ML13253A122

Request for Additional Information Related to Reactor Vessel Internals Program Submittal for Fulfillment of License Renewal Commitment 25 (TAC Nos. MF0052 and MF0053)

ML13253A122
Person / Time
Site:	Prairie Island
Issue date:	09/18/2013
From:	Wengert T J Plant Licensing Branch III
To:	Lynch J E Northern States Power Co
Wengert T J
References
TAC MF0052, TAC MF0053
Download: ML13253A122 (6)

Text

UNITED NUCLEAR REGULATORY WASHINGTON, D.C. 20555-0001 September 18, 2013 Mr. James E. Lynch Site Vice President Northern States Power Company -Minnesota Prairie Island Nuclear Generating Plant 1717 Wakonade Drive East Welch,'MN 55089-9642 PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNITS 1 AND 2 REQUEST FOR ADDITIONAL INFORMATION RELATED TO REACTOR VESSEL INTERNALS PROGRAM SUBMITTAL FOR FULFILLMENT OF LICENSE RENEWAL COMMITMENT 25 (TAC NOS. MF0052 AND MF0053)

Dear Mr. Lynch:

By letter dated October 1, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 12276A041), as supplemented by letters dated March 7, 2013, March 22, 2013, and June 24,2013 (ADAMS Accession Nos. ML 13067A284, ML 13084A378, and ML 13175A333, respectively), Northern States Power Company, a Minnesota corporation (NSPM, the licensee), doing business as Xcel Energy, submitted an aging management program (AMP) for the reactor vessel internals at Prairie Island Nuclear Generating Plant (PINGP), Units 1 and 2. Materials Reliability Program-227-A report, "Pressurized Water Reactor (PWR) Internals Inspection and Evaluation Guidelines," and its supporting reports were used as technical bases for developing the PINGP AMP. The U.S. Nuclear Regulatory Commission (NRC) staff is reviewing your submittal and has determined that additional information is required to complete the review. The specific information reques.ted is addressed in the enclosureto this letter. On August 27,2013, a draft version of this request for additional information (RAI) was discussed between the licensee and the NRC staff to clarify the request. Following the teleconference, it was agreed that you would provide a response to this request within 30 days of the date of this letter. The NRC staff acknowledged that the licensee may not be able to respond to RAI 2-1 until that issue-is resolved on an industry-wide basis. Therefore, the schedule for the licensee's response to RAJ 2-1 will be determined at a later date. The NRC staff considers that timely responses to RAls help ensure sufficient time is available for staff review and contribute toward the NRC's goal of efficient and effective use of staff resources.

J. Lynch -2 If circumstances result in the need to revise the requested response date, please contact me at (301)415-4037.

Sincerely.

Thomas J. Wengert, Senior Project Manager Plant Licensing Branch 111-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-282 and Request for Additional cc w/encl: Distribution via REQUEST FOR ADDITIONAL INFORMATION ) PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNITS 1 AND 2 DOCKET NOS. 50-282 AND 50-306 By letter dated October 1, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 12276A041), as supplemented by letters dated March 7,2013, March 22,2013, and June 24,2013 (ADAMS Accession Nos. ML 13067A284, ML 13084A378, and ML 13175A333, respectively), Northern States Power Company, a Minnesota corporation (NSPM, the licensee), doing business as Xcel Energy, submitted an aging management program (AMP) for the reactor vessel internals (RVI) at Prairie Island Nuclear Generating Plant (PINGP), Units 1 and 2. MRP-227-A report, "Pressurized Water Reactor (PWR) Internals Inspection and Evaluation Guidelines," and its supporting reports were used as the technical bases for developing the PINGP AMP. The U.S. Nuclear Regulatory Commission (NRC) staff reviewed this report and issued a final safety evaluation (SE) on December 16, 2011. Based on the review of PINGP's AMP conducted thus far,the staff has developed a second round of requests for additional information (RAI), as addressed below. The NRC staff may, however, issue additional RAls based on the resolution of Action Items 1 and 2 addressed in the staff's SE for the MRP-227 -A report. RAI2-1: As discussed in References 1 and 2 below, provide the following information related to verification of the applicability of MRP-227-A to PINGP, Units 1 and 2: Do the PINGP, Units 1 and 2, RVI have non-weld or bolting austenitic stainless steel components with 20 percent cold work or greater and, if so, do the affected components have operating stresses greater than 30 ksi? If so, perform a plant-specific evaluation to determine the aging management requirements for the affected components. Have PINGP, Units 1 and 2, ever utilized atypical fuel 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?

If so, describe how the differences were reconciled with the assumptions of MRP-227 -A, or provide a specific aging management program for the affected components, as appropriate.

References Meeting Summary Electric Power Research Institute (EPRI) -Westinghouse January 22-23, 2013, dated February 21, 2013 (ADAMS Accession No. ML 13042A048) February 25,2013 Summary of Teleconference with EPRI and Westinghouse Electric Company, dated March 15, 2013 (ADAMS Accession No. ML 13067A262)

Enclosure

-2 RAI.2-2: In the licensee's March 22, 2013, submittal it is not evident which of the RVI components in the PINGP design are specifically defined in the current licensing basis (CLB) as ASME Section XI, Examination Category B-N-3 removable core support structure components, or how these components relate to the four inspection categories that are defined for Westinghouse-designed . RVI components in Technical Report (TR) No. MRP-227-A (Le., as MRP-defined "Primary Category," "Expansion Category," "Existing Program," or "No Additional Measures" com ponents).

Part (a) -Identify all RVI components in the PINGP plant design that are defined in the CLB as ASME Section XI, Examination Category B-N-3 core support structure components.

For each of these components, identify which of the four inspection categories in MRP-227 -A is applicable to the component.

Part (b) -If a component identified in the reply to Part (a) is defined as either a "Primary Category" or "Expansion Category" component, identify any differences between the inspections that would be performed on the components under MRP-227 -A versus the plant's ASME Section XI inservice inspection (lSI) program. For each of these components identified in Part (b), clarify how the differences in inspection bases for these components will be reconciled consistent with the CLB for the facility.

RAI2-3: By letter dated March 7,2013, the licensee provided a response to Action Item 3 that was addressed in the NRC staff's SE for the MRP-227-A.

In its response to Action Item 3, the licensee provided its basis for why the replacement control rod guide tube (CRGT) assembly support pins (i.e., split pins) at PINGP (which are made from Type 316 cold-worked austenitic stainless steel) would not need to be inspected under the augmented inspection basis in TR MRP-227-A.

However, Updated Safety Analysis Report (USAR) Section 3.6.2.2 establishes the following bases with respect to the design of the CRGT assemblies:

The guide tube assemblies, shown on Figure 3.6-3, sheath and guide the control rod drive shafts and control rods and provide no other mechanical functions.

They are fastened to the upper support plate and are guided by pins in the upper core plate for proper orientation and support. Additional guidance for the control rod drive shafts is provided by the upper guide tube which is bolted to the upper 'support plate and guide tube. Based on this USAR information, it is not evident why the replacement CRGT split pins not need to be inspected in accordance with the ASME Section XI, Table Examination Category S-N-3 lSI requirements, as invoked by the lSI requirements *10 CFR 50.55a. Part (a) -Clarify whether the CRGT split pins are defined as ASME Section XI, Examination Category B-N-3 components for the PINGP CLB. If the CRGT split pins are defined in the CLB as ASME Section XI, Examination Category B-N-3 core support structure components, justify why the CRGT split pins would not need to be inspected as a part of the "Existing Program"

-bases of the PWR Vessel Internals Program or alternatively in accordance with the aging management program (AMP) for the facility that corresponds to GALL AMP XI.Ml, "ASME Section Xllnservice Inspection, Subsections IWB, IWC, and IWD" Program. Part (b) -Justify why the response to Applicant/Licensee Action Item #3 did not specifically address whether the ASME Section XI "Existing Program" bases in the CLBfor the CRGT split pins is sufficient for ensuring adequate aging management of the split pins during the period of extended operation.

Otherwise, amend the submittal to provide a response to the AI LA I that specifically addresses the adequacy of ASME Section XI lSI bases for the CRGT split pins and whether these bases are sufficient to manage aging in the components during the period of extended operation.

RAI2-4: The NRC staff requests that the licensee address the following issues: Pages 43 -45 of Attachment 1 of the licensee's March 22, 2013, submittal includes the "Expansion Category" components.

Clarify whether the "Expansion Link" column for that "Expansion Coniponent" Table should be interpreted as a "Primary Link" column for the table. Page 46 of Attachment 1 of the licensee's March 22, 2013, submittal includes the "Existing Program" components.

Clarify whether the "Expansion Link" col.umn for that "Existing Program Component" Table should be interpreted as an "Existing Program Reference" column for the table. .

J. E. Lynch -2 If circumstances result in the need to revise the requested response date, please contact me at (301) 415-4037.

Sincerely, IRA! Thomas J. Wengert, Senior Project Manager Plant Licensing Branch 111-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-282 and 50-306 .

Enclosure:

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