ML16042A421

Response to Request for Additional Information Regarding Reactor Internals Program

ML16042A421
Person / Time
Site:	Ginna
Issue date:	02/11/2016
From:	Jim Barstow Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CAC MF6713
Download: ML16042A421 (7)

Text

200 Exelon Way Exelon Generation Kennett Square. PA 19348 www.exeloncorp.com 10 CFR 50.90 February 11, 2016 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 R.E. Ginna Nuclear Power Plant Renewed Facility Operating License No. DPR-18 NRG Docket No. 50-244

Subject:

Response to Request for Additional Information Regarding Reactor Vessel Internals Program (CAC No. MF6713)

References:

1. Letter from Thomas G. Mogren (GENG) to U.S. Nuclear Regulatory Commission, "License Renewal Aging Management Submit Revised Reactor Vessel Internals Program Document in Accordance with RIS 2011-07," dated September 28, 2012.

2. Letter from Diane Render, U.S. Nuclear Regulatory Commission, to Bryan C. Hanson, Exelon Generation Company, LLC, "R.E. Ginna Nuclear Power Plant - Request for Additional Information Regarding Reactor Vessels Internals Program (CAC NO. MF6713)," dated January 7, 2016.

By letter dated September 28, 2012 (Reference 1), Constellation Energy Nuclear Generation Group (now operating as Exelon Generation Company, LLC (Exelon)) submitted for approval the document titled, "Reactor Vessel Internals Program, Rev 3," which is based on the NRC-approved report MRP-227-A, for R.E. Ginna Nuclear Power Plant (Ginna). This submittal is part of the Aging Management Program for the Reactor Vessel Internals at Ginna.

The NRG staff reviewed the information provided that supports the submittal and identified the need for additional information in order to complete their evaluation. The Request for Additional Information (RAI) was sent from the NRG to Exelon on January 7, 2016 (Reference 2). Subsequent discussion with the NRG established February 11, 2016, as the due date for the response to the RAI. The response to the RAI is provided in the attachment to this letter.

There are no regulatory commitments in this letter.

In accordance with 10 CFR 50.91, "Notice for public comment; State consultation,"

paragraph (b), Exelon is notifying the State of New York of this RAI response by transmitting a copy of this letter and its attachments to the designated State Official.

U.S. Nuclear Regulatory Commission Response to Draft Request for Additional Information Reactor Vessel Internals Program Docket No. 50-244 February 11, 2016 Page2 If you have any questions or require additional information, please contact Laura A. Lynch at 610-765-5729.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 11th day of February 2016.

Respectfully,

~~lk-James Barstow Director - Licensing and Regulatory Affairs Exelon Generation Company, LLC

Attachment:

Response to Request for Additional Information Regarding Reactor Vessel Internals Program cc: Regional Administrator - NRC Region I w/ attachment NRC Senior Resident Inspector - Ginna NRC Project Manager, NRA - Ginna A. L. Peterson, NYSERDA

ATTACHMENT R.E. Ginna Nuclear Power Plant Renewed Facility Operating License No. DPR-18 NRC Docket No. 50-244 Response to Request for Additional Information Regarding Reactor Vessel Internals Program

Response to Draft Request for Additional Information Attachment Reactor Vessel Internals Program Page 1of4 Docket No. 50-244 By letter dated September 28, 2012 (Reference 1), Constellation Energy Nuclear Generation Group (now operating as Exelon Generation Company, LLC (Exelon)) submitted for approval the document titled, "Reactor Vessel Internals Program, Rev 3," which is based on the NRC-approved topical report Materials Reliability Program (MRP) MRP-227-A, for R.E. Ginna Nuclear Power Plant (Ginna). This submittal is part of the Aging Management Program (AMP) for the Reactor Vessel Internals (RVI) at Ginna.

The NRC staff reviewed the information provided and determined that additional information was needed to complete their review (Reference 2). The following questions were provided.

RAl-1 The MRP-2013-025, "MRP-227-A Applicability Template Guidelines," (Agencywide Documents Access and Management System Accession No. ML13322A454) report identifies two additional issues that all Combustion Engineering, Inc. and Westinghouse design plants referencing topical report MRP-227-A must address to close Applicant/Licensee Action Item 1 related to plant-specific applicability of the topical report. The staff therefore requests the following information:

1. Do the Ginna RVI components have non-weld or bolting austenitic stainless steel components with 20% cold work or greater? If so, do the affected components have operating stresses greater than 30 ksi? The licensee can apply "Option 1" or "Option 2,"

as addressed in Appendix A of the MRP-2013-025 report. If "Option 2" is applicable to Ginna, the licensee should list plant-specific RVI components that have been exposed to cold work equal to or greater than 20%.

2. Has Ginna ever utilized atypical design or fuel management that could make the assumptions of MRP-227-A regarding core loading/core design non-representative for that plant, including power changes/uprates? The licensee is requested to use MRP-2013-025 and apply "Option 1" or "Option 2," as addressed in Appendix B of the report.

If Option 1 is used, the following plant-specific values should be submitted:

(a) Active fuel to upper core plate distance; (b) Average core power density; and (c) Heat generation figure of merit.

Response

RAl-1.1:

As communicated to the staff in a public MRP-227-A Action Item Clarification Call on November 6, 2015 (Reference 3), the industry intends to develop a generic response to this question based upon additional data gathering done for the U.S. Pressurized Water Reactor (PWR) fleet to date. In that call, the NRC staff noted that Industry reported that greater than 1/3 of PWR plants have done record reviews and found no RVI components with greater than 20% cold work, and that the staff would be receptive to a revision of the MRP guidance with adequate documentation of bases. Ginna is participating in the Pressurized Water Reactor Owners

Response to Draft Request for Additional Information Attachment Reactor Vessel Internals Program Page 2 of 4 Docket No. 50-244 Group (PWROG) project to create this basis. It is expected to be completed in early 2016 with a discussion with the NRC staff anticipated sometime in the spring of 2016. Ginna intends to comply with the revised generic industry guidance that is adopted and supported by that additional basis.

RAl-1.2:

Ginna complies with the MRP-227-A assumptions regarding core loading I core design.

Neutron fluence and heat generation rates are concluded to be acceptable based on the following assessment to the limiting MRP guidance threshold values given in Electric Power Research Institute (EPRI) letter MRP 2013-025 (Option 1):

• The Ginna active fuel to upper core plate distance was confirmed to be > 12.2 inches.

• All of the cycles for the Ginna average core power densities were confirmed to be <

124 Watts/cm 3 *

• Ginna heat generation figure of merit for all reload cycles, except those specified below, was confirmed to bes 68 watts/cm 3 . To demonstrate plant-specific applicability and compliance, the below information is provided.

o In certain, early plant-life, reload cycles, the heat generation figure of merit exceeded the criteria of s 68 watts/cm 3 . These periods included:

Criteria Figure of Merit that Cycle (Watts/cm3) Exceeded (Watts/cm 3) 18 s 68 Corner 1 - 72.606 2 s 68 Corner 1 - 72.932 Corner 1 - 71 .374 4 s 68 Corner 2 - 68.570 5 s 68 Corner 1 - 79.967 6 s 68 Corner 1 - 78.997 7 s 68 Corner 1 - 73.476 Corner 1 - 76.522 8 s 68 Corner 2 - 69.369 Corner 1 - 73.620 9 s 68 Corner 2-73.742 10 s 68 Corner 2 - 68.908 11 s 68 Corner 1 - 70.573 12 s 68 Corner 1 - 71.438

Response to Draft Request for Additional Information Attachment Reactor Vessel Internals Program Page 3 of 4 Docket No. 50-244 The total time that the heat generation figure of merit exceeded 68 Watts/cm 3 was 7.3 Effective Full Power Years (EFPY), which is greater than the two years stipulated in EPRI letter MRP 2013-025, Attachment 1. The relatively short duration, 5.3 EFPY, beyond the two year limit is offset by the many years of operation where the heat generation figure of merit was within that criterion. Ginna has not operated outside the heat generation figure of merit criterion since Cycle 12, which ended in March 1983. Ginna is currently on Cycle 39 and is expected to satisfy the heat generation figure of merit criterion given in EPRI letter MRP 2013-025 moving forward.

To ensure that these limits are met in future core designs, the core design process will be modified to include a review for the following parameters:

• Active Fuel to upper core plate distance > 12.2 inches

• Average core power density < 124 watts/cm 3

• Heat generation figure of merit :::; 68 Watts/cm 3 RAl-2 Historically, the following materials used in the PWR RVI components were known to be susceptible to some of the aging degradation mechanisms that are identified in the MRP-227-A report. In this context, the NRC staff requests that the licensee confirm that these materials are not currently used in the RVI components at Ginna. This RAI is applicable to the components classified under "Primary," or "Expansion," or "Existing," categories in MRP-227-A report.

(1) Nickel base alloys- lnconel 600; Weld Metals-Alloy 82 and 182 and Alloy X-750 (excluding control rod guide tube split pins)

(2) Alloy A-286 ASTM A 453 Grade 660, Condition A or B (3) Stainless steel type 347 material (excluding baffle-former bolts, and, barrel former bolts)

(4) Precipitation hardened stainless steel materials 4 and 15-5 (5) Type 431 stainless steel material

Response

Ginna reviewed the materials currently used in the RVI components. Specifically, the materials listed below were reviewed, as applicable to the components classified under "Primary," or "Expansion," or "Existing," categories in MRP-227-A report. The results of this review are as follows:

(1) Nickel base alloys - lnconel 600; Weld Metals - Alloy 82 and 182 and Alloy X-750 (excluding control rod guide tube split pins):

• One component that is listed under the "Primary", or "Expansion", or "Existing" Westinghouse categories in the MRP-227-A report exists in the Ginna RVls that is composed of a nickel base alloy. The Ginna clevis insert bolts are made of X-750.

Response to Draft Request for Additional Information Attachment Reactor Vessel Internals Program Page 4 of 4 Docket No. 50-244 (2) Alloy A-286 ASTM A 453 Grade 660, Condition A or B

• There are no components in the Ginna RVls that are listed under the "Primary",

or "Expansion", or "Existing" Westinghouse categories in the MRP-227-A report made of Alloy A-286 ASTM A 435 Grade 660, Condition A or B.

(3) Type 347 stainless steel material (excluding baffle-former bolts, and, barrel former bolts)

• There are no components in the Ginna RVls that are listed under the "Primary",

or "Expansion", or "Existing" Westinghouse categories in the MRP-227-A report made of stainless steel type 347 (excluding the baffle-former bolts and barrel-former bolts).

(4) Precipitation hardened stainless steel materials 4 and 15-5

• There are no components in the Ginna RVls that are listed under the "Primary",

or "Expansion", or "Existing" Westinghouse categories in the MRP-227-A report made of precipitation hardened stainless steel materials 4 and 15-5.

(5) Type 431 stainless steel material

• There are no components in the Ginna RVls that are listed under the "Primary,"

or "Expansion," or "Existing" Westinghouse categories in the MRP-227-A report made of type 431 stainless steel.

References:

1. Letter from Thomas G. Mogren (CENG) to U.S. Nuclear Regulatory Commission, "License Renewal Aging Management Submit Revised Reactor Vessel Internals Program Document in Accordance with RIS 2011-07," dated September 28, 2012.

2. Letter from Diane Render, U.S. Nuclear Regulatory Commission, to Bryan C. Hanson, Exelon Generation Company, LLC, "R.E. Ginna Nuclear Power Plant- Request for Additional Information Regarding Reactor Vessels Internals Program (CAC NO.

MF6713)," dated January 7, 2016.

3. Memorandum from Joseph J. Holonich, NRC Senior Project Manager, to Kevin Hsueh, Chief Licensing Processes Branch, "Summary of November 6, 2015, Conference Call with the Electric Power Research Institute on Materials Reliability Program (MRP)-227-A, "Pressurized Water Reactor Internals Inspection and Evaluation Guidelines","

December 9, 2015.