ML20217E600
| ML20217E600 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 04/22/1998 |
| From: | Croteau R NRC (Affiliation Not Assigned) |
| To: | Reid D VERMONT YANKEE NUCLEAR POWER CORP. |
| References | |
| GL-92-01, GL-92-1, TAC-MA1212, NUDOCS 9804270352 | |
| Download: ML20217E600 (6) | |
Text
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J-f a ato k UNITED STATES
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NUCLEAR REGULATORY COMMISSION WASHINGTON, D.c. 20066 4001
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April 22, 1998 Mr. Donald A. Reid Senior Vice President, Operations Vermont Yankee Nuclear Power Corporation 185 Old Ferry Road Brattleboro, VT 05301
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION REGARDING REACTOR PRESSURE VESSEL INTEGRITY AT VERMONT YANKEE NUCLEAR POWER STATION (TAC NO. MA1212)
Dear Mr. Reid:
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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 in order to identify, collect, and report any new data pertinent to the analysis of the structuralintegrity of their RPVs and to assess the impact of those data on their RPV integrity analyses relative to the requirements of Section 50.60 of Title 10 of the Code of Federal Reoulations (10 CFR Part 50.60),10 CFR 50.61, Appendices G and H to 10 CFR Part 50 (which encompass pressurized themial shock (PTS) and upper shelf energy (USE) evaluations), and any potential impact on low temperature overpressure (LTOP) limits or pressure-temperature (P-T) limits.
After reviewing your response, the NRC issued a letter dated August 1,1996, acknowledging receipt of your response, and noting that additional RPV information may become available as a result of Owners Groups' efforts and requested that you provide us with the results of the Owners Groups' programs relative to your plant. We further indicated that a plant-specific TAC Number may be opened to review this material. Following issuance of these letters, the BWR Vessel and Intemals Project (BWRVlP) submitted the report " Update of Bounding Assessment of BWR/2-6 Reactor Pressure Vessel Integrity issues (BWRVIP-46)." This report included bounding 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 PWR and BWR 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 you re-evaluate the RPV weld chemistry values that you have previously submitted as part of your licensing basis in light of the information presented in the CEOG, FTl and BWRVIP reports. The staff expects that you will assess this new information to determine whether any values of RPV weld chemistry need to be revised for your facility.
Therefore, in order to provide a complete response to items 2,3 and 4 of the GL, the NRC requests that you provide a response to the enclosed request for additional information within 90 days of receipt of this letter. If a question does not apply to your situation, please indicate this in your RAI response along with your technical basis and, per GL 92-01, Rev.1, Supp. i, provide a certification that previously submitted evaluations remain valid.
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i The information provided will be used in updating the Reactor Vessel Integrity Database (RVID).
Also, please note that RPV integrity analyses utilizing newly identified data could result in the need for license amendments in order to maintain compliance with 10 CFR Part 50.60, and j
Appendices G and H to 10 CFR Part 50, and to address any potential impact on P-T limits, if additional license amendments or assessments are necessary, the attached requests thct you provide a schedule for such submittals.
If you should have any questions regarding this request, please contact me at (301) 415-1475.
Sincerely,-
Original signed by Richard P. Croteau, Project Manage:
Project Directorate 1-3 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation Docket No. 50-271
Enclosure:
Request for Additional information cc w/ encl: See next page DISTRIBUTION Docket File -
PUBLIC Vermont Yankee r/f J. Zwolinski R. Croteau T. Clark O. Cowgill, R-l A. Lee G. Vissing ACRS OGC D. Mcdonald
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l' D. Reid Vermont Yankee Nuclear Power Station cc:
l Regional Administrator, Region i Mr. Raymond N. McCandless U. S. Nuclear Regulatory Commission Vermont Division of Occupational l
475 Allendale Road and Radiological Health King of Prussia, PA 19406 Administration Building Montpelier, VT 05602 i
Mr. David R. Lewis Shaw, Pittman, Potts & Trowbridge Mr. Gautam Sen l
2300 N Street, N.W.
Licensing Manager Washington, DC 20037-1128 Vermont Yankee Nuclear Power Corporation l
Mr. Richard P. Sedano, Commissioner 185 Old Ferry Road Vermont Department of Public Service Brattleboro, VT 05301 120 State Street,3rd Floor l
Montpelier, VT 05602 Resident inspector Vormont Yankee Nuclear Power Station i
Public Service Board U. S. Nuclear Regulatory Commission State of Vermont P.O. Box 176 120 State Street Vemon, VT 05354 Montpelier, VT 05602 Mr. Peter LaPorte, Director Chairman, Board of Selectmen ATTN: James Muckerheide Town of Vemon Massachusetts Emergency Management P.O. Box 116 Agency Vemon, VT 05354-0116 400 Worcester Rd.
P.O. Box 1496 Mr. Richard E. McCullough Framingham, MA 01701-0317 Operating Experience Coordinator Vermont Yankee Nuclear Power Station Jonathan M. Block, Esq.
P.O. Box 157 Main Street Govemor Hunt Road P. O. Box 566 Vemon, VT 05354 Putney, VT 05346-0566 G. Dana Bisbee, Esq.
Deputy Attomey General 33 Capitol Street Concord, NH 03301-6937 Chief, Safety Unit Office of the Attomey General One Ashburton Place,19th Floor Boston, MA 02108 Ms. Deborah B. Katz Box 83 Shellbume Falls, MA 01370 l
REQUEST FOR ADDITIONAL INFORMATION REACTOR PRESSURE VESSEL INTEGRITY Section 1.0; Assessment of Best-Estimate Chemistry The staff recently received the BWRVIP report " Update of Bounding Assessment of BWR/2-6 Reactor Pressure Vessel Integrity issur n (BWRVIP-46)".
Based on this information, in accordance with the provisions of Generic Letter (GL) 92-01, Revision 1, Supplement 1, (GL 92-01, Rev.1, Supp.1) the NRC requests the following:
1.
An evaluation of the bounding assessment in the reference above and its applicability to the determination of the best-estimate chemistry for all of your RPV beltline welds. Based upon this reevaluation, supply the information necessary to completely fill out the data requested in Table 1 for each RPV beltline weld material. If the limiting material for your vessel's P-T limits evaluation is not a weld, include the information requested in Table 1 for the limiting material also.
With respect to your response to this question, the staff notes that some issues regarding the ovaluation of the data were discussed in a public meeting between the staff, NEl, and industry representatives on November 12,1997. A summary of this rheeting is documented 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"(Reference 1). The information in Reference 1 may be useful in helping you to prepare your response.
Ir addition to the issues discussed in the referenced meeting, you 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) were 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. Ifinformation 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.
Section 2.0: P-T Limit Evaluation 2.
If the limiting material for your plant changes or if the adjusted reference temperature for the limiting materialincreases as a result of the above evaluations, provide the revised RT, value for the limiting material. In addition, if the adjusted RT,a value increased, provide a schedule for revising the P-T limits. The schedule should ensure that compliance with 10 CFR 50 Appendix G is maintained.
ENCLOSURE
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l Reference 1.
Memorandum dated November 19,1997, from Keith R. Wichman to Edmund J. Sullivan,
" Meeting Summary for November 12,1997 Mesting with Owners Group Representatives i
and NEl Regarding Review of Responses to Gen:;iic Letter 92-01, Revision 1, Supplement 1 Rcsponses."
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