ML20216G891

Forwards RAI Re Util 950817 & 1117 Responses to GL 92-01,rev 1,Suppl 1, Reactor Vessel Structural Integrity. Response Requested within 90 Days of Receipt of Ltr

ML20216G891
Person / Time
Site:	Beaver Valley
Issue date:	04/08/1998
From:	Brinkman D NRC (Affiliation Not Assigned)
To:	Cross J DUQUESNE LIGHT CO.
References
GL-92-01, GL-92-1, TAC-MA0525, TAC-MA0526, TAC-MA525, TAC-MA526, NUDOCS 9804200520
Download: ML20216G891 (10)

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p *a UNITED STATES 6o--33y g- j R

NUCLEAR REGULATORY COMMISSION l o WASHINGTON, D.C. 30086 4001

% * * * * * +o April 8, 1998 Mr. J. E. Cross President-Generation Group Duquesne Light Company Post Office Bor 4 .

i Shippingport, PA 15077

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING REACTOR PRESSURE VESSEL INTEGRITY AT BEAVER VALLEY POWER STATION, UNIT NOS.1 AND 2 (TAC NOS. MA0525 AND MA0526)

Dear Cross:

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 structural integrity of their RPVs and to assess the impact of those data en their RPV integrity analyses relative to the requirements of Section 50.60 of Title 10 of the Code of Federal Reaulations (10 CFR 50.60),10 CFR 50.61, Appendices G and H to 10 CFR Part 50 (which encompass pressurized thermal shock (PTS) and upper shelf energy (USE) evaluations), and any potential impact on low temperature overpressure (LTOP) limits or pressure-temperature (PT) limits.

After reviewing your responses of August 17 and November 17,1995, the NRC issued you a letter dated August 2,1996. In this letter we acknowledged receipt of your responses, noted that additional RPV information may become available as a result of Owners Group 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. In July 1997, the Combustion Engineering Owners Group (CEOG) provided a report with additional RPV weld chemistry data for RPVs fabricated by CE. This additional RPV weld - 4 chemistry data may affect previous RPV integrity enslyses supplied by licensees with CE fabricated RPVs. As a follow-up to the letter and the CEOG report, and 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 RAI within 90 days of receipt of this letter. If a question does not apply to your situation, olease indicate this in your RAI response along with your technical basis and, per GL 92-01, Rev.1, Supp.1, 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 10 CFR 50.60,10 CFR 50.61 (pressurized thermal shock, PTS), and Appendices G and H to 10 CFR Part 50, and to address any potential impact on low temperature overpressure (LTOP) limits or pressure-temperature (PT) limits. If additionallicense amendments or assessments are necessary, the enclosed requests that you provide a schedule for such submittals.

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.a J. Cross If you should have any questions regarding this request, please contact me at (301) 415-1409.

Sincerely,

/s/

Donald S. Brinkman, Senior Project Manager Project Directorate 1-2 Division of Reactor Projects - 1/II Office of Nuclear Reactor Regulation Docket Nos. 50-334/50-412 Encisaure: RAI cc w/ encl: See next page 1

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l DISTRIBUTION Docket File MO'Brien PUBLIC OGC -

PDI-2 Reading ACRS JZwolinski ESullivan RCapra AHiser DBrinkman MEvans, RGN-l l OFFICE PDI-2/PM 4 s PDf-2/CVN PDI-2'D E NAME DBrinkman e RCapra W DATE // /7 /98 M/N/98 4 /~1 /98 OFFICIAL RECORD COPY /

DOCUMENT NAME: BV0525.RAI

J. Cross If you should have any questions regarding this request, please contact me at (301) 415-1409.

Sincerely,

& k. b Donald S. Brinkman, Senior Project Manager Project Directorate 1-2 Division of Reactor Projects - 1/il ~

i Office of Nuclear Reactor Regulation Docket Nos. 50-334/50-412

Enclosure:

RAI cc w/ encl: See next page

J. E. Cross Beaver Valley Power Station, Units 1 & '2 Duquesne Light Company cc:

Jay E. Silberg, Esquire Bureau of Radiation Protection Shaw, Pittman, Potts & Trowbridge Pennsylvania Department of 2300 N Street, NW. Environmental Resources Washington, DC 20037

• ATTN: Michael P. Murphy Post Office Box 2063 Director-Safety and Licensing Harrisburg, PA 17120 Department (BV-A)

Duquesne Light Company _ - . .

Mayor of the Borrough of -

Beaver Valley Power Station Shippingport PO Box 4 Post Office Box 3 Shippingport, PA 15077 Shippingport, PA 15077 Commissioner Roy M. Smim Regional Administrator, Region i West Virginia Department of Labor U.S. Nuclear Regulatory Commission Building 3, Room 319 475 Allendale Road Capitol Complex King of Prussia, PA 19406 Charleston, WVA 25305 Resident inspector Director, Utilities Department U.S. Nuclear Regulatory Commission Public Utilities Commission Post Office Box 298 180 East Broad Street Shippingport, PA 15077 Columbus, OH 43266-0573 Director, Pennsylvania Emergency Duquesne Light Company  !

Management Agency Beaver Valley Power Station {

Post Office Box 3321 PO Box 4 l Harrisburg, PA 17105-3321 Shippingport, PA 15077 ,

ATTN: S. C. Jain, Vice President Ohio EPA-DERR Nuclear Services (BV-A) ,

ATTN: Zack A. Clayton  !

Post Office Box 1049 Columbus, OH 432GG-Ou9 Dr. Judith Johnsrud National Energy Committee Sierra Club 433 Orlando Avenue State College, PA 16803 Duquesne Light Company Beaver Valley Power Station PO Box 4 Shippingport, PA 15077 ATTN: R. L. Grand, r + ion Vice President, Nuclear On~'"nns Group and Plant Manager (BV-SOSB-7)

REQUEST FOR ADDITIONAL INFORMATION (RAli REGARDING REACTOR PRESSURE VESSEL INTEGRITY BEAVER VALLEY POWER STATION. UNIT NOS.1 AND 2 DOCKET NOS. 50-334 AND 50-412 1

Section 1.0: Assessment of Best-Estimate Chemistry The staff recently received additionalinformation that may affect the determination of the best- ,

estimate chemistry composition for your RPV welds or your surveillance weld material. This l information was provided to the NRC by the Combustion Engineering Owners' Group in report CE NPSD-1039, Revision 02, "Best Estimate Copper and Nickel Values in CE Fabricated -

Reactor Vessel Welds," dated June 1997.

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 information in the reference above and an assessment of its applicability to the determination of the best-estimate chemistry for all of your RPV beltline welds. Based upon this reevaluation, supply the information riecessary to completely fill out the data requested in Table 1 for each RPV beltline weld material. Also provide a discussion for the copper and nickel values chosen for each we!d wire heat noting what heat-specific data were included and excluded from the analysis and the analysis method chosen for determining the best-estimate. If the limiting material fo pur vessel's PTS /PT limits evaluation is not a weld, include the information requested ir, hble 1 (see Attachment 1) for the limiting material also.

Furthermore, you should consider the information provided in Section 2.0 of this RAI on the use of surveillance data when responding.

With respect to your 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, Nuclear Energy Institute (NEI), and industry representatives on November 12,1997. A summary of this meeting 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.

In 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 coiis 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.

ENCLOSURE

4 2

Section 2.0: Evaluation and Use of Surveillance Data The chemical composition report referenced in Section 1.0 includes updated chenistry estimates for heats of weld metal. These reports not only provide a suggest.ed best estimate value but also include the source data used in estimating the chemical composition of the heat of material. This permits the determination of the best estimate chemical composition for the various sources of data including surveillance welds. Since the evaluation of surveillance data rely on both the best estimate chemical composition of the RPV weld and the surveillance weld. the information in these reports may result in the need to revise previous evaluations of RPV integrity (including LTOP setpoints and PT limits) per the requirements of 10 CFR 50.60,10 CFR 50.61, and ~ ~ ~ ~~ ~ '

Appendices G and H to 10 CFR Part 50.

Based on this information and consistent with the provisions of Generic Letter 92-01, Revision 1, Supplement 1, the NRC requests the following:

2. that (1) the information listed in Table 2, Table 3 (see Attachment 2), and the chemistry factor from the surveillance data be provided for each heat of material for which surveillance weld data are available add a revision in the RPV integrity analyses (i.e., current licensing basis) is needed or (2) a certification that previously submitted evaluations remain valid. Separate tables should be used for each heat of material addressed. If the limiting material for your vessel's PTS /PT limits evaluation is not a weld, include the information requested in the tables for the limiting material (if surveillance data are available for this material).

The information discussed in Section 1.0 of this RAI regarding the chemistry reports should be considered in this response along with the following questions and comments.

All surveillance program results for the heats of material in an RPV should be considered in evaluating its integrity regcrdless of source per 10 CFR 50.61 (" Surveillance program results means any data that demonstrates the embrittlement trends for the limiting beltline material, including but not limited to data from test reactors or from surveillance programs at other plants with or without surveillance program integrated per 10 CFR 50, Appendix H."). If any of the data provided in Table 2 is not used in the calculation of the embrittlement trend for a particular RPV weld, the technical basis for not including /using the data should be provided. '

When assessing credibility of surveillance data that come from more than one source, adjustments to the surveillance data may be needed to account for differences in the chemical composition and irradiation environment of the different sources consistent with the requirements i in 10 CFR 50.61. A method for accounting for there differences is discussed in Reference 1.

Based on the information provided in Table 2, the credibility of the surveillance data can be evaluated. The results of these analyses including the slope of the best fit line through the surveillance data can be provided in a format similar to that of Table 3. If the method for adjusting and/or norma!! zing the surveillance data when assessing credibility differs from the methods documented in Reference 1, provide the technical basis for the adjustment and/or the normalization procedure. If the chemical composition of the surveillance weld is not determined in accordance with Reference 1 (i.e., the mean of all chemistry analyser perfomied on the surveillance weld), provide the technical basis for the estimate.

1 When determining the chemistry factor for an RPV weld fro.. suweillance data, adjustments to the surveillance data may be norded to account for diffs e m in the chemical composition and j irradiation environment between the surveillance specina... 1 the vessel being assessed consistent with the requirements in 10 CFR 50.61. A method to account for these differences is provided in Reference 1.

I in addition,10 CFR 50.61(c)(2) specifies that licensees shall consider plant-specific information (e.g., operating temperature and surveillance data) to voirify that the RTer for each vessel beltline material is a bounding value. Regulatory Guide 1.99, Revision 2, desuibes two methods for determining the amount of margin and the chemistry factor used in determining rte 1 Position 1.1 describes the use of the Generic Tables in the Regulatory Guide. Position 2.1 describes the use of credible surveillance data, if the surveillance data are credible, the o, may be reduced in half to calculate the margin term and the chemistry factor is to be determined from the best-fit line of the surveillance data, if the evaluation of the surveillance data indicates that the surveillance data set is not credible and the measured values of ARTer are less than the projected mean from the Tables plus the generic 203, the chemistry fccior may be calculated j using either Position 1.1 or Position 2.1; however, the full margin term must be applied. The j method chosen must bound all the surveillance data to be in compliance with 10 CFR l

50.61(c)(2).

Based on the information provided in Table 2 along with the best estimate chemical composition i of the heat of material and the irradiation temperature of the plant whose vesselis being  !

assessed, the chemistry factor of the RPV weld can be determined. Note that the adjusted ,

ARTwy for a particular surveillance data point may be one value when determining credibility and I another value when determining the chemistry factor as a result of the different normalization i procedures, if the method for adjusting and/or normalizing the surveillance data when

. determining the chemistry factor diffut from the methods documented in Reference 1, provide  !

the technical basis for the adjustment and/or the normalization procedure. i in a meeting between the staff and industry representatives ut the NRC on February 12,1998, an industry representative requested a clarification as to when th:e ratio orocedure should be used to evaluate surveillance data. The ratio procedure is described in the PTS rule and RG 1.99, Revision 2. The ratio procedure is used to adjust the measured value of ARTer to account for differences in the chemical composition between the surveillance weld and the vessel beltline weld. The PTS rule and RG 1.99, Revision 2, indicate that when there is clear evidence that the copper and nickel content of the surveillance weld differs from the vessel weld, i.e. differs from the average for the weld wire heat number associated with the vessel weld and the surveillance weld, the ratio procedure must be used.

Section 3.0: PTS /PT Limit Evaluation

3. 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 RTris value for the limiting material in accordance with 10 CFR 50.61, in addition, if the adjusted RTm7 value increased, provide a schedule for revising the PT and LTOP limits. The schedule should ensure that compliance with 10 CFR Part 50, Appendix G, is ma'ntained.

o 1

. 4 Reference

1. Memorandum from Keith R. Wichman, NRC, to Edmund J. Sullivan, NRC, " 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", dated November 19,1997.

Attachments:

1. Table 1

2. Tables 2,3 .

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