ML24218A228

Request for Confirmation of Information for Relief Request RR-017, Inservice Inspection Impracticality During the Fifth Ten-Year Interval

ML24218A228
Person / Time
Site:	Monticello
Issue date:	08/05/2024
From:	Ballard B NRC/NRR/DORL/LPL3
To:	Jacobson R, Mark Miller Northern States Power Company, Minnesota, Xcel Energy
Ballard B, NRR/DORL/LPL3
References
EPID L-2024-LLR-0014
Download: ML24218A228 (1)

Text

Brent Ballard

From: Brent Ballard Sent: Monday, August 5, 2024 2:03 PM To: Miller, Michael A; Jacobson, Ronald G.

Cc: Jeff Whited

Subject:

Monticello - Final RCI for RR-017 ISI Impracticality (EPID L-2024-LLR-0014)

Attachments: Monticello - Final RCI for RR-017.docx

Good morning, Mike and Ron,

By leer dated January 30, 2024 (Agencywide Documents Access Management System (ADAMS) Accession No. ML24033A295), Northern States Power Company, a Minnesota corporaon, doing business as Xcel Energy, submi ed inservice inspecon (ISI) relief request RR-017 for the "h ten-year ISI interval for the Moncello Nuclear Generang Plant. The RR-017 submi al requests relief for a number of designated reactor pressure vessel (RPV) nozzle-to-vessel welds on the basis that achievement of the required examinaon coverage of "essenally 100 percent," as required in Paragraph IWA-2200(c) of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Secon XI, Division 1, is impraccal due to physical obstrucons and the limitaons in the geometry of the RPV design.

The NRC sta has determined that addional informaon is needed to complete its review. A ached is NRC stas request for con"rmaon of informaon (RCI). The NRC sta is requesng a response to the RCI within 30 days of the date of this email, which is September 4, 2024. Please let me know if you have any quesons.

Thank you, Brent

Brent Ballard Project Manager Plant Licensing Branch III Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission 301-415-0680

1 REQUEST FOR CONFIRMATION OF INFORMATION ON

10 CFR 50.55a RELIEF REQUEST NO. RR-017

FOR FIFTH 10-YEAR INSERVICE INSPECTION INTERVAL

MONTICELLO NUCLEAR GENERATING PLANT

NORTHERN STATES POWER COMPANY

DOCKET NO. 50-263

By letter L-MT-2024-001 dated January 30, 2024 (Agencywide Documents Access Management System (ADAMS) Accession No. ML24033A295), Northern States Power Company, a Minnesota corporation, doing business as Xcel Energy, (NSPM, the licensee) submitted inservice inspection (ISI) relief request RR-017 for the fifth ten-year ISI interval for the Monticello Nuclear Generating Plant (Monticello).

In RR-017, the licensee requests relief for a number of designated reactor pressure vessel (RPV) nozzle-to-vessel (NV) welds listed in Tables A, B, and C of Enclosure Attachment 1 to the L-MT-2024-001 letter. The licensee justified the requested relief on the basis that achievement of the required examination coverage of "essentially 100 percent," as required in Paragraph IWA-2200(c) of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section XI, Division 1 (ASME Section XI), is impractical due to physical obstructions and the limitations in the geometry of the RPV design. Therefore, pursuant to 10 CFR 50.55a(g)(5)(iii), NSPM requested authorization of an alternative to the requirements of ASME Section XI Table IWB-2500-1, Category B-D, Item B3.90 and associated ASME Code Case N-613-1 and proposes to use the actual coverages of completed fifth interval examinations on the specified welds as an acceptable alternative that provides reasonable assurance of continued structural integrity of the RPV and of the NV welds in the RPV.

Regulatory Basis: The regulation in 10 CFR 50.55a, Paragraph (g)(4) requires, in part, that license holders of commercial operating licenses (including renewed and subsequent renewed licenses) to implement the ISI requirements of ASME Section XI for structures, systems and components (SSCs) identified as ASME Code Class 1, 2, and 3 SSCs. Acceptable editions of ASME Section XI for implementation are defined in 10 CFR 50.55a, Paragraph (a)(1)(ii). The regulation in 10 CFR 50.55a, Paragraph (g)(5)(iii) requires that, if the licensee has determined that conformance with a Code requirement is impractical for its facility, the licensee must notify the NRC and submit, as specified in § 50.4, information to support the determinations. The regulation in 10 CFR 50.55a(g)(5)(iii) requires the determinations of impracticality to be based on the demonstrated limitations experienced when attempting to comply with the ASME requirements during the ISI interval for which the request is being submitted and states that the ISI impracticality requests must be submitted to the NRC no later than 18 months after the expiration of the initial or subsequent 120-month inspection interval for which relief is sought.

The regulation in 10 CFR 50.55a, Paragraph (g)(6) states that the Commission: (1) will evaluate determinations submitted under 10 CFR 50.55a, Paragraph (g)(5) that the code requirements

1 are impractical, and (2) may grant such relief and may impose such alternative requirements as it determines that the alternatives are authorized by law, will not endanger life or property or the common defense and security, and are otherwise in the public interest giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.

Request for Confirmation of Information (RCI)

RCI #RR-017-1

Incoming Request and Background Information. The RR-017 impracticality request contains what appears to be contradictory information in the submittal. In section 6.2.1, on page 5 of the Enclosure in NSPM Letter No. L-MT-24-001, the licensee states that:

For the examinations conducted, satisfactory results were achieved, and no flaw indications were detected.

However, in the Indications Reported column entry of the line item for the NV weld of RPV main steam line nozzle N-3C in Table A of Enclosure, Attachment 1 in letter L-MT-24-001, the licensee reports that one acceptable flaw indication was detected in the weld (i.e., for the UT examination that was performed on the weld during the Year 2019 refueling outage). The footnote for Table A (the staff notes the footnote does not have a corresponding superscript in Table A; assumed to be for the N -3C NV weld as it is the only indication reported) states, "Previously recorded sub-surface indication was re-confirmed and re-evaluated as acceptable per Code paragraph IWB-3512-1. No observed change since previous exam in 2009."

Additionally, Table A of Enclosure 2 to NSPM's fourth interval alternative request (ML101300050) has a similar footnote for the N-3C NV weld and says no observed change since the 1998 exam.

In NSPMs response (ML24046A132) to RAI #RR-002-1, asked during the NRC staff's review of NSPM's RR-002 alternative request, a table provided in Attachment 1 shows a B3.90 relevant indication (RI) was found on the N-3C NV weld in 2019. NSPM also stated in the RAI response that, "One B3.90 relevant indication (RI) was evaluated for the N-3C NV weld that was accepted per IWB-3512-1 of the 2007 Edition with 2008 Addenda ASME Section XI for the 5th ISI Interval.

Request:

The staff requests that the licensee confirm the footnote for Table A of the Enclosure, in letter L-MT-24-001 is applicable to the N-3C NV weld. Further, the staff requests NSPM confirm one RI was detected during the 2019 exam for the N-3C NV weld, evaluated, and determined to be acceptable per IWB-3512-1, and that the statement in Section 6.2.1 on page 5 of the submittal enclosure, " For the examinations conducted, satisfactory results were achieved, and no flaw indications were detected," is in error. If necessary, please provide additional information to reconcile the apparent contradictory information between Table A and the quoted text in Section 6.2.1 on page 5 of the submittal enclosure.

2