ML17191A630

Forwards Request for Addl Info Re Reactor Pressure Vessel Integrity at Dresden Nuclear Power Station

ML17191A630
Person / Time
Site:	Dresden
Issue date:	04/30/1998
From:	Rossbach L NRC (Affiliation Not Assigned)
To:	Kingsley O COMMONWEALTH EDISON CO.
References
TAC-MA1186, TAC-MA1187, NUDOCS 9805060030
Download: ML17191A630 (6)

Text

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UNITED STATES NUCLEAR REGULATORY COMMl.SSION Mr. Oliver D. Kingsley, President Nuclear Generation Group Commonwealth Edison Company Executive Towers West Ill 1400 Opus Place, Suite 500 Downers Grove, IL 60515 WASHINGTON, D.C. ~1 April 30, 1998

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION REGARDING REACTOR PRESSURE VESSEL INTEGRITY AT DRESDEN NUCLEAR POWER STATION UNITS 2 AND 3 (TAC NOS. MA 1186 AND MA 1187)

Dear Mr. Kingsley:

Generic Letter 92-01, Revision 1, Supplement 1 (GL), uReactor 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 structural integrity 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 Regulations (10 CFR 50.60), 10 CFR 50.61, Appendices G and H to 10 CFR Part 50 (which enccimpass pressurized thermal shock (PTS) and upper shelf energy (USE) evaluations), and any potential impact on low temperature overpressure (L TOP) limits or pressure-temperature (P-T) limits.

After reviewing ComEd's response, the NRC issued ComEd a letter dated April 21, 1997, for Dresden, Units 2 and 3. In this letter the NRC acknowledged receipt of ComEd's response, noted that additional RPV information may become available as a result of Owners Group efforts and requested that ComEd provide the NRC with the results of the Owners Groups' programs relative to Dresden. We further indicated that a plant specific TAC Number may be opened to review this material. Following issuance of these letters, the Boiling Water Reactor Vessel and Internals Project (BWRVIP) submitted the report, uUpdate of Bounding Assessment of BWR/2-6 Reactor Pressure Vessel Integrity Issues (BWRVIP-46).D This report included bounding assessments of new data from (1) the Combustion Engineering Owners Group (CEOG)*database released in July 1997 that contains all known data for Combustion Engineering (CE) fabricated welds in Pressurized Water Reactor (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) FTl'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 ComEd re-evaluate the RPV weld chemistry values that ComEd has previously submitted as part of the licensing basis in 1ight of the information presented in the r I CEOG, FTI and BWRVIP reports. The staff expects that ComEd will assess this new information to determine whether any values of RPV weld chemistry need to be revised for Dresden.

Therefore, in order to provide a complete response to items 2, 3 and 4 of the GL, the NRC requests that ComEd provide a response to the enclosed request for additional information (RAI) "!)'fO'

.980-5060030-980430 1. PDR ADOCK 05000237 I p PDR u

0. Kingsley Aprii 30, 1998

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within 90 days of receipt of this letter. If a qJ~stion does not apply to Dresden, please indicate this in the RAI response alq.rlg with the. technical basis and, per the GL, provide a certification that previously submitte~ evaluations. re_main valid~

.,:.i The information-provid~d vtill be used in updating the Rea,ctor. Vessel Integrity Database (RVID).

Also, please note that 'RPV integrity analyses. utilizing newly identified data could result in the need for license amend'ments fn order. to ma.intain compliance with 10 CFR 50.60, and Appendices G and Hto 10 CFR.Part' 50, and to address any potential impact on P-T limits. If.

additional license amendmer.its br'asses~rnents are n~cessary, the enclosed requests that ComEd provide a schedule for such submittals.

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IOhere should be,any questions:regarding thifreques(ple~se,contact me at 301-415-2863. *

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Docket Nos. 50-237, 50-249

Enclosure:

RAI cc w/encl: See next page

_ Distribution:

-Docket-File

• PUBLIC PDlll-2 r/f E. Adensam, EGA 1 S. Richards C. Moore L. Rossbach OGC, 015818 ACRS, T2E26 M. Ring, Riii A D. Lee, 0704

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ORIG.: *SIGNED BY:

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• Lawr~nce W. Rossbach, Project Manager

• -. '.' ~- ;: Project Directorate 111-2 Division of Reactor Projects - Ill/IV

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• Qffice of Nuclear Reactor Regulation

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,J DOCUMENT NAME: G:\\CMNTSP\\DRESDEN\\DR1186.RAI To receive a cop of thla document, indicat n the box: *c* = Copy without enclosures "E" = Copy with enclosures "N" = No copy OFFICE PM:PDlll-2 D:PDlll-2 NAME LROSSBAC DA TE 04/ -J *i:> /98

/98 OFFICIAL RECORD COPY

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0. Kingsley within 90 days of receipt of this letter. If a question does not apply to Dresden, please indicate this in the RAI response along with the technical basis and, per the GL, provide a certification that previously submitted evaluations remain valid.

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 1 O CFR 50.60, and 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 enclosed requests that ComEd provide a schedule for such submittals.

If there should be any questions regarding this request, please contact me at 301-415-2863.

Docket Nos. 50-237, 50-249

Enclosure:

RAI cc w/encl: See next page Sincerely, Lawrence W. Rossbach, Project Manager Project Directorate 111-2 Division of Reactor Projects - Ill/IV Office of Nuclear Reactor Regulation

0. Kingsley Commo~wealth Edison Company cc:

Michael I. Miller, Esquire Sidley and Austin One First National Plaza Chicago, Illinois 60603 Commonwealth Edison Company Site Vice President - Dresden 6500 N. Dresden Road Morris, Illinois 60450-9765 Commonwealth Edison Company

.Dresden Station Manager 6500 N. Dresden Road Morris, Illinois 60450-9765 U.S. Nuclear Regulatory Commission Dresden Resident Inspectors Office 6500 N. Dresden Road Morris, Illinois 60450-9766

. Regional Administrator U.S. NRC, Region Ill 801 Warrenville Road Lisle, Illinois 60532-4351 Illinois Department of Nuclear Safety Office of Nuclear Facility Safety 1035 Outer Park Drive Springfield, Illinois 62704 Chairman Grundy County Board Administration Building 1320 Union Street Morris, Illinois 60450 Document Control Desk-Licensing Commonwealth Edison Company 1400 Opus Place, Suite 400 Downers Grove, Illinois 60515 Mr. David Helwig Senior Vice President

, commonwealth Edison Company Executive Towers West Ill 1400 Opus Place, Suite 900 Downers Grove, IL 60515 Dresden Nuclear Power Station Units 2-and 3 Mr. Gene H. Stanley PWR's Vice President Commonwealth Edison Company Executive Towers West Ill 1400 Opus Place, Suite 900 Downers Grove, IL 60515 Mr. Steve Perry BWR's Vice President Commonwealth Edison Company Executive Towers West Ill 1400 Opus Place, Suite 900 Downers Grove, IL 60515 Mr. Dennis Farrar Regulatory Services Manager Commonwealth Edison Company Executive Towe rs West Ill 1400 Opus Place, Suite 500 Downers Grove, IL 60515 Ms. Irene Johnson, Licensing Director Nuclear Regulatory Ser\\tices Commonwealth Edison Company Executive T ewers West Ill 1400 Opus.Place, Suite 500 Downers Grove, IL 60515 Commonwealth Edison Company Reg. Assurance Supervisor-Dresden 6500 N. Dresden Road Morris, Illinois 60450-9765 Mr. Michael J. Wallace Senior Vice President Commonwealth Edison Company Executive Towers West Ill 1400 Opus Place, Suite 900 Downers Grove, IL 60515

REQUEST FOR ADDITIONAL INFORMATION REACTOR PRESSURE VESSEL INTEGRITY Section 1.0: Assessment of Best-Estimate Chemistry The staff recently received the Boiling Water Reactor Vessel and Internals Project (BWRVl.P) report, "Update of Bounding Assessment of BWR/2-6 Reactor Pressure Vessel Integrity Issues (BWRVIP-46)."

Based on this information, in accordance with the provisions of Generic Letter 92-01, Revision 1, Supplement 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 the reactor pressure vessel (RPV) beltline welds. Based upon this reevaluation, supply the information necessary to completely fill out the data requested in Table 1 (attached) for each RPV beltline weld material. If the limiting material for the vessel's pressure-temperature (P-n limits evaluation is not a weld, include the information requested in Table 1 for the limiting material also.

With respect to ComEd's response to this question, the staff notes that some issues regarding the evaluation of the data were discussed in a public meeting between the staff, NEI, and industry representatives on November 12, 1997. A summary of this meeting is documented in a meeting summary dated November 19, 1997 (Reference 1). The information in Reference.1 may be useful in helping to prepare the response.

In addition to the issues discussed in the referenced meeting, ComEd 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. 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.

Section 2.0: P-T Limit Evaluation

2. If the limiting material for Dresden changes or if the adjusted reference temperature for the limiting material increases as a result of the above evaluations, provide the revised RT nc11 value for the limiting material. In addition, if the adjusted RT NOT value increased, provide a schedule for revising the P-T limits. The schedule should ensure that compliance with 10 CFR Part 50, Appendix G, is maintained.

Reference

1. Memorandum from Keith R. Wichman to Edmund J. Sullivan, "Meeting Summary for November 12, 1997 Meeting with Owners Group Representatives and NEI Regarding Re"iew of Responses to Generic Letter 92-01, Revision 1, Supplement 1 Responses," dated November 19, 1997.

Attachment:

Table 1 ENCLOSURE

TABLE 1 Facility: ____ _

Vessel Manufactµrer: -------

Information Requested on RPV Weld and/or Limiting Materials RPV Best-Best-EOLID Assigned Method of Initial RT NOT Weld Wire Estimate Estimate Fluence Material Determining (RTNDT(UJ)

Heat <1>

Copper Nickel (x 1019)

Chemistry CF<2>

Factor (CF)

(1) or the material identification of the limiting material as requested in Section 1.0 (1.)

(2) determined from tables or from surveillance data

.. Discussion of the Analysis Method and Data Used for Each Weld Wire Heat Weld Wire Heat Discussion a,

06 Margin ARTorRTndt at EOL