANT, UNITS 1,2, AND 3 (TAC NOS. MA1179, MA1180, AND MA1181)
Dear Mr. Zeringue:
Generic Letter (GL) 92-01, Revision 1, Supplement 1 (GL 92-01, Rev.1, Supp.1), " Reactor Vessel Structural Integrity" was issued in May 1995. This GL requested licensees to perform a review of their reactor pressure vessel (RPV) structural integrity assessments to identify, collect, and report any new data pertinent to the analysis of the structural integrity of their RPVs.
Licensees were asked to assess the impact of those data on their RPV integrity analyses relative to the requirements of Title 10 of the Code of Federal Regulations. Sections 50.60 and 50.61, Appendices G and H which encompass pressurized thermal shock and upper shelf energy evaluations, and any potential impact on low temperature over pressure limits or pressure-temperature (P-T) limits.
After reviewing the Tennessee Valley Authonty (TVA) response submitted on July 7,1992, for the Browns Feny Nuclear Plant Units 1,2, and 3 (BFN), the U.S. Nuclear Regulatory Commission (NRC) acknowledged by letter to TVA dated July 26,1996, that TVA had submitted the requested information and had asserted that the previously submitted evaluations remained valid. As a result, the NRC concluded that no additional information regarding the structural integrity of the BFN RPVs was available at that time. Subsequently, the boiling-water reactor Vessel and intemals Project (BWRVIP) submitted its report, " Update of Bounding Assessment of BWR/2-6 Reactor Pressure Vessel Integrity issues (BWRVIP-46)." This report included bounding i
assessments of new data from (1) the Combustion Engineering Owners Group (CEOG) database released in July 1997 which contains all known data for CE fabricated welds in pressurized-water reactor and SWR vessels; (2) Framatome Technologies incorporated (FTI) analyses of Linde 80 welds which are documented in NRC Inspection Report 99901300/97-01 dated January 28,1998; (3) FTI's analysis of electro-slag welds which was referenced in a Dresden and Quad Cities P-T limits submittal dated September 20,1996; and (4) Chicago Bridge and Iron quality assurance records. New data for one vessel fabricated by Hitachi was also included in the BWRVIP report.
The staff is requesting that TVA re-evaluate the RPV weld chemistry values that were submitted previously as part of the BFN licensing bases in light of the information presented in the CEOG, FTl and BWRVIP reports. The staff expects that TVA will assess this new information to
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Mr. O. J. Zeringue idetermine whether any values of RPV weld chemistry need to be revised for BFN Therefore, to t
provide a complete response to items 2,3 and 4 of the GL, the NRC requests a response to the enclosed request for additionalinformation within 90 days of receipt of this letter. If a question does not apply to the BFN situation, please indicate this in the response along with the technical basis.. Additionally,' per GL 92-01, Rev.1,~ Supp.1, please provide a certification that the previously submitted evaluations remain valid.
The information provided will be used in updating the Reactor Vessel integrity Database. Please note that RPV integrity analyses utilizing newly identified data could require license amendments to maintain complisnce with 10 CFR 50.60 and Appendices G and H to 10 CFR Part 50, and to address any potential impact on P-T limits. If licer,se amendments or additional assessments are necessary, please provide the schedule for such submittals.
- Sincerely, (Original Signed By)
Albert W. De Agazio, Senior Project Manager Project Directorate ll-3 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation Docket Nos. 50-259,50-260, and 50-296 Serial No. BFN-98-013_
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Mr. O. J. Zeringue BROWNS FERRY NUCLEAR PLANT Tennessee Valley Authority cc:
Mr. J. A. Scalice, Senior Vice President Mr. Mark J. Burrynski, Managar Nuclear Operations Nuclear Licensing Tennessee Valley Authority Tennessee Valley Authority 6A Lookout Place 4J Blue Ridge 1101 Market Street 1101 Market Street Chattanooga, TN 37402-2801 Chattanooga, TN 37402-2801 Mr. Jack A. Bailey, Vice President Mr. Timothy E. Abney, Manager Engineering & Technical Services Licensing and Industry Affairs Tennessee Valley Authority Browns Ferry Nuclear Plant 6A Lookout Place Tennessee Valley Authority 1101 Market Street P.O. Box 2000 Chattanooga, TN 37402-2801 Decatur, AL 37402-2801 Mr. C. M. Crane, Site Vice President Regional Administrator, Region ll Browns Ferry Nuclear Plant U.S. Nuclear Regulatory Commission Tennessee Valley Authority 61 Forsyth Street, SW., Suite 23T85 P.O. Box 2000 Atlanta, GA 30303-3415 Decatur, AL 3560g i
Mr. Leonard D. Weri General Counsel Senior Resident inspector Tennessee Valley Authority U.S. Nuclear Regulatory Commission ET 10H Browns Ferry Nuctsar Plant 400 West Summit Hill Drive 10833 Shaw Road Knoxville, TN 37902 Athens, AL 35611 Mr. Raul R. Baron, General Manager State Health Officer Nuclear Assurance Alabama Dept. of Public Health Tennessee Valley Authority 434 Monroe Street 4J Blue Ridge Montgomery, AL 35130-1701 1101 Market Street Chattanooga, TN 37402-2801 Chairman Limestone County Commission Mr. Karl W. Singer, Plant Manager 310 West Washington Street Browns Ferry Nuclear Plant Athens, AL 35611
. Tennessee Valley Authority P.O. Box 2000 Decatur, AL 3560g l'
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k REQUEST FOR ADDITIONAL INFORMATION REACTOR PRESSURE VESSEL INTEGRITY 1
Assessment of Best-Estimate Chemistry The U.S. Nuclear Regulatory Commission (NRC) staff recently received the Boiling-Water Reactor Vessel and Intervals Project (BWRVIP) report, " Update of Bounding Assessment of BWR/2-6 Reactor Pressure Vessel Integrity issues (BWRVIP-46)." Based on information in the BWRVIP report, in accordance with the provisions of Generic Letter 92-01, Revision 1, Supplement 1, the NRC requests the following:
An evaluation of the bounding assessment in the reference above and its applicability to the determination of the best-estimate chemistry for all of Browns Ferry Nuclear Plant, Units 1,2 and 3 (BFN) reactor pressure vessel (RPV) beltline welds. Based upon this re-evaluation, supply the information necessary to complete the data requisted in Table 1 for each RPV beltline weld material. If the limiting material for the BFN vessels' pressure-temperature (P-T) limits evaluation is not a weld, also include the information requested in Table 1 for the limiting material.
With respect to Tennessee Valley Authority's (TVA's) response to this question, the staff notes that some issues regarding evaluation of the data were discussed in a public meeting between the staff, Nuclear Energy Institute (NEI), and industry representatives on November 12,1997. A summary of this meeting is documented (Reference 1)in a meeting summary dated November 19,1997, " Meeting Summary for November 12,1997 Meeting with Owners Group Representatives and NEl Regarding Review of Responses to Generic Letter 92-01, Revision 1, Supplement 1 Responses". The information in Reference 1 may be usefulin helping you to prepare your response.
In addition to the issues discussed in the referenced meeting, TVA should also consider what method should be used for grouping sets of chemistry data (in particular, those from weld qualification tests) as being from "one weld" or from multiple welds. This is an important consideration when a mean-of the-means or coil-weighted average approach is determined to be the appropriate method for determining the best-estimate chemistry. If a weld (or welds) is fabricated as weld qualification specimens by the same manufacturer, within a short time span, using similar welding input parameters, and using the same coil (or coils in the case of tandem arc welds) of weld consumables, it may be appropriate to consider all chemistry samples from that weld (or welds) as samples from "one weld" for the purposes of best-estimate chemistry determination. If information is not available to confirm the aforementioned details, but sufficient evidence exists to reasonably assume the details are the same, the best-estimate chemistry should be evaluated both by assuming the data came from "one weld" and by assuming that the data came from an appropriate number of" multiple welds." A justification should then be provided for which assumption was chosen when the best-estimate chemistry was determined.
2 P-T Limit Evaluation If the limiting material for BFN changes or if the adjusted reference temperature for the
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limiting materialincreases as a result of the above evaluations, please provide the revised RT, value for the limiting material. In addition, if the adjusted RTc value increased, please provide a schedule for revising the P-Tlimits. The schedule should ensure that compliance with 10 CFR Part 50 Appendix G is maintained.
.. Reference t
1 1.
Memorandum dated November 19,1997, from Keith R. Wichman to Edmund J. Sullivan,
" Meeting Summary for November 12,1997 Meeting with Owners Group Representatives and NEl Regarding Review of Responses to Generic Letter 02-01, Revision 1, P' f.oment 1 Responses."
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