ML17335A340

Forwards RAI Re Util Response to GL 92-01,rev 1,suppl 1, Reactor Vessel Structural Integrity. Response Requested by 990401

ML17335A340
Person / Time
Site:	Cook
Issue date:	11/16/1998
From:	Stang J NRC (Affiliation Not Assigned)
To:	Powers R INDIANA MICHIGAN POWER CO.
References
GL-92-01, GL-92-1, TAC-MA0539, TAC-MA539, NUDOCS 9811180333
Download: ML17335A340 (16)

Text

0,

~

UNITED STATES NUCLEAR REGULATORY COMIVIISSION WASHINGTON, D.C. 20555-0001 gAg REGNI

~o Cy o

v 4o~.

e

~o

++*++

November 16, 1998 Mr. Robert P. Powers, Senior Vice President Indiana Michigan Power Company Nuclear Generation Group 500 Circle Drive Buchanan, Ml 49107 1395

SUBJECT:

REQUEST FOR ADDITIONALINFORMATIONREGARDING REACTOR

~

PRESSURE VESSEL INTEGRITYAT DONALDC. COOK NUCLEAR PLANT, UNIT 1, TAC NO. MA0539

Dear Mr. Powers:

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 on their RPV integrity analyses relative to the requirements of Section 50.60 of Title 10 of the Code of eral Re u a '10 CFR Part 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 response dated November 20, 1995 (AEP:NRC:1137F), the NRC issued you a letter dated February 28, 1996 for the Donald C. Cook Nuclear Plant, Unit 1.

In this letter we acknowledged receipt of your response and requested additional information to complete NRC staff review of this issue.

In your response dated August 12, 1996 (AEP:NRC:1173G), it was noted that additional RPV information may become available as a result of Owners Group

. efforts and that you would provide us with the results of the Owners Groups'rograms relative to your plant.

In July 1997, the Combustion Engineering Owners Group (GEOG) provided a report with additional RPV weld chemistry data for RPVs fabricated by CE. This additional RPV weld chemistry data may affect previous RPV integrity analyses 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 request for additional information. Ifa 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. 1, provide a certification that previously submitted evaluations remain valid.

The information provided willbe 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, 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. Ifadditional license amendments or assessments are necessary, the attached requests that you provide a schedule for such submittals.

98iii80333 98iii6 PDR ADQCK 050003i5 P

PDR

@AD>g Fjgpg Q!E)@Q C~PII

'ih

The attached request was discussed with Mr. Carl Toth of your staff on November 11, 1998. A mutually agreeable target date of April 1, 1999, for your response was established.

If circumstances result in the need to revise the target date, please call me at the earliest

= opportunity.

Ifyou should have any questions regarding this request, please contact me at (301) 415-1345.

Sincerely, Jo n F. Stang, Jr., Senior Project Manager Project Directorate III-1 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation Docket No. 50-315

Enclosure:

As Stated ccw/encl: See next page

Mr. Robert P. Powers November 16, 1998 The attached request was discussed with Mr. Carl Toth of your staff on November 11, 1998. A mutually agreeable target date of April 1, 1999, for your response was established.

If circumstances result in the need to revise the target date, please call me at the earliest opportunity.

Ifyou should have any questions regarding this request, please contact me at (301) 415-1345.

Sincerely, Griginal signed by:

f John F. Stang, Jr., Senior Project Manager Project Directorate III-1 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation Docket No. 50-315

Enclosure:

As Stated ccw/encl: See next page

~ll

~ 0 Docket File Public PDIII-1 r/f EGA1 OGC ACRS A. Hiser G. Vissing B. Burgess, Rill DOCUMENT NAME:G:)DCCOOK>MA0539.RAI To receive a copy of this document, indicate in the box: "C" ~ Copy wit OFFICE PM:PDIV-1 C

LA:PDIII-2 C

P ures "E" ~ Copy with enclosures "N" ~ No copy P

IIIPtI, C

D:PDIII-1 NAME CNolan ~

DATE 11/ (5 /98 Jst EBarnhill 11/

L

/98 11

'98 OFFICIAL REC RD COPY CCarpenter t.

11/l5 /98

k

Mr. Robert P. Powers November 16, 1998 The attached request was discussed with Mr. Carl Toth of your staff on November 11, 1998. A mutually agreeable target date of April 1, 1999, for your response was established.

If circumstances result in the need to revise the target date, please call me at the earliest opportunity.

Ifyou should have any questions regarding this request, please contact me at (301) 415-1345.

Sincerely, Original signed by:

John F. Stang, Jr., Senior Project Manager Project Directorate III-1 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation Docket No. 50-315

Enclosure:

As Stated ccw/encl: See next page DISTRIBUTION Docket File Public PDIII-1 r/f EGA1

.OGC ACRS A. Hiser G. Vissing B. Burgess, Rill DOCUMENT NAME:G:>DCCOOK)MA0539.RAI To receive a copy of this document, indicate in the box: "C" ~ Copy witij u ures "E" ~ Copy with enclosures "N" ~ No copy OFFICE NAME PM:PDIV-1 C

CNolan~

LA:PDIII-2 C

EBarnhill Jst P

II D:PDIII-1 CCarpenter C DATE 11/(3

/98 11+ '. /98 11/ i

/98 OFFICIAL RECORD COPY 11/i'0 /98

Robert P. Powers Indiana Michigan Power Company CC:

Regional Administrator, Region III U.S. Nuclear Regulatory Commission 801 Warrenville Road Lisle, IL 60532-4351 Attorney General Department ofAttorney General 525 West Ottawa Street Lansing, Ml 48913 Township Supervisor Lake Township Hall P.O. Box 818 Bridgman, Ml 49106 U.S. Nuclear Regulatory Commission Resident Inspector's Office 7700 Red Arrow Highway Stevensville, MI 49127 Jeremy J.

Euto, Esquire Indiana Michigan Power Company Nuclear Generation Group 500 Circle Drive Buchanan, Ml 49107 Mayor, City of Bridgman P.O. Box 366 Bridgman, Ml 49106 Special Assistant to the Governor Room 1 - State Capitol Lansing, Ml 48909 Donald C. Cook Nuclear Plant Units 1 and 2 Drinking Water and Radiological Protection Division Michigan Department of Environmental Quality 3423 N. Martin Luther King Jr Blvd P.O. Box 30630 CPH Mailroom Lansing,. Ml 48909-81 30 Regulatory Affairs Director Indiana Michigan Power Company

.Nuclear Generation Group 500 Circle Drive Buchanan, Ml 49107 David A. Lochbaum Union of Concerned Scientists 1616 P Street NW, Suite 310 Washington, DC 20036-1495 John R. Sampson, Vice President Indiana Michigan Power Company Nuclear Generation Group One Cook Place Bridgman, Ml 49106

f

R UES 0

DIT AL INFO MA I

REACTOR PR U

VES L IN I

~Sec ion 0: Assessment of Best-Estimate Chemistry The staff recently received additional information that may affect the determination of the best-estimate chemistry composition for your RPV welds or your surveillance weld material. This information was provided to the NRC by the Combustion Engineering Owners'roup 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:

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 necessary to completely fillout 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 weld wire heat noting what heat-specific data were included and excluded from the analysis and the analysis method chosen for determining the best-estimate.

Ifthe limiting material for your vessel's PTS/PT limits evaluation is not a weld, include the information requested in

, Table 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, 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 NEI 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.

Ifa 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~confir 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". Ajustification

3 r

should then be provided for which assumption was chosen when the best-estimate chemistry was determined.'

~

Ssectio

$ 2 0 Evaluation and Uae of Surveillance Data The chemical composition report referenced in Section 1.0 includes updated chemistry estimates for heats of weld metal. These reports not only provide a suggested best estimate value but also include the source data used in estimating the chemical composition of the heat of material.'his permits the determination of the best estimate chemical composition for the various sources of data including surveillance welds.'ince 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:

that (1) the information listed in Table 2, Table 3, and the chemistry factor from the surveillance data be provided for each heat of material for which surveillance weld data,.

are available.~an 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.

Ifthe 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 (ifsurveillance 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.

~Allsurveillance program results for the heats of material in a RPV should be considered in evaluating its integrity regardless 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."). Ifany of the data provided in Table 2 are 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 in 10 CFR 50.61. A method for accounting for these 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. Ifthe method for adjusting and/or normalizing the surveillance data when assessing credibility differ from the

4

• ~

methods documented in Reference 1, provide the technical basis for the adjustment 'and/or the normalization procedure.

Ifthe chemical composition of the surveillance weld is not determined in accordance with Reference 1 (i.e., the mean of all chemistry analyses performed on the surveillance weld), provide the technical basis for the estimate.

When determining the chemistry factor for a RPV weld from surveillance data, adjustments to the surveillance data may be needed to account for differences in the chemical composition and irradiation environment between the surveillance specimens and 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.

In addition, 10 CFR 50.61(c)(2) specifies that licensees shall consider plant-specific information (e.g., operating temperature and surveillance data) to verify that the R$>> for each vessel beltline material is a bounding value. Regulatory Guide 1.99, Revision 2 describes two methods for determining the amount of margin and the chemistry factor used in determining R$>>.

Position 1.1 describes the use of the Generic Tables in the Regulatory Guide.

Position 2.1 describes the use of credible surveillance data.

Ifthe surveillance data are credible, the g 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.

Ifthe evaluation of the surveillance data indicate that the surveillance data set is not credible and the measured values ofhRT>> are less than the projected mean from the Tables plus the generic 2q the chemistry factor may be calculated using either Position 1.1 or Position 2.1; however, the full margin term must be applied. The method chosen must bound all the surveillance data to be in compliance with 10 CFR 50.61(c)(2).

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

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

Note that the adjusted ZLRTg>> for a particular surveillance data point may be one value when determining credibility

.and another value when determining the chemistry factor as a result of the different normalization procedures.

Ifthe method for adjusting and/or normalizing the surveillance data when determining the chemistry factor differs from the methods documented in Reference 1,

provide the technical basis for the adjustment and/or the normalization procedure.

In a meeting between the staff and industry representatives at the NRC on February 12, 1998, an industry representative requested a clarification as to when the ratio procedure 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 ofBR'>> 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.

~Sa tio 3.0 PTS/PT Limit Evaluation Ifthe limiting material for your plant changes or ifthe adjusted reference temperature for the limiting material increases as a result of the above evaluations, provide the revised RTpyg value for the limiting material in accordance with 10 CFR 50.61.

In addition, ifthe adjusted RT>> value increased, provide a schedule for revising the PT and LTOP limits.

The schedule should ensure that compliance with 10 CFR 50 Appendix G is maintained.

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

dated November 19, 1997.

Attachments:

1. Table1

2. Tables 2t 3

TABLE 1 Facility:

Vessel Manufacturer:

Information requested on RPV Weld and/or Limiting Materials RPV Weld Wire Heat"'est-Estimate Copper Best-Estimate Nickel EOL ID Fluence (x 10")

Assigned Material Chemistry Factor (CF)

Method of Determining CF(')

Initial Ropy (RTwotiui) o~

Margin ART or RTpy8 at EOL (1) or the material identification of the limiting material as requested in Section 1.0 (1.)

(2) determined from tables or from surveillance data Discussionof he n

I si M

h dandDa sedforEachWeidWireHeat Weld Wire Hea

~Di g~>~sio Attachment 1

Table 2: Heat xxxx Capsule ID (including source)

Cu Ni Irradiation Temperature

('F)

Fluence (x10"n/can)

Measured BRT~)r

('F)

Data Used in Assessing Vessel (Yor N)

Table 3: Heat xxxx

,Capsule ID (including source)

Cu Ni Irradiation Temperature

('F)

Fluence Factor Measured hRT~r

('F)

Adjusted BRT~r

( F)

Predicted hRT~z

.('F)

(Adjusted-Predicted) BRT~r

('F)

0 0

~r

~

4 1

~

A