ML23214A241

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Letter: Aging Management Audit - Monticello Unit 1 - Subsequent License Renewal Application
ML23214A241
Person / Time
Site: Monticello Xcel Energy icon.png
Issue date: 08/31/2023
From: Mary Johnson
NRC/NRR/DNRL/NLRP
To: Hafen S
Northern States Power Co
References
EPID L-2022-SLR-0000
Download: ML23214A241 (134)
v • d • e


Text

August 31, 2023 Mr. Shawn Hafen Site Vice President Northern States Power Company -

Minnesota Monticello Nuclear Generating Plant 2807 West County Road 75 Monticello, MN 55362

SUBJECT:

MONTICELLO NUCLEAR GENERATING PLANT, UNIT 1 - REPORT FOR THE AGING MANAGEMENT AUDIT REGARDING THE SUBSEQUENT LICENSE RENEWAL APPLICATION REVIEW (EPID NO. L-2022-SLR-0000)

Dear Mr. Hafen:

By letter dated January 9, 2023 (Agencywide Documents Access and Management System (ADAMS) Package Accession No. ML23009A352), as supplemented by letters dated April 3, 2023 (ML23094A136), June 26, 2023 (ML23177A218), July 13, 2023 (ML23193B025), July 18, 2023 (ML23177A218), August 15, 2023 (ML23227A175) and August 28, 2023 (ML23240A695),

Northern States Power Company, a Minnesota corporation (NSPM, the applicant), submitted an application for subsequent license renewal of Renewed Facility Operating License No. DPR-22 for Monticello Nuclear Generating Plant (MNGP), Unit 1, to the U.S. Nuclear Regulatory Commission (NRC). NSPM submitted the application pursuant to Title 10 of the Code of Federal Regulations part 54, Requirements for Renewal of Operating Licenses for Nuclear Power Plants, for subsequent license renewal.

The NRC staff completed its aging management audit from February 27, 2023 - May 25, 2023, in accordance with the audit plan (ML23048A023). The audit report is enclosed.

S. Hafen If you have any questions, please contact me by email at Marieliz.Johnson@nrc.gov.

Sincerely,

/RA/

Marieliz Johnson, Project Manager License Renewal Projects Branch Division of New and Renewed Licenses Office of Nuclear Reactor Regulation Docket No. 50-263

Enclosure:

Audit Report cc w/encl: Listserv S. Hafen

SUBJECT:

MONTICELLO NUCLEAR GENERATING PLANT, UNIT 1 - REPORT FOR THE AGING MANAGEMENT AUDIT REGARDING THE SUBSEQUENT LICENSE RENEWAL APPLICATION REVIEW (EPID NO. L-2021-SLR-0002)

DATED: AUGUST 31, 2023 DISTRIBUTION:

EMAIL:

PUBLIC MJohnson, NRR/DNRL TMcGowan, RIII/DORS JHammock, NRR/DNRL CNorton, RIII/DORS LGibson, NRR/DNRL HPeterson, RIII/DORS JUmana, NMSS/REFS NFeliz-Adorno, RIII/DORS TSmith, NMSS/REFS MDomke, RIII/DORS BSmith, NRR/DNRL ABarker, RIII/FCO BThomson, NRR/DNRL HLogaras, RIII/FCO BBallard, NRR/DORL VMitlyng, RIII/FCO NSalgado, NRR/DORL PChandrathil, RIII/OCA MMcCoppin, OEDO SBurnell, HQ/OPA EMAIL:

DRoth, OGC Max.W.Smith@xcelenergy.com DJohnson, OEDO/AO paul.b.young@xcelenergy.com CWolf, OCA stephen.sollom@xcelenergy.com ADAMS Accession Nos.:

PKG: ML23214A232 LTR: ML23214A241 NONPROP: ML23214A242 PROP: ML23214A240 NRR-106 OFFICE PM:NRLP:DNRL LA:NRLP:DNRL BC:SCPB:DSS BC:NPHP:DNRL NAME MJohnson KThomson BWittick MMitchell DATE 08/X02/2023 08/14/2023 06/23/2023 06/23/2023 OFFICE BC:NCSG:DNRL BC:NVIB:DNRL BC:ESEB:DEX BC:ELTB:DEX NAME SBloom ABuford ITseng (GThomas for) JPaige DATE 07/27/2023 08/18/2023 06/22/2023 06/26/2023 OFFICE BC:SNSB:DSS BC:NRLP:DNRL PM:NRLP:DNRL NAME PSahd LGibson MJohnson DATE 06/21/2023 08/28/2023 08/31/2023 AUDIT REPORT Aging Management Audit Monticello Nuclear Generating Plant, Unit 1 Subsequent License Renewal Application February 27, 2023 - May 25, 2023 Division of New and Renewed Licenses Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Enclosure

U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR REACTOR REGULATION DIVISION OF NEW AND RENEWED LICENSES Docket No: 50-263 License No: DPR-22 Licensee: Northern States Power Company, a Minnesota corporation (NSPM)

Facility: Monticello Nuclear Generating Plant (MNGP), Unit 1 Location: Rockville, Maryland Monticello, Minnesota Dates: February 27, 2023 - May 25, 2023 Approved By: Steven D. Bloom, Chief Corrosion and Steam Generator Branch Division of New and Renewed Licenses Angie R. Buford, Chief Vessels and Internals Branch Division of New and Renewed Licenses Ian Tseng, Chief Structural, Civil, Geotech Engineering Branch B Division of Engineering and External Hazards Lauren K. Gibson, Chief License Renewal Projects Branch Division of New and Renewed Licenses Jason Paige, Acting Chief Long Term Operations and Modernization Branch Division of Engineering and External Hazards Philip Sahd, Chief Nuclear Systems Performance Branch Division of Safety Systems Matthew A. Mitchell, Chief Piping and Head Penetrations Branch Division of New and Renewed Licenses Brian D. Wittick, Chief Containment & Plant Systems Branch Division of Safety Systems Reviewers: Name Organization Naeem Iqbal PRA Licensing B (APLB)/Division of Risk Assessment (DRA)

Daniel Ju APLB/DRA Adakou Foli Long Term Operations & Modernization Branch (ELTB)/Division of Engineering and External Hazards (DEX)

Matthew McConnell ELTB/DEX Jorge Cintron ELTB/DEX Gurcharan (Singh) Matharu ELTB/DEX Liliana Ramadan ELTB/DEX Andrew Prinaris Structural, Civil, Geotech Engineering (ESEB)/DEX Bryce Lehman ESEB/DEX George Thomas ESEB/DEX George Wang ESEB/DEX Ata Istar ESEB/DEX Zuhan Xi ESEB/DEX Shaohua Lai ESEB/DEX Andrew Johnson Corrosion and Steam Generator (NCSG)/New and Renewed Licenses (DNRL)

Brian Allik NCSG/DNRL Gregory Makar NCSG/DNRL James Gavula NCSG/DNRL Joel Jenkins NCSG/DNRL Leslie Terry NCSG/DNRL Lydiana Alvarado NCSG/DNRL Matthew Yoder NCSG/DNRL Paul Klein NCSG/DNRL Reena Boruk NCSG/DNRL Tony Gardner NCSG/DNRL Ali Rezai Piping and Head Penetrations (NPHP)/DNRL Bart Fu NPHP/DNRL Varoujan Kalikian NPHP/DNRL Seung Min NPHP/DNRL Karen Sida NPHP/DNRL Carolyn Fairbanks Vessels and Internals (NVIB)/DNRL Cory Parker NVIB/DNRL David Dijamco NVIB/DNRL Emma Haywood NVIB/DNRL Michael Benson NVIB/DNRL On Yee NVIB/DNRL Brian Lee Containment and Plant Systems (SCPB)/Division of Safety Systems (DSS)

David Nold SPCB/DSS Goldon Curran SCPB/DSS Christopher Jackson Nuclear Systems Performance (SNSB)/DSS Santosh Bhatt SNSB/DSS Ben Parks Nuclear Methods and Fuels (SFNB)/DSS Brandon Wise SFNB/DSS Chris Tyree License Renewal Projects Branch (NLRP)/DNRL Marieliz Johnson NLRP/DNRL Jessica Hammock NLRP/DNRL Vaughn Thomas NLRP/DNRL TABLE OF CONTENTS AUDIT REPORT ...................................................................................................................... TABLE OF CONTENTS ........................................................................................................... ACRONYMS ............................................................................................................................ 1. Introduction ....................................................................................................................... 2. Audit Activities .................................................................................................................. SLRA Section 2.1, Scoping and Screening Methodology .................................................... SLRA Sections 2.3.3.6, Emergency Diesel Generators; 2.3.3.8, Emergency Service Water; 2.3.3.10, Fuel Pool Cooling and Cleanup; 2.3.3.14, Reactor Building Closed Cooling Water; 2.3.3.15, Reactor Water Cleanup; 2.3.3.16, Service and Seal Water; 2.3.3.17, Standby Liquid Control; and 2.3.4.6, Turbine Generator ................................................................ 2.3.3.6 Emergency Diesel Generators. ............................................................................. 2.3.3.8 Emergency Service Water. ................................................................................... 2.3.3.10 Fuel Pool Cooling and Cleanup. ......................................................................... 2.3.3.14 Reactor Building Closed Cooling Water. ............................................................ 2.3.3.15 Reactor Water Cleanup. ..................................................................................... 2.3.3.16 Service & Seal Water. ......................................................................................... 2.3.3.17 Standby Liquid Control. ...................................................................................... 2.3.4.6 Turbine- Generator. ........................................................................................ SLRA AMP B.2.2.1, Fatigue Monitoring ............................................................................... SLRA AMP B.2.2.2, Neutron Fluence Monitoring Program ................................................ SLRA AMP B.2.2.3, Environmental Qualification of Electric Equipment ............................ SLRA AMP B.2.3.1, ASME Section XI Inservice Inspection, Subsections IWB, IWC, and IWD ............................................................................................................................... SLRA AMP B.2.3.2, Water Chemistry ................................................................................ SLRA AMP B.2.3.3, Reactor Head Closure Stud Bolting ................................................... SLRA AMP B.2.3.4, BWR Vessel ID Attachment Welds .................................................... SLRA AMP B.2.3.5, BWR Stress Corrosion Cracking........................................................ SLRA AMP B.2.3.6, BWR Penetrations ............................................................................. SLRA AMP B.2.3.7, BWR Vessel Internals ........................................................................ SLRA AMP B.2.3.8, Thermal Aging Embrittlement of Cast Austenitic Stainless Steel (CASS) . -

21 -

SLRA AMP B.2.3.9, Flow-Accelerated Corrosion .............................................................. SLRA AMP B.2.3.10, Bolting Integrity ................................................................................ SLRA AMP B.2.3.11, Open-Cycle Cooling Water System ................................................. SLRA AMP B.2.3.12, Closed Treated Water Systems .......................................................

SLRA AMP B.2.3.13, Inspection of Overhead Heavy Load and Light Load (Related to Refueling) Handling Systems ......................................................................................... SLRA AMP B.2.3.14, Compressed Air Monitoring ............................................................. SLRA AMP B.2.3.15, Fire Protection ................................................................................. SLRA AMP B.2.3.16, Fire Water System ........................................................................... SLRA AMP B.2.3.17, Outdoor and Large Atmospheric Metallic Storage Tanks ................ SLRA AMP B.2.3.18, Fuel Oil Chemistry ........................................................................... SLRA AMP B.2.3.19, Reactor Vessel Material Surveillance .............................................. SLRA AMP B.2.3.20, One-Time Inspection ....................................................................... SLRA AMP B.2.3.21, Selective Leaching ........................................................................... SLRA AMP B.2.3.22, ASME Code Class 1 Small-Bore Piping .......................................... SLRA AMP B.2.3.23, External Surfaces Monitoring of Mechanical Components .............. SLRA AMP B.2.3.24, Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components ................................................................................................................... SLRA AMP B.2.3.25, Lubricating Oil Analysis ................................................................... SLRA AMP B.2.3.26, Monitoring of Neutron-Absorbing Materials Other Than Boraflex .... SLRA AMP B.2.3.27, Buried and Underground Piping and Tanks ..................................... SLRA AMP B.2.3.28, Internal Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, and Tanks .................................................................................................. SLRA AMP B.2.3.29, ASME Section XI, Subsection IWE .................................................. SLRA AMP B.2.3.30, ASME Section XI, Subsection IWF .................................................. SLRA AMP B.2.3.31, 10 CFR Part 50, Appendix J ............................................................ SLRA AMP B.2.3.32, Masonry Walls ................................................................................. SLRA AMP B.2.2.33, Structures Monitoring ....................................................................... SLRA AMP B.2.3.34, Inspection of Water-Control Structures Associated With Nuclear Power Plants .............................................................................................................................. SLRA AMP B.2.3.35, Protective Coating Monitoring and Maintenance ............................. SLRA AMP B.2.3.36, Electrical Insulation for Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements ......................................... SLRA AMP B.2.3 37, Electrical Insulation for Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Used in Instrumentation Circuits ............................................................................................................................ SLRA AMP B.2.3.38, Electrical Insulation for Inaccessible Medium-Voltage Power Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements ............................ SLRA AMP B.2.3.39, Electrical Insulation for Inaccessible Instrument and Control Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements ............................ SLRA AMP B.2.3.40, Electrical Insulation for Inaccessible Low-Voltage Power Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements ............................ SLRA AMP B.2.3.41, Metal Enclosed Bus .........................................................................

SLRA AMP B.2.3.42, Electrical Cable Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements .................................................................... SLRA TLAA Section 4.1, Identification of Time-Limited Aging Analyses ........................... SLRA TLAA Section 4.2.1, Neutron Fluence Projections ................................................... SLRA TLAA Sections 4.2.2, RPV Materials Upper Shelf Energy (USE) Reduction Due to Neutron Embrittlement through 4.2.4, RPV Thermal Limit Analysis: Operating P-T Limits .... -

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SLRA TLAA Section 4.2.5, RPV Circumferential Weld Examination Relief ....................... SLRA TLAA Section 4.2.6, RPV Axial Weld Failure Probability ......................................... SLRA TLAA Section 4.2.7, Reflood Thermal Shock Analysis of the RPV .......................... SLRA TLAA Section 4.2.8, Reflood Thermal Shock Analysis of the RPV Core Shroud .... SLRA TLAA Section 4.2.9, Loss of Preload for Core Plate Rim Holddown Bolts............... SLRA TLAA Section 4.2.10, Susceptibility to IASCC ......................................................... SLRA TLAA Section 4.3.1, 80-Year Transient Cycle Projections ...................................... SLRA TLAA Section 4.3.2, ASME Section III, Class 1 Fatigue Waivers ............................ SLRA TLAA Section 4.3.3, RPV Fatigue Analysis ............................................................. SLRA TLAA Section 4.3.4, Fatigue Analysis of RPV Internals .......................................... SLRA TLAA Section 4.3.5, ASME Section III, Class 1 ....................................................... SLRA TLAA Section 4.3.6, ASME Section III, Class 2 and 3 and ANSI B31.1 .................. SLRA TLAA Section 4.3.7, Environmentally-Assisted Fatigue ........................................... SLRA TLAA Section 4.4, Environmental Qualification of Electric Equipment .................. - 101 -

SLRA TLAA Section 4.5, Containment Liner Plate, Metal Containments and Penetrations Fatigue, and SLRA TLAA Section 4.6.2, Fatigue Analyses of High-Pressure Coolant Injection (HPCI) and Reactor Core Isolation Cooling (RCIC) Turbine Exhaust Penetrations . -

102 -

SLRA TLAA Section 4.6.1, Fatigue of Cranes ............................................................... - 104 -

SLRA TLAA Section 4.6.3, Condensate Backwash Receiving Tank Fatigue Evaluation . - 105 -

AMR Items Not Associated with an AMP ......................................................................... - 106 -

SLRA Sections 3.2.2.2.2, 3.2.2.2.4, 3.2.2.2.8, 3.2.2.2.10, 3.3.2.2.3, 3.3.2.2.4, 3.3.2.2.8, 3.3.2.2.10, 3.4.2.2.2, 3.4.2.2.3, 3.4.2.2.7, and 3.4.2.2.9, Further Evaluations for Stress Corrosion Cracking and Loss of Material for Stainless Steel, Nickel Alloys, and Aluminum Alloys ............................................................................................................................ - 106 -

SLRA AMR FE 3.5.2.2.2.6, Reduction of Strength and Mechanical Properties of Concrete Due to Irradiation .......................................................................................................... - 107 -

Bruck et al., Structural assessment of radiation damage in light water power reactor concrete biological shield walls, Nuclear Engineering and Design, Volume 350, pages 9-20 ............ - 108 -

SLRA Section 3.6.2.2.3, Loss of Material Due to Wind-Induced Abrasion, Loss of Conductor Strength Due to Corrosion, and Increased Resistance of Connection Due to Oxidation or Loss of Preload for Transmission Conductors, Switchyard Bus, and Connections ................................................................................................................. - 113 -

SLRA AMR Evaluation 3.6.2.3.1, Fuse Holders ........................................................... - 114 -

SLRA AMR Evaluation 3.6.2.3.2, High-Voltage Electrical Insulators ............................ - 115 -

3. Supplements to the SLRA ............................................................................................ - 116 -
4. Audit Questions Provided to NSPM .............................................................................. - 117 -
5. Applicant Personnel Contacted During Audit ............................................................... - 119 -
6. Exit Meeting .................................................................................................................. - 120 -

ACRONYMS ADAMS Agencywide Documents Access and Management System ALE adverse localized environment AMP aging management program AMR aging management review AR Action Request ART Adjusted reference temperature ASME American Society of Mechanical Engineers ASR alkali-silica reaction BWR boiling water reactor CAP corrective action program CASS Cast Austenitic Stainless Steel CBR condensate backwash receiving CDE Condensate Demineralizer Effluent CFR Code of Federal Regulations CLB current licensing basis CR change request CUF cumulative usage factor CUFen environmentally adjusted cumulative usage factor DBA design basis accident DM dissimilar metal EAF Environmentally Assisted Fatigue EEQ Electrical Environmental Qualification EFPY effective full-power years EPRI Electric Power Research Institute EPU Extended power uprate FAC Flow-Accelerated Corrosion FE Further Evaluation FMP fatigue monitoring program FSAR final safety analysis report GALL-SLR NUREG-2191, Generic Aging Lessons Learned for Subsequent License Renewal GE General Electric HDFSS High Density Fuel Storage System HELB high energy line break HPCI High-Pressure Coolant Injection IASCC irradiation-assisted stress corrosion cracking IE irradiation embrittlement IPA Integrated Plant Assessment ISG interim staff guidance ISI inservice inspection ISP Integrated Surveillance Program kV kilovolts LCB lower core barrel LOFT loss of fracture toughness LR license renewal MIC Microbiologically-Influenced Corrosion MNGP Monticello Nuclear Generating Plant NA not applicable NDE nondestructive examination NEI Nuclear Energy Institute NRC U.S. Nuclear Regulatory Commission OBE operating basis earthquake OE operating experience PBD program basis document PCR procedure change request PFM probabilistic fracture mechanics P-T pressure-temperature PTS pressurized thermal shock PWR pressurized-water reactor PWSCC primary water stress corrosion cracking RAI request for additional information RCI request for confirmation of information RCP reactor coolant pressure RHR residual heat removal RIS regulatory issue summary RPV reactor pressure vessel RTNDT reference temperature nil ductility RTPTS reference temperature for pressurized thermal shock RV reactor vessel RVI reactor vessel internals SAR safety analysis report SCC stress corrosion cracking SE safety evaluation SG steam generator SLR Subsequent License Renewal SLRA subsequent license renewal application SRV Safety Relief Valves SSCs systems, structures, and components TLAA Time-Limited Aging Analysis TGS Turbine Generator System USAR Updated Safety Analysis Report USE upper-shelf energy UT ultrasonic testing VT visual examination WO work order WOL weld overlay Report for the Aging Management Audit Monticello Nuclear Generating Plant, Unit 1 Subsequent License Renewal Application

1. Introduction The U.S. Nuclear Regulatory Commission (NRC) staff conducted an aging management audit of Northern States Power Company, a Minnesota corporation (NSPM, the applicant) of (1) plant-specific operating experience (OE), (2) methodology to identify the systems, structures, and components (SSCs) to be included within the scope of license renewal (LR) and subject to an aging management review (AMR) (Scoping and Screening Portion), and (3) aging management programs (AMPs), AMR items, Time-Limited Aging Analyses (TLAAs), and associated bases and documentation as applicable (AMP and TLAA Portion) for the subsequent license renewal (SLR) of Renewed Facility Operating License No. DPR-22 for Monticello Nuclear Generating Plant (MNGP), Unit 1.

The purpose of the plant-specific OE portion of the audit is to identify examples of age-related degradation, as documented in the applicants corrective action program (CAP) database, and to provide a basis for the staffs conclusions on the ability of the applicants proposed AMPs to manage the effects of aging in the period of extended operation. NSPM searched their OE database and provided the results for the associated AMPs and TLAAs for NRC staff review.

Additional word searches were performed by NSPM upon NRC staffs request, and the results were provided to the NRC staff for review.

The purpose of the Scoping and Screening portion of the audit is to evaluate the scoping and screening process as documented in the LR application, implementing procedures, reports, and drawings, such that the NRC staff:

  • Obtain an understanding of the process used to identify the SSCs within the scope of LR and to identify the structures and components subject to an AMR; and
  • Have sufficient docketed information to allow the staff to reach a conclusion on the adequacy of the scoping and screening methodology as documented and applied.

The purpose of the AMP and TLAA Portion of the audit is to:

  • Assess the adequacy of the TLAAs.

Enhancements and exceptions will be evaluated on a case-by-case basis. The NRC staffs review of enhancements and exceptions will be documented in the safety evaluation (SE).

The regulatory basis for the audit was Title 10 of the Code of Federal Regulations (10 CFR) part 54, Requirements for Renewal of Operating Licenses for Nuclear Power Plants. The staff also considered the guidance contained in NUREG-2192, Standard Review Plan for Review of Subsequent License Renewal Applications for Nuclear Power Plants (SRP-SLR), dated July 2017, and NUREG-2191. The SRP-SLR allows an applicant to reference in its LR application the AMPs described in the GALL-SLR Report. By referencing the GALL-SLR Report AMPs, the applicant concludes that its AMPs correspond to those AMPs reviewed and approved in the GALL-SLR Report and that no further staff review is required. If an applicant credits an AMP for being consistent with a GALL-SLR Report program, it is incumbent on the applicant to ensure that the plant program contains all of the elements of the referenced GALL-SLR Report program. The applicant should document this determination in an auditable form and maintain the documentation onsite.

2. Audit Activities A regulatory audit is a planned, license-related activity that includes the examination and evaluation of primarily non-docketed information. A regulatory audit is conducted with the intent to gain greater understanding of an application, to verify information, and, if applicable, to identify information that will require docketing to support the staffs conclusions that form the basis of the licensing or regulatory decision.

The subsequent license and renewal application (SLRA) states that every AMP in the SLRA is consistent with the program elements of the GALL-SLR Report. To verify this claim of consistency, the staff audited each AMP, including any enhancements or exceptions associated with an AMP.

The SLRA discusses each TLAA, the disposition of the TLAA in accordance with 10 CFR 54.21(c)(1), and the basis for that disposition. To verify that the applicant provided a basis to support its disposition of the TLAA, the staff audited each TLAA.

The staff also audited AMR items not associated with an AMP to determine if the information in the SLRA is consistent with the further evaluation (FE) information in the SRP-SLR.

Furthermore, the staff audited the updated safety analysis report (USAR) descriptions for each AMP and TLAA for consistency with the SRP-SLR. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the SLRA and provided by the applicant via the ePortal.

For the OE review, the applicant made a presentation on the process used to identify and evaluate the pertinent OE. Afterwards, the staff conducted its review of the applicants methodology and OE by reviewing documentation contained in the SLRA and ePortal.

Licensing conclusions or staff findings are not made in the audit reports since licensing and regulatory decisions cannot be made solely based on an audit. Therefore, items identified but not resolved within the scope of the audit will be followed using other NRC processes, such as requests for additional information (RAIs), requests for confirmation of information (RCIs), and public meetings. Licensing conclusions, staff findings, staff review of enhancement and exceptions, and resolution of audit items will be documented in the staffs SE.

The following sections discuss the SLRA areas reviewed by the staff.

SLRA Section 2.1, Scoping and Screening Methodology Summary of Information in the Application. SLRA Section 2.1 describes the process for identifying and determining the MNGP SSCs that are included within the scope of LR and subject to an AMR. 10 CFR 54.21, Contents of Application - Technical Information, requires that each application for LR contain an integrated plant assessment (IPA). The IPA must list, for SSCs within the scope of LR, the structures and components that are subject to an AMR.

10 CFR 54.4(a), Scope, provides the criteria for inclusion of SSCs within the scope of LR.

10 CFR 54.21(a)(1) requires that structures and components (SCs) within the scope of LR that are determined to be passive and not periodically replaced (long-lived), are subject to an AMR.

Audit Activities. During its audit, the staff reviewed documentation contained in the SLRA and provided by the applicant via the ePortal.

The table below lists the document that was reviewed by the staff and was found relevant to SLRA Section 2.1,Scoping and Screening Methodology. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELM017-REPT-001 Monticello Nuclear Generating Plant Subsequent License Revision 1 Renewal System/Structure Scoping Report During the audit, the staff verified that the applicants scoping and screening process was performed in accordance with its written requirements and was consistent with the guidance provided in the SRP-SLR and Nuclear Energy Institute (NEI) 17-01. The staff determined that the scoping and screening methodology was consistent with the requirements of 10 CFR part 54 for the identification of SSCs that meet the scoping and screening criteria.

SLRA Sections 2.3.3.6, Emergency Diesel Generators; 2.3.3.8, Emergency Service Water; 2.3.3.10, Fuel Pool Cooling and Cleanup; 2.3.3.14, Reactor Building Closed Cooling Water; 2.3.3.15, Reactor Water Cleanup; 2.3.3.16, Service and Seal Water; 2.3.3.17, Standby Liquid Control; and 2.3.4.6, Turbine Generator Summary of Information in the Application. SLRA Section 2.1 Scoping and Screening Methodology, states in part:

The initial step in the scoping process was to define the entire plant in terms of systems and structures. The systems and structures were then individually evaluated against the scoping criteria in 10 CFR 54.4(a)(1), (a)(2), and (a)(3) to determine if the systems or structures perform or support a safety-related (SR) function, if failure of the systems or structures prevent performance of a safety-related function, or if the systems or structures perform functions that are integral to one of the five LR regulated events. The intended function(s) that are the bases for including systems and structures within the scope of SLR were also identified.

If any portion of a mechanical system met the scoping criteria of 10 CFR 54.4(a)(1), (a)(2), and (a)(3), it was included within the scope of SLR.

The mechanical systems in the scope of SLR were then further evaluated to determine the system components that support the identified system intended function(s). The individual mechanical screening and AMR reports provide the details on the boundaries of in-scope mechanical systems.

To verify this approach, the staff audited SLRA Sections:

2.3.3.6 Emergency Diesel Generators 2.3.3.8 Emergency Service Water 2.3.3.10 Fuel Pool Cooling and Cleanup 2.3.3.14 Reactor Building Closed Cooling Water 2.3.3.15 Reactor Water Cleanup 2.3.3.16 Service and Seal Water 2.3.3.17 Standby Liquid Control 2.3.4.6 Turbine Generator Audit Activities. During the audit, the staff placed proportionately weighted focus on those systems identified in the document Risk Insights for Evaluating the Monticello SLRA (Proprietary, Non-Public); the staff also reviewed the USAR and other documentation contained in the SLRA. During its audit, the staff interviewed the applicants staff and reviewed the SLR documentation provided by the applicant on the Certrec internet portal.

The tables that follow list the documents that were reviewed by the staff and were found relevant to the audit.

2.3.3.6 Emergency Diesel Generators.

Document Title Revision / Date XCELMO00017-REPT-037 Monticello Nuclear Generating Plant Subsequent License Revision 1 Renewal Screening and Aging Management Review Results Emergency Diesel Generators System DBD-B.09 Emergency Diesel Generator System Design Basis Document Revision 82 The audit breakout discussions pertained to:

1) SLRA boundary drawing SLR-36051 - piping between the Diesel Pump House to Intake Structure wall;
2) SLRA boundary drawing SLR-36051 yard components Diesel Oil Receiving Tank T-83; Pump P-92; and tank influent and effluent piping; and
3) SLRA boundary drawing SLR-36051 - each EDGs lubricating oil base tanks volume capacity.

These discussions provided the staff with additional understanding of the plant design and of the SLRA scoping and screening results (i.e., components subject to AMR). There was no need for the applicant to amend and/or supplement the SLRA based on these discussions.

2.3.3.8 Emergency Service Water.

Document Title Revision / Date XCELMO00017- Monticello Nuclear Generating Plant Subsequent License Revision 1 REPT-026 Renewal Screening and Aging Management Review Results Emergency Service Water System DBD-B-08.01.04 Emergency Service Water System Design Basis Document Revision 6 The audit breakout discussions pertained to:

1) SLR-36664 - Drawing Note 2;
2) SLR-36246 - Backup Safety Related Instrument air supply Note 2; and
3) SLRA Table 3.3.2-8 Emergency Service Water - Summary of Aging Management Evaluation - the location of buried piping and bolting listed in the table.

These discussions provided the staff with additional understanding of the plant design and of the SLRA scoping and screening results (i.e., components subject to AMR). There was no need for the applicant to amend and/or supplement the SLRA based on these discussions.

2.3.3.10 Fuel Pool Cooling and Cleanup.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 016 Renewal Screening and Aging Management Review Results Fuel Pool Cooling and Cleanup System The audit breakout discussions pertained to:

1) SLR-36257 - a(2) Spatial/Structural function of pressure indicators; flow elements; differential pressure indicators;
2) SLRA Table 3.3.2-10 Fuel Pool Cooling and Cleanup - Summary of Aging Management Evaluation - Material of Carbon Steel (with Internal Coating) listed in table for Tanks (Skimmer Surge Tanks); and
3) SLR-36257 - representation of tubing to SX-2795 and SX-2796 as not subject to AMR.

These discussions provided the staff with additional understanding of the plant design and of the SLRA scoping and screening results (i.e., components subject to aging management review). There was no need for the applicant to amend and/or supplement the SLRA based on these discussions.

2.3.3.14 Reactor Building Closed Cooling Water.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 019 Renewal Screening and Aging Management Review Results Reactor Building Closed Cooling Water System The audit breakout discussions pertained to:

1) whether the subject components of thermowells, radiation monitor wells, and flow elements as displayed on SLR-36042 are encompassed within the Component Type Piping, Piping components on their respective SLRA Table 2.3.3-14 and Table 2.4-1; and
2) whether the instrumentation associated with the subject radiation monitor well should have an a(2) Functional (i.e., red) intended function.

These discussions provided the staff with additional understanding of the plant design and of the SLRA scoping and screening results (i.e., components subject to AMR). There was no need for the applicant to amend and/or supplement the SLRA based on these discussions.

Following the breakout discussion pertaining to Containment Penetrations X-23 & X-24 as displayed on SLRA boundary drawing SLR-36042-2, staff issued RAI-SCPB-1. In particular, the staff requested that the applicant confirm that the non-safety related piping connected to Penetrations X-23 & X-24 is seismically supported consistent with the guidance of NUREG-1800, Revision 2 and NEI 95-10, Revision 6.

2.3.3.15 Reactor Water Cleanup.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 010 Renewal Screening and Aging Management Review Results Reactor Water Cleanup System The audit breakout discussions pertained to:

1) SLR-36254 - thermowells; temperature elements; annular type flow elements; proper interpretation of Note 2;
2) SLR-36255 - Y-strainers; strainer elements; the spatial interaction intended function for differential pressure monitors; and
3) SLR-36255 - RWCU instrumentation and tubing with intended function of a(2)

Spatial/Structural.

These discussions provided the staff with additional understanding of the plant design and of the SLRA scoping and screening results (i.e., components subject to AMR). As an outcome of the discussion for Breakout Questions, the applicant agreed to amend SLR-35254. There were no other issues that needed the applicant to amend and/or supplement the SLRA.

2.3.3.16 Service & Seal Water.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 036 Renewal Screening and Aging Management Review Results Service and Seal Water System The audit breakout discussions pertained to:

1) SLR-36041 - intended function a(2) - Functional versus a(2) - Spatial/Structural for components from V-EAC-14A/B to the Circ Water Discharge Pipe (within the EFT Building and Turbine Building); and
2) SLRA Table 3.3.2-16 Service and Seal Water - Summary of Aging Management Evaluation and SLR-36665 - internal environment for valves and piping exposed to biocide and dispersant.

These discussions provided the staff with additional understanding of the plant design and of the SLRA scoping and screening results (i.e., components subject to AMR). As an outcome of the discussion for Breakout Question Number 2, the applicant agreed to amend SLRA boundary drawing SLR-36041. There were no other issues that needed the applicant to amend and/or supplement the SLRA.

2.3.3.17 Standby Liquid Control.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 024 Renewal Screening and Aging Management Review Results Standby Liquid Control System The audit breakout discussions pertained to:

1) SLR-36253 and Table 3.3.2-17 Standby Liquid Control - Summary of Aging Management Evaluation - an internal environment of sodium pentaborate solution for the two standby liquid control system accumulators;
2) SLR-36253 - the intended function of a(2) Spatial/Structural for Line DW8-1-HS and Valve DM-56;
3) SLR-36253 - the SLRA intended functions of pipeline DW7-1-HK (attached to the Standby Liquid Control System (SLC) Tank) and the Sparger in the SLC Tank;
4) SLR-36253 - the SLRA intended functions of the vent line on the Standby Liquid Control Tank and pipeline D68-3-HC; and
5) SLR-36253 - the SLRA intended function of IA to Standby Liquid Control Tank level instrumentation is not subject to AMR (black) on the Instrument and Service Air (AIR) side but has an a(3) ATWS function (red) on the SLC side of the flag of demarcation.

These discussions provided the staff with additional understanding of the plant design and of the SLRA scoping and screening results (i.e., components subject to AMR). As an outcome of the discussion for Breakout Question Number 2, the applicant agreed to amend SLR-35253.

There were no other issues that needed the applicant to amend and/or supplement the SLRA.

2.3.4.6 Turbine Generator.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 032 Renewal Screening and Aging Management Review Results Turbine Generator System The audit breakout discussions pertained to:

1) SLR-36033 and Table 2.3.4-6 Turbine Generator System Components Subject to Aging Management Review. - Expansion Joints XJ-1271/-1272/-1273/-1274 on this drawing are color coded as a(2) Spatial/Structural but not listed in Table 2.3.4-6.
2) SLR-36033 - a(2) Spatial/Structural intended function is discussed versus a(2)

Functional (i.e., AST plate out) for piping configuration from Main Condenser penetrations #47 and #37 to Turbine Vacuum Trip No. 1 and No. 2;

3) SLR-36033 - Clarification of Subsequent License Renewal Notes: 2. Components Shown in Red for the Turbine Generator System (TGS) are in the Scope for a FUNCTIONAL (a)2 Intended Function in Support of Alternate Source Term;
4) SLR-36034 - Notes 2 and 3 for lines V30-8-HB and V21-8-HB are not defined on drawing - SLR drawing to be amended to remove no longer needed notes
5) SLR-36050 and Table 2.3.4 Breakout Question Number 3 is a six-part question pertaining to Vapor Extractor, Pump Casing (EPR Oil Pump), T-41A H2 Seal Oil Conditioner Drain Tank 22 Gal Cap, Clean Oil Overflow between the Clean Oil Storage Tank and the Dirty Lube Oil Storage Tank, and Pump Casing (Turbine Bearing Lift Pump)- Applicant indicated that they would amend SLRA and SLR-36050 for question subparts (a), (b), (f). Subpart (e) is to be evaluated further by the applicant to determine what corrections are necessary.
6) SLR-M8107L-087 - Breakout Question Number 4 is a five-part question pertaining to (a) turbine bearing oil supply lines encased within the large trunk drain line, (b) Turning Gear Oil Pump casing, (c) DC Powered Pump Casing (Emergency Bearing Oil Pump),

(d) Booster Pump Casing, and (d) Pump Casing (Turb Aux Oil Pump). - Applicant indicated that they would amend SLRA and SLR-M8107L-087 for question subparts (a),

(b), (c) and (e).

These discussions provided the staff with additional understanding of the plant design and of the SLRA scoping and screening results (i.e., components subject to AMR). As an outcome of these discussions, the applicant agreed to amend the SLRA along with SLRA boundary drawings SLR-36034, SLR-36050, and SLR-M8107L-087. There were no other issues that needed the applicant to amend and/or supplement the SLRA.

SLRA AMP B.2.2.1, Fatigue Monitoring Summary of Information in the Application. The SLRA states that the AMP B.2.2.1, Fatigue Monitoring, is an existing preventive program with enhancements that is consistent with the program elements in GALL-SLR AMP X.M1, Fatigue Monitoring. At the time of the audit, the applicant had not yet fully developed the documents necessary to implement this enhanced program, and the staffs audit addressed only the program elements described in the applicants basis document.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 0 002 Renewal - Aging Effects Operating Experience Report XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 067 Renewal Aging Management Program Basis Document -

Fatigue Monitoring Action Request (AR) NRC RIS 2011-14 Metal Fatigue Analysis Performed by 4/3/2012 01321009 Computer CAP 500001476693 NRC Information Notice 2015-04 Fatigue in Branch 4/24/2015 Connection Welds CAP 501000026533 In-Vessel Visual Inspection Examinations of the Steam Dryer 4/29/2019 CR (Change Request) 2019-2021 Equipment Cycles Update 9/24/2021 608000000752 CR 608000000435 2017-2019 Equipment Cycles Update 1/17/2020 EC 0000025816 Fatigue Cycles Update for 2013 - 2015 9/21/2015 LTR-PCBE-19-10 Evaluation of Indications Found on Steam Dryer During Revision 0 /

Monticello RFO29 Outage 5/3/2019 EWI-11.01.18 Metal Fatigue of Reactor Coolant Pressure Boundary Revision 2 Procedure 1475 Equipment Cycle Surveillance Revision 7 Structural Integrity 80-Year Cycle Projections for Monticello Revision 0 Associates (SIA)

Calculation 2100507.301 SIA Calculation 80-Year Fatigue Analysis of Reactor Pressure Vessel (RPV), Revision 0 2100507.302P Reactor Vessel Internals (RVI), and Penetrations SIA Calculation 80-Year Fatigue Analysis of Selected Class 1 Reactor Coolant Revision 0 2100507.303 Pressure Boundary (RCPB) Piping SIA Calculation Evaluation of ANSI B31.1 and ASME Class 2 and 3 Piping and Revision 0 2100507.304 Components (Non-Class 1 Fatigue)

SIA Calculation Monticello Environmentally Assisted Fatigue Analysis for 80 Revision 0 2100507.305P Years, NUREG/CR-6260 Locations SIA Calculation Monticello Environmentally Assisted Fatigue Screening Revision 0 2100507.306 SIA Calculation Fatigue Exemption of Monticello Reactor Pressure Vessel Revision 0 2100507.309 (RPV) Components APED-5460 Design and Performance of General Electric Boiling Water September 1968 Reactor Jet Pumps During the audit, the staff audited the applicants claim that the scope of program, preventive actions, detection of aging effects, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP or will be consistent after implementation of the identified enhancements.

The staff found that, for the parameters monitored or inspected and monitoring and trending program elements, sufficient information was not available to verify whether they were consistent with the corresponding program elements of the GALL-SLR Report AMP. The staff will consider issuing RAIs in order to obtain the information necessary to verify whether these program elements are consistent with the corresponding program elements of the GALL-SLR Report AMP.

During the audit, the staff made the following observations.

  • In relation to the parameters monitored or inspected program element, Enhancement 2 of the Fatigue Monitoring AMP states that the plant procedure for the AMP will be updated to identify and require monitoring of the 80-year plant design cycles, or projected cycles that are utilized as inputs to component CUFen (cumulative usage factor Environmental-Assisted Fatigue) calculations, as applicable. The plant design transients are listed in SLRA Table 4.3.1-1. The SLRA table does not include plant loading and unloading transients that may be associated with load-following operation. In comparison, Monticello updated USAR Section 3.2.5, which addresses the performance characteristics of normal operation, indicates that variable recirculation flow control provides limited manual load-following capability. However, Enhancement 2 and SLRA Table 4.3.1-1 do not clearly address monitoring of plant loading and unloading transients.
  • In relation with the monitoring and trending program element, Enhancement 4 states that the plant procedure for the Fatigue Monitoring AMP will be updated to require that trending be performed to ensure that the fatigue parameter limits will not be exceeded during the subsequent period of extended operation. However, the SLRA does not clearly describe which fatigue parameters will be monitored against their limits in the enhancement.

The staff also audited the description of the SLRA Fatigue Monitoring AMP provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.2.2, Neutron Fluence Monitoring Program Summary of Information in the Application. Neutron fluence is a time-dependent input parameter for projecting the decrease in fracture toughness due to neutron irradiation. The Neutron Fluence Monitoring Aging Management Program (AMP) provides a means to ensure the validity of the neutron fluence analysis and related neutron fluence-based, time-limited aging analyses (TLAAs) and describes the monitoring program which monitors and tracks the neutron fluence as it increases with operation.

Section B.2.2.2 of the SLRA states that the existing Neutron Fluence Monitoring AMP is an existing program that is consistent with the program elements in GALL-SLR Report AMP X.M2, Neutron Fluence Monitoring Program, as modified by SLR-ISG-2021-02-MECHANICAL, Updated Aging Management Criteria for Mechanical Portions of the Subsequent License Renewal Guidance. To verify this claim of consistency, the staff audited the SLRA AMP.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date BWRVIP-86-R1-A Boiling Water Reactor Vessel and Internals Project Reactor Revision 1 Pressure Vessel Integrated Surveillance Program NEDC-32983P General Electric Methodology for Reactor Pressure Vessel Fast Sept. 2001 Neutron Flux Evaluation BWRVIP-199-NP BWR Vessel and Internals Project, Testing and Evaluation of the Aug. 2010 Monticello 300° Capsule During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP.

The staff also audited the description of the SLRA AMP on Neutron Fluence Monitoring provided in the UFSAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR.

SLRA AMP B.2.2.3, Environmental Qualification of Electric Equipment Summary of Information in the Application. The SLRA notes that AMP B.2.2.3, Environmental Qualification of Electric Equipment, is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP X.E1, Environmental Qualification of Electric Equipment. At the time of the audit, the applicant had not yet fully developed the documents necessary to implement this enhanced program, and the staffs audit addressed only the program elements described in the applicant's basis document.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 060 Renewal Management Program Basis Document -

Environmental Qualification of Electrical Equipment EWI-04.05.01 Thermography Program Revision 14 EWI-08.11.01 Equipment Qualification Users Manual Revision 26 AR01492160/AT-0175 Action Requests Record Revision 3 NA Electrical Environmental Qualification (EEQ) Program Health 1/20/2020 Report NA Electrical Environmental Qualification (EEQ) Program Health 7/20/2020 Report During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP or will be consistent after implementation of the identified enhancements.

The staff also audited the description of the SLRA Environmental Qualification of Electric Equipment provided in the USAR supplement. The staff verified this description is consistent with the descriptions provided in the GALL-SLR Report.

SLRA AMP B.2.3.1, ASME Section XI Inservice Inspection, Subsections IWB, IWC, and IWD Summary of Information in the Application. The SLRA states that AMP B.2.3.1, ASME Section XI Inservice Inspection, Subsections IWB, IWC, and IWD is an existing program that is consistent with the program elements in GALL-SLR Report AMP XI.M1, ASME Section XI Inservice Inspection, Subsections IWB, IWC, and IWD.

Audit Activities. In addition to the OE documentation contained in the SLRA and ePortal, the staff observed the applicants search of its OE database using the keywords: cracking, crack, leak, wear, loss of material, failure, stress corrosion cracking, SCC, degradation, flaw, repair, weld, program assessment, peer assessment, self assessment, missed examination, missed item, missed inspection, missed flaw, and program deficiency.

The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017- Monticello Nuclear Generating Plant Subsequent License Revision 1 /

REPT-042 Renewal Aging Management Program Basis Document - ASME 11/17/2022 Section XI Inservice Inspection, Subsections IWB, IWC, and IWD AR 6001475767 Failure to Measure Interpass Temperature Revision 0 SAR-01512092-16 Proactive OE Search - ISI 4/24/2015 AR6060000952 License renewal Phase IV Self Assessment Plan 9/23/2019 CAP501000032299 Current IS Program Notes could not be located Revision 0 CAP501000032327 Effectiveness reviews have not been completed for AMPs Revision 0 contrary to guidance in 4 AWI-08.11.04 and NEI-1412 CAP501000004833 NRC Commitment M05043A - Change required Revision 0 CAP501001556336 RFO28 ISI indications Revision 0 CAP501000032327 Nine out of 25 AMP owners have not completed the job Revision 0 familiarization guide FL-EPE-AMP-001 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP.

The staff also audited the description of the SLRA AMP provided in the USAR supplement. The staff verified that this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.2, Water Chemistry Summary of Information in the Application. The SLRA states that AMP B2.3.2, Water Chemistry, is an existing program with one exception that is consistent with the program elements in GALL-SLR Report AMP XI.M2, Water Chemistry, as modified by SLR-ISG-2021-02-MECHANICAL, Updated Aging Management Criteria for Mechanical Portions of Subsequent License Renewal Guidance, dated February 2021 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20181A434).

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO0001-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 0 002 Renewal - Aging Effects Operating Experience Report XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 061 Renewal Aging Management Program Basis Document-Water Chemistry Issue ID 501000052351 Occurrence Date This report was created to document Feedwater conductivity 5/20/2021 exceeding BWR Action Level 1 value and GE Fuel Warranty Completion Date Continuous Limit.

5/24/2021 Issue ID 501000033877 This report was created to document the increase in Occurrence Date Condensate Demineralizer Effluent (CDE) and Feedwater (FW) 10/25/2019 dissolved oxygen concentration and to note that it was Completion Date approaching the Good Practice value. 10/31/2019 Issue ID 501000017581 This report was created to document Reactor Water Occurrence Date Conductivity exceeding BWR Action Level 1 value and Reactor 9/26/208 Water Dissolved Oxygen exceeding the Good Practice Value Completion Date because of an HWC Trip. 9/28/2018 AR 01468275 2015 Select AMP Effectiveness Reviews Origination Date 3/2/2015 Completion Date 9/29/2015 AR 606000000952 License Renewal Phase IV Self-Assessment Plan Start Date 9/23/2019 End Date 9/26/2019 AR 606000001098 2019-2020 AMP Effectiveness Reviews Origination Date Document Title Revision / Date 11/13/2019 Completion Date 4/23/2020 II.01 Strategic Chemistry Plan Revision 31 II.16 Plant Chemistry Program Revision 1 II.05 Chemistry Limits & Sampling Frequencies Revision 40 EPRI-3002002623 EPRI Proprietary. BWRVIP-190: BWR Vessel and Internals Revision 1 Project: BWR Water Chemistry Guidelines NA EPRI Proprietary. 2019 BWR Water Chemistry Guidelines March 2019 Interim Guidance Issue ID 50100032338 LR FSA: AMP Documents outdated/incorrect Origination Date 9/26/2019 Completion Date 5/31/2020 XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 024 Renewal Screening and Aging Management Results Standby Liquid Control System SLR-36253 Subsequent License Renewal Boundary Drawing Standby Revision 0 Liquid Control System During the audit, the staff verified the applicants claim that the scope of program, preventive actions, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program element(s) of the SLRA AMP are consistent with the corresponding element(s) of the GALL-SLR Report AMP.

The staff also verified the applicants claim that aspects of the parameters monitored or inspected program element not associated with the exception identified in the SLRA are consistent with the corresponding program elements in the GALL-SLR Report AMP.

The staff also audited the description of the SLRA AMP Water Chemistry provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.3, Reactor Head Closure Stud Bolting Summary of Information in the Application. The SLRA states that AMP B.2.3.3, Reactor Head Closure Stud Bolting, is an existing program with enhancements and exceptions that is consistent with the program elements in GALL-SLR Report AMP XI.M3, Reactor Head Closure Stud Bolting. To verify this claim of consistency, the staff audited the SLRA AMP.

Audit Activities. For SLRA AMP B.2.3.3, in addition to the OE documentation contained in the SLRA and ePortal, the applicant searched for the additional keywords head nut, washer, bushing, and gall. Afterwards, the staff conducted its review of the applicants methodology and OE by reviewing documentation contained in the SLRA and ePortal.

The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017- Monticello Nuclear Generating Plant Subsequent License Renewal Revision 1 REPT-082 Aging Management Program Basis Document - Reactor Head Closure Stud Bolting XCELMO00017- Monticello Nuclear Generating Plant Subsequent License Renewal Revision 0 REPT-002 - Aging Effects Operating Experience Report EWI-11.01.21 Reactor Head Closure Studs Revision 1 FP-PE-RLP-01 License Renewal Implementation Revision 9 USAR-K Renewed Operating License - USAR Supplement Appendix K Revision 37 G0802020 OETS Action Closeout Documentation Form Revision 3 /

2/16/1990 MN-102711 UT Bolting/Stud Examination 4/19/2021 ALT-RR-015 MNGP - Request for Alternative for Examination of Reactor 12/21/2020 Pressure Vessel Threads in Flange NRC Response L-MT-20-002 10 CFR 50.55a(z)(1) Request RR-015: Proposed Alternative for 1/31/2020 Examination of ASME Section XI, Examination Category B-G-1, Item Number B6.40, Threads in Flange During the audit, the staff verified the applicants claim that the scope of program, parameters monitored or inspected, detection of aging effects, monitoring and trending, and acceptance criteria program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP. The staff also verified the applicants claim that aspects of the preventive actions and corrective actions program elements not associated with the exceptions identified in the SLRA or by the staff during the audit are consistent with the corresponding program elements in the GALL-SLR Report AMP.

During the audit, the staff made the following observations:

  • The applicant stated that most replacement studs available have ultimate tensile strengths greater than 170 ksi, which is above the recommended value in NUREG-2191 and which is meant to reduce the potential for SCC.
  • Procurement procedures will be updated to require that all newly procured studs have a measured yield strength of less than 150 ksi.
  • No cracking or damage has been reported on the closure studs.

The staff also audited the description of the SLRA Reactor Head Closure Stud Bolting provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.4, BWR Vessel ID Attachment Welds Summary of Information in the Application. The SLRA states that AMP B.2.3.4, BWR Vessel ID Attachment Welds, is an existing program that is consistent with the program elements in GALL-SLR Report AMP XI.M4, BWR Vessel ID Attachment Welds.

Audit Activities. For the OE review, the applicant made a presentation on the process used to identify and evaluate the pertinent OE. Afterwards, the staff conducted its review of the applicants methodology and OE by reviewing documentation contained in the SLRA and ePortal. Furthermore, the staff conducted additional OE searches on the applicants CAP database, and inservice inspection (ISI) reports and summaries.

The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 044 Renewal Aging Management Program Basis Document - BWR Vessel ID Attachment Welds BWRVIP-48-A Vessel ID Attachment Weld and Inspection and Flaw Evaluation November 2004 Guidelines EWI-09.04.00 ASME Section XI Inservice Inspection Program Revision 17 EWI-08.01.02 BWRVIP Implementation Guidelines Revision 11 EWU-11.01.22 BWR Vessel ID Attachment Welds Revision 2 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP.

During the audit, the staff made the following observations:

  • The applicants SLRA (Sections A.2.2.4 and B.2.3.4) and program basis document for its BWR Vessel ID Attachment Welds Program appeared to indicate that a proposed alternative, which was approved in accordance with 10 CFR 50.55a only for the 5th Inservice Inspection interval (Reference ML16208A462), was applicable to the subsequent period of extended operation. To address this inconsistency with the 5th inservice inspection interval, by letter dated June 26, 2023, the applicant revised SLRA Section B.2.3.4 to clarify that with respect to the BWR Vessel ID Attachment Welds AMP that any deviation from the ASME Code,Section XI requirements (including those documented in a BWRVIP) will be approved by the NRC in prior to use. The staffs review of this clarification will be addressed in the SE.

The staff also audited the description of the SLRA AMP, BWR Vessel ID Attachment Welds provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.5, BWR Stress Corrosion Cracking Summary of Information in the Application. The SLRA states that AMP B.2.3.5, BWR Stress Corrosion Cracking is an existing program that is consistent with the program elements in GALL-SLR Report AMP XI.M7, BWR Stress Corrosion Cracking.

Audit Activities. In addition to the OE documentation contained in the SLRA and ePortal, the staff observed the applicants search of its OE database using the keywords: rcs leakage, stress corrosion, IGSCC, HAZ cracking, base metal cracking, and heat affected zone.

The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT-045 Subsequent License Renewal Aging Management Program Revision 1 Basis Document - BWR Stress Corrosion Cracking EWI-11.01.25 BWR Stress Corrosion Cracking Revision 2 EWI-09.04.00 ASME Section XI Inservice Inspection Program Revision 17 4AWI-09.04.03 ASME Section XI Repair/Replacement Program Revision 25 4AWI-07.03.01 Nondestructive Examination Revision 12 CR-606000001098 2019-2020 AMP Effectiveness Reviews April 2020 XCELMO00017-REPT-002 Monticello Nuclear Generating Plant Subsequent License Revision 0 Renewal - Aging Effects Operating Experience Report Document Title Revision / Date XCELMO00017-REPT-008 Monticello Nuclear Generating Plant Subsequent License Revision 1 Renewal Screening and Aging Management Review Results

- Reactor Coolant Pressure Boundary and Connected Piping CAP-500001284528 Non Documented Sealant Used on XR-31-1 Downstream 3/16/2017 Pipe Cap CR-610000000222 OE: ICES 326122 - Dissimilar Metal Weld Flaw on Residual 12/3/2019 Heat Removal Piping CR-610000000260 OE: ICES 414634 - Instrument Line Nozzle Leak Identified 5/13/2020 During Reactor Pressure Vessel Leakage Test During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding program elements in the GALL-SLR Report AMP.

The staff also audited the description of the SLRA AMP provided in the USAR supplement. The staff verified this description is consistent with the description provided in the SRP-SLR.

SLRA AMP B.2.3.6, BWR Penetrations Summary of Information in the Application. The SLRA states that AMP B.2.3.6, BWR Penetrations, is an existing program that is consistent with the program elements in GALL-SLR Report AMP XI.M8, BWR Penetrations.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 043 Renewal Aging Management Program Basis Document -

BWR Penetrations AR-610000000260- Assessment of applicability of Limerick, Unit 2, water level 2017 20200512-000 instrument nozzle penetration leakage OE to Monticello EWI-11.01.26 BWR Penetrations Revision 2 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of SLRA AMP are consistent with the corresponding elements of GALL-SLR Report AMP.

The staff also audited the description of the SLRA BWR Penetrations provided in the USAR supplement. The staff verified this description is consistent with the description provided in GALL-SLR Report.

SLRA AMP B.2.3.7, BWR Vessel Internals Summary of Information in the Application. The SLRA states that AMP B.2.3.7, BWR Vessel Internals is an existing program with enhancement and exception that will be consistent with the program elements in GALL-SLR Report AMP XI.M9, BWR Vessel Internals.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date 501000038264 Corrective Action Report April 2020 501000038263 Corrective Action Report April 2020 501000026533 Corrective Action Report May 2019 602000015043 Change Request Close Out Report April 2020 0000018068 Summary of 2011 Shroud Support Inspection and April 2012 Evaluation Activities 604000000484 Change Request Close Out Report February 2021 0000023663 MNGP Shroud Support Structure Flaw Evaluation Review March 2014 and Summary Vendor Prepared Evaluation 0000027346R000 RF028 Steam Dryer Inspection Update August 2016 NA AMP Effectiveness Reviews of 35 Active Aging March 2020 Management Programs 700020838 Completed WO Operation Report January 2020 Perform In-Vessel Visual Inspections11-224 Task Report T0303, RPV Internals Mechanical Evaluation October 2011 During the audit, the staff verified the applicants claim that the preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP or will be consistent after implementation of the identified enhancements. The staff also verified the applicants claim that aspects of the scope of program program element not associated with the exception identified in the SLRA are consistent with the corresponding program elements in the GALL-SLR Report AMP.

During the audit, the staff made the following observations:

  • The applicant references licensing topical report BWRVIP-315 as part of the BWR vessel internals AMP. The staffs review of this topical report was ongoing at the time of the audit.
  • The BWRVIP supplemented BWRVIP-315 by letter dated January 20, 2022. The applicant should consider supplementing their application by incorporating the new information contained in the January 2022, letter, in order to ensure that the applicants proposed AMP for vessel internals accounts for the latest available information.
  • The inspection and evaluation guidelines for the lower plenum found in BWRVIP-47-A do not address reinspection guidance. The applicant should consider supplementing their application by describing and justifying reinspection plans for the lower plenum components.
  • BWRVIP-315 lists limitations in Section 4.5.1 of the topical report. The applicant should consider supplementing their application by describing how they will meet the specified limitations.

The staff also audited the description of the SLRA AMP, BWR Vessel Internals, provided in the USAR supplement. The staff found that sufficient information was not available to determine whether the description provided in the USAR supplement was an adequate description of the SLRA AMP, BWR Vessel Internals. Specifically, the staff noted that the USAR supplement did not describe the applicants use of the BWRVIP-315 licensing topical report, as supplemented by the January 2022, BWRVIP letter. The staff will consider issuing an RAI in order to obtain the information necessary to verify the sufficiency of the USAR supplement program description.

SLRA AMP B.2.3.8, Thermal Aging Embrittlement of Cast Austenitic Stainless Steel (CASS)

Summary of Information in the Application. The SLRA states that AMP B.2.3.8, Thermal Aging Embrittlement of Cast Austenitic Stainless Steel (CASS), is a new program that is consistent with the program elements in GALL-SLR Report AMP XI.M12, Thermal Aging Embrittlement of Cast Austenitic Stainless Steel (CASS), as modified by SLR-ISG-2021-02-MECHANICAL, Updated Aging Management Criteria for Mechanical Portions of the Subsequent License Renewal Guidance.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 088 Renewal Aging Management Program Basis Document -

Thermal Aging Embrittlement of Cast Austenitic Stainless Steel (CASS)

During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP.

The staff also audited the description of the SLRA Thermal Aging Embrittlement of CASS provided in the USAR supplement. The staff verified this description is consistent with the description provided in GALL-SLR Report.

SLRA AMP B.2.3.9, Flow-Accelerated Corrosion Summary of Information in the Application. The SLRA states that AMP B.2.3.9, Flow-Accelerated Corrosion, is an existing program that is consistent with the program elements in GALL-SLR Report AMP XI.M17, Flow-Accelerated Corrosion.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Aging Management Program Basis Document - Flow-Accelerated Revision 1 062 Corrosion XCELMO00017-REPT- Aging Effects Operating Experience Report Revision 0 002 FP-PE-FAC-01 Flow-Accelerated Corrosion Program Revision 17 FP-IT-SQA-03 Classifying Software Products Revision 17 EWI-11.01.15 Flow-Accelerated Corrosion Revision 4 EC 26689 Program for Erosive Degradation of Piping Systems Revision 0 CR 602000013670 Revise aging management plan for flow-accelerated corrosion 8/10/2021 CR 601000001494 Replace damaged FAC piping D4-6-EB 8/22/2019 AR01176069 Thin elbow identified during MIC exam on RHRSW 3/31/2009 Document Title Revision / Date AR01426391 Piping change to non-susceptible material 4/11/2014 AR01468275 Audit aging management programs to verify all commitments 3/2/2015 AR01377167 FAC 1R26 damage to piping reducer found during replacement 4/26/2013 WO700054775 Replace damage FAC piping D4-6-EB 10/10/2019 501000051147 FAC detected line VSB-1-GB Turbine Building 4/27/2021 501000025960 Unacceptable FAC on line D4-6-EB 4/19/2019 501000026214 Unacceptable FAC on line D54-6-HB 4/24/2019 EC0000023887 Change MPS-1010 to allow the use of 1-1/4 or 2-1/4 CR material 4/29/2015 AR600000229895 Proactive Operating Experience Search for FAC December 2019 AR606000000952 License Renewal Phase IV Self-Assessment Plan 9/23/2019 NA MNGP-1R29 Outage Summary Report 9/16/2019 NA MNGP 1R28 Outage Summary Report 8/3/2017 NA MNGP 1R27 Outage Summary Report 8/6/2015 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring or trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP.

The staff also audited the description of the SLRA Flow-Accelerated Corrosion (FAC) AMP provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report Table XI-01 for XI.M17, Flow-Accelerated Corrosion.

SLRA AMP B.2.3.10, Bolting Integrity Summary of Information in the Application. The SLRA states that AMP B.2.3.10, Bolting Integrity, is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP XI.M18, Bolting Integrity.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- MNGP Subsequent License Renewal Aging Management Revision 1 073 Program Basis Document - Bolting Integrity XCELMO00017-REPT- MNGP Subsequent License Renewal Aging Management Revision 1 042 Program Basis Document - ASME Section XI Inservice Inspection, Subsections IWB, IWC, and IWD XCELMO00017-REPT- MNGP Subsequent License Renewal Aging Management Revision 1 082 Program Basis Document - Reactor Head Closure Stud Bolting XCELMO00017-REPT- MNGP Subsequent License Renewal Aging Management Revision 1 075 Program Basis Document - 10 CFR Part 50, Appendix J XCELMO00017-REPT- MNGP Subsequent License Renewal Aging Management Revision 1 076 Program Basis Document - ASME Section XI, Subsection IWE Aging EWI-11.01.33 Bolting Integrity Revision 2 FP-E-SE-05 Strategic Engineering Walkdowns Revision 7 MMP-008 Bolting Practices Revision 12 MD-09.01 Torque Determination Guide Revision 3 FP-CY-CCP-01 Chemical Control Program Revision 13 EWI-09.04.00 ASME Section XI Inservice Inspection Program Revision 17 FP-PE-NDE-510 Visual Examination, VT-1 Revision 8 FP-PE-NDE-520 Visual Examination for Leakage, VT-2 Revision 9 FP-WM-LMP-01 Leak Management Process Revision 23 FP-PA-OE-01 Operating Experience Program Revision 29 AR 01476159 EDG Colling HX Documentation Issue 6/26/2015 Document Title Revision / Date AR 01475890 Lack of Full Thread Engagement on Heat Exchanger End Bell 4/30/2015 AR 501000041342 2020 LR NRC Insp: Inadequate CAP Closure 11/09/2020 AR 501000027407 1R29: CRD-46-15 Under-vessel Flange Leak 5/17/2019 AR 501000036476 AMP Plant-Specific OE Review / Bolting 3/22/2020 AR 606000000952 License Renewal Phase IV Self-Assessment Plan 9/26/2019 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP or will be consistent after implementation of the identified enhancements.

The staff also audited the description of the SLRA Bolting Integrity program provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.11, Open-Cycle Cooling Water System Summary of Information in the Application. The SLRA states that AMP B.2.3.11, Open-Cycle Cooling Water System, is an existing program with enhancements that will be consistent with the NUREG-2191,Section XI.M20, Open-Cycle Cooling Water System. At the time of the audit, the applicant had not yet fully developed the documents necessary to implement this enhanced program, and the staffs audit addressed only the program elements described in the applicants basis document.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date Monticello Nuclear Generating Plant Subsequent License XCELMO00017-REPT-064 Renewal Aging Management Program Basis Document -

Revision 1 Open-Cycle Cooling Water System EWI-11.01.12 Open-Cycle Cooling Water System Revision 6 Service Water (SW) / Microbiologically-Influenced FP-PE-SW-01 Revision 15 Corrosion (MIC) Program Document Title Revision / Date EWI-08.22.01 Generic Letter 89-013 Program Revision 14 FP-FP-HX-01 Balance of Plant Heat Exchanger Program Revision 2 EWI-11.01.31 Protective Coating Monitoring and Maintenance Program Revision 4 Health Report Service Water / MIC Program 1/20/2021 Health Report GL 89-13 Program 1/20/2020 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP or will be consistent after implementation of the identified enhancements. The staff also audited the description of the Open-Cycle Cooling Water System AMP provided in the USAR supplement.

The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.12, Closed Treated Water Systems Summary of Information in the Application. The SLRA states that AMP B.2.3.12, Closed Treated Water Systems, is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP XI.M21A, Closed Treated Water Systems, as modified by SLR-ISG-2021-02-MECHANICAL. At the time of the audit, the applicant had not yet fully developed the documents necessary to implement this enhanced program, and the staffs audit addressed only the program elements described in the applicants basis document.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date Monticello Nuclear Generating Plant Subsequent License XELMO00017-REPT-Renewal Aging Management Program Basis Document - Closed Revision 1 063 Treated Water Systems AR01472225 Diesel Coolant System practices to minimize bacterial spread 3/30/2015 4131-PM RBCCW Heat Exchanger Inspection and Cleaning Revision 24 MP 10012385 PM E-5A Clean 11 RBCCW HX 4131PM NA Closed Cooling Water Treatment Guidelines Revision 0 II.18 Document Title Revision / Date II.16 Plant Chemistry Program Revision 1 II.05 Chemistry Limits and Sampling Frequencies Revision 40 I.06.01 Periodic System and Program Reviews Revision 10 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP or will be consistent after implementation of the identified enhancements. The staff also audited the description of the Closed Treated Water Systems AMP provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.13, Inspection of Overhead Heavy Load and Light Load (Related to Refueling) Handling Systems Summary of Information in the Application. The SLRA states that AMP B.2.3.13, Inspection of Overhead Heavy Load and Light Load (Related to Refueling) Handling Systems, is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP XI.M23, Inspection of Overhead Heavy Load and Light Load (Related to Refueling) Handling Systems.

Audit Activities. From March 21 to March 22, 2023, the staff participated in an onsite audit at MNGP in Monticello, MN to gain a general overview of current conditions of the structures compared to the provided OE and an understanding on the settlement issue for the Diesel Fuel Oil Transfer House and Diesel Oil Storage Tank. While onsite, the staff engaged with the applicant staff, conducted walkdowns, and reviewed documents provided by the applicant.

The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- MNGP SLR AMP Basis Document - Inspection of Overhead Revision 1 074 Load and Light Load (Related to Refueling) Handling Systems XCELMO00017-REPT- MNGP SLR TLAA Exemption Evaluation Revision 0 091 XCELMO00017-REPT-005 MNGP SLR TLAA Exemption Identification Revision 1 XCELMO00017-REPT- Screening and AMR Results Plant Structures and Commodities Revision 2 040 Document Title Revision / Date XCELMO00017-REPT-090 MNGP SLR TLAA Technical Specification Impact Report Revision 0 CR No. 601000001170 RX Building Crane Rail Trolley Rail Repair 7/14/2020 QIM 501000017224 - 43 Noise noted from H-2 Troller Rail 5/15/2019 CMAA, Specification, Specification for Electric Overhead Travelling Cranes 1975 No.70 EOCI, Specification No. Specification for Electric Overhead Travelling Cranes 1961 61 ANSI N14.6-1993 Special Lifting Devices for Containers Weighing 10,000 Pounds 1993 or More NUREG-0554 Single-Failure Proof Cranes for Nuclear Power Plants May 1979 NUREG-0612 Control of Heavy Loads at Nuclear Power Plants July 1980 ASME NUM-1 Rules for Construction of Cranes, Monorails, and Hoists (With 2016 ridge or Trolley or Hoist of the Underhung Type)

ASME NOG-1 Rules for Construction of Overhead and Gantry Cranes (Top 2015 Running Bridge, Multiple Girder)

ASME B30.2 Overhead and Gantry Cranes (Top Running Bridge, Single or 2005 Multiple Girder, Top Running Trolley Hoist)

ASME B30.16 Overhead Hoists (Underhung) 2016 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP or will be consistent after implementation of the identified enhancements.

During the onsite audit, the staff performed walkdowns of the Diesel Fuel Oil Transfer House (also called Diesel Oil Pump House), Diesel Oil Storage Tank, Turbine Building, and Reactor Building, etc. The staff made the following observation during walkdowns:

  • During the walkdown of the Reactor Building, the applicant provided information on the identified issue on the railing of Reactor Building Crane and provided the associated documentation on how this issue was resolved.

The staff also audited the description of the SLRA AMP provided in the USAR supplement in Section A.2.2.13., Inspection of Overhead Heavy Load and Light Load (Related to Refueling)

Handling Systems. The staff verified this description is consistent with the description provided in the GALL-SLR.

SLRA AMP B.2.3.14, Compressed Air Monitoring Summary of Information in the Application. The SLRA states that AMP B.2.3.14, Compressed Air Monitoring, is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP XI.M39, Compressed Air Monitoring.

Audit Activities. At the time of the audit, the applicant had not yet fully developed the documents necessary to implement this enhanced program, and the staffs audit addressed only the program elements described in the applicants basis document including the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, corrective actions, and confirmation process. The table below lists the documents that were reviewed by the staff and were found relevant to the Compressed Air Monitoring Program.

These documents were provided by the applicant on their ePortal. The staff will document its review of relevant OE in the SE.

Document Title Revision / Date Report NO. REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 XCELMO00017-071 Renewal Aging Management Program Basis Document Compressed Air Monitoring ANSI/ISA 7.0.01 1996 Quality Standard for Instrument Air 11/12/1996 ASME- American Society of Performance Testing of Instrument Air Systems in Light Water Revision of ASME Mechanical Engineers Reactor Power Plants Division 2, Part 28 OM-2012 CAP - Corrective Action 15 Instrument & Service Dew Point High 7/6/2018 Program ID: 501000013873 CAP - Corrective Action Out of Specifications Air Dryer Dew Point on K-1G 9/12/2018 Program ID: 501000016630 PM 4159 Instrument and Service Air Leak Survey Revision 5 EPRI TR-103595 Report of the Instrument Air Working Group April 1994 PM 4954 Instrument & Service Air System Air Dryers (S-121, S-122, or S- Revision 7 123)

Document Title Revision / Date PM 4953 Instrument & Service Air System Air Compressor (K-1E, K-1F, or Revision 14 K-1G)

Engineering Work Instruction Compressed Air Monitoring Revision 2 EWI - 11.01.19 Work Order: 700041111 15 Instrument & Service Dew Point XMTR Revision 2 /

2/11/2020 NEI 14-12 Aging Management Program Effectiveness Revision 0 During the audit, the staff verified Monticellos claim that the scope of program program element of the SLRA AMP is consistent with the corresponding element of the GALL-SLR Report AMP. During the audit, the staff verified the Monticellos claim that the preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP will be consistent after implementation of the identified enhancements. For the OE review, the applicant made a presentation on the process used to identify and evaluate the pertinent OE.

Afterwards, the staff conducted its review of the applicants methodology and OE by reviewing documentation contained in the SLRA and ePortal. The staff will evaluate any identified plant-specific OE in the SE.

The staff also audited the description of the SLRA AMP Compressed Air Monitoring program provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.15, Fire Protection Summary of Information in the Application. The SLRA states that Aging Management Program (AMP) B.2.3.15, Fire Protection, is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP XI.M26, Fire Protection.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date AR 01473624 Fire penetrations found degraded in control room 4/9/2015 AR 01511810 Leakage identified at halon fitting 2/10/2016 NA Operating Experience Write-up 3/2/2022 AR 01555410 Non-conforming fire penetration 4/11/2017 Document Title Revision / Date WR 00054419 Caulk floor seams 6/17/2016 AR 01486369 Fire penetration seal 7/16/2015 AR 01510919 Adverse trend in halon performance 2/3/2016 AR 01524333 Fire door skin crack 6/7/2016 Issue ID Fire penetration seal inspections 2/26/2020 501000038097 AR 01214390 Wetted fireproof material 1/19/2010 WO 00546903 Install new fire door 4/12/2017 WO 00560780 Repair fire penetrations 1/18/2018 WO 00541467 Replace halon fittings 9/28/2016 CR 606000001098 2019-2020 AMP Effectiveness Reviews 4/24/2020 1

AR 01185125 Damper does not cycle close as designed 0/9/2009 AR 01294835 NEIL Fire Barrier Inspection - Non Conformances 7/15/2011 AR 01220837 Security computer room fire dampers failed to close 3/2/2010 AR 01274556 Fire damper damaged 3/10/2011 NA Fire Protection Program Health Report 1/19/2021 XCELMO00017-REPT- Subsequent License Renewal Aging Management Program Revision 1 065 Basis Document - Fire Protection 1216-01 Fire Door Inspections Revision 63 Engineering Work Fire Protection Program Revision 3 Instruction (EWI)-

11.01.09 Document Title Revision / Date Procedure 1158-B Diesel Fire Pump Weekly Check Revision 31 Procedure 0275-04 1R 4KV Bus Duct Fire Seal Visual Inspection Revision 16 Procedure 0275-05 2R 4KV Bus Duct Fire Seal Visual Inspection Revision 16 Procedure 0261 Fire Pump Exercise and Fuel Quantity Check Revision 59 Procedure 0265 Diesel Fire Pump Engine Inspection Revision 4 FIREPROTECT Fire Protection Program Plan Revision 1 Procedure 4190-PM Diesel Engine, Fire Protection Pump Revision 32 Procedure 0192 Diesel Fuel Quality Check Revision 43 Procedure 0275-01 Fire Barrier Penetration Seal Visual Inspection Revision 28 Procedure 0275-03 Fire Door Inspections Revision 47 Procedure 0328 Cable Spreading Room Halon System Revision 28 Procedure 0266 Fire Pumps Simulated Auto-Actuation and Capability Test Revision 69 Procedure 0275-02 Fire Barrier Wall, Damper and Floor Inspection Revision 48 4 AWI-08.01.00 Fire Protection Program Plan Revision 23 B.08.05-05 Operations Manual Section: Fire Protection Revision 81 Specification Number Quad-5-80-009 Installation of Electrical & Mechanical Revision 10 MPS-0924 Penetration Seals During the audit, the staff verified that for the program elements that the applicant declared were consistent, namely, the scope of the program, preventive actions, and detection of aging effects program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP.

The staff also verified the applicants claim that aspects of the parameters monitored or inspected and corrective actions program elements not associated with the enhancements identified in the SLRA are consistent with the corresponding program elements in the GALL-SLR Report AMP.

In addition, the staff found that for the monitoring and trending and acceptance criteria program elements, sufficient information was not available to determine whether they are consistent with the corresponding program elements of the GALL-SLR Report AMP. The staff will consider issuing RAIs in order to obtain the information necessary to verify whether the program elements are consistent with the corresponding program elements of the GALL-SLR Report AMP.

During the audit, the staff made the following observation:

  • The PURPOSE section of Revision 28 of Procedure 0328, Cable Spreading Room Halon System, states that the halon system headers and nozzles are visually inspected every 18 months, and STEP 1 in the PROCEDURE section specifies all accessible external surfaces, including supporting, restraining, and contact surfaces. The applicant confirmed during the audit that Procedure 0328 requires visual inspection of the accessible external surfaces of the halon system, including the nozzles and headers.

During the audit of the OE program element, the staff reviewed a search of results of the plant-specific database to identify any previously unknown or recurring aging effects. The staff will evaluate the identified plant-specific OE in the SE.

The staff also audited the description of the SLRA Fire Protection program provided in the USAR supplement.

SLRA AMP B.2.3.16, Fire Water System Summary of Information in the Application. The SLRA states that AMP B.2.3.16, Fire Water System, is an existing program with exceptions and enhancements that will be consistent with the program elements in GALL-SLR Report AMP XI.M27, Fire Water System.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 2 066 Renewal Aging Management Program Basis Document - Fire Water System Work Order (WO) Fire protection header pitting 1/19/ 2018 00561419 AR 01228174 Selective leaching of diesel fire pump 4/20/2010 WO 395634 Replace sprinkler and destructively examine for selective 4/6/2010 leaching Document Title Revision / Date WO 00449386 Measure slope of radwaste sprinkler piping 10/12/2012 WO 00464607 Correct the slope of the radwaste sprinkler piping 12/3/2014 WO 00464608 Replace radwaste sprinkler system flush connections 6/30/2022 AR 01226439 Corrosion on removed fire protection valve 4/8/2010 WO 00449385 Measure slope of 13 diesel generator sprinkler piping 8/6/2012 WO 00442710 Sprinkler replacement in Zone 1 7/18/2013 AR 01306899 Portions of intake sprinkler system may not meet NFPA 10/4/2011 requirements AR 01444916 Evaluation of LR-ISG-2012 wall thinning due to erosion 8/29/2014 mechanisms Issue ID Pinhole leak on fire protection piping 8/182017 501000001734 Issue ID Hose station piping with degraded coating 4/14/2019 501000025527 Issue ID Fire system drain line and orifice plugged 8/21/2019 501000031006 AR 01394607 Pinhole leak in fire system piping 8/26/2013 WO 00486248 Pinhole leak in fire system piping 4/29/2016 WO 00497546 Replace fire pipe in intake structure and intake tunnel 6/30/2022 Change Request (CR) Replacement of fire pump basket strainer 10/30/2019 601000001879 Engineering Change Install auxiliary drains for intake fire sprinkler piping 3/9/2014 (date (EC) 0000019072 closed)

AR 01302334 Intake sprinkler piping plugged with clay like debris 9/2/2011 Document Title Revision / Date WO 700038281 Inspection of sprinkler mains 1/4/2019 WO 700028094 Intake fire pipe replacement 2/19/2021 (date closed)

C.6-020-A-29 SCR WASH/FIRE PUMP P-104 TRANS-FIRE SYS Revision 4 C.6-020-A-39 DIESEL FIRE PUMP, P-105 RUNNING/TROUBLE Revision 9 C.6-020-A-36 FIRE PUMP P-110 RUNNING Revision 6 1078-03 Fire Protection 1R Transformer Deluge Test Revision16 1078-01 Fire Protection Main Transformer and TB Siding Deluge Test Revision 16 0268 Fire Protection System Flow Test Revision 24 0272 Fire Hose Station - Hose and Gasket Inspection Revision 33 I.05.31 Operation of the Non-oxidizing Biocide System Revision 17 0324 Fire Protection System - Sprinkler System Tests Revision 53 0319 Fire Protection System - Yard Hydrant Barrel Inspection Revision 25 0267 Fire Protection System Header Flush Revision 20 0269 Fire Protection Valve Check Revision 39 1402-04 Fire Detection Instrumentation - Radwaste (Zone 21) Revision 30 MPS-0795 Technical Specification for Fire System Piping, Fittings, 1/171985 Hydrants, and Valves 0273 Fire Host Station Valve Operability and Flow Blockage Test Revision 27 B.08.05-05 Operations Manual Section: Fire Protection Revision 81 EWI-11.01.08 Fire Water System Program Revision 5 Document Title Revision / Date EWI-11.01.09 Fire Protection Program Revision 3 During the audit, the staff verified that for the program elements that the applicant declared were consistent, the scope of the program and preventive actions program elements of the SLRA AMP were consistent with the corresponding elements of the GALL-SLR Report AMP.

The staff also verified the applicants claim that aspects of the parameters monitored or inspected, monitoring and trending, acceptance criteria, and corrective actions program elements not associated with the exception and enhancements identified in the SLRA are consistent with the corresponding program elements in the GALL-SLR Report AMP.

In addition, the staff found that for the detection of aging effects program element, sufficient information was not available to determine whether it is consistent with the corresponding program element of the GALL-SLR Report AMP. The staff will consider issuing RAIs in order to obtain the information necessary to verify whether the program element is consistent with the corresponding program element of the GALL-SLR Report AMP.

During the audit of the OE program element, the staff reviewed a search of results of the plant-specific database to identify any previously unknown or recurring aging effects. The staff will evaluate the identified plant-specific OE in the SE.

The staff also audited the description of the SLRA Fire Water System program provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report for this program.

SLRA AMP B.2.3.17, Outdoor and Large Atmospheric Metallic Storage Tanks Summary of Information in the Application. The SLRA states that AMP B2.3.17, Outdoor and Large Atmospheric Metallic Storage Tanks, is a new program that will be consistent with the program elements in GALL-SLR Report AMP XI.M29, Outdoor and Large Atmospheric Metallic Storage Tanks. At the time of the audit, the applicant had not yet fully developed the documents necessary to implement this new program, and the staffs audit addressed only the program elements described in the applicants basis document including the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, corrective actions, and confirmation process.

Audit Activities. The table below lists the documents that were reviewed by the staff and were found relevant to the Outdoor and Large Atmospheric Metallic Storage Tanks Program. These documents were provided by Monticello. The staff will document its review of relevant OE in the SE.

Document Title Revision / Date Report NO. XCELMO Monticello Nuclear Generating Plant Subsequent License Revision 1 00017-REPT-070 Renewal Aging Management program Basis Document -

Outdoor and Large Atmospheric Metallic Storage Tanks ANSI/ISA - S7.3 - 1975 Quality Standard for Instrument Air 11/16/1981 Document Title Revision / Date ASME OM 2012 Operation and Maintenance of Nuclear Power Plants 4/8/2013 NEI 14-12 Aging Management Program Effectiveness Revision 0 EPRI TR 108147 Compressor and Instrument Air System Maintenance Guide March 1998 EWI-11.01.19 Compressed Air Monitoring Revision 2 PM-4953 Instrument in Service Air System Air Compressor (K-1E, K- Revision 14 1F, or K-1G)

PM-4159 Instrument and Service Air Leak Survey Revision 5 PM-4954 Instrument and Service Air System Air Dryers (S-121, S-122, Revision 7 or S-123)

CAP ID. 15 Instrument and Service Dew Point Hight, Unit 1 6/29/2018 501000013873 CR NO: 60600001098 2019-2020 AMP Effectiveness Reviews 4/24/2020 AR Number: 01468275 Audit Aging Management Programs Revision 3 EPRI TR-103595 Report of the Instrument Air Working Group April 1994 PM-1362 Air Quality Test for the Instrument Air System Revision 21 During the audit, the staff verified Monticellos claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, corrective actions, and confirmation process program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP. For the OE review, the applicant made a presentation on the process used to identify and evaluate the pertinent OE. Afterwards, the staff conducted its review of the applicants methodology and OE by reviewing documentation contained in the SLRA and ePortal.

The staff also audited the description of the SLRA Outdoor and Large Atmospheric Metallic Storage Tanks Program provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.18, Fuel Oil Chemistry Summary of Information in the Application. The SLRA states that AMP B.2.3.18, Fuel Oil Chemistry, is an existing program with enhancements and exceptions that will be consistent with the program elements in GALL-SLR Report AMP XI.M30, Fuel Oil Chemistry.

The SLRA states that AMP Fuel Oil Chemistry is an existing plant specific AMP. The staff audited the SLRA AMP to determine consistency with SRP-SLR Section A.2.2.18, Aging Management Program Elements.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the Fuel Oil Chemistry Program. The staff will document its review of this information in the SE.

Document Title Revision / Date Report NO. XCELMO Monticello Nuclear Generator Plant Subsequent License Revision 1 00017-REPT-069 Renewal Aging Management Program Basis Document Fuel Oil Chemistry Procedure 11 Emergency Diesel Generator/ 11 ESW Monthly Pump & Revision 41 Valve Tests Procedure Diesel Fuel Quality Revision 43 Procedure Maintenance Emergency Diesel 1 Cycle Revision 41 Procedure Maintenance 11 and 12 Emergency Diesel Generator 12-year Maintenance Revision 45 Procedure Maintenance Diesel Engine, Fire Protection Pump Revision 32 EWI - 11.01.11 Fuel Oil Chemistry Revision 2 Engineering Work Instruction Procedure Visual Examination, VT-3 Revision 10 FP-PE-NDE-530 Procedure MPS-0049 Monticello Fuel Oil Specification Revision 3 Procedure Diesel Fuel Oil Tank Inspections Revision 6 NSP-DOL-0598 Procedure Fuel Oil Receiving Quality Check Revision 20 OSP-DOL-0543 Procedure PM-4190 Diesel Engine, Fire Protection Pump Revision 32 Procedure 12 Emergency Diesel Generator/ 12 ESW Quarterly Pump & Revision 105 Valve Tests PM - 4190 Diesel Engine, Fire Protection Pump Revision 32 Procedure MPS - 049 Monticello Fuel Oil Specification Revision 3 Document Title Revision / Date Picture Internals T-44 3/19/2013 Picture G-3B_wide 3/19/2023 Picture G-3A_wide 3/19/2023 Picture T-100 South 3/19/2023 During the audit, the staff verified the applicants claim that the scope of program and detection of aging effects program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP. During the audit, the staff verified Monticellos claim that the preventive actions, parameters monitored or inspected, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP will be consistent after implementation of the identified enhancements with the corresponding elements of the GALL-SLR Report AMP. During the audit, the staff reviewed exceptions associated with the detection of aging effects program element.

The staff also audited the description of the SLRA AMP provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.19, Reactor Vessel Material Surveillance Summary of Information in the Application. The SLRA states that AMP B.2.3.19, Reactor Vessel Material Surveillance is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP XI.M31, Reactor Vessel Material Surveillance. To verify this claim of consistency, the staff audited the SLRA AMP.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 / 7/15/2022 048 Renewal Aging Management Program Basis Document -

Reactor Vessel Material Surveillance NUREG-1865 Safety Evaluation Report Related to the License Renewal of the October 2006 Monticello Nuclear Generating Plant BWRVIP-321-A Boiling Water Reactor Vessel and Internals Project, Plan for April 2021 Extension of the BWR Integrated Surveillance (ISP) Through the Second License Renewal (SLR)

BWRVIP-321-A, Alternate SSLR Surveillance Capsule Withdrawal Schedule to 12/12/2022 Appendix F BWRVIP-321-A Document Title Revision / Date BWRVIP-86, Revision 1- BWR Vessels and Internals Project, Updated BWR Integrated October 2012 A Surveillance Program (ISP) Implementation Plan BWRVIP-78 BWR Vessel and Internals Project BWR Integrated Surveillance December1999 Program Plan During the audit, the staff verified the applicants claim that the scope of program, preventative actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding program elements of the GALL-SLR Report AMP or will be consistent after implementation of the enhancement.

During the audit, the staff made the following observations:

  • The enhancement in SLRA Section B.2.3.19 was inconsistent with the enhancement provided in SLRA Section A.2.2.19 and Commitment No. 22 in SLRA Table A-3.

Specifically, SLRA Section B.2.3.19 did not indicate the SLRA AMP would be enhanced to implement subsequent NRC approved revisions of BWRVIP-321-A.

The staff also audited the description of the SLRA Reactor Vessel (RV) Material Surveillance program, as supplemented by letter dated June 26, 2023, provided in the USAR supplement.

The staff verified this description is consistent with the description in the GALL-SLR Report.

SLRA AMP B.2.3.20, One-Time Inspection Summary of Information in the Application. The SLRA states that AMP B.2.3.20, One-Time Inspection, is a new program that will be consistent with the program elements in GALL-SLR Report AMP XI.M32, One-Time Inspection. At the time of the audit, the applicant had not yet fully developed the documents necessary to implement this new program, and the staffs audit addressed only the program elements described in the applicants basis document.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date Monticello Nuclear Generating Plant Subsequent License XCELMO00017-REPT-086 Renewal Aging Management Program Basis Document -

Revision 1 One-Time Inspection One-Time Inspection Program - Inspection Program Methods NA 6/8/2010 and Results Report Visual Examination, VT-1 Revision 8 FP-PE-NDE-510 Document Title Revision / Date FP-PE-NDE-425 Ultrasonic Thickness Examination - Localized Corrosion Revision 3 AR 01207023 License Renewal Snapshot Assessment 11/16/2009 AR 01175545 Inadequate One-Time Inspection Results Documentation 3/29/2009 AR 01175477 License Renewal Inspections Requirements Not Followed 3/28/2009 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP. The staff also audited the description of the One-Time Inspection program AMP provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.21, Selective Leaching Summary of Information in the Application. The SLRA states that AMP B.2.3.21, Selective Leaching, is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP XI.M33, Selective Leaching.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 087 Renewal Aging Management Program Basis Document -

Selective Leaching EWI-08.26.02 Selective Leaching Inspection Process Revision 2 EWI-11.01.35 Selective Leaching of Material Revision 0 PEI-03.01.03 Selective Leaching Inspection Revision 2 AR 01228174 FP-13, License Renewal, Evidence of Selective Leaching 4/20/2010 AR 01249063 Selective Leaching Identified on FP-7-2 Valve 9/9/2010 CAP 501000043959 SL [Selective Leaching] Identified on Removed BS [Basket 9/9/2020 Strainer] - 1967 Document Title Revision / Date WO 00414130 Replace FP-43, FP-44 and FP-45 6/9/2013 During the audit, the staff verified the applicants claim that the parameters monitored or inspected, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP, or will be consistent after implementation of the identified enhancements. In addition, the staff found that for the scope of program, preventive actions, and detection of aging effects program elements, sufficient information was not available to determine whether they were consistent with the corresponding program elements of the GALL-SLR Report AMP. The staff will consider issuing RAIs in order to obtain the information necessary to verify whether these program elements are consistent with the corresponding program elements of the GALL-SLR Report AMP.

The staff also audited the description of the SLRA Selective Leaching program provided in the USAR supplement. The staff found that sufficient information was not available to determine whether the description provided in the USAR supplement was an adequate description of the SLRA Selective Leaching program. The staff will consider issuing RAIs in order to obtain the information necessary to verify the sufficiency of the USAR supplement program description.

SLRA AMP B.2.3.22, ASME Code Class 1 Small-Bore Piping Summary of Information in the Application. The SLRA states that AMP B.2.3.22, ASME Code Class 1 Small-Bore Piping, is a new condition monitoring program that will be consistent with the program elements in GALL-SLR Report AMP XI.M35, ASME Code Class 1 Small-Bore Piping.

Audit Activities. In addition to the OE documentation contained in the SLRA and ePortal, the staff observed the applicants search of its OE database using the keywords: fatigue, low cycle fatigue, high cycle, fatigue cracking, thermal fatigue, stress corrosion, SCC, socket weld, and small bore, small-bore, dissimilar metal, RCS leak, low cycle, thermal fatigue, socket weld, weldolet, branch connection, through wall thru wall, weld crack, high cycle, 82 weld, alloy weld, and drain line.

The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017- Monticello Nuclear Generating Plant Subsequent License Revision 1 REPT-050 Renewal Aging Management Program Basis Document - 7/9/2022 ASME Code Class 1 Small-Bore Piping XCELMO00017- Monticello Nuclear Generating Plant Subsequent License Revision 1 REPT-008 Renewal Aging Management Review Results - Reactor Coolant Pressure Boundary and Connected Piping Document Title Revision / Date MPS-1107 Technical Specification for Small-Bore Piping and Tubing Revision 2 Design 5/31/2013 NRC IN 2014-02 Failure to Properly Pressure Test Reactor Vessel Flange 2/25/2014 Leak-off Lines NRC IN 2015-04 Fatigue in Branch Connection Welds 4/24/2015 CAP501000032327 Effectiveness reviews have not been completed for Revision 0 AMPs contrary to guidance in 4 AWI-08.11.04 and NEI-1412 L-MT-21-038 2021 Refueling Outage 90-Day Inservice Inspection (ISI) Revision 0 Summary Report CAP501001556336 RFO28 ISI indications Revision 0 CAP01220928 Perform a Condition Evaluation on the License Renewal 8/7/2010 Age Management of Small-Bore Piping Issue CAP01228441 Annual Update Letter for License Renewal (L-MT-6-18) 8/8/2010 related to Small-Bore Piping Population Contained an Error During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP.

The staff also audited the description of the SLRA AMP provided in the USAR supplement. The staff verified that this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.23, External Surfaces Monitoring of Mechanical Components Summary of Information in the Application. The SLRA states that AMP B.2.3.23, External Surfaces Monitoring of Mechanical Components, is an existing program with enhancements that will be consistent with the program elements in the GALL-SLR Report AMP XI.M36, External Surfaces Monitoring of Mechanical Components. At the time of the audit, the applicant had not yet fully developed the documents necessary to implement this enhanced program, and the staffs audit addressed only the program elements described in the applicants basis document.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date External Surfaces Monitoring of Mechanical Components XCELMO00017-REPT-083 Revision 1 Aging Management Program Basis Document Aging Management Snapshot Self-Assessment in AR01533999 9/7/2016 preparation for 2016 PI&R Inspection 606000000952 License Renewal Phase IV Self-Assessment Plan 9/26/2019 01468275 2015 Select AMP Effectiveness Reviews 4/21/2020 EWI-11.01.13 System Condition Monitoring Program Revision 4 NX-41825 V-AC-8A Cooling Coil Drawing Revision 76 NX-41826 V-AC-8B Cooling Coil Drawing Revision A EPRI Long-Term Operations: Subsequent License EPRI 3002011822 Renewal Non-Class 1 Mechanical Implementation April 2018 Guideline and Mechanical Tools NX-8763-23-1 RHR/Core Spray Pump Room Cooling Coil Drawing Revision 77 NX-20020-7 Air Condition Unit Model C-343 Drawing Revision 79 NX-9216-9 645E4 Turbocharged Engine Maintenance Manual Revision 18 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP or will be consistent after implementation of the identified enhancements. The staff also audited the description of the External Surfaces Monitoring of Mechanical Components AMP provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.24, Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components Summary of Information in the Application. The SLRA states that AMP B.2.3.24, Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components, is a new program that will be consistent with the program elements in GALL-SLR Report AMP XI.M38, Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components. At the time of the audit, the applicant had not yet fully developed the documents necessary to implement this new program, and the staffs audit addressed only the program elements described in the applicants basis document.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELM000017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 085 Renewal Aging Management Program Basis Document -

Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components 501000013937 SW-101 Found w/ Corrosion and Degradation 7/3/2018 501000012864 Localized Thinning RHR HX E-200A 6/5/2018 AR 01353629 Slight Corrosion on E-23 Heat Exchanger 11/1/2012 AR 01396233 Rx/Rad Waste Chilled Water Piping Severely Degraded 9/10/2013 AR 01341754 P-127 (SW Rad Monitor Pump) Discharge Pipe Mostly Plugged 6/14/2012 AR 01371305 RHRSW Piping near Tmin found during SW-MIC Examinations 2/21/2013 AR 01452029 V-E-AC-14B Condenser Degradation 10/20/2014 AR 01519672 11 RBCCW HTX Sound End-Bell Corrosion 4/21/2016 AR 01553131 SW-MIC Pitting Detected in Line ESW1-3-HBD - EFT Building 3/15/2017 AR 01346049 Pinhole in Piping Upstream of SW-174-2 7/26/2012 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP. The staff also audited the description of the SLRA Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components program provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.25, Lubricating Oil Analysis Summary of Information in the Application. The SLRA states that AMP B.2.3.25, Lubricating Oil Analysis, is an existing program with enhancement and exceptions that will be consistent with the program elements in GALL-SLR Report AMP XI.M39, Lubricating Oil Analysis.

Audit Activities. The table below lists the documents that were reviewed by the staff and were found relevant to the Lubricating Oil Analysis. The staff will document its review of relevant OE in the SE.

Document Title Revision / Date XCELMO00017-REPT-068 Monticello Nuclear Generating Plant Subsequent License Revision 1 Renewal Aging Management Program Basis Document Lubricating Oil Analysis PCR 01530575 Lube Oil Filter Press and Transfer Pump Operation Revision 2 PCR 01539318 Plant Equipment Oil Addition Revision 10 PCR 01530575 Lube Oil Filter and Transfer Pump Operation Revision 2 PCR 01329237 Lubricating and Oil Replacement Revision 6 Procedure Rotork Motor Operated Valves - Inspection and Maintenance Revision 28 NSPM-1 Quality Assurance Topical Report Revision 15 5/28/2021 FP-PE-RPL-01 License Renewal Implementation Revision 9 Work Order: 700053414 11 Condensate Pump Motor 10/10/2019 At- 0175 Action Request Indication of Water in P-208B Oil 1/2/2013 Record Report CAP: 501000025490 Increase in Lube Oil Properties 4/16/2019 CAP: 501000006129 Small Ferreous Material in 13RHR ML Oil 12/13/2017 CAP: 501000010078 Small Amount Ferreous Material in P-202D 4/2/2018 During the audit, the staff verified Monticellos claim that the scope of program program element of the SLRA AMP is consistent with the corresponding elements of the GALL-SLR Report AMP. During the audit, the staff verified Monticellos claim that the preventive actions, parameters monitored or inspected, monitoring and trending acceptance criteria, and corrective actions program element of the SLRA AMP will be consistent after implementation of the identified enhancements with the corresponding elements of the GALL-SLR Report AMP.

During the audit, the staff identified the exception associated with the detection of aging effects program element.

The staff also audited the description of the SLRA AMP Lubricating Oil Analysis program provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.26, Monitoring of Neutron-Absorbing Materials Other Than Boraflex Summary of Information in the Application. The SLRA states that AMP B.2.3.26, Monitoring of Neutron-Absorbing Materials Other Than Boraflex, is an existing program that is consistent with the program elements in GALL-SLR Report AMP XI.M40, Monitoring of Neutron-Absorbing Materials Other Than Boraflex.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date 01234500-20101022- AT-0175 Action Request Record Report Revision 2 000.pdf Boral Coupon Testing Boral Coupon Testing Evaluation 6/28/2016 Eval_0000026539-20160627-000.pdf 606000001098- Change Request Close Out Report 4/24/2020 20200423-000.pdf EWI-11.01.34.pdf Spent Fuel Pool Boral Monitoring Program Revision 3 High Density Fuel HDFSS Boral Sample Evaluation Revision 6 Storage System [HDFSS]

Boral Sample Eval_1178.pdf During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring or trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP.

The staff also audited the description of the SLRA Monitoring of Neutron-Absorbing Materials Other Than Boraflex AMP provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report Table XI-01 for XI.M40, Monitoring of Neutron-Absorbing Materials Other Than Boraflex.

SLRA AMP B.2.3.27, Buried and Underground Piping and Tanks Summary of Information in the Application. The SLRA states that AMP B.2.3.27, Buried and Underground Piping and Tanks program, is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP XI.M41, Buried and Underground Piping and Tanks.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017- Monticello Nuclear Generating Plant Subsequent License Renewal Revision 2 REPT-072 Aging Management Program Basis Document - Buried and Underground Piping and Tanks EWI-11.01.14 Buried Piping and Tanks Inspection Revision 2 FP-PE-UPT-01 Underground Piping and Tanks Integrity Program Revision 4 MPS-0984 Technical Specification for Excavation and Backfill Revision 1 5828/6453-M-108 Specification for Coating and Wrapping Pipe Revision 0 NX-8431-5 50,000 Gal. U.G. Oil Tank (T44) Revision 5 B.08.14-05 Operations Manual Section: Cathodic Protection System Revision 4 ESP-0597 Cathodic Protection Rectifier Test Revision 9 2100198.401 MNGP InTellusASTM 2021 Annual Survey Report Revision 0 1200191.403.R0 Soil Analysis Results for Monticello Nuclear Plant 2/10/2014 1404-01 EDG ESW Heat Exchanger Performance Testing Revision 21 0268 Fire Protection System Flow Test Revision 24 NSP-DOL-0598 Diesel Fuel Oil Tanks Inspections Revision 6 1350 Underground Storage Tank Liquid Level Correlation Revision 12 UPTI-PLAN Underground Pipe and Tank Inspection Plan Revision 7 AR 01240741 Underground Piping Discovered Not Coated 2/15/2011 AR 01383079 UPTI 1R26 CST Dig Coating Failure and Heat Trace Degraded 7/30/2013 AR 01484133 Potential Groundwater Adverse Trend; Chlorides 12/29/2015 AR 01475213 Flanged Joints on Buried EDG Oil Line Not Wrapped 5/22/2015 Document Title Revision / Date SL-008367 Nuclear Management Company Monticello Nuclear Generating Plant Revision 0 Cathodic Protection System Evaluation Report WO 0202752 Clean and Inspect Diesel Fuel Oil Storage Tank 1/9/2004 10040-M-656 Technical Specification for Fire Protection Sprinkler and Standpipe Revision 0 Systems During the audit, the staff verified the applicants claim that the parameters monitored or inspected and monitoring and trending program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP or will be consistent after implementation of the identified enhancements. In addition, the staff found that for the scope of program, preventive actions, detection of aging effects, acceptance criteria, and corrective actions program elements, sufficient information was not available to determine whether they were consistent with the corresponding program elements of the GALL-SLR Report AMP. The staff will consider issuing RAIs in order to obtain the information necessary to verify whether these program elements are consistent with the corresponding program elements of the GALL-SLR Report AMP.

The staff also audited the description of the SLRA Buried and Underground Piping and Tanks program provided in the USAR supplement. The staff found that sufficient information was not available to determine whether the description provided in the USAR supplement was an adequate description of the SLRA Buried and Underground Piping and Tanks program. The staff will consider issuing RAIs in order to obtain the information necessary to verify the sufficiency of the USAR supplement program description.

SLRA AMP B.2.3.28, Internal Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, and Tanks Summary of Information in the Application. The SLRA states that AMP B.2.3.28, Internal Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, and Tanks, will be a new program that will be consistent with the program elements in GALL-SLR Report AMP XI.M42, Internal Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, and Tanks, as modified by SLR-ISG-2021-02-MECHANICAL, Updated Aging Management Criteria for Mechanical Portions of Subsequent License Renewal Guidance.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 084 Renewal Aging Management Program Basis Document -- Internal Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, And Tanks Document Title Revision / Date EWI-11.01.31 Protective Coating Monitoring and Maintenance Program Revision 4 4 AWI-08.11.03 Nuclear Coatings Program Revision 16 FP-PE-HX-01 Balance of Plant Heat Exchanger Program Revision 2 FP-PE-SW-01 SW/MIC Program Revision 15 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP.

The staff also audited the description of the SLRA Internal Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, and Tanks program provided in the USAR supplement.

The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.29, ASME Section XI, Subsection IWE Summary of Information in the Application. The SLRA states that AMP B.2.3.29, ASME Section XI, Subsection IWE, is an existing program with enhancements and exceptions that will be consistent with the program elements in GALL-SLR Report AMP XI.S1,ASME Section XI, Subsection IWE.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE as necessary.

Document Title Revision / Date XCELMO00017-REPT- MNGP Subsequent License Renewal Aging Management Revision 1 076 Program Basis Document - ASME Section XI, Subsection IWE XCELMO00017-REPT- MNGP Subsequent License Renewal - Aging Effects Operating Revision 0 002 Experience Report; Attachment 4 - Aging Effect OE for Structures, Structural Components and Commodities, and Section 3.3.2 Structures, Structural Components, and Commodities NX-8291-76 Monticello Project, General Plan Pressure Suppression Revision C Containment Vessel Drawing, Chicago Bridge and Iron Company IWE PLAN (3rd Interval) Containment Inservice Inspection Plan (IWE Plan) - Third Interval Revision 0 /

September 9, 2019 Through September 8, 2029 9/05/2019 Document Title Revision / Date IWE PLAN (2nd Interval) Containment Inservice Inspection Plan (IWE Plan) - 2nd Interval Revision 3 September 9, 2009 Through September 8, 2019 9001 Reactor Well & Dryer-Separator Storage Pool Filling Procedure Revision 33 9210 Master RPV Disassembly Procedure Revision 29 FP-PA-OE-01 Operating Experience Program, Nuclear Department Fleet Revision 29 Procedure (NDFP)

MMP-008 Bolting Practices Procedure (torquing of bolts) Revision 12 MDI-09.01 Torque Determination Guide, Maintenance Department Revision 3 Instructions IILCP Inservice Inspection Licensee Control Program, Administrative Revision 0 Work Instruction FP-PE-RLP-01 License Renewal Implementation, Nuclear Department Fleet Revision 9 Procedure EWI-09.04.00 ASME Section XI Inservice Inspection Program, Engineering Revision 17 Work Instruction EWI-11.01.30 Primary Containment Inservice Inspection, Engineering Work Revision 1 Instruction 4AWI-07.03.01 Non-Destructive Examination, NDFP Revision 12 FP-PE-NDE-540 IWE Visual Examination, NDFP Revision 4 0515 Primary Containment Visual Examination for Structural Problems, Revision 17 Surveillance Requirement 602000020655 Procedure Change Request (PCR) - 0515 Rev 16 TR Complete 5/12/2021 (Primary Containment Visual Examination F) Revised to add inspection guidance/requirements for insulated components Issue ID 501000050476 ISI - OE Review Prompts CAP-QIM (OE from Quad Cities re 4/14/2021 Insulation Removal for General Visual Examination) 4AWI-09.04.03 ASME Section XI Repair/Replacement Program Revision 25 Document Title Revision / Date CA-03-122 Determination of Torus Pitting Acceptance Criteria, Calculation Revision 0 NA OE Raw Data Printouts 2/21/2023 NA Inservice Inspection (ISI) Program Health Reports 7/25/2022 &

7/20/2020 WO 700058583 0515 PCT Visual Exam for Structural Problems 12/15/2021 WO 700002171 RFO 29 Follow-up IWE Examinations in Torus 4/6/2020 AR 01280133 ISI Indication: Torus Hatch Stud with Minor thread damage 4/11/2011 AR 0278904 ISI Indications - IWE Exams of Torus Downcomers by Divers 4/4/2011 (VT-1 followup)

AR 501000052285 Primary Containment (PCT) Degraded Coating: 1R30 inspection 5/19/2021 AR 01558080 Numerous Small Areas of Primary Containment Coatings Failed 5/5/2017 Acceptance Criteria AR 01477384 Numerous small areas of PCT coatings failed acceptance criteria 5/13/2015 AR 01378342 IWE Inspection Results (Degraded coating on underwater torus) 4/10/2013 AR 01082766 Numerous small areas of PCT coatings failed acceptance criteria 3/18/2007 AR 01378157 RFO-26 ISI: Small Random Weld Bead on Torus Shell Interior 4/9/2013 AR 01084149 IWE Indications, Arc Strikes, Torus Interior 5/29/2007 AR 01014492 Station OE Screening Team Review of External OE 7/27/2007 01176895 0140/0135 Drywell/Torus Surface Inspection Results 91/2009 Issue ID 501000026270 Three Arc Strikes and One Pit in Torus (including photos) 4/24/2019 AR 01278920 Numerous small areas of PCT coatings failed procedure 4/4/2011 acceptance criteria (areas found with bare metal, rust bleed Document Title Revision / Date through, minor rusting, and loose/peeling coatings; similar conditions found in previous outages evaluated in CAP)

WO 700004439 RFO28 Repair Underwater Coating During - PCT Suppression 1/23/2020 Chamber (Torus)

WO 700014153 0515 PCT Visual Exam for Structural Problem (incl photos) 4/6/2020 WO 700020823 0140 Drywell Interior Surface Inspection (inc photos) 10/30/2019 WO 00444115 CDVR - Torus, IWE Examination Inside Torus Below Waterline 2/13/2018 (incl photos)

AR 01177886 Items Noted during 1132, Torus Internal Structural Inspection 4/13/2009 AR 01298156 OE-NRC IN 2011-15, Steel Containment Degradation and 8/5/2011 Associated LR Aging Management Issues AR 01429697 OE: NRC IN 2014-07 5/7/2014 AR 01521881 OE: NRC RIS 2016-07 5/13/2016 AR 500001307948 Torus Shell Wall Thickness/Pitting Corrosion 3/16/2017 Photographs Drywell Airlock, Drywell Basement, Torus Interior Downcomer 5/17/2023 AR 500001557365 Torus Penetration X-205 Degraded Paint 6/21/2017 500001278780 Small corroded spots/potential loose coating on torus bottom 4/2/2011 500001307948 Torus Shell Wall Thickness / Pitting Corrosion (UT done and 12/6/2011 found within accept criteria)

EC 22180 Evaluation of RFO 26 coatings/IWE Inspection Results, 6/3/2013 Engineering Change LR-ISG-2006-01 Final Plant-Specific Aging Management Program for Inaccessible 11/16/2006 (ML063210029) Areas of BWR Mark I Steel Containment Drywell Shell, License Renewal Interim Staff Guidance NA Discussion of Monticellos 3-drain paths for removing leakage that May 1987 may result from refueling or spills of water into the drywell air gap

- part of MNGP response to NRC Generic Letter 87-05 Document Title Revision / Date 2100507.308 Fatigue Exemption of Monticello Drywell, Structural Integrity Revision 0 /

Associates Calculation 9/23/2022 041 MNGP Breakout Responses to Breakout Questions - TRP 41 Posted 05/11/2023 Questions AMP AMR ASME XI - IWE Thomas_5-10.pdf During the audit, the staff verified the applicants claim that the scope of program, preventive actions, monitoring and trending, and acceptance criteria program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP or will be consistent after implementation of the identified enhancements.

The staff also verified the applicants claim that aspects of the parameters monitored or inspected and detection of aging effects program element not associated with the exceptions identified in the SLRA or by the staff during the audit are or will be consistent with the corresponding program element in the GALL-SLR Report AMP. In addition, the staff found that for the parameters monitored or inspected, detection of aging effects, and corrective actions program elements, sufficient information was not available to determine whether they were consistent with the corresponding program elements of the GALL-SLR Report AMP. The staff will consider issuing RAIs or use a voluntary SLRA supplement to obtain the information necessary to verify whether these program elements are consistent with the corresponding program elements of the GALL-SLR Report AMP.

During the audit, the staff made the following observations:

  • The staff reviewed procedure MMP-008, Revision 12, and noted that General Note 7 on page 3 of 13 states: Use only thread lubricant that is approved for use by the Chemical Control Program. Other thread lubricants may be used as specified by procedures or work plans. Thread lubricant containing Molybdenum Disulfide (MoS2) SHALL NOT be used on systems/materials susceptible to Stress Corrosion Cracking.
  • The staff reviewed the program basis document(PBD) XCELMO00017-REPT-076 (Revision 1) Section 4.3 and Procedures 9001 (Revision 33) and 9210 (Revision 29),

and noted that to provide reasonable assurance that moisture levels associated with an accelerated corrosion rate do not exist in the exterior portion of the MNGP steel containment drywell shell, the drywell air gap drains and sand pocket drain line outlets are monitored for blockage and leakage during each refueling outage when the refueling cavity is flooded.

  • The staff reviewed Section 4.4 of PBD and noted that drywell shell measurements taken in 1986 and 1987 detected no thinning of the exterior shell. A review of plant-specific OE since the date of issuance of the first renewed license has not identified any occurrence or recurrences of measure-able metal shell corrosion (base metal material loss exceeding 10 percent of nominal plate thickness) initiated on the inaccessible side or areas of the containment vessel.
  • The staff reviewed procedure 0515 (Revision 17) and noted that the applicant added as Step 25 an related NOTE in Part E, via PCR 602000020655 (5/21/2021),

criteria/requirements for inspection of the condition of insulated components/surface areas when the containment surface is not accessible and evaluation of suspect conditions that may be indicative of degradation of the underlying containment surfaces.

  • The staff reviewed SLRA Section B.2.3.29 and noted that the plant-specific OE section stated that the program performance was exceptional. However, the staff noted that this appeared to be inconsistent with the assessment in 2020 and 2022 program health reports, which the applicant should reconcile in an SLRA supplement.
  • The staff reviewed SLRA Sections B.2.3.29 (under subsection titled Exceptions to NUREG-2191) and 3.5.2.2.1.5, and PBD XCELMO00017-REPT-076 (Revision 1)

Section 4.3 and noted that an assessment was performed which concluded that the drywell shell, non-high temperature drywell penetrations, and penetration sleeves are subjected to a small amount of fatigue such that neither fatigue analysis nor a fatigue waiver is required. As such, cracking due to cyclic loading does not require aging management for drywell shell, non-high temperature drywell penetrations, and penetration sleeves. Based on review of documents on the ERR, the staff noted that the stated assessment appears to be the Structural Integrity Associates (SIA) calculation 2100507.308, Revision 0 (9/29/2022), Fatigue Exemption of the Monticello Drywell, and noted it performed a fatigue waiver analysis of select drywell components (without current licensing basis (CLB) fatigue analysis), including non-high temperature mechanical and electrical penetrations, in accordance with NE-2222.4(d) Vessel Not Requiring Analysis for Cyclic Operation of the ASME Code, 1974 edition and demonstrated that the fatigue waiver criteria therein were met. This could justify that cracking due to cyclic loading does not require aging management for these components consistent with the acceptance criteria in Section 3.5.2.2.1.5 of SLRA-ISG-2021 STRUCTURES, February 2021. However, the SLRA does not appear to provide information on what analysis was performed as part of the assessment, the inputs used, and a summary of the results, including how the acceptance criteria were met to justify the exceptions and that the aging of cracking due to cyclic loading does not require management for the credited components with no CLB fatigue analysis. The applicant should supplement the SLRA to address the above and provide related clarity.

  • The staff reviewed SLRA Section B.2.3.29 and SLRA Table A-3 (item 32) and noted that the enhancement (corresponds to SLR Commitment 32(c)) to the detection of aging effects program element regarding supplemental surface or enhanced visual examinations to detect cracking of high temperature piping penetrations does not specify the temperature threshold that defines high-temperature piping penetrations. The applicant should supplement the SLRA to revise the enhancement to specify the temperature threshold.
  • The staff reviewed SLRA Section B.2.3.29 and SLRA Table A-3 (item 32) and noted the SLRA includes enhancements to detection of aging effects program elements, corresponding to SLR Commitments 32(c) and 32(d), related to supplemental periodic and supplemental one-time examinations to detect cracking due to cyclic loading and SCC, respectively. However, the staff noted a lack of clarity if there are components that are subject to both these commitments, and the basis of that determination, which the applicant should clarify in an SLRA supplement.
  • The staff reviewed SLRA Section B.2.3.29 and SLRA Table A-3 (item 32) and noted the SLRA enhancement (corresponding to SLR Commitment 32(e)) regarding plant-specific OE trigger-based one-time volumetric examination of containment shell metal surfaces inaccessible from one side. The SLRA enhancement states that the triggering OE would be specific to that identified through code inspections, which appeared to be inconsistent with the corresponding GALL-SLR AMP XI.S1 recommendation which is neutral to how (method, program, or process) the triggering OE is identified. The staff also noted that the SLR Commitment 32(e) does not appear to provide a schedule for implementing the one-time volumetric examination with respect to the date of occurrence of the triggering OE. The applicant should supplement the SLRA to address these concerns.
  • The staff reviewed SLRA Section B.2.3.29 and SLRA Table A-3 (item 32) and noted the SLRA includes an enhancement to the corrective actions program element (corresponds to SLR Commitment 32(f)) regarding corrective actions if SCC is identified.

This enhancement states, in part: This will include one additional penetration with DMWs associated with greater than 140oF stainless steel piping systems until cracking is no longer detected. There appears to be lack of clarity and context regarding how sample expansion (additional inspection) will be conducted if SCC is detected or absence of SCC cannot be confirmed as a result of the initial sample of supplemental one-time inspections. The staff also noted the SLRA Section A.2.2.29 USAR supplement does not appear to include a description of the proposed one-time inspection to confirm the absence of SCC. The applicant should supplement the SLRA to address these issues.

  • The staff reviewed SLRA Tables 3.5-1 and 3.5.2-1, and SLRA Sections 3.5.2.2.1.3.1, and noted inconsistencies in the referenced SLRA Sections with regard to the non-applicability claim of AMR items 3.5.1-004 and 3.5.1-035 for accessible, inaccessible, and embedded areas of drywell shell given that the component material and environment for the aging effect exists for the MNGP drywell (i.e., to be consistent with corresponding AMR items in SLRA Table 3.5.2-1). The applicant should supplement the SLRA to correct, clarify, and reconcile these AMR inconsistencies.
  • The staff reviewed SLRA Tables 3.5-1 and 3.5.2-1 and SLRA Section 3.5.2.2.1.6 and noted inconsistency between SLRA Section 3.5.2.2.1.6 and Table 3.5-1 regarding the non-applicability of item 3.5.1-038. The staff also noted that SLRA Section 3.5.2.2.1.6 does not appear to address plant-specific OE of stress corrosion cracking (SCC) for the applicable components. The applicant should supplement the SLRA to correct or clarify the inconsistency and address whether there has been plant-specific OE of SCC.

The staff will consider issuing RAIs and/or use a voluntary SLRA supplement offered by the applicant to obtain the necessary information to address the above noted issues identified during the audit. The staff will document its review of these issues in the SE.

The staff also audited the description of the SLRA AMP ASME Section XI, Subsection IWE, provided in the USAR supplement. The staff found that sufficient information was not available to determine whether the description provided in the USAR supplement was an adequate description of the SLRA AMP ASME Section XI, Subsection IWE. The staff will consider issuing an RAI or use a voluntary SLRA supplement to obtain the information necessary to verify the sufficiency of the USAR supplement program description.

SLRA AMP B.2.3.30, ASME Section XI, Subsection IWF Summary of Information in the Application. The SLRA states that AMP B.2.3.30, ASME Section XI, Subsection IWF, is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP XI.S3, ASME Section XI, Subsection IWF.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- MNGP Subsequent License Renewal - Aging Effects Operating Revision 0 002 Experience Report; Attachment 4 - Aging Effect OE for Structures, Structural Components and Commodities XCELMO00017-REPT- MNGP Subsequent License Renewal Aging Management Revision 1 077 Program Basis Document - ASME Section XI, Subsection IWF NA OE Raw Data Printouts 2/21/2023 ISI-PLAN-5-BASIS MNGP Inservice Inspection (ISI) Classification Basis Document - Revision 0 Fifth Ten-Year Inspection Interval (Class 1, 2 and 3 Components and their supports) 5th INTERVAL-ISI PLAN MNGP Inservice Inspection (ISI) Plan - Fifth Ten-Year Inspection Revision 2 Interval (September 1, 2012 through May 31, 2023*) *Interval end date extended per IWA-2430(c):

4 AWI-07.03.01 Nondestructive Examination, Administrative Work Instruction Revision 12 IILP Inservice Inspection Licensee Control Program Revision 0 FP-PE-RLP-01 License Renewal Implementation Procedure Revision 9 MMP-008 Bolting Practices Procedure Revision 12 MDI-09.01 Torque Determination Guide (Maintenance Department Revision 3 Instructions)

EWI-11.01.28 ASME Section XI, Subsection IWF (Identify and describe the IWF Revision 1 AMP)

MS-SA-325-2 Material Specification, Cherne Contracting Corporation Revision 0 (prescribes requirements for HS structural bolting materials [SA-325], 1.5 inch diameter and smaller, Type 1 or 2 only)

Document Title Revision / Date FP-PA-OE-1 Operating Experience Program (Fleet) Revision 29 4903 Snubber Changeout Procedure Revision 28 FP-CY-CCP-01 Chemical Control Program Revision 13 FP-PA-ARP-01 CAP Process (Fleet Procedure) Revision 60 EWI-09.04.00 ASME Section XI Inservice Inspection Program (5th interval Revision 17 2007/2008a program requirements for ISI of ASME 1, 2, 3 & MC components and 1, 2, 3 component supports)

FP-PE-NDE-530 Visual Examination, VT-3 (Fleet Procedure) Revision 10 4 AWI-09.04.03 ASME Section XI Repair/Replacement Program, MNGP Revision 25 PEI-01.02.05 5th Interval ISI Detailed [Implementation] Schedule, MNGP Revision 0 AR 01555956 RFO28 NDE Observed Debris in Seismic Restraint 4/22/2017 WR 00132531 Remove Debris from Seismic Restraint Between Paddle and 5/10/2017 Clamp Issue ID 501000026821 RFO29 ISI Hanger Discrepancies (PSH-116, loose nut - 6/14/2019 corrected)

NA MNGP Aging Management Program Effectiveness Self- NA Assessment - ASME Section XI, Subsection IWF - EWI-11.01.28 Issue ID 501000026320 RF029 ISI VT Hanger Indication (PSH-116 loose nut found - 6/14/2019 corrected)

WO 700054851 PSH-116 QIM_501000026320_RF029 ISI VT Hanger Indication 6/22/2020 AR 01302876 OE - Evaluation of Industry OE for week of 09/05/2011 9/12/2011 AR 01172899 Station OE Evaluation of NRC IN 2009-04 6/10/2009 CR 606000001098 2019-2020 AMP Effectiveness Reviews (Snapshot 4/24/2020 Assessment/Evaluation)

Document Title Revision / Date NSPM-1 Quality Assurance Topical Report (QATR) Revision 15 500001281071 ISI Hanger Issues - Hanger H-2 (FPWH-111) on FPW12-8-GE 3/15/2017 (Wear) 500001276604 ISI Indication moderate rust on pipe restraint (RHR service water 3/15/2017 restraint SF-79) Eval to IWF-3410 500001249145 Support Bracket for B RHR Pipe Loose from Wall Mount 3/17/2017 500001545855 Visual Observation of HPCI System Hanger SR-708 show 3/16/2017 accumulation of fine debris on surfaces below steam pipe hanger 500001345334 Snubber Examinations Not Performed Per Code Requirements 7/18/2012 (IWF-5000) 501000032584 During removal of SW-1-1 (P-102A SW Pump Discharge Check 10/02/2019 Valve) the elbow support pad was found degraded and 2 pad guides were rusted badly and came apart from the pad.

AR 01558248 PSH-116 Hanger Rod Has Slight Bend (evaluated as acceptable) 5/11/2017 AR 01558183 RFO28 ISI Indication - Loose Nut on Hanger (tightened) 5/11/2017 EC 0000022145 Evaluation of Hanger TWH-48 Condition Identified during 2013 Revision 000 RFO Issue ID 501000025520 RFO29 ISI Hanger Exam Drawing Discrepancy (TWH-171, 6/17/2019 missing lock nuts)

WO 00522228 CNST - PSH-116, Replace Bolt on Clamp 2/28/2018 AR 01512092 2016 MT Proactive OE Searches 1/10/2017 EC 0000025599 Analysis of PS1-18-ED Piping For Correct Snubber Orientations Revision 000 /

8/25/2015 WO 700006331 1385 Periodic Structural Inspection 2/5/2020 MN-23-MT-004 Magnetic Particle Examination Report of Bottom Head to Skirt 5/3/2023 Weld (Summary No. MN-102636)

Document Title Revision / Date MN-23-VT-033 through Visual Examination of Pipe Hanger, Support or Restraint (VT-3) 4/28/2023 through MN-23-VT-058 of Drywell Female and Male Stabilizers; Vessel Stabilizer Lugs, 5/1/2023 and Bioshield to Containment Truss Photographs MNGP stabilizer support images and under vessel images 4/25/2023 2011VT024 ISI Exam Reports - Visual Examination of Component Supports 3/14/2011 and Snubbers (VT-3) RV Component H-1SB 2011VT065 ISI Exam Reports - Visual Examination of Component Supports 3/29/2011 and Snubbers (VT-3) RV Support Skirt - Examined vessel skirt where accessible from under vessel 20110314-022 ISI Exam Reports - Visual Examination of Component Supports 3/14/2011 and Snubbers (VT-3) RV Component H-3SB 2011VT023 ISI Exam Reports - Visual Examination of Component Supports 3/14/2011 and Snubbers (VT-3) RV Component H-4SB Vsl Stablizer Lug @

270 deg 2011VT025 ISI Exam Reports - Visual Examination of Component Supports 3/14/2011 and Snubbers (VT-3) RV Component H-2SB Vsl Stablizer Lug @

90 deg 2011MT005 ISI Exam Reports - Magnetic Particle Examination, RV 4/3/2011 Component W-12 BH to Skirt Weld 2005VT069 ISI Exam Reports - Visual Examination of Component Supports 3/29/2005 and Snubbers (VT-3) RV - Vsl Stablzr 2005VT071 ISI Exam Reports - Visual Examination of Component Supports 3/29/2005 and Snubbers (VT-3) RV - Vsl Stablzr Lug @ 180 deg 2005VT070 ISI Exam Reports - Visual Examination of Component Supports 3/29/2005 and Snubbers (VT-3) RV - Vsl Stablzr Lug @ 90 deg 2005VT072 ISI Exam Reports - Visual Examination of Component Supports 3/30/2005 and Snubbers (VT-3) RV - Vsl Stablzr Lug @ 270 deg During the audit, the staff verified the applicants claim that the preventive actions and corrective actions program elements of the LRA/SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP or will be consistent after implementation of the identified enhancements. In addition, the staff found that for the scope of program, parameters monitored or inspected, detection of aging effects, monitoring and trending, and acceptance criteria program elements, sufficient information was not available to determine whether they were consistent with the corresponding program elements of the GALL-SLR Report AMP. The staff will consider issuing RAIs or use a voluntary SLRA supplement to obtain the information necessary to verify whether these program elements are consistent with the corresponding program elements of the GALL-SLR Report AMP.

During the audit, the staff made the following observations:

  • The staff reviewed SLRA B.2.3.30 and SLRA Table A-3, item 33, and noted that the enhancement (Commitment 33(a)) to the scope of program element related to evaluation of inaccessible areas, which appears to only address inaccessible areas of Class 1, 2 and 3 supports. However, the scope of the SLRA AMP includes Class MC components, which appears to be not included in the enhancement. Therefore, there is a lack of clarity if the scope of program of the SLRA AMP will be consistent with that of GALL-SLR AMP XI.S3.
  • The staff reviewed SLRA B.2.3.30 and SLRA Table A-3, item 33 and noted that the enhancement and corresponding Commitment 33(g) to detection of aging effects program element appears to include tactile inspection of only elastomeric vibration isolation elements, whereas the corresponding GALL-SLR element includes elastomeric or polymeric vibration isolation elements. Also, a related SLRA enhancement to parameters monitored or inspected element includes polymeric vibration isolation elements. Therefore, there is a lack of clarity if the detection of aging effects program element of the SLRA AMP will be consistent with that of GALL-SLR AMP XI.S3.
  • The staff reviewed SLRA B.2.3.30 and SLRA Table A-3, item 33, and noted that the monitoring and trending element includes an enhancement and corresponding Commitment 33(i), which states: Revise procedures to increase or modify inspection population when a component support is repaired to as-new condition by However, the corresponding program element of the GALL-SLR AMP XI.S3, uses the phrase inspection sample rather than the phrase inspection population. Therefore, there is a lack of clarity if the monitoring and trending program element of the SLRA AMP will be consistent with that of GALL-SLR AMP XI.S3.
  • The staff reviewed SLRA B.2.3.30 and SLRA Table A-3, item 33, and noted that two related program enhancements and corresponding SLRA commitments, regarding sliding surfaces, used inconsistent phrases for the aging effect being addressed ( i.e.,

Commitment 33(e)) uses phrase significant loss of material whereas Commitment 33(j) uses excessive wear, which the applicant should reconcile and make consistent for clarity).

  • The staff reviewed SLRA B.2.3.30, SLRA Table 3.5.2-1 and Table 3.5.2-7 and noted a lack of clarity of how the aging effects due to irradiation embrittlement will be adequately managed for the RV steel support assembly components, and how included within the scope of the IWF program credited, and that corresponding Table 2 AMR items appeared to be not included.
  • The staff reviewed SLRA Table 3.5-1 and noted that the non-applicability claim of AMR item 3.5.1-068 related to SCC of high strength bolting of component supports appeared to be unclear or not sufficiently justified.
  • The staff reviewed the USAR supplement description in SLRA Section A.2.2.30 and noted that it includes language such as the AMP recommends additional one-time inspections and that volumetric examination should be performed. However, the staff notes that an adequate USAR supplement summary description is expected to describe what the program will do and not what it recommends or what should be done.

The staff will consider issuing RAIs and/or use a voluntary SLRA supplement offered by the applicant to obtain the necessary information to address issues identified during the audit. The staff will document its review of these issues in the SE.

The staff also audited the description of the SLRA AMP ASME Section XI, Subsection IWF, provided in the USAR supplement. The staff found that sufficient information was not available to determine whether the description provided in the USAR supplement was an adequate description of the SLRA AMP ASME Section XI, Subsection IWF. The staff will consider issuing an RAI or use a voluntary SLRA supplement to obtain the information necessary to verify the sufficiency of the USAR supplement program description.

SLRA AMP B.2.3.31, 10 CFR Part 50, Appendix J Summary of Information in the Application. The SLRA states that AMP B2.3.31, 10 CFR Part 50, Appendix J, is an existing program that is consistent with the program elements in GALL-SLR Report AMP XI.S4, 10 CFR Part 50, Appendix J.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- MNGP Subsequent License Renewal Aging Management Revision 1 075 Program Basis Document - 10 CFR Part 50, Appendix J EWI-08.06.01 MNGP Primary Containment Leakage Rate Testing Program Revision 22 EWI-08.06.02 MNGP LLRT Extended Eligibility Determination Revision 11 EWI-08.06.02 MNGP LLRT Extended Eligibility Determination Revision 12 NA Safety Evaluation - Appendix J Review for License No. DPR-22 6/3/1984 Northern States Power Company Monticello Nuclear Generating Plant MNGP TS 50- Renewed Facility Operating License DPR-22 for Monticello Amendment 210 263_Changes_210 Nuclear Generating Plant, Unit 1 USAR-05 Monticello Updated Safety Report - Section 5: Containment Revision 37 System Document Title Revision / Date 501000025541 Corrective Action Program Comp Date:

6/17/2019 501000025519 Corrective Action Program Comp Date:

6/17/2019 Comp Date:

501000026099 Corrective Action Program 7/11/2019 AR 01558998 AT-0175 Action Request Record Report Orig Date: 5/6/2017 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP.

The staff also audited the description of the SLRA AMP 10 CFR Part 50, Appendix J program provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.32, Masonry Walls Summary of Information in the Application. The SLRA states that AMP B.2.3.32, Masonry Walls, is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP XI.S5, Masonry Walls. To verify this claim of consistency, the staff audited the SLRA AMP.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT-079 MNGP Subsequent License Renewal Aging Management Revision 1 Program Basis Document - Masonry Walls XCELMO00017-REPT-080 MNGP Subsequent License Renewal Aging Management Revision 0 Program Basis Document - Structures Monitoring XCELMO00017-REPT-065 MNGP Subsequent License Renewal Aging Management Revision 1 Program Basis Document - Fire Protection XCELMO00017-REPT-040 MNGP Subsequent License Renewal Screen and Aging Revision 1 Management Review Results - Plant Structures and Commodities Procedure 1385 Periodical Structural Inspection Revision 17 Document Title Revision / Date NSPM-1 Quality Assurance Topical Report (QART) Revision 15 FP-E-MR-07 Maintenance Rule - Structures Monitoring Revision 2 AR 01365309 Wall T324 Stresses May Exceed Allowables Revision 2 AR 01386074 Masonry Wall Deterioration on Intake Screenhouse Revision 2 WO 00483890 Repair Degraded Masonry Wall on Intake Screenhouse Revision 8 AR 01389768 Issues with Optional Sandbag Barriers in the TBA Revision 3 AR 01398462 Need Evaluation of Items Found on 1385 Periodic Inspect Revision 3 AR 01313182 EC 11445 50.59 Screening Shortfalls Revision 2 AR 01416248 Perform Periodic Inspection of AD Items on 1385 Report Revision 3 WO 494312 Repair Spalled Concrete on Off Gas Stack Revision 8 WO 00475254 Repair Grout Pad Revision 8 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP or will be consistent after implementation of the identified enhancements.

The staff also audited the description of the SLRA Masonry Walls program provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.2.33, Structures Monitoring Summary of Information in the Application. The SLRA states that AMP B.2.3.33, Structures Monitoring, is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP XI.S6, Structures Monitoring.

Audit Activities. On March 21 - March 22, 2023, the staff participated in an onsite audit at MNGP in Monticello, MN to gain a general overview of current conditions of the structures compared to the provided OE, and an understanding of the settlement issue for the Diesel Fuel Oil Transfer House and Diesel Oil Storage Tank. While onsite, the staff engaged with the applicant staff, conducted walkdowns, and reviewed additional documentation provided by the applicant.

The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 080 Renewal Aging Management Program Basis Document -

Structures Monitoring Procedure 1385 Periodic Structural Inspection Revision 17 Procedure 1396 Equipment/Structures Settling Check Revision 10 MNGP 1478 External Flood Monthly and Annual Surveillance Revision 24 MNGP I.05.50 Sampling Ground Water Monitoring Wells Revision 16 Nuclear Department Fleet Maintenance Rule - Structures Monitoring Revision 2 Procedure FP-E-MR-07 MNGP EWI-11.01.07 Structures Monitoring Program Revision 3 Drawing No. Subsequent License Renewal Boundary Drawing - Site Plan 12/15/2003 SLR-36444 AR01434726 Various Turbine Building Leaks During Rainfall 6/20/2014 AR01502195 Diesel Fuel Oil Pump House Water Leak 11/21/2015 AR01500214 Diesel Oil Pump House Settlement Check per Procedure 1396 11/14/2015 AR01437825 Degraded Roof Beam Found in Recombiner Pump Room 7/05/2016 AR01219259 Mississippi Flooding Predicted in St. Paul 3/04/2010 AR01318363 Discharge Structure Water In leakage 12/27/2011 Document Title Revision / Date AR01282172 T-114, Diesel Fuel Storage Tank Diking Water Seepage in the 4/27/2011 Southeast Corner AR01362317 Penetrations in Flood Barrier for A.6 11/26/2013 AR01392502 Water Seepage Through Discharge Structure Wall Cracks 8/20/2013 WO00534301 Equipment/Structures Settling Check 3/21/2016 AR01311921 Continued Degradation of the Turbine Building Roof 1/5/2012 AR01242883 Blistering and Peeling Paint around a Grouted Pipe Penetration 7/26/2010 AR01310372 Corrosion on the Offgas Stack Supports and Hangers 10/28/2011 AR01434726 Leaks in the Turbine Building Roof 6/14/2014 AR501000032029 Mineral Deposits were found accumulating on the West Wall of 9/18/2019 the High Pressure Coolant Injection (HPCI) Room 896 AR01036358 1396, Equip/Structures Settling Check, Procedure Issues 10/17/2006 WRA No. 90-06014 Reactor Building South and West - Cracks in Exterior Walls 5/24/1990 Drawing No. NX-257172-1 Missile Barrier - Fuel Oil Pump House Revision 0 Drawing No. NX-257172-2 Missile Barrier - Fuel Oil Pump House Revision 0 Drawing No. C-130 Diesel Fuel Pump House Revision 2 During the audit, the staff verified the applicants claim that the preventive actions and corrective actions program elements of the SLRA AMP are consistent with the corresponding element of the GALL-SLR Report AMP. In addition, the staff found that for the scope of program, parameters monitored or inspected, detection of aging effects, monitoring and trending, and acceptance criteria program elements, sufficient information was not available to determine whether they were consistent with the corresponding program elements of the GALL-SLR Report AMP. The staff will consider issuing RAIs in order to obtain the information necessary to verify whether these program elements are consistent with the corresponding program elements of the GALL-SLR Report AMP.

During the audit, the staff made the following observations:

  • During the review of SLR boundary drawing No. SLR-36444, the staff noted that the buildings identified within the scope in the SLR boundary drawing are not consistent with the SLRA.
  • The staff noted that the AMP basis document lists parameters monitored or inspected as unique map or cracking that would indicate the presence of alkali-silica reaction (ASR). SRP-SLR describes the indication of ASR as map or patterned cracking, alkali-silica gel exudations, surface staining, expansion causing structural deformation, relative movement or displacement, or misalignment/distortion of attached components.

The staff notes ASR has more characteristics than the ones described in the AMP basis document.

  • During the review of procedure 1385, Revision 17, the staff noted that the inspection intervals for those normally inaccessible areas may exceed five years. Procedure 1385 does not define these normally inaccessible areas and their inspection interval.

During the review of procedure 1385, Revision 17, the staff could not locate the information related to quantitative results (measurements) and qualitative information from periodic inspections are trended with sufficient detail, such as photographs and surveys for the type, severity, extent, and progression of degradation, to ensure that corrective actions can be taken prior to a loss of intended function, which was stated in SLRA Appendix A.2.2.33.

  • During the review of the Action Requests (ARs), the staff noted the settlement issue for the Diesel Fuel Oil Transfer House, starting from the late 1970 and early 1980. The staff further noted the Northwest corner of the Diesel Fuel Oil Transfer House was approaching the lower limit of the settlement range.

During the onsite audit, the staff performed walkdowns of the Diesel Fuel Oil Transfer House (also called Diesel Oil Pump House), Diesel Oil Storage Tank, Turbine Building, and Reactor Building, etc. The staff made the following observations during walkdowns:

  • During the walkdown of the Diesel Fuel Oil Transfer House and the Diesel Oil Storage Tank, the staff noted that recent construction placed a large concrete slab over the Diesel Oil Storage Tank (T-44) and a large heavy I-beams on the roof of the Diesel Fuel Oil Transfer House, which added significant weight to the structure. The staff also noted that the Diesel Fuel Oil Transfer House is visibly leaning to the west. The staff reviewed the settlement data provided by the applicant, and interviewed the applicant about settlement history, past construction, settlement monitoring, and corrective actions.
  • During the walkdown of the exterior Reactor Building, the staff noted caulking on the exterior walls (south and west) of the Reactor Building.
  • During the walkdown of the structures and components within the scope of subsequent LR, the staff noted the degradations observed during the walkdowns were found to be consistent with the OE for which the GALL-SLR Report program was evaluated.

The staff also audited the description of the SLRA Structures Monitoring program provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.34, Inspection of Water-Control Structures Associated With Nuclear Power Plants Summary of Information in the Application. The SLRA states that AMP B.2.3.34, Inspection of Water-Control Structures Associated with Nuclear Power Plants, is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP XI.S7, Inspection of Water-Control Structures Associated with Nuclear Power Plants.

Audit Activities. On March 21 - March 22, 2023, the staff participated in an onsite audit at MNGP in Monticello, MN to gain a general overview of current conditions of the water-control structures and how it compares to the provided OE. While onsite, the staff engaged with the applicant staff, conducted walkdowns, and reviewed additional documentation provided by the applicant.

The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 078 Renewal Aging Management Program Basis Document -

Inspection of Water-Control Structures Associated with Nuclear Power Plants Procedure 1385 Periodic Structural Inspection Revision 17 Procedure 4125 East Service Water Bay Inspection/Dredging Revision 22 Procedure 4126 West Service Water Bay Inspection/Dredging Revision 22 AR01489054 Intake Roof Leak 8/21/2015 AR01434337 Liquid Leaking in the Overhead of the Intake Structure 7/22/2014 AR01434611 Intake Structure Walkdown for Leeching Results 9/22/2014 AR01453838 9005 Flooding Compliance Determination 1/24/2014 CAP ID 501000024250 Water Intrusion Intake Structure 3/14/2019 AR01436397 Dried White Paper Residue on piping and ceiling 7/7/2014 Document Title Revision / Date AR01424021 Intake Structure Roof Coating Degradation 3/25/2014 AR01476955 ST15: Degraded Wall - Intake Structure 12/18/2015 WO00499766 Recoat Intake Structure Roof 12/26/2014 AR01467653 Degraded Concrete Discovered in Intake Structure Ceiling 3/24/2015 CAP ID: 501000022600 Document Intake Structure Roof Study 5/28/2021 AET Project No. Report of Observations, Sampling and Analysis of the Intake 1/18/2019 05-07138 Structure AET Project No. Intake Structure Roof and Wall Repair 6/9/2020 05-20437 WO700086535-0030 Install SIKA 7600 on the Intake Structure Roof Revision 0 AR01401048 Conduit Penetrations identified in Intake Structure 10/10/2013 Drawing Nos. G1, BE1 Cover Sheet, Roof Plan, Elevations, Details for Intake Structure 5/7/2020 through BE5 Roof and Wall Repairs During the audit, the staff verified the applicants claim that the preventative actions, monitoring and trending, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP.

In addition, the staff found that for the scope of program, parameters monitored or inspected, detection of aging effects, and acceptance criteria program elements, sufficient information was not available to verify whether they were consistent with the corresponding program elements of the GALL-SLR Report AMP. The staff will consider issuing RAIs in order to obtain the information necessary to verify whether these program elements are consistent with the corresponding program elements of the GALL-SLR Report AMP.

During the audit, the staff made the following observations:

  • The staff could not locate the component trash racks in the SLRA, which are usually within the scope of SLR.
  • The staff noted that the AMP basis document lists parameters monitored or inspected as unique map or cracking that would indicate the presence of ASR. The staff notes that ASR has more characteristics than ones described in the AMP basis document.
  • The staff noted that provisions for increased inspection frequency are missing from the AMP basis document.
  • During the review of the AMP basis document, the staff noted that quantitative second tier acceptance criteria are used to evaluate the need for corrective action of an observed degradation. The criteria, which are identified in implementing procedure 1385, are based on industry guidelines/criteria such as ACI 349.3R-96 and ACI 201.1.

However, the staff could not find this acceptance criteria in procedure 1385.

  • The staff noted that SLRA Appendix A - USAR supplement does not match the description of the GALL-SLR Report recommendation.

During the onsite audit, the staff performed walkdowns of the Intake Structure. The staff made the following observations during walkdowns:

  • During the walkdown of the Intake Structure, the staff observed the residue/water-in-leakage indications on the Intake Structure ceiling. The staff also observed the water leakage due to the isolation valves BH-650 and/or BH-653 leaking from the heating boiler/HVAC system.
  • The staff reviewed Report of observations, sampling and analysis of the Intake Structure by American Engineering Testing, Inc., AET Project No. 05-07138, Revised on 1/18/2019.
  • During the walkdown of the structures and components within the scope of SLR, the staff noted the degradations observed during the walkdowns were found to be consistent with the OE for which the GALL-SLR Report program was evaluated.

The staff also audited the description of the SLRA Inspection of Water-Control Structures Associated with Nuclear Power Plants program provided in the USAR supplement. The staff found that sufficient information was not available to determine whether the description provided in the USAR supplement was an adequate description of the SLRA Inspection of Water-Control Structures Associated with Nuclear Power Plants program. The staff will consider issuing an RAI in order to obtain the information necessary to verify the sufficiency of the USAR supplement program description.

SLRA AMP B.2.3.35, Protective Coating Monitoring and Maintenance Summary of Information in the Application. The SLRA states that AMP B.2.3.35, Protective Coating Monitoring and Maintenance, is an existing program with enhancements that will be consistent with the GALL-SLR Report AMP XI.S8, Protective Coating Monitoring and Maintenance.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date 01475667-20150516-Action Request Record Report: Torus Internal Corrosion 5/17/2015 000.pdf Document Title Revision / Date 01558080-20170609- Action Request Record Report: PCT Coatings Failed 6/13/2017 000.pdf Acceptance Criteria 01427935_FL-ESP-PGM- Fleet Mentor Guide: Safety Related Coatings Program Revision 2 060M.pdf Owner 01468275 - 2015 Select Action Request Record Report: Audit Aging Management AMP Effectiveness Reviews 4/21/2020 Programs (1).pdf Completed WO Task Report: Drywell Interior Surface 00355178-20170907- 2/8/2018 Inspection Results 000.pdf 602000001946-20180226- Change Request Close Out Report: Drywell Interior Surface 2/25/2019 000.pdf Inspection 700004439-20191113- Completed WO Operation Report: Repair Underwater 1/23/2020 000.pdf Coating 700014153-20200212-000-PCT Vis Exam for Structural Problem 2/12/2020 SP1.pdf 00490719-20150610- Completed WO Task Report: Torus Painted Surface Internal 6/11/2015 000.pdf Coating INSP Evaluation of Effect of Paint Chips on Debris Loading Effects CA-01-135, Rev. 0.pdf 8/17/2001 of ECCS Suction Strainers Determination of Degraded Coating Limit on ECCS Suction 13-052.pdf 5/17/2013 Strainers with Reduced Sludge Loading 9.8_4 AWI-08.11.03.pdf Nuclear Coatings Program Revision 16 Nuclear Coating Applicator and Application Inspector MWI-8-M-5.05.pdf Revision 12 Performance Qualification and Certification Program During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP or will be consistent after implementation of the identified enhancements.

The staff also audited the description of the SLRA Protective Coating Monitoring and Maintenance AMP provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report Table XI-01 for XI.S8, Protective Coating Monitoring and Maintenance.

SLRA AMP B.2.3.36, Electrical Insulation for Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Summary of Information in the Application. The SLRA notes that AMP B.2.3.36, Electrical Insulation for Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements, is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP XI.E1, Electrical Insulation for Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements. At the time of the audit, the applicant had not yet fully developed the documents necessary to implement this enhanced program, and the staffs audit addressed addressed only the applicants basis document, available procedures, and referenced documents.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Subsequent License Renewal Aging Management Program Basis Revision1 053 Document - Electrical Insulation for Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements EWI - 11.01.03 Electrical Cables and Connections Not Subject to 10 CFR 50.49 Revision 6 Environmental Qualification Requirements Program FP-PE-CBL-01 Cable Condition Monitoring Program Revision 5 AR 01374300 AT-0175 Action Request Record Report: Compromised Integrity Revision 2 of Existing Cable B1243-M1243/1 WO 00476134 Compromised Integrity of Existing Cable B1243-M1243/1 Revision 8 WO 00380779 Perform Visual Inspection of Cable in Various Areas for 1R24 Revision 5 AR 01342845 Degraded Conductors in cable W969 Revision 2 AR 01376428 V-EF-30 Feeder Cable B4246-M4246/1 Revision 2 CNN 10915-100 Construction Change Notice EC10915-10EC11, EC10915- 4/8/2013 10ER05, EC10915-11NR09, NF-36274-4 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP or will be consistent after implementation of the identified enhancements.

The staff also conducted an onsite audit where the staff interviewed the applicants staff and performed walkdowns of the facility. Specifically, the staff conducted onsite walkdowns of the switchyard and cable raceways and examined pictures of electrical manholes.

The staff also audited the description of the SLRA Electrical Insulation for Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3 37, Electrical Insulation for Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Used in Instrumentation Circuits Summary of Information in the Application. The SLRA notes that AMP B.2.3.37, Electrical Insulation for Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Used in Instrumentation Circuits, is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP XI.E2, Electrical Insulation for Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Used in Instrumentation Circuits. At the time of the audit, the applicant had not yet fully developed the documents necessary to implement this enhanced program, and the staffs audit addressed only the applicants basis document, available procedures, and referenced documents.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Subsequent License Renewal Aging Management Program Basis Revision 1 056 Document - Electrical Insulation for Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements used in Instrumentation Circuits 501000025041 Intermediate RNG Neutron Monitor Startup Range Monitoring Sys 4/3/2019 501000042966 MT:1:NIS:IRM-11 Intermediate RNG Neutron Monitor Startup 8/10/2020 Range monitoring SYS 501000048594 MT:1:PRM;RM-7992A TURB BLDG NORM SUMP RADIATION 2/11/2021 MONITOR 501000044780 MT:1:ARM:RM-A20 (A-20) Control Room Low Range ARM Area 10/1/2020 Radiation Monitors WO 700090575 Intermediate RNG Neutron Monitor Revision 2 WO 700052702 Intermediate RNG Neutron Monitor Revision 2 Document Title Revision / Date EWI-11.01.04 Electrical Cables Not Subject to 10 CFR 50.49 EQ Requirements Revision 3 Used in Instrumentation Circuits Program 0428-02 Containment High Range Radiation Detectors Calibration Revision 10 Procedure 7207 LPRM Insulation Resistance and Voltage Breakdown Testing Revision 8 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP or will be consistent after implementation of the identified enhancements.

The staff also conducted an onsite audit where the staff interviewed the applicants staff and performed walkdowns of the facility. Specifically, the staff conducted onsite walkdowns of the switchyard and cable raceways and examined pictures of electrical manholes.

The staff also audited the description of the SLRA Electrical Insulation for Inaccessible Medium-Voltage Power Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Used in Instrumentation Circuits provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.38, Electrical Insulation for Inaccessible Medium-Voltage Power Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Summary of Information in the Application. The SLRA notes that AMP B.2.3.38, Electrical Insulation for Inaccessible Medium-Voltage Power Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements, is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP XI.E3A, Electrical Insulation for Inaccessible Medium-Voltage Power Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements, as modified by SLR-ISG-2021-04-ELECTRICAL, Updated Aging Management Criteria for Electrical Portions of the Subsequent License Renewal Guidance. At the time of the audit, the applicant had not yet fully developed the documents necessary to implement this enhanced program, and the staffs audit addressed only the applicants basis document, available procedures, and referenced documents.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Revision/Date Document Title XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 057 Renewal Aging Management Program Basis Document-Electrical Insulation for Inaccessible Medium-Voltage Power Cables Not Subject to 10CFR 50.49 EQ Requirements AR501000043547 Water in several cable vaults onsite 8/31/2020 Revision/Date Document Title AR01447918 N1N7-C Tan Delta Test Results not as expected 9/24/2014 AR01330437 Water found in ISFSI electrical manholes 3/22/2012 AR01346641 AF1-2 Cable Condition Monitoring Program self-assessment 7/31/2012 W053144-01 MNGP 2RS Transformer Feeding 2R 5/3/2017 Maintenance Plan Plan 10004355 Test Cables from 2RS to 2R 6/10/2009 WO350074-07 Perform Megger/Tan Delta Test on Cable from 1N6 to 1AR 3/30/10 Transformer Plant Health Report Plant Health Monitor 13K-13.8KV 2021 WO376867 Megger Tan Delta 1/11/2007 MWI-8-M-4.13 MNGP Testing Instructions for Electrical Conductors rated Revision 9 greater than 600V Work Plan Inspection of Manholes/Vaults for Water or Evidence of Water Revision 0 EWI-08.19.01 MNGP Cable Condition Monitoring Program Revision 9 EWI-11.01.02 MNGP Inaccessible Medium Voltage (2KV to 34.5KV) Cables Revision 7 Not Subject to 10CFR50.49 EQ Requirements Program During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP as modified by SLR-ISG-2021-04-ELECTRICAL, or will be consistent after implementation of the identified enhancements.

The staff also conducted an onsite audit where the staff interviewed the applicants staff and performed walkdowns of the facility. Specifically, the staff examined medium-voltage power cables, connections, and manholes that are in the scope of SLR.

The staff also audited the description of the SLRA Electrical Insulation for Inaccessible Medium-Voltage Power Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report as modified by SLR-ISG202104-ELECTRICAL.

SLRA AMP B.2.3.39, Electrical Insulation for Inaccessible Instrument and Control Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Summary of Information in the Application. The SLRA notes that AMP B.2.3.39, Electrical Insulation for Inaccessible Instrument and Control Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements, is a new program that will be consistent with the program elements in GALL-SLR Report AMP XI.E3B, Electrical Insulation for Inaccessible Instrument and Control Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements, as modified by SLR-ISG202104-ELECTRICAL, Updated Aging Management Criteria for Electrical Portions of the Subsequent License Renewal Guidance. At the time of the audit, the applicant had not yet fully developed the documents necessary to implement this new program, and the staffs audit addressed only the applicants basis document, available procedures, and referenced documents.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision/ Date XCELMO00017-Rept- MNGP Subsequent License Renewal Aging Management Revision 1 058 Program Basis Document-Electrical Insulation for Inaccessible Instrument and Control Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements AR01209347 ISFSI manholes discovered with water 12/4/2009 AR01513997 Unexpected Test Results on Cable C24B-100J12/1 2/29/2016 AR01302959 CAP generated under WO404100 Cable Vault Inspection 9/8/2011 WO700039754 SWFP Motor Control Cable Inspection Condition 11/25/2019 AR01489802 Water found in MCC-124 feeder cables in cable vault 8/20/2015 NMH304 AR01426338 Low Megger Results on Cable from 51/1N6/CT to 345 4/10/2014 House AR01294159 Water in underground vaults 7/12/2011 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP as modified by SLR-ISG202104-ELECTRICAL.

The staff also conducted an onsite audit where the staff interviewed the applicants staff and performed walkdowns of the facility. Specifically, the staff examined instrument and control cables, connections, and manholes that were in the scope of SLR.

The staff also audited the description of the SLRA Electrical Insulation for Inaccessible Instrument and Control Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report as modified by SLR-ISG202104-ELECTRICAL.

SLRA AMP B.2.3.40, Electrical Insulation for Inaccessible Low-Voltage Power Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Summary of Information in the Application. The SLRA notes that AMP B.2.3.40, Electrical Insulation for Inaccessible Low-Voltage Power Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements, is a new program that will be consistent with the program elements in GALL-SLR Report AMP XI.E3C, Electrical Insulation for Inaccessible Low-Voltage Power Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements, as modified by SLR-ISG202104-ELECTRICAL, Updated Aging Management Criteria for Electrical Portions of Subsequent License Renewal Guidance. At the time of the audit, the applicant had not yet fully developed all the documents necessary to implement this new program, and the staffs audit addressed only the applicants basis document, available procedures, and referenced documents.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO000017- Monticello Nuclear Generating Plant Subsequent License Revision 1 REPT-059 Renewal Aging Management Program Basis Document-Electrical Insulation for Inaccessible Low-Voltage Power Cables not subject to 10CFR50.49 Environmental Qualification Requirements.

QF0406 AMP Effectiveness Reviews of 35 Active Aging Management Revision 4 Programs FP-PE-CBL-01 Cable Condition Monitoring Program (CCMP) Revision 5 L-MT-07-41 Response to NRC Generic Letter 2007-01: Inaccessible or 5/7/2007 Underground Power Cable Failures that Disable Accident Mitigation Systems or Cause Plant Transients EWI-11.01.02 Inaccessible Medium Voltage (2KV to 34.5 KV) Cables Not Revision 7 Subject to 10 CFR50.49 EQ Requirements EMP-01.14 Tan Delta Cable Testing Revision 1 AR501000030239 Underground vaults found with water 8/1/2019 Document Title Revision / Date AR01487526 Manhole NMH304 allows water intrusion 7/30/2015 AR01387093 MCC-115 Feeder Cable Megger Results 3/14/2013 AR01439323 Water/Mud found in manholes while conducting inspection 7/22/2014 EC273408 Monticello system report-4160 VAC Safety Related Sw. Gear 1/9/2019 Tier 2 2018 Period 1 AR01447918 N1N7-C Tan Delta Test Results not as expected 9/24/2014 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP as modified by SLR-ISG202104-ELECTRICAL.

The staff also conducted an onsite audit where the staff interviewed the applicants staff and performed walkdowns of the facility. Specifically, the staff examined low-voltage power cables, connections, and manholes that were in the scope of SLR.

The staff also audited the descriptions of SLRA Electrical Insulation for Inaccessible Low-Voltage Power Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report as modified by SLR-ISG202104-ELECTRICAL.

SLRA AMP B.2.3.41, Metal Enclosed Bus Summary of Information in the Application. The SLRA notes that AMP B.2.3.41, Metal-Enclosed Bus, is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP XI.E4, Metal Enclosed Bus. At the time of the audit, the applicant had not yet fully developed the documents necessary to implement this enhanced program, and the staffs audit addressed only the applicants basis document, available procedures, and referenced documents.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision/Date XCELMO00017-REPT-051 Subsequent License Renewal Aging Management Program Revision 1 Basis Document -Metal Enclosed Bus 501000002848 1R XFMR - Enclosed bus needs sealing 9/22/2017 501000002818 1R XFMR - Moisture found in 13.8kV bus 9/22/2017 Document Title Revision/Date AR 01375076 1R Bus Duct Inspection - brittle tape in one location 3/18/2013 EWI-11.01.01 Bus Duct Inspection Program Revision 5 4858 PM 2R Transformer and associated bus PM Revision 21 606000001098 Perform AMP Effectiveness Reviews in accordance with NEI 3/1/2020 14-12 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP or will be consistent after implementation of the identified enhancements.

The staff also conducted an onsite audit where the staff interviewed the applicants staff and performed walkdowns of the facility. Specifically, the staff discussed OE related to metal enclosed bus that are in the scope of SLR.

The staff also audited the description of the SLRA Metal-Enclosed Bus provided in the USAR supplement. The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA AMP B.2.3.42, Electrical Cable Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Summary of Information in the Application. The SLRA notes that AMP B.2.3.42, Electrical Cable Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements, is an existing program with enhancements that will be consistent with the program elements in GALL-SLR Report AMP Section XI.E6, Electrical Cable Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements. At the time of the audit, the applicant had not yet fully developed the documents necessary to implement this enhanced program, and the staffs audit addressed only the applicants basis document, available procedures, and referenced documents.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision/Date Monticello Nuclear Generating Plant Electrical Cable EWI-11.05.01 Connections Not Subject to 10 CFR 50.49 Environmental Revision 1 Qualification Requirements Monitoring Program XCELMO00017-REPT- Subsequent License Renewal Aging Management Program Revision 1 052 Basis Document - Electrical Cable Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Monitoring Program Document Title Revision/Date AR 01401163 AT-0175 Action Request Report Loose Terminal Connections Revision 3 /

1/22/2015 AR 01360558 AT-0175 Action Request Report Loose Cable Connections Revision 2 /

12/10/2012 CR 606000001098 Change Request Closeout Report 2019-2020 AMP 4/24/2020 Effectiveness Reviews AR 01336098 AT-0175 Action Request Report - Thermography in RPS Panel Revision 2 AR 01330035 AT-0175 Action Request Report Adverse Trend CRD Position Revision 3 Indication Maintenance Plan Thermography Turbine Building MCCs NA 10003838 EWI-04.05.01 Thermography Program Revision 13 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the SLRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP or will be consistent after implementation of the identified enhancements.

The staff also conducted an onsite audit where the staff interviewed the applicants staff and performed walkdowns of the facility. Specifically, the staff discussed OE related to electrical cable connections that are in the scope of SLR.

The staff also audited the description of the SLRA Electrical Cable Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements provided in the USAR supplement.

The staff verified this description is consistent with the description provided in the GALL-SLR Report.

SLRA TLAA Section 4.1, Identification of Time-Limited Aging Analyses Summary of Information in the Application. SLRA Section 4.1, Identification of Time-Limited Aging Analyses, discusses the methodology for the identifying of TLAAs in the SLRA.

Audit Activities. The table below lists a document that was reviewed by the staff and was found relevant to the TLAA. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 0 091 Renewal Time Limited Aging Analysis and Exemption Evaluation Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 1 005 Renewal Time Limited Aging Analysis (TLAA) and Exemption Identification MPS-0171 General Requirement for Isolation Valves (Steam Piping System) Revision 1

- GE21A1062 During the audit, the staff verified that the applicant has provided its basis and methodology for identifying TLAAs in accordance with disposition of 10 CFR 54.21(c).

During the audit, the staff made the following observations:

  • The staff reviewed XCELMO00017-REPT-091 and XCELMO00017-REPT-005 and confirmed that CLB and design basis documentation were searched to identify potential TLAAs. The staff noted that specific keywords were used during this search that would identify potential TLAAs.
  • The staff reviewed XCELMO00017-REPT-091 and XCELMO00017-REPT-005 and confirmed that each potential TLAA was reviewed against the six criteria of 10 CFR 54.3(a) and that those that met all six criteria were identified as TLAAs, which require evaluation for the subsequent period of extended operation.
  • The staff reviewed XCELMO00017-REPT-091 and XCELMO00017-REPT-005, and confirmed that a search of docketed licensing correspondence, the operating license, and the USAR identified exemptions granted pursuant to 10 CFR 50.12. Additionally, the staff noted that XCELMO00017-REPT-091 and XCELMO00017-REPT-005 identifies the exemptions currently in effect that were granted pursuant to 10 CFR 50.12.
  • The staff reviewed XCELMO00017-REPT-091 and XCELMO00017-REPT-005, and confirmed that these active exemptions were then reviewed to determine whether the exemptions granted pursuant to 10 CFR 50.12 were based on a TLAA.
  • The reference in footnote 6 of SLRA Table 4.1-1 to jet pump assemblies, is specific to jet pump nozzles.

SLRA TLAA Section 4.2.1, Neutron Fluence Projections Summary of Information in the Application. SLRA Section 4.2.1, Neutron Fluence Projections, discusses the fluence projections that quantify the number of neutrons that contact RV surfaces.

These projections have been used as input to the neutron embrittlement analyses that evaluate the reduction of fracture toughness aging effect resulting from neutron irradiation. The TLAA for the MNGP 80-year SPEO.

The MNGP Reactor Pressure Vessel (RPV) fluence evaluation for SLR was generated with the methods in compliance with RG 1.190. TransWare has benchmarked the Radiation Analysis Modeling Application (RAMA) Fluence Methodology against industry standard benchmarks and plant-specific dosimetry measurements for BWRs and PWRs. RAMA was developed by TransWare and is described in BWRVIP-114-A.

Audit Activities. During its audit, the staff discussed with the licensee staff and the TransWare staff the evaluation performed in Section 4.2.1. In Section 4.2.1.2 of the SLRA, the licensee mentions RAMA Fluence Methodology for determining fluence in BWR top guide and core shroud components under BWRVIP-145NP-A.

The associated SE for BWRVIP-145NP-A states that:

for licensing actions provided that the calculational results are supported by sufficient justification that the proposed values are conservative for the intended application.

The licensee states in Section 4.2.1.2 the same guidance as BWR145-VIP was applied for determining conservative fluence for all RVI components evaluated.

The NRC staff requested that the licensee to provide a detailed description of how the RAMA methodology was applied to determining fluence to all RVI components, including descriptions of the various conservatisms applied to justify use of RAMA code for Monticello SLRA.

Similarly, for the RVI components the licensee states in Section 4.2.1 that the maximum fast neutron fluence (E >1.0 MeV) is specifically reported for the various RVI components. The statement is followed with list of components and the location within the component where the maximum fluence is reported.

The NRC staff requested licensee to provide a brief description of geometric modeling approach for each of the components of the RPV and the RVI, including any modeling limitations, conservatisms, or special considerations.

During the breakout sessions held during April 7, 2023, as part of the audit, the NRC staff mentioned to the licensee that it is looking for a description similar in nature and depth to that provided in Section 1.1 of the licensee uploaded calculation (MNT-FLU-001-R-001) in the audit portal.

The table below lists documents that were reviewed by the staff and were found relevant to the TLAA. The staff will document its review of this information in the SE.

Document Title Revision / Date MNT-FLU-001-R-001 Monticello Nuclear Generating Plant Fluence Methodology Report Revision 1 A call was held with the licensee on May 23, 2023 to further clarify what type of supplemental information was needed.

Audit Observations. During the audit/breakout session, the staff made the following observations:

  • During the audit the staff reviewed the documents uploaded by the licensee and verified that the applicant performed neutron fluence projections to 80 years of life (72 effective full-power years (EFPY)) for the RPV and reactor vessel instrument (RVI) regions that are projected to exceed the 1E17 neutrons per square centimeter.
  • The staff reviewed the licensee referenced neutron fluence methodology for the RPV and RVI region to verify that an NRC-approved methodology that is compliant with RG 1.190 guidance was used for the fluence estimates.
  • The staff requested licensee to provide portions of the licensee uploaded calculation file (MNT-FLU-001-R-001) on the docket. The staff noted that a brief description of geometric modeling approach for each of the components of the RPV and the RVI, including any modeling limitations, conservatisms, or special considerations docketed would be necessary for staff to make a safety finding.
  • The licensee agreed to provide proprietary and publicly available versions of the document (MNT-FLU-001-R-001) as a supplement.

SLRA TLAA Sections 4.2.2, RPV Materials Upper Shelf Energy (USE) Reduction Due to Neutron Embrittlement through 4.2.4, RPV Thermal Limit Analysis: Operating P-T Limits Summary of Information in the Application. The staffs audit addresses the following TLAAs collectively due to their relationship in analyzing the RV neutron embrittlement:

  • SLRA Section 4.2.2, RPV Materials Upper Shelf Energy (USE) Reduction Due to Neutron Embrittlement discusses the analysis for assessing the projected reduction in the upper-shelf energy (USE) properties of RPV base metal and weld components. The applicant dispositioned the TLAA in accordance with 10 CFR 54.21(c)(1)(ii).

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the TLAA. The staff will document its review of this information in the SE.

Document Title Revision / Date EE608000000852 TLAA of PTLR for SLR Revision 0 2100300.301P.R1 Evaluation of RPV Materials USE Reduction due to Neutron Revision 1 Embrittlement 2100300.301P.R2 Evaluation of RPV Materials USE Reduction due to Neutron Revision 2 Embrittlement Document Title Revision / Date 2100300.302P.R2 Evaluation of Adjusted Reference Temperatures and Reference Revision 2 Temperature Shifts BWRVIP-135 Integrated Surveillance Program (ISP) Data Source Book and Revision 4 Plant Evaluations BWRVIP-347 Testing and Evaluation of the Monticello 120° ISP(E) Surveillance October 2022 Capsule During the audit of the TLAA, the staff verified that the applicant has provided its basis that supports its disposition of 10 CFR 54.21(c)(1)(ii) for SLRA Sections 4.2.2 and 4.2.3, and its disposition of 10 CFR 54.21(c)(1)(iii) for SLRA Section 4.2.4. However, the staff found that sufficient information was not available to complete its review of the applicants basis for its TLAA disposition. As discussed below, following its audit, the applicant provided additional information that will be addressed in the SER.

During the audit, the staff made the following observations:

  • The staff verified that the material information (e.g., initial reference temperature nil ductility (RTNDT). %Cu, %Ni, initial USE, margin values) for the RPV materials contained in SLRA Tables 4.2.2-1, 4.2.3-1, and 4.2.3-2 are consistent with the applicants CLB (e.g., USAR, license amendments associated with power uprates, and Pressure-Temperature Limits Reports).
  • The staff verified the applicants assessment of surveillance data from the Monticello 30° and 300° capsule was performed in accordance with Regulatory Guide 1.99, Rev. 2, for the lower/intermediate shell I-14 and I-15 (Course 2) with Heat No. C2220-1 and C2220-2, respectively (contained in BWRVIP-135, Revision 4). In particular, the staff verified the applicants use of applicable surveillance data is credible in accordance with Regulatory Guide 1.99, Rev. 2, for this RPV material, and the associated chemistry factor and margin values are reflected in the applicants letter dated April 3, 2023 (ML23094A136). However, the staff was not able to verify the applicants assessment and use, if applicable, of surveillance data from the Monticello 120° capsule in accordance with Regulatory Guide 1.99, Rev. 2, for the lower/intermediate shell I-14 and I-15 (Course 2) with Heat No. C2220-1 and C220-2, respectively. Following its audit, by letter dated July 18, 2023 (ML23199A154 (Supplement 4)), the applicant revised SLRA Sections 4.2.2 and 4.2.3 to discuss its assessment of the Monticello 120° capsule. The staffs review of this assessment will be documented in the SER.
  • The staff noted that the circumferential and axial RPV welds have the same heat ID (i.e.,

E8018N). However, the initial is 0 degrees for the circumferential weld (i.e., VCBA-2 and VCBA-3); whereas initial is 12.7 degrees for the axial RPV welds (i.e., VLAA-1 &-2, VLBA-1 &-2, and VLCB-1 &-2). Following its audit, by letter dated July 18, 2023 (ML23199A154 (Supplement 4)), the applicant revised SLRA Section 4.2.3 to address this discrepancy for the circumferential and axial welds.

  • The staff noted the neutron fluence values used in the determination of USE and ART in SLRA Sections 4.2.2 and 4.2.3, respectively, are inconsistent with the neutron fluence values presented in SLRA Section 4.2.1, Neutron Fluence Projections. Following its audit, by letter dated July 18, 2023 (ML23199A154 Supplement 4), the applicant revised SLRA Sections 4.2.2, providing an explanation and the basis for the discrepancy in neutron fluence values. The staffs review of this explanation will be documented in the SER.

The staff also audited the description of the TLAAs in SLRA Section 4.2.2, 4.2.3 and 4.2.4 provided in the USAR supplement. The staff verified this description is consistent with the description provided in the SRP-SLR.

SLRA TLAA Section 4.2.5, RPV Circumferential Weld Examination Relief Summary of Information in the Application. SLRA Section 4.2.5, RPV Circumferential Weld Examination Relief, discusses the analysis for the elimination of ASME Code,Section XI examination of RPV circumferential welds. The applicant dispositioned the TLAA in accordance with 10 CFR 54.21(c)(1)(iii).

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the TLAA. The staff will document its review of this information in the SE.

Document Title Revision / Date BWRVIP-05P BWR Vessels and Internals Project: September 1995 BWR Reactor Pressure Vessel Shell Weld Inspection Recommendations BWRVIP-329-A BWR Vessels and Internals Program: Updated Probabilistic December 2021 Fracture Mechanics Analyses for BWR PWR Welds to Address Extended Operations SIA 2100300.401P Reactor Pressure Vessel Axial and Circumferential Weld 10/5/2022 Analysis with BWRVIP-329-A During the audit of the TLAA, the staff verified that the applicant has provided its basis that supports its disposition of 10 CFR 54.21(c)(1)(iii).

During its audit, the staff assessed the plant-specific RPV dimensions and the plant-specific end-of-interval reference temperature (RTmax) values to verify the applicants RPV is within the envelope of limiting RTmax values established in BWRVIP-329-A. The staff noted that the plant-specific end-of-interval RTmax values were calculated based on the material properties of the RV (e.g., initial RTNDT, weight % Cu, weight % Ni, and chemistry factor) based on 72 EFPY.

During the audit, the staff made the following observations:

  • The plant-specific dimensions of the applicants RPV are enveloped by the RPV dimensions assessed in the probabilistic fracture mechanics (PFM) analyses in BWRVIP-329-A.
  • The plant-specific end-of-interval RTmax values for the limiting plate and circumferential weld was calculated based on plant-specific material properties of the RV based on 72 EFPY.
  • The plant-specific end-of-interval RTmax values were calculated consistent with BWRVIP-329-A. The staff noted that the applicant conservatively included an additional margin term to its plant-specific end-of-interval RTmax value.

o The staff noted that the licensees internal SIA Calc 2100300.401P and SLRA Sections 4.2.5 and 4.2.6 interchangeably used the terms RTmax and ART though these terms are defined differently. During its audit, the licensee acknowledged the staffs observation. The staffs review of this observation will be discussed in its SER.

  • The plant-specific end-of-interval RTmax value for the limiting plate and circumferential weld, including the respective conservative margin term, was less than the corresponding limiting RTmax value for plates and circumferential welds in BWRVIP-329-A.

Based on its audit, the staff confirmed that the RPV dimensions are within the limits of the enveloping RPV dimensions of BWRVIP-329-A. The staff also verified and confirmed that the applicants plant-specific calculations using material chemistry values of the limiting circumferential weld. More specifically, that the end-of-interval RTmax was less than the limiting circumferential weld RTmax as calculated in reference to BWRVIP-329-A.

The staff also audited the description of the SLRA TLAA for RPV circumferential weld examination relief provided in the USAR supplement. The staff verified this description is consistent with the description provided in the SRP-SLR for TLAAs.

SLRA TLAA Section 4.2.6, RPV Axial Weld Failure Probability Summary of Information in the Application. SLRA Section 4.2.6, RPV Axial Weld Failure Probability, discusses the analysis for the reduction of ASME Code,Section XI examination of RPV axial welds. The applicant dispositioned the TLAA in accordance with 10 CFR 54.21(c)(1)(ii).

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the TLAA. The staff will document its review of this information in the SE.

Document Title Revision / Date BWRVIP-05P BWR Vessels and Internals Project: September 1995 BWR Reactor Pressure Vessel Shell Weld Inspection Recommendations BWRVIP-329-A December 2021 Document Title Revision / Date BWR Vessels and Internals Program: Updated Probabilistic Fracture Mechanics Analyses for BWR PWR Welds to Address Extended Operations SIA 2100300.401P Reactor Pressure Vessel Axial and Circumferential Weld Analysis 10/5/2022 with BWRVIP-329-A During the audit of the TLAA, the staff verified that the applicant has provided its basis that supports its disposition of 10 CFR 54.21(c)(1)(ii).

During its audit, the staff assessed the plant-specific RPV dimensions and the plant-specific end-of-interval RTmax values to verify the applicants RPV is within the envelope of limiting RTmax values established in BWRVIP-329-A. The staff noted that the plant-specific end-of-interval RTmax values were calculated based on the material properties of the RV (e.g., initial RTNDT, weight % Cu, weight % Ni, and chemistry factor) based on 72 EFPY.

During the audit, the staff made the following observations:

  • The plant-specific dimensions of the applicants RPV are enveloped by the RPV dimensions assessed in the PFM analyses in BWRVIP-329-A.
  • The plant-specific end-of-interval RTmax values for the limiting plate and axial weld was calculated based on plant-specific material properties of the RV based on 72 EFPY.
  • The plant-specific end-of-interval RTmax values were calculated consistent with BWRVIP-329-A. The staff noted that the applicant conservatively included an additional margin term to its plant-specific end-of-interval RTmax value.

o The staff noted that the licensees internal SIA Calc 2100300.401P and SLRA Sections 4.2.5 and 4.2.6 interchangeably used the terms RTmax and ART though these terms are defined differently. During its audit, the licensee acknowledged the staffs observation. The staffs review of this observation will be discussed in its SER.

  • The plant-specific end-of-interval RTmax value for the limiting plate and axial weld, including the respective conservative margin term, was less than the corresponding limiting RTmax value for plates and axial welds in BWRVIP-329-A.

Based on its audit, the staff confirmed that the RPV dimensions are within the limits of the enveloping RPV dimensions of BWRVIP-329-A. The staff also verified and confirmed that the applicants plant-specific calculations using material chemistry values of the limiting axial weld.

More specifically, that the end-of-interval RTmax was less than the limiting axial weld RTmax as calculated in reference to BWRVIP-329-A.

The staff also audited the description of the SLRA TLAA for RPV axial weld failure probability provided in the USAR supplement. The staff verified this description is consistent with the description provided in the SRP-SLR for TLAAs.

SLRA TLAA Section 4.2.7, Reflood Thermal Shock Analysis of the RPV Summary of Information in the Application. SLRA Section 4.2.7, Reflood Thermal Shock Analysis of the RPV, discusses the analysis for non-ductile failure of the RPV for all postulated plant conditions. The applicant dispositioned the TLAA in accordance with 10 CFR 54.21(c)(1)(ii).

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the TLAA. The staff will document its review of this information in the SE.

Document Title Revision/Date NA Fracture Mechanics Evaluation of a Boiling Water Reactor Vessel August 1979 Following a Postulated Loss of Coolant Accident GE Report No. An Analytical Study on Brittle Fracture of GE-BWR Vessels Subject June 1969 NEDO-10029 to the Design Basis Accident NA ASME Code Section XI 2004 Edition During the audit of the TLAA, the staff verified that the applicant has provided its basis that supports its disposition of 10 CFR 52.21(c)(1)(ii).

During the audit, the staff made the following observations:

  • A referenced SIA Calculation for determining the maximum stress intensity factor in the postulated case of a brittle/ductile transition fracture used a postulated accident temperature of 174.4°F as opposed to the stated 0T ART value from the SLRA of 197.8°F.
  • A maximum KIapplied value of 105 ksiin is used during the postulated transient, which differed from the stated value of 103 ksiin from the LRA. The staff will address the use of a maximum KIapplied value of 105 ksiin used during the postulated transient in the SER.

The staff also audited the description of the SLRA Reflood Thermal Shock Analysis of the RPV provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-SLR.

SLRA TLAA Section 4.2.8, Reflood Thermal Shock Analysis of the RPV Core Shroud Summary of Information in the Application. SLRA Section 4.2.8, Reflood Thermal Shock Analysis of the RPV, discusses the analysis for non-ductile failure of the RPV core shroud for all postulated plant conditions. The applicant dispositioned the TLAA in accordance with 10 CFR 54.21(c)(1)(ii).

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the TLAA. The staff will document its review of this information in the SE.

Document Title Revision/Date BWRVIP-66 BWR Vessel and Internals Project, Review of Test Data for 1999 Irradiated Stainless Steel Components ML050880245 and Monticello Application for Renewed Operating License March 2005 ML050880237 BWRVIP-06-A BWR Vessel and Internal Project, Safety Assessment of BWR 2002 Reactor Internals BWRVIP-25 BWR Vessel and Internal Project, BWR Core Plate Inspection and Revision 1-A / 2020 Flaw Evaluation Guidelines BWRVIP-315 BWR Vessel and Internals Project Reactor Internals Aging Final / July 2019 Management Evaluation for Extended Operations During the audit of the TLAA, the staff verified that the applicant has provided its basis that supports its disposition of 10 CFR 52.21(c)(1)(ii).

During the audit, the staff made the following observations:

  • In Table 4.2.1.2-1 of the SLRA the maximum fast neutron fluence for the core shroud was listed as 3.68 x 1021 n/cm2, this value was also used in the supporting SIA Calculation 2100300.402. In SLRA Section 4.2.8 the maximum quoted fluence for the core shroud was 5.68 x 1021 n/cm2 (E > 1 MeV) for 80 years of operation.
  • By letter dated June 26, 2023, the applicant revised SLRA Section 4.2.8 to clarify that the maximum fluence value for the core shroud is 3.68 x 1021, which will be addressed in the SER.

The staff also audited the description of the SLRA Reflood Thermal Shock Analysis of the RPV Core Shroud provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-SLR.

SLRA TLAA Section 4.2.9, Loss of Preload for Core Plate Rim Holddown Bolts Summary of Information in the Application. SLRA Section 4.2.9, Loss of Preload for Core Plate Rim Holddown Bolts, discusses the analysis for the loss of preload for core plate rim holddown bolts. The applicant dispositioned the TLAAs in accordance with 10 CFR 54.21(c)(1)(ii).

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the TLAA. The staff will document its review of this information in the SE.

Document Title Revision / Date BWRVIP-25, Rev 1-A BWR Core Plate Inspection and Flaw Evaluation Guidelines 2020 Document Title Revision / Date 2100300.403P Stress Relaxation of Core Plate Rim Holddown Bolts Analysis 10/6/2022 NX-7831-197-1 Xcel Energy Drawing - Monticello Nuclear Generating Plant 10/6/2022 Reactor Vessel & Internals EC0000019006 SC 11-05 Seismic Channel Control Interference Revision 0 Xcel Energy Design Input Monticello Shroud Flaw Evaluation, SIA Proposal 10/20/2010 Transmittal 13638-05 No.1001207.R0 NUC 03.19 Channel Bow Management Program at Monticello Revision 7 MFN 08-420 R1 Update to GEH Surveillance Program for Channel-Control Blade 12/16/2013 Interface Monitoring MFN 10-245 R4 Part 21 Reportable Condition Notification: Failure to Include 9/26/2011 Seismic Input in Channel-Control Blade Interface AR 01411208 GNF Cell Friction Safety Communication revisions issued 2/17/2014 1054 Control Rod Drive Normal Drive Timing Test Revision 27 Ops Man C.1 Operations Manual Section: Startup Procedure C.1 Revision 94 During the audit of the TLAA, the staff verified that the applicant has provided its basis that supports its disposition of 10 CFR 54.21(c)(1)(ii).

During the audit, the staff made the following observations:

  • Appendix I of BWRVIP-25, Rev 1-A contains steps to be addressed by the licensee to determine if BWRVIP-25, Rev. 1-A is applicable for justifying that inspections of core plate bolts are no longer required.
  • The staff verified through its review of the USAR and plant-specific procedures, drawings, calculations, and basis documents that the applicant adequately addressed the all steps in Appendix I of BWRVIP-25, Rev 1-A to determine application of the analysis results from BWRVIP-25, Rev 1-A for its plant.

The staff also audited the description of the TLAA for loss of preload for core plate rim holddown bolts provided in the USAR supplement. The staff verified this description is consistent with the description provided in the SRP-SLR for TLAAs.

SLRA TLAA Section 4.2.10, Susceptibility to IASCC Summary of Information in the Application. SLRA Section 4.2.10, Susceptibility to IASCC, discusses the analysis for RVI that may be susceptible to irradiation-assisted stress corrosion cracking (IASCC). The applicant dispositioned the TLAA in accordance with 10 CFR 54.21(c)(1)(iii).

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the TLAA. The staff will document its review of this information in the SE.

Document Title Revision / Date EE608000000839 MNGP Evaluation - TLAA of IASCC Revision 1 BWRVIP-315 BWR Vessel and Internals Project Reactor Internals Aging 2019 Management Evaluation for Extended Operations During the audit, the staff made the following observations:

During the audit of the TLAA, the staff verified that the applicant has provided its basis that supports its disposition of 10 CFR 54.21(c)(1)(iii). However, the staff found that sufficient information was not available to complete its review of the applicants basis for its TLAA disposition. In order to obtain the necessary information, the staff will consider issuing an RAI.

During the audit, the staff made the following observations:

  • There were inconsistencies with the components identified as being susceptible to IASCC between initial LR and SLR. The staff will address this topic or RAI in the SE.
  • There were inconsistencies with the components identified in SLRA Section 4.2.1 and SLRA Section 4.2.10 that exceeded the neutron fluence threshold for being susceptible to IASCC. The staff will address this topic or RAI in the SE.

The staff also audited the description of the TLAA for Susceptibility to IASCC provided in the USAR supplement. The staff found that sufficient information was not available to determine whether the description provided in the USAR supplement was an adequate description of the TLAA for Susceptibility to IASCC. The staff will consider issuing an RAI in order to obtain the information necessary to verify the sufficiency of the USAR supplement program description.

SLRA TLAA Section 4.3.1, 80-Year Transient Cycle Projections Summary of Information in the Application. SLRA Section 4.3.1, 80-Year Transient Cycle Projections, discusses the 80-year transient cycle projections for fatigue analyses. The applicant indicated that the 80-year transient cycle projections are not a TLAA because the transient cycle projections are used only as input to fatigue TLAAs and the specific dispositions of fatigue TLAAs are described in SLRA Sections 4.3.2 through 4.3.7. To verify the adequacy of the transient cycle projections, the staff audited the 80-year cycle projections.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the 80-year cycle projections. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 0 002 Renewal - Aging Effects Operating Experience Report SIA Calculation 80-Year Cycle Projections for Monticello Revision 0 2100507.301 SIA Calculation 80-Year Fatigue Analysis of Reactor Pressure Vessel (RPV), Revision 0 2100507.302P Reactor Vessel Internals (RVI), and Penetrations SIA Calculation 80-Year Fatigue Analysis of Selected Class 1 Reactor Revision 0 2100507.303 Coolant Pressure Boundary (RCPB) Piping SIA Calculation Evaluation of ANSI B31.1 and ASME Class 2 and 3 Piping Revision 0 2100507.304 and Components (Non-Class 1 Fatigue)

SIA Calculation Monticello Environmentally Assisted Fatigue Analysis for 80 Revision 0 2100507.305P Years, NUREG/CR-6260 Locations SIA Calculation Monticello Environmentally Assisted Fatigue Screening Revision 0 2100507.306 SIA Calculation Fatigue Exemption of Monticello Reactor Pressure Vessel Revision 0 2100507.309 (RPV) Components CR 608000000752 2019-2021 Equipment Cycles Update 9/24/2021 During the audit of the 80-year cycle projections, the staff verified that the applicant has provided its basis that supports the adequacy of the cycle projections. However, the staff found that sufficient information was not available to complete its review of the applicants basis for the 80-year cycle projections. In order to obtain the necessary information, the staff will consider issuing RAIs.

During the audit, the staff made the following observations.

  • SLRA Section 4.3.1 explains that the transient cycle projections are based on the cycle accumulation rates of the most recent 10-year evaluation period up to May 31, 2021.

However, the SLRA does not clearly address why the cycle projections do not consider the full cycle accumulation rates observed since the start of the plant operation.

The staff also audited the description of the 80-year cycle projections for fatigue analyses provided in the USAR supplement. The staff verified this description is consistent with the guidance in the SRP-SLR.

SLRA TLAA Section 4.3.2, ASME Section III, Class 1 Fatigue Waivers Summary of Information in the Application. SLRA Section 4.3.2, ASME Section III, Class 1 Fatigue Waivers, discusses the fatigue waiver TLAA for ASME Code Section III, Class 1 components. The applicant dispositioned the TLAA in accordance with 10 CFR 54.21(c)(1)(iii).

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the fatigue waiver TLAA. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 0 002 Renewal - Aging Effects Operating Experience Report SIA Calculation 80-Year Cycle Projections for Monticello Revision 0 2100507.301 SIA Calculation 80-Year Fatigue Analysis of Reactor Pressure Vessel (RPV), Revision 0 2100507.302P Reactor Vessel Internals (RVI), and Penetrations SIA Calculation 80-Year Fatigue Analysis of Selected Class 1 Reactor Revision 0 2100507.303 Coolant Pressure Boundary (RCPB) Piping SIA Calculation Fatigue Exemption of Monticello Reactor Pressure Vessel Revision 0 2100507.309 (RPV) Components Chicago Bridge & Iron Section S14, Stress Analysis Instrumentation Nozzles N11A- Revision 1 (CB&I) CA-68-667 B and N12A-B Monticello-NSP Reactor Vessel Document Title Revision / Date CB&I CA-68-668 Section S15, Stress Analysis Jet Pump Instrumentation, Revision 1 Nozzles N8A & B Monticello-NSF Reactor Vessel CB&I CA-69-515 Section S12, Stress Analysis Head Cooling Spray and Revision 2 Instrumentation Nozzles N6A-B Monticello-NSP Reactor Vessel CB&I CA-69-516 Section S13, Stress Analysis of Vent Nozzle N-7 Monticello- Revision 2 NSP Reactor Vessel General Electric (GE) Reactor Vessel Head Cooling Spray and Instrumentation Revision 0 23A4279 Nozzles N6A and N6B GE 23A4280 Reactor Vessel Vent Nozzle N7 Revision 0 CR 608000000752 2019-2021 Equipment Cycles Update 9/24/2021 During the audit of the TLAA, the staff verified that the applicant has provided its basis that supports its disposition of 10 CFR 54.21(c)(1)(iii). However, the staff found that sufficient information was not available to complete its review of the applicants basis for its TLAA disposition. In order to obtain the necessary information, the staff will consider issuing RAIs.

During the audit, the staff made the following observations.

  • In SLRA Section 4.3.2 (page 4.3-6), the heading of the paragraph for TLAA disposition indicates that the fatigue waiver TLAA is dispositioned in accordance with 10 CFR 54.21(c)(1)(ii) that the analysis has been projected to the end of the subsequent period of extended operation. In contrast, the text under the paragraph heading indicates that the fatigue waiver TLAA is dispositioned in accordance with 10 CFR 54.21(c)(1)(iii) that the effects of aging on the intended function(s) will be adequately managed for the subsequent period of extended operation.
  • SLRA Section 4.3.2 indicates that the following RPV components have existing (original) fatigue waiver evaluations: (1) main closure flange, (2) head cooling spray and instrumentation nozzles; (3) vent nozzle; (4) instrumentation nozzles; (5) jet pump instrumentation nozzles; (6) intermediate range monitor/source range monitor (IRM/SRM) dry tube; (7) power range detector assembly; and (8) in-core detector assembly. However, the design stress analyses for the instrumentation nozzles (N11A-B and N12A-B nozzles) and jet pump instrumentation nozzles (N8A-B nozzles) in the following references do not include a fatigue waiver evaluation for these nozzles (

References:

(1) CA-68-667, Revision 1, Section S14, Stress Analysis of Instrumentation Nozzles N11A-B and N12A-B, Monticello-NSP Reactor Vessel; and (2) CA-68-668, Revision 1, Section S15, Stress Analysis of Jet Pump Instrumentation, Nozzles N8A & B, Monticello-NSF Reactor Vessel).

  • SLRA Section 4.3.2 does not clearly discuss why the existing fatigue waiver evaluations remain valid for the subsequent period of the extended operation for the head cooling spray and instrumentation nozzles (N6A and N6B nozzles) and vent nozzle (N7 nozzle). In addition, SLRA Table 4.3.1-1 indicates that the following transients are not listed in the USAR and accordingly USAR does not define a design cycle limit for these transients:

(1) sudden start transient; (2) hot standby with drain shutoff transient; (3) core spray injection transient; and (4) operating basis earthquake (OBE) transient. SLRA Table 4.3.1-1 also indicates that these transients have not occurred during the plant operation (as of May 31, 2021) and each of these transients is estimated to have one projected cycle for 80 years of operation. However, the applicant did not clearly discuss whether these non-USAR-listed transients have an impact on the validity of the fatigue wavier evaluations discussed in SLRA Section 4.3.2.

The staff also audited the description of the fatigue waiver TLAA for ASME Code Section III, Class 1 components provided in the USAR supplement. The staff verified this description is consistent with the description provided in the SRP-SLR.

SLRA TLAA Section 4.3.3, RPV Fatigue Analysis Summary of Information in the Application. SLRA Section 4.3.3, RPV Fatigue Analysis, discusses the analyses for the RPV Class 1 fatigue analyses. The applicant dispositioned the TLAAs in accordance with 10 CFR 54.21(c)(1)(iii).

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the TLAA. The staff will document its review of this information in the SE.

Document Title Revision / Date 2100507.302P 80-Year Fatigue Analysis of Reactor Pressure Vessel (RPV), Revision 0 Reactor Vessel Internals (RVI), and Penetrations 2100507.301 80-year Cycle Projections for Monticello Revision 0 Monticello Nuclear Generating Plant Subsequent License XCELMO00017-REPT- Renewal Aging Management Program Basis Document - Fatigue Revision 1 067 Monitoring During the audit of the TLAA, the staff verified that the applicant has provided its basis that supports its disposition of 10 CFR 54.21(c)(1)(iii). During the audit, the staff made the following observations:

  • Fatigue analysis of RPV components for the subsequent period of extended operation was performed using a methodology consistent with the existing CLB analyses, but was only updated to include projected cycles for 80 years of operation.

The staff also audited the description of the SLRA TLAA for RPV fatigue analyses provided in the USAR supplement. The staff verified this description is consistent with the description provided in the SRP-SLR.

SLRA TLAA Section 4.3.4, Fatigue Analysis of RPV Internals Summary of Information in the Application. SLRA Section 4.3.4, Fatigue Analysis of RPV Internals, discusses the fatigue TLAA for RPV internal components. The applicant dispositioned the TLAA in accordance with 10 CFR 54.21(c)(1)(i).

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the fatigue TLAA for RPV internals. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 0 002 Renewal - Aging Effects Operating Experience Report SIA Calculation 80-Year Cycle Projections for Monticello Revision 0 2100507.301 SIA Calculation 80-Year Fatigue Analysis of Reactor Pressure Vessel Revision 0 2100507.302P (RPV), Reactor Vessel Internals (RVI), and Penetrations CAP 501000026533 In-Vessel Visual Inspection Examinations of the Steam 4/29/2019 Dryer USAR Section Reactor Steam Dryer Analyses Revision 36 12.2.2.17 USAR Section 3.6.3.3 Performance of Reactor Internals Revision 38 APED-5460 Design and Performance of General Electric Boiling Water September 1968 Reactor Jet Pumps CR 608000000752 2019-2021 Equipment Cycles Update 9/24/2021 During the audit of the TLAA, the staff verified that the applicant has provided its basis that supports its disposition of 10 CFR 54.21(c)(1)(i). However, the staff found that sufficient information was not available to complete its review of the applicants basis for its TLAA disposition. In order to obtain the necessary information, the staff will consider issuing RAIs.

During the audit, the staff made the following observations.

  • In SLRA Section 4.3.4, the heading of the paragraph for TLAA disposition indicates that the fatigue TLAA for RPV internal components is dispositioned in accordance with 10 CFR 54.21(c)(1)(ii) that the analysis has been projected to the end of the subsequent period of extended operation. In contrast, the text under the paragraph heading indicates that the fatigue TLAA is dispositioned in accordance with 10 CFR 54.21(c)(1)(i) that the analysis remains valid for the subsequent period of extended operation.

The staff also audited the description of the fatigue TLAA for RPV internal components provided in the USAR supplement. The staff verified this description is consistent with the description provided in the SRP-SLR.

SLRA TLAA Section 4.3.5, ASME Section III, Class 1 Summary of Information in the Application. SLRA Section 4.3.5, ASME Section III, Class 1, discusses the fatigue TLAA for ASME Code Section III, Class 1 piping systems. The applicant dispositioned the TLAA in accordance with 10 CFR 54.21(c)(1)(iii).

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the fatigue TLAA for ASME Code Section III, Class 1 piping systems. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 0 002 Renewal - Aging Effects Operating Experience Report SIA Calculation 80-Year Cycle Projections for Monticello Revision 0 2100507.301 SIA Calculation 80-Year Fatigue Analysis of Selected Class 1 Reactor Coolant Revision 0 2100507.303 Pressure Boundary (RCPB) Piping GE-NE-0000-0077- Nuclear Management Company, LLC (NMC) Monticello Nuclear Revision 0 1167-TR-R0 Generating Plant Extended Power Uprate (2044 MWt)

CR 608000000752 2019-2021 Equipment Cycles Update 9/24/2021 During the audit of the TLAA, the staff verified that the applicant has provided its basis that supports its disposition of 10 CFR 54.21(c)(1)(iii). However, the staff found that sufficient information was not available to complete its review of the applicants basis for its TLAA disposition. In order to obtain the necessary information, the staff will consider issuing RAIs.

During the audit, the staff made the following observations.

  • In relation to the fatigue TLAA for Class 1 piping, Section 4.2 of SIA Report 2100507.303, Revision 0 discusses the fatigue analysis for the core spray line. The analysis in the SIA report considered the original condition as well as the temperature and pressure conditions for the extended power uprate (EPU). With respect to the core spray line, Table 4 of the SIA report indicates that the bounding thermal transient of the original condition is 546 °F to 80 °F in comparison with the bounding thermal transient of the EPU condition, 549 °F to 80 °F. The table also explains that the original condition for pressure is 1000 psia in comparison with the EPU pressure of 1025 psia. Based on these data, the applicant determined a pressure ratio of 1.025 for the implementation of the EPU (i.e., 1025/1000). In contrast, SLRA Section 4.3.5 indicates that the thermal transient from 546 °F to 80 °F, which corresponds to the original thermal transient according to the SIA report, is the basis for the EPU condition and the associated loading that are evaluated in the fatigue analysis for the core spray line. Additionally, SLRA Section 4.3.5 indicates that the bounding transient of the EPU condition for the residual heat removal (RHR) intertie line is the transient from 150 °F to 546 °F in contrast with the SIA report that refers to a thermal transient from 150 °F to 549 °F as the bounding transient of the EPU condition.
  • SLRA Section 4.3.5 explains that the recirculation and RHR piping systems were analyzed in 2005 through 2006. The SLRA section also indicates that the recirculation piping, including inlet nozzle safe ends and RHR supply and return lines to the containment penetrations, was replaced in 1985 and that the bounding cumulative usage factor (CUF) is 0.923 at a branch line connection to the RHR intertie line. SLRA Section 4.3.5 further explains that the applicant reanalyzed the bounding location for 80 years of operation, considering the cycles adjusted to remove the cycles accumulated before piping replacement and the EPU condition. In addition, the SLRA section indicates that the 80-year CUF was estimated to be 0.399 in the reanalysis for 80 years of operation. Therefore, the applicant significantly reduced the bounding CUF value for the recirculation and RHR piping systems (from 0.923 to 0.399). However, the applicant did not clearly address the following items: (1) the operating time period for which the previous CUF value of 0.923 was determined (e.g., 60 years or 40 years); (2) how the applicant removed the conservatism from the previous CUF (0.923) in addition to the removal of the cycles accumulated before the piping replacement; and (3) whether the Fatigue Monitoring AMP will monitor, if any, reduced cycles used in the 80-year CUF analysis, as opposed to the original design cycles in case such reduced cycles are assumed in the 80-year CUF analysis.

The staff also audited the description of the fatigue TLAA for ASME Code Section III, Class 1 piping systems provided in the USAR supplement. The staff verified that this description is consistent with the description provided in the SRP-SLR.

SLRA TLAA Section 4.3.6, ASME Section III, Class 2 and 3 and ANSI B31.1 Summary of Information in the Application. SLRA Section 4.3.6, ASME Section III, Class 2 and 3 and ANSI B31.1, discusses the fatigue TLAA for ASME Code Section III, Class 2 and 3 and ANSI B31.1 piping systems. The applicant dispositioned the TLAA in accordance with 10 CFR 54.21(c)(1)(i).

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the fatigue TLAA for ASME Code Section III, Class 2 and 3 and ANSI B31.1 piping systems. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 0 002 Renewal - Aging Effects Operating Experience Report SIA Calculation 80-Year Cycle Projections for Monticello Revision 0 2100507.301 SIA Calculation Evaluation of ANSI B31.1 and ASME Class 2 and 3 Piping Revision 0 2100507.304 and Components (Non-Class 1 Fatigue)

During the audit of the TLAA, the staff verified that the applicant has provided its basis that supports its disposition of 10 CFR 54.21(c)(1)(i). However, the staff found that sufficient information was not available to complete its review of the applicants basis for its TLAA disposition. In order to obtain the necessary information, the staff will consider issuing RAIs.

During the audit, the staff made the following observations.

  • USAR, Appendix I describes the CLB evaluation of the high energy line breaks outside the containment. Specifically, USAR Appendix I,Section I.3.1 indicates that the postulation of high energy line break (HELB) locations is, in part, based on the allowable stress range for expansion stress (SA), consistent with Branch Technical Position (BTP) 3-3, Appendix B (ML070800027). SA may need to be adjusted by a stress range reduction factor based on the number of transient cycles that are evaluated in the implicit fatigue analysis. However, SLRA Section 4.3.6 does not identify the HELB analysis as a TLAA based on the HELB location postulation that involves SA and the associated cycle-dependent stress range reduction factor.

The staff also audited the description of the fatigue TLAA for ASME Code Section III, Class 2 and 3 and ANSI B31.1 piping systems provided in the USAR supplement. The staff found that sufficient information was not available to determine whether the description provided in the USAR supplement was an adequate description of the fatigue TLAA for ASME Code Section III, Class 2 and 3 and ANSI B31.1 piping systems. The staff will consider issuing an RAI in order to obtain the information necessary to verify the sufficiency of the USAR supplement description in relation to the HELB analysis discussed above.

SLRA TLAA Section 4.3.7, Environmentally-Assisted Fatigue Summary of Information in the Application. SLRA Section 4.3.7, Environmentally-Assisted Fatigue, discusses the environmentally assisted fatigue (EAF) TLAA for reactor coolant pressure (RCP) boundary (ASME Code Section III, Class 1) piping and components. The applicant dispositioned the TLAA in accordance with 10 CFR 54.21(c)(1)(iii).

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the EAF TLAA for the RCP boundary piping and components. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 0 002 Renewal - Aging Effects Operating Experience Report SIA Calculation 80-Year Cycle Projections for Monticello Revision 0 2100507.301 SIA Calculation Monticello Environmentally Assisted Fatigue Analysis for 80 Revision 0 2100507.305P Years, NUREG/CR-6260 Locations SIA Calculation Monticello Environmentally Assisted Fatigue Screening Revision 0 2100507.306 SIA Calculation 80-Year Fatigue Analysis of Reactor Pressure Vessel Revision 0 2100507.302P (RPV), Reactor Vessel Internals (RVI), and Penetrations Document Title Revision / Date SIA Calculation 80-Year Fatigue Analysis of Selected Class 1 Reactor Revision 0 2100507.303 Coolant Pressure Boundary (RCPB) Piping CR 608000000752 2019-2021 Equipment Cycles Update 9/24/2021 During the audit of the TLAA, the staff verified that the applicant has provided its basis that supports its disposition of 10 CFR 54.21(c)(1)(iii). However, the staff found that sufficient information was not available to complete its review of the applicants basis for its TLAA disposition. In order to obtain the necessary information, the staff will consider issuing RAIs.

During the audit, the staff made the following observations.

  • SLRA Section 4.3.7 indicates that the EAF screening evaluation to determine the limiting locations (also called sentinel locations) uses bounding environmental fatigue correction factor (Fen) based on material types. However, the SLRA does not clearly describe how the applicant calculated the bounding Fen values.
  • SLRA Section 4.3.7 does not list the recirculation outlet nozzle as one of the NUREG/CR-6260 locations. Instead, the SLRA section identifies the recirculation outlet nozzle location as one of the additional plant-specific evaluation locations subject to EAF screening. The SLRA also explains that the recirculation outlet nozzle (safe end location) is screened out because its screening environmental cumulative usage factor (screening CUFen) is less than the screening threshold of 1.0. However, it is not clear to staff whether the screening evaluation of the recirculation outlet nozzle includes both the nozzle body and the adjacent piping location (e.g., safe end or safe end weld). In addition, the SLRA does not clearly discuss whether the recirculation outlet nozzle body is bounded by the recirculation inlet nozzle body or other RPV nozzle bodies.
  • SLRA Section 4.3.7 does not clearly describe the following items related to the EAF screening evaluation: (1) how the applicant determined thermal zones or sections that group certain components and piping lines for adequate comparisons of the screening CUFen values considering the applicable transient conditions; (2) whether the limiting EAF location is determined for each material type (e.g., stainless steel, nickel alloy, and carbon/low alloy steel); and (3) how the applicant compared the highest values of the screening CUFen values to determine the final limiting locations (e.g., how the limiting locations were determined when the highest CUFen values are close to each other in a thermal zone).
  • SLRA Section 4.3.7 indicates that, after the screening evaluation, the applicant removed the conservatism associated with the screening CUFen values in more detailed EAF evaluation to determine the refined CUFen values for 80 years of operation that are described in SLRA Table 3.4.7-1. However, the SLRA does not clearly describe how the conservatism was removed from the screening CUFen values to determine the 80-year projected CUFen values.
  • The following reference discusses the EAF analysis for the NUREG/CR-6260 locations applicable to the Monticello Nuclear Generating Plant that is an older vintage GE plant

(

Reference:

Structural Integrity Associates (SIA), Calculation Package No. 2100507.305P, Monticello Environmentally Assisted Fatigue Analysis for 80 Years, NUREG/CR-6260 Locations, June 24, 2022). Section 3.1 of the SIA report indicates that, for the loss of

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recirculation pumps transient, the design cycle number (i.e., 20 cycles) is used in the EAF analysis for 80 years of operation. Based on the use of the design cycles in the EAF analysis for the recirculation and RHR return piping, the SIA report recommends a review of operating logs to validate this assumption for the transient cycle number used in the EAF analysis. However, SLRA Section 4.3.7 does not clearly indicate whether the applicant confirmed that the use of the design cycles (20 cycles) of the loss of recirculation pumps transient is adequate for the EAF analysis.

The staff also audited the description of the EAF TLAA for the RCP boundary piping and components provided in the USAR supplement. The staff verified this description is consistent with the description provided in the SRP-SLR.

SLRA TLAA Section 4.4, Environmental Qualification of Electric Equipment Summary of Information in the Application. SLRA Section 4.4, Environmental Qualification of Electric Equipment, discusses the thermal, radiation, and cyclical aging analyses for the plant electrical components. The applicant dispositioned the TLAA in accordance with 10 CFR 54.21(c)(1)(iii).

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the TLAA. The staff will document its review of this information in the SE.

Document Title Revision / Date Monticello Nuclear Generating Plant Subsequent License XCELMO00017-REPT-Renewal Management Program Basis Document - Revision 1 060 Environmental Qualification of Electrical Equipment EWI-04.05.01 Thermography Program Revision 14 EWI-08.11.01 Equipment Qualification Users Manual Revision 26 AR01492160/AT-0175 Action Requests Record Revision 3 Electrical Environmental Qualification (EEQ) Program Health NA 1/20/2020 Report Electrical Environmental Qualification (EEQ) Program Health NA 7/20/2020 Report During the audit of the TLAA, the staff verified the applicant has provided its basis that supports its disposition of 10 CFR 54.21(c)(1)(iii).

The staff also audited the description of the SLRA Environmental Qualification of Electric Equipment provided in the USAR supplement. The staff verified this description is consistent with the descriptions provided in the SRP-SLR Report.

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SLRA TLAA Section 4.5, Containment Liner Plate, Metal Containments and Penetrations Fatigue, and SLRA TLAA Section 4.6.2, Fatigue Analyses of High-Pressure Coolant Injection (HPCI) and Reactor Core Isolation Cooling (RCIC) Turbine Exhaust Penetrations Summary of Information in the Application. SLRA Section 4.5.1, Fatigue Analysis of Suppression Chamber, Vents, and Downcomers, discusses the fatigue analysis for the carbon steel primary containment suppression chamber (torus), vents and downcomers. The applicant dispositioned the TLAAs in accordance with 10 CFR 54.21(c)(1)(iii).

SLRA Section 4.5.2, Fatigue Analysis of the Safety Relief Valves (SRVs) Discharge Piping Inside the Suppression Chamber, discusses the fatigue analysis for the carbon steel SRV discharge piping inside the suppression chamber (torus). The applicant dispositioned the TLAAs in accordance with 10 CFR 54.21(c)(1)(iii).

SLRA Section 4.5.3, Fatigue Analysis of Suppression Chamber External Piping and Penetrations, including Ring Header, discusses the fatigue analysis for the carbon steel suppression chamber external piping and penetrations. The applicant dispositioned the TLAAs in accordance with 10 CFR 54.21(c)(1)(iii).

SLRA Section 4.5.4, Drywell to Suppression Chamber Vent Line Bellows Fatigue Analysis, discusses the fatigue analysis for the carbon steel drywell to suppression chamber vent line bellows. The applicant dispositioned the TLAAs in accordance with 10 CFR 54.21(c)(1)(i).

SLRA Section 4.5.5, Primary Containment Process Penetration Bellows Fatigue Analysis, discusses the fatigue analysis for the carbon steel primary containment process penetration bellows. The applicant dispositioned the TLAAs in accordance with 10 CFR 54.21(c)(1)(i).

SLRA Section 4.6.2, Fatigue Analyses of High-Pressure Coolant Injection (HPCI) and Reactor Core Isolation Cooling (RCIC) Turbine Exhaust Penetrations, discusses the fatigue analyses for the carbon steel HPCI and RCIC turbine exhaust penetrations. The applicant dispositioned the TLAAs in accordance with 10 CFR 54.21(c)(1)(ii).

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the TLAA. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- MNGS SLR Time Limited Aging Analysis (TLAA) and Exemption Revision1 005 Identification; Enercon Report (Sections 2.6, 2.7.2)

XCELMO00017-REPT- MNGS SLR Time Limited Aging Analysis (TLAA) and Exemption Revision 0 091 Evaluation 22-014 (SIA 80-Year Fatigue Analysis of Selected Suppression Chamber Revision 0 / 6/23/2022 2100507.307) Components, Structural Integrity Associates (SIA) Calculation NA MNGP Plant Unique Analysis Report, Volume 2-5 Revision 1 SIA Calculation Evaluation of ANSI B31.1 and ASME Class 2 and 3 Piping and Revision 0 2100507.304 Components (Non-Class 1 Fatigue)

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Document Title Revision / Date MNGS SLR - Aging Effects Operating Experience Report, XCELMO00017-REPT- Enercon Report, Attachment 4 - Aging Effect OE for Structures, Revision 0 002 Structural Components and Commodities (OE Search period 01/01/10 - 07/29/21)

Fatigue Exemption of Monticello Drywell, Structural Integrity 2100507.308 Revision 0 / 9/23/2022 Associates Calculation 80-Year Fatigue Analysis of Reactor Pressure Vessel (RPV),22-009 (SIA Reactor Vessel Internals (RVI), and Penetrations 80-Year Cycle Revision 0 / 6/23/2022 2100507.302P) Projections for Monticello - Proprietary [Penetrations included are HPCI and RCIC turbine exhaust]

During the audit of the listed TLAAs, the staff verified that the applicant has provided its basis that supports its disposition of 10 CFR 54.21(c)(1)(i), (ii), or (iii), as stated previously. However, the staff found that, with exception of TLAA 4.5.4, sufficient information was not available to complete its review of the applicants basis for its TLAA dispositions. To obtain the necessary information as indicated in observations below, the staff will consider issuing RAIs or use a SLRA voluntary supplement offered by the applicant.

During the audit, the staff made the following observations:

  • During the audit, the staff reviewed calculation 22-014, Revision 0 (SIA Calculation 2100507.307) and noted it revised the existing fatigue analyses of the suppression chamber to incorporate 80-year fatigue usage. During the audit, the staff reviewed Section 4.7 of this calculation and verified the transient cycles, fatigue usage and related information stated in SLRA Section 4.5.4 for the drywell to suppression chamber vent line bellows. The staff also verified from review of this calculation the fatigue usage results presented in SLRA Sections 4.5.1, 4.5.2, 4.5.3 and summarized in SLRA Table 4.5-1 for suppression chamber components.
  • During the audit, the staff reviewed Sections 4.12 and 4.13 of Calculation 22-009, Revision 0 (SIA 2100507.302P, Rev 0) and verified that the calculated fatigue usage factors for 40 years of operation for the HPCI and RCIC turbine exhaust penetrations are 0.111 and 0.343, respectively, and corresponding conservatively projected 80-year values of 0.222 and 0.686, as stated in the SLRA 4.6.2. The staff also noted that the 40-year calculations were based on 480 thermal/pressure cycles, 1000 OBE cycles, 3670 SRV cycles and 1 design basis accident (DBA) cycle.
  • The staff noted, for the TLAAs in SLRA Sections 4.5.1, 4.5.2 and 4.5.3 which are dispositioned in accordance with 10 CFR 54.21(c)(iii), the effects of fatigue will be managed by the Fatigue Monitoring AMP (B.2.2.1). The applicant should supplement the SLRA to describe what transients in each of these TLAA evaluations will be monitored by the Fatigue Monitoring AMP, and how they are included and controlled within the scope of the AMP.
  • The staff reviewed SLRA A.3.5.5 and noted the USAR supplement description for Primary Containment Process Bellows Fatigue Analysis states the evaluation was performed as part of ASME Section III, Class 2 and 3 and ANSI B31.1 fatigue evaluation and is described in Section A.3.3.5. It appears that the SLRA intended to cross

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reference Section A.3.3.6 for non-Class 1 piping and not A.3.3.5 (which addresses Class 1 piping). However, Section A.3.3.6 makes no mention of bellows to which the summary description in A.3.5.5 applies, and therefore does not appear to provide an adequate USAR supplement for the TLAA. The staff also noted SLRA A.3.5.5 does not appear to include what the number of cycles for which the bellows were implicitly designed. The applicant should supplement the SLRA Section A.3.5.5 to provide an adequate USAR supplement description.

  • The staff reviewed SLRA Section 4.6.2 and noted it does not appear to include the transients or transient load combinations and corresponding number of cycles, based on which the higher fatigue usage of 0.111 (HPCI penetration) and 0.343 (RCIC penetration) for 40 years were calculated and projected to 80 years. The staff also noted the USAR supplement description in SLRA A.3.6.2 for HPCI and RCIC turbine exhaust penetrations does not include a TLAA disposition pursuant to 10 CFR 54.21(c)(1). The applicant should supplement the SLRA to include the information.
  • The staff noted from a search of the SLRA that Table 2 AMR item(s) is not included crediting the TLAAs in SLRA Section 4.6.2 for fatigue of HPCI and RCI turbine exhaust penetrations, which are characterized as torus attached penetrations. The applicant should supplement the SLRA to include corresponding Table 2 AMR item(s).

The staff also audited the description of SLRA 4.5.1 through 4.5.5 and 4.6.2 TLAAs provided in USAR supplement in SLRA A.3.5.1 through A.3.5.5 and A.3.6.2. The staff verified the descriptions in SLRA Sections A.3.5.1, A.3.5.2, and A.3.5.4 are consistent with the descriptions provided in the GALL-SLR Report/SRP-SLR. The staff found that sufficient information was not available in SLRA Sections A.3.5.3, A.3.5.5, and A.3.6.2 to determine whether the description provided in the USAR supplement was an adequate description of the corresponding SLRA TLAAs. The staff will consider issuing RAIs or use a voluntary SLRA supplement to obtain the information necessary to verify the sufficiency of the USAR supplement program descriptions.

SLRA TLAA Section 4.6.1, Fatigue of Cranes Summary of Information in the Application. SLRA Section 4.6.1, Fatigue of Cranes, discusses the analyses for the Reactor Building Crane and Turbine Building Crane. The applicant dispositioned the TLAAs in accordance with 10 CFR 54.21(c)(1)(i).

Audit Activities. From March 21 to March 25, 2023, the staff participated in an onsite audit at MNGP in Monticello, MN to gain a general overview of current conditions of the structures compared to the provided OE, and an understanding on the settlement issue for the Diesel Fuel Oil Transfer House and Diesel Oil Storage Tank. While onsite, the staff engaged with the applicant staff, conducted walkdowns, and reviewed documents provided by the applicant.

The table below lists documents that were reviewed by the staff and were found relevant to the TLAA. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- MNGP SLR AMP Basis Document - Inspection of Overhead Revision 1 074 Load and Light Load (Related to Refueling) Handling Systems

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Document Title Revision / Date XCELMO00017-REPT-MNGP SLR TLAA Exemption Evaluation Revision 0 091 XCELMO00017-REPT-MNGP SLR TLAA Exemption Identification Revision 1 005 XCELMO00017-REPT-Screening and AMR Results Plant Structures and Commodities Revision 2 040 XCELMO00017-REPT-MNGP SLR TLAA Technical Specification Impact Report Revision 0 090 CMAA, Specification, Specification for Electric Overhead Travelling Cranes 1975 No.70 EOCI, Specification No.

Specification for Electric Overhead Travelling Cranes 1961 61 Special Lifting Devices for Containers Weighing 10,000 Pounds ANSI N14.6-1993 1993 or More NUREG-0554 Single-Failure Proof Cranes for Nuclear Power Plants May 1979 NUREG-0612 Control of Heavy Loads at Nuclear Power Plants July 1980 Rules for Construction of Cranes, Monorails, and Hoists (With ASME NUM-1 2016 ridge or Trolley or Hoist of the Underhung Type)

Rules for Construction of Overhead and Gantry Cranes (Top ASME NOG-1 2015 Running Bridge, Multiple Girder)

Overhead and Gantry Cranes (Top Running Bridge, Single or ASME B30.2 2005 Multiple Girder, Top Running Trolley Hoist)

During the audit of the TLAA, the staff verified that the applicant has provided its basis that supports its disposition of 10 CFR 54.21(c)(1)(i).

During the onsite audit, the staff performed walkdowns of the Diesel Fuel Oil Transfer House (also called Diesel Oil Pump House), Diesel Oil Storage Tank, Turbine Building, and Reactor Building, etc. The staff made the following observation during walkdowns:

  • During the audit, the staff identified an editorial discrepancy between the SLR application and the TLAA report on how the Reactor Building and Turbine Building Cranes load cycle limits were projected through the SPEO.

The staff also audited the description of the SLRA provided in the USAR supplement in Section A.3.6.1, Fatigue of Cranes. The staff verified this description is consistent with the description provided in the SRP-SLR for TLAAs.

SLRA TLAA Section 4.6.3, Condensate Backwash Receiving Tank Fatigue Evaluation Summary of Information in the Application. SLRA Section 4.6.3, Condensate Backwash Receiving Tank Fatigue Evaluation, discusses the fatigue TLAA for the condensate backwash receiving (CBR) tank that collects backwashed sludge from the condensate demineralizers in

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the liquid waste management system. The applicant dispositioned the TLAA in accordance with 10 CFR 54.21(c)(1)(ii).

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the fatigue TLAA for the CBR tank. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 0 002 Renewal - Aging Effects Operating Experience Report NSPM Calculation No. Evaluation of Condensate Backwash Receiving Tank T-33 Revision 0 10-076 for Receiving Pressure During the audit of the TLAA, the staff verified that the applicant has provided its basis that supports its disposition of 10 CFR 54.21(c)(1)(ii). However, the staff found that sufficient information was not available to complete its review of the applicants basis for its TLAA disposition. In order to obtain the necessary information, the staff will consider issuing RAIs.

During the audit, the staff made the following observations.

  • SLRA Section 4.6.3 indicates that the annular number of airburst cycles of the CBR tank is conservatively estimated to be 160 cycles/year. However, the SLRA does not clearly discuss how the applicant estimated the annular number of airburst cycles. In addition, the SLRA does not clearly discuss whether the fatigue analysis for the CBR tank needs to consider the transient cycles in the upset and test conditions.

The staff also audited the description of the fatigue TLAA for the CBR tank provided in the USAR supplement. The staff found that sufficient information was not available to determine whether the description provided in the USAR supplement was an adequate description of the fatigue TLAA for the CBR tank. The staff will consider issuing an RAI in order to obtain the information necessary to verify the sufficiency of the USAR supplement description in relation to the basis for the annular number of airburst cycles discussed above.

AMR Items Not Associated with an AMP SLRA Sections 3.2.2.2.2, 3.2.2.2.4, 3.2.2.2.8, 3.2.2.2.10, 3.3.2.2.3, 3.3.2.2.4, 3.3.2.2.8, 3.3.2.2.10, 3.4.2.2.2, 3.4.2.2.3, 3.4.2.2.7, and 3.4.2.2.9, Further Evaluations for Stress Corrosion Cracking and Loss of Material for Stainless Steel, Nickel Alloys, and Aluminum Alloys Summary of Information in the Application. The SLRA addresses FE of cracking due to SCC, and loss of material due to pitting and crevice corrosion, of stainless steel, nickel alloys, and aluminum alloys in the Engineered Safety Features systems, Auxiliary systems, and Steam and Power Conversion systems. The SLRA Sections for these FE discussions are: 3.2.2.2.2, 3.2.2.2.4, 3.2.2.2.8, 3.2.2.2.10, 3.3.2.2.3, 3.3.2.2.4, 3.3.2.2.8, 3.3.2.2.10, 3.4.2.2.2, 3.4.2.2.3, 3.4.2.2.7, and 3.4.2.2.9.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to these FE sections. The staff will document its review of this information in the SE.

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Document Title / Description Revision / Date XCELMO0001-REPT- Monticello Nuclear Generating Plant Subsequent License Revision 0 /

002 Renewal - Aging Effects Operating Experience Report 12/22/2022 Monticello Nuclear Generating Plant Subsequent License XCELMO00017-REPT- Revision 0 /

Renewal Screening and Aging Management Review Results Off-015 11/07/2022 Gas System SLRA AMR FE 3.5.2.2.2.6, Reduction of Strength and Mechanical Properties of Concrete Due to Irradiation Summary of Information in the Application. During the audit, the staff reviewed plant documentation associated with the following:

  • SLRA Section 3.5.2.2.2.6, which describes the applicants Further Evaluation or FE of the aging effects of irradiation on concrete of the biological shield wall (BSW) around the RV and its support pedestal, and the RV support steel assembly. This FE is associated with SLRA Table 3.5.1, Items 3.5.1-097 for concrete and other associated Table 2 AMR items as itemized below. SLRA Table 1 items 3.1.1-004, 3.1.1-113, 3.5.1-091, 3.5.1-057, and 3.5.1-077 with associated Table 2 AMR items as noted below address steel components associated with this FE.
  • SLRA Table 3.5.2-1 Primary Containment - Summary of Aging Management Evaluation, which cites Concrete (reinforced): Interior (drywell equipment foundation, RPV pedestal) exposed to air - indoor uncontrolled environment in multiple entries.
  • SLRA Table 3.5.2-1 Primary Containment - Summary of Aging Management Evaluation, which cites steel liner, liner anchors and integral attachments of RPV pedestal exposed to air - indoor uncontrolled environment.
  • SLRA Table 3.1.2-1 Reactor Pressure Vessel - Summary of Aging Management Evaluation, which cites carbon steel [RV] support skirt and attachment welds exposed to air - indoor uncontrolled (external) environment associated with Table 1, items 3.1.1 004, 3.1.1-113, and 3.5.1-091.
  • SLRA Table 3.5.2-7 Hangers and Supports Commodity Group - Summary of Aging Management Evaluation, which cites steel ASME Class 1 supports (includes RV skirt and seismic restraint/stabilizers at elevation of top of BSW) exposed to air - indoor uncontrolled environment associated with Table 3.5-1, items 3.5.1-091 and 3.5.1-057.

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Interior Platforms, Stabilizers, Radial Beam Seats, etc.) exposed to air - indoor uncontrolled environment associated with Table 1, item 3.5.1-077.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the FE in SLRA Section 3.5.2.2.2.6. The staff will document its review of this information in the SE.

Document Title Revision / Date Fluence:

Transware Technical Letter - Biological Shield Neutron Fluence Revision 0 /

MNT-FLU-001-T-001 and Gamma Dose at 72 Effective Full Power Years (EFPY) 10/4/2022 Transware Technical Letter - Displacements per Atom in the Steel Revision 0 /

MNT-FLU-001-T-002 Cladding of the Biological Shield at 72 EFPY and Fast Neutron 10/4/2022 Fluence in Peripheral Fuel Support Plug 22-016 (Transware MNT- Monticello Nuclear Generating Plant (MNGP) Fluence Revision 0 /

FLU-001-R-001) Methodology Report, Transware Enterprises Inc 9/2/2022 Monticello Nuclear Reactor Pressure Vessel Fluence Evaluation - Revision 0 /

MNT-FLU-001-R-002 End of Cycle 30, Transware Enterprises Inc. June 2022 Bioshield/Pedestal Concrete Embrittlement:

Monticello SLR Concrete Embrittlement Assessment of Biological SIA Calculation Package Revision 0 /

Shield Wall, Evaluation of Concrete Degradation of MNGP 2200285.301 10/5/2022 Bioshield, Structural Integrity Associates, Inc (SIA)

Irradiation Damage of the Concrete Biological Shield: Basis for 3002011710 Evaluation of Concrete Biological Shield Wall for Aging 2018 Management, EPRI Report Xcel Energy, Design Input Transmittal Tracking # 601000003895, NA ECR 3895, DIT02, Issue calc for RPV support TLAA - includes 9/22/2022 Proprietary content Biological Shield Wall Frame, Structural Design Criteria Revision 0 /

CA-68-009 4/24/1968 Revision 0 /

CA-68-860 RB Concrete Ring at Biological Shield Wall 4/12/1968 Bruck et al., Structural assessment of radiation damage in light NA water power reactor concrete biological shield walls, Nuclear 8/15/2019 Engineering and Design, Volume 350, pages 9-20 Includes General Electric Company APED Summary of Monticello AR01085507 4/4/2009 Biological Shield Wall Strength) - includes Proprietary content MNGP Subsequent License Renewal Aging Management XCELMO00017-REPT-080 Revision 1 Program Basis Document - Structures Monitoring A Review of the Effects of Radiation on Microstructure and NUREG/CR-7171 November 2013 Properties of Concretes Used in Nuclear Power Plants Reactor Building - Drywell Interior Concrete - Section & Elevation Bechtel Drawing C-381 Revision 3 (NF-36514)

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Document Title Revision / Date RPV Supports/Bioshield Steel Embrittlement Monticello Nuclear Generating Plant - Unit 1, Reactor Bldg:

Bechtel Drawing No. C-374 Revision 2 Drywell Vessel Fdn-Sht. 1, NF-36169 Monticello Nuclear Generating Plant - Unit 1, Reactor Bldg:

Bechtel Drawing No. C-384 Revision 2 Drywell Int. Conc.-Vessel Skirt Shotcreting, NF-36795 Monticello Nuclear Generating Plant - Unit 1, Reactor Building:

Bechtel Drawing No. C-393 NA Drywell Int. Framing Plan, NF-36291 Monticello SLR Steel Embrittlement Assessment of Biological SIA Calculation Package Revision 0 /

Shield Wall, Evaluation of Structural Steel Degradation of MNGP 2200285.302 11/15/2022 Bioshield, Structural Integrity Associates, Inc.

BWRVIP-342 (EPRI TR BWR Vessel and Internals Project: Aging Management of Reactor 2022 3002020999) Vessel Supports for Extended Operations, EPRI Calculation 22-035 (SIA Calculation Packages Evaluation of Adjusted Reference Temperatures and Reference 3/15/2023 2100300.302; Temperature Shifts 2100300.302P)

RPV load calc MO2557 Design Input Transmittal, Approval 602000005221, Tracking 10/6/2022 and 2593.pdf Number 601000003895, Issue Calc for RPV support TLAA 076 MNGP Breakout_Questions Irradiation Effects Concrete Responses to breakout questions for TRP 76 5/4/2023 BSW Steel RV Support_5_23_23_PDF to NRC.pdf Assessment of weldment chemistries of A36 steel and E70 weld Weld Assessment.pdf NA electrode Magnetic Particle Examination Report of Bottom Head to Skirt MN-23-MT-004 5/3/2023 Weld (Summary No. MN-102636)

Visual Examination of Pipe Hanger, Support or Restraint (VT-3) of MN-23-VT-033 through 4/28/2023 through Drywell Female and Male Stabilizers; Vessel Stabilizer Lugs, and MN-23-VT-058 5/1/2023 Bioshield to Containment Truss Photographs MNGP stabilizer support images and under vessel images 4/25/2023 ISI-EXAM REPORTS- Magnetic Particle Examination Report for B-K/B10.10, B.H. to 4/2/2011 20110403-005.pdf Skirt Weld ISI-EXAM REPORTS- Visual Examination of Component Supports and Snubbers (VT-3), 3/14/2011 20110314-023.pdf F-A/F1.40c, Vsl Stblzr/Lug @270 deg.

ISI-EXAM REPORTS- Visual Examination of Component Supports and Snubbers (VT-3),

3/28/2011 20110329-065.pdf F-A/F1.40c, RPV Support Skirt MNGP Subsequent License Renewal Aging Management XCELMO00017-REPT-077 Revision 1 Program Basis Document - ASME Section XI, Subsection IWF During the audit, the staff made the following observations:

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  • The staff reviewed TransWare letter MNT-FLU-001-R-001, Monticello Nuclear Generating Plant Fluence Methodology Report, Transware Enterprises, Inc., and noted the following:

The letter report describes the methodology used to determine the peak neutron fluence and gamma dose estimates at 72 EFPY for the RV and surrounding structures, including the BSW concrete. The applicant determined that the evaluation is consistent with RG 1.190, Calculational and Dosimetry Methods for Determining Pressure Vessel Neutron Fluence.

The staff noted a need to clarify the neutron fluence/gamma dose calculation methodology used by TransWare. It appears that the methodology does not directly calculate the gamma dose. Instead, it appears to assume the gamma dose to be proportional to neutron fluence and not necessarily account for secondary sources of gamma radiation when neutrons activate atoms in concrete. Supplemental information is needed describing how secondary gamma radiation was accounted for in the SLRA reported peak gamma dose estimate.

o The staff reviewed SIA Calculation 2200285.301, Revision 0, Monticello SLR Concrete Embrittlement Assessment of Biological Shield Wall (BSW), and noted that the evaluation for the reduction of strength and loss of mechanical properties of concrete from the expected gamma dose irradiation levels for Monticello BSW and concrete pedestals at 72 EFPY considered effects of irradiation-related strength reduction applied to the design calculations consistent to the procedure outlined in Electric Power Research Institute (EPRI) 3002011710. However, the staff noted that no details of this evaluation were provided in the SLRA, and further it was not clear if the evaluation adequately assessed the effects of radiation-induced gamma heating on the concrete temperature. The applicant should supplement the SLRA with a summary description of the evaluation in sufficient technical detail including assumptions and conservatisms used, how effects of gamma heating were included, and provide a summary of the results, and how the acceptance criteria were met.

o The staff reviewed SLRA Section 3.5.2.2.2.6 and audited TransWare Report MNT-FLU-001-T-001, Revision 0, and noted that Figure 1 of the report shows the existence of an inner and outer RV air cavity separated by a thermal insulation surrounding the BSW. The staff noted lack of clarity whether effects of thermal leakage due to reactor piping penetration of insulation surrounding the inner cavity has been considered in estimation of RV outer cavity temperatures on the concrete surface. There was also lack of clarity whether the applicants calculations considered gamma heating within the bioshield/pedestal concrete and whether further consideration was given to the production of secondary gamma rays potentially increasing temperature of the concrete locally beyond the SRP-SLR limit of 200 oF.

o The staff reviewed SIA Calculation 2200285.301, Revision 0, and noted Assumption 1 in those states, in part: The variation of gamma flux along the height of the Monticello biological shield wall is taken from a generic curve available in EPRI report [3002011710] [4] for a 3-loop PWR, and that plant-specific variation of gamma dose along the height is not available in the design input. The staff also noted that the location of bounding TransWare fluence/gamma radiation at inside BSW surface for 72 EFPY corresponds to that at the reactor fuel core midplane.

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The applicant should clarify the rationale and its adequacy for use of a generic normalized curve for variation of gamma flux along core height for a PWR for MNGP BWR.

  • The staff reviewed SIA Calculation 2200285.301, Revision 0, and noted an apparent discrepancy, in the evaluation of the BSW, regarding the stated effect of gamma heating and the cited reference NUREG/CR-7171. The applicant should supplement the SLRA clarifying the aforementioned.
  • The staff reviewed SIA Calculation 2200285.301, Revision 0, and noted a potential discrepancy, in the evaluation of the BSW, between the critical load combination(s)

(including jet forces) and the allowable stress (increased by a factor 1.5), apparently based on the original calculation and criteria for the design of Class 1 support structures in USAR Section 12.2.1.4.2; which may need to be reconciled/clarified.

  • The staff reviewed SLRA Section 3.5.2.2.2.6 and noted that it does not appear to include an evaluation for the reinforced concrete RV support pedestal. It is not clear to the staff if and how the reinforced concrete pedestal, which is in the vicinity of the RV and would fall under the scope of the SRP-SLR 3.5.2.2.2.6 FE was evaluated for applicable irradiation aging effects.
  • The staff reviewed SLRA Table 3.5-1 and noted that AMR item 3.5.1-097 is applicable and consistent with NUREG-2191 and includes, as noted above, corresponding AMR items in Table 3.5.2-1 crediting the SLRA B.2.3.33 Structures Monitoring Program to manage aging effects of irradiated concrete. However, the credited SLRA B.2.3.33 AMP description and its PBD, XCELMO00017-REPT-080, Revision 1, in the electronic reading room, do not appear to include reduction of strength; loss of mechanical properties due to irradiation (i.e., radiation interactions with material and radiation-induced heating) as aging effects/mechanism that will be managed by the program. The applicant should supplement the SLRA and the referenced PBD connecting the reactor cavity concrete structures and components exposed to radiation effects with the credited SLRA AMP program elements.
  • The staff reviewed SIA Calculation 2200285.302, Revision 0 (11/15/22), Monticello SLR Steel Embrittlement Assessment of Biological Shield Wall, and noted the following:

The calculation of adjusted nil-ductility transition NDT temperature in Section 5.2, NDT Transition Analysis of the document did not include the location of the peak dpa (displacement per atom)-induced damage on structural steel and weldments along the height of the BSW. For the 72 EFPY SLRA reported 2.07x10-3 dpa along the height of the BSW, the staff calculated an adjusted NDT temperature of 168.6°F based on the NDT shift values in Figure 3-1 of NUREG-1509. This adjusted NDT temperature was based on a generic initial NDT temperature with a 1.3 standard deviation margin provided in NUREG-1509 for ASTM A36 steel.

The stress analysis in Section 5.3, Stress Analysis, of the document did not appear to include weld residual stresses and effects of thermal expansion of the concrete within the steel liner plates of the BSW due to radiation exposure. Also,

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Section 5.3 of the above noted SIA document did not clearly identify the design basis load combinations and the limiting load combination. It is not clear whether the applicant considered these in its Biological Shield Structural Steel Evaluation.

  • The staff reviewed the General Notes for Structural Steel in Bechtel Drawing No. C-393 and noted the following not reported in the SLRA:

o Structural steel plates and shapes are specified as ASTM-A36 steel.

o Welding electrodes are specified as E-70 electrodes.

  • File Weld Assessment.pdf shows chemistry factor values for a range of generic chemistries of A36 base metal and E70 weld electrode. No plant-specific certified mill test report chemistries of the ASTM-A36 W27x177 columns (and associated welds) were provided.
  • Following the review of the EPRI proprietary technical report BWRVIP-342 cited in the SLRA and audit discussions with the applicant regarding the report, the staff was not clear how the BWRVIP-342 was used in the SLRA Reactor Vessel Support Steel Irradiation Evaluation.
  • After reviewing SIA Calculations 2200285.301 and 2200285.302 and the SLRA, the staff noted that summaries of the calculations need to be included in the SLRA to clarify the bases for the applicants evaluations.
  • To date, ASME Section XI, Subsection IWF inservice inspection reports indicated acceptable results for the RV steel supports.
  • The staff reviewed SLRA Section 3.5.2.2.2.6 and noted that loss of fracture toughness (LOFT) due to irradiation embrittlement remains an applicable aging effect for the RV steel supports. The staff further noted from audit of the PBD for the SLRA B.2.3.30 ASME Section XI, Subsection IWF AMP (XCELMO00017-REPT-077), in the electronic reading room, that, although Table 2 of the PBD includes LOFT due to irradiation embrittlement as an aging effect managed by the program, SLRA Sections 3.5.2.1.1, 3.5.2.1.7, Table 3.5.2-1, and Table 3.5.2-7 do not appear to include AMR items that indicate that this aging effect will be managed by the IWF AMP. Additionally, the staff noted that SLRA B.2.3.33 Structures Monitoring AMP and its PBD (XCELMO00017-REPT-080) program elements do not appear to include LOFT due to irradiation embrittlement as aging effect/mechanism for the BSW structural steel that is credited to be managed by the program. Also, the SLRA Table 3.5.2-1 does not appear to include corresponding AMR items. The applicant should supplement the SLRA and applicable PBD connecting the BSW structural steel and other applicable steel components exposed to radiation effects with the credited SLRA AMP program elements, as well as include corresponding Table 2 AMR items identified above.
  • The staff reviewed SLRA Section 3.5.2.2.2.6 and noted lack of clarity regarding whether the steel RV seismic restraint and stabilizer structure, which is part of the RV supports and would fall under the scope of the SRP-SLR 3.5.2.2.2.6, was evaluated for LOFT due to irradiation embrittlement effects. The staff also noted that corresponding AMR items

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appeared to be absent from the SLRA for managing the aging effect for these components.

The staff will consider issuing RAIs and/or use a voluntary SLRA supplement offered by the applicant to obtain the necessary information to address issues identified and communicated during the audit. The staff will document its review of this information and resolution of the issues in the SE.

SLRA Section 3.6.2.2.3, Loss of Material Due to Wind-Induced Abrasion, Loss of Conductor Strength Due to Corrosion, and Increased Resistance of Connection Due to Oxidation or Loss of Preload for Transmission Conductors, Switchyard Bus, and Connections Summary of Information in the Application. During the audit, the staff reviewed plant documentation associated with the AMR discussed in SLRA Section 3.6.2.2.3 and the following:

  • SLRA Table 3.6-1, Summary of Aging Management Evaluations for Electrical Commodities, Item Number Table 3.6-1, 004-Transmssion conductors composed of aluminum; steel exposed to air-outdoor Loss of Conductor Strength (Corrosion)
  • SLRA Table 3.6-1, 3.6-1, 005-Transmission connectors composed of aluminum; steel exposed to air-outdoor-Increased Resistance of Connection (Oxidation)
  • SLRA Table 3.6-1, 3.6-1,006-Switchyard bus and connections composed of aluminum; copper, bronze; stainless steel; galvanized steel exposed to air-outdoor-Increased Resistance of Connection (Loss of Preload)
  • SLRA Table 3.6-1, 3.6-1,007-Transmission Conductors composed of aluminum; steel exposed of air-outdoor-Loss of Material (wear due to wind-induced abrasion)

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the AMR of loss of material due to wind-induced abrasion, loss of conductor strength due to corrosion, and increased resistance of connection due to oxidation or loss of preload for transmission conductors, switchyard bus, and connections. The staff will document its review of this information in the SE.

Document Title Revision / Date Report No. XCELMO00017- Subsequent License Renewal Aging Screening And Aging Revision 1 REPT-041 Management Review Results - Electrical Systems The staff also conducted an onsite audit where the staff interviewed the applicants staff and performed walkdowns of the MNGP switchyard. Specifically, the staff observed transmission conductors, switchyard bus, and connections associated with the SLRA. The staff did not identify any adverse or abnormal conditions with these items during the walkdowns.

During the audit, the staff made the following observations:

The staff noted that the overhead conductors at MNGP are Aluminum Conductor Steel Reinforced that have been evaluated for limited degradation due to environmental factors by Ontario Hydro and accepted by NRC staff. The SLRA did not identify any adverse events documented via the correction action program applicable to the overhead conductors.

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SLRA AMR Evaluation 3.6.2.3.1, Fuse Holders Summary of Information in the Application. The staff audited the AMR discussed in SLRA Section 3.6.2.3.1, Fuse Holders, by reviewing plant documentation associated with the following:

  • SLRA Table 3.6-1, Summary of Aging Management Evaluations for Electrical Commodities, Item 3.6.1-008 - Electrical insulation for electrical cables and connections (including terminal blocks, fuse holders, etc.) composed of various organic polymers (e.g., EPR, SR, EPDM, XLPE) exposed to an adverse localized environment (ALE) caused by heat, radiation, or moisture.
  • SLRA Table 3.6-1, Item 3.6.1-022 - Fuse holders (not part of active equipment):

insulation material composed of electrical insulation material: bakelite; phenolic melamine or ceramic; molded polycarbonate, and other, exposed to air - indoor, controlled or uncontrolled.

  • SLRA Table 3.6.2-1, Electrical Commodities - Summary of Aging Management Evaluation, Plant-Specific Note 1 states: 1. In alignment with GALL-SLR, no AMP is required when fuse holders are located in an environment that does not subject them to environmental aging mechanisms. Fuse holder insulation material in an ALE [adverse localized environment] is managed via the XI.E1 AMP. MNGP fuse holders (not in active components) insulation material and environment combination has no aging effects requiring management.

SLRA Section 3.6.2.3.1 states: MNGP fuse holders (not part of active equipment): insulation material that may be subject to an ALE that may affect insulation resistance are addressed as part of Electrical Insulation for Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements. Fuse holder insulation material that is not subject to an adverse environment does not have aging effects requiring management.

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the AMR of fuse holders. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-Rept-041 Monticello Subsequent License Renewal Screening and Revision 1 Aging Management Review Results - Electrical Systems OE raw data - Database NA 2/21/2023 Printouts OE raw data expanded pt 1 NA 2/21/2023

- Database Printouts OE raw data expanded pt 2 NA 2/21/2023

- Database Printouts

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Document Title Revision / Date Pictures of Cabinets - NA 12/9/2021 Fuses During the audit, the staff made the following observations:

  • The staffs audit addressed the applicants assessment for the insulation materials of fuse holders within the scope of SLR.
  • NUREG-2192 Table 3.6-1, Summary of Aging Management Programs for the Electrical Components Evaluated in Chapter VI of the GALL-SLR Report, identified aging effects/mechanisms on the insulation materials of fuse holders. SLRA Table 3.6-1 Item 3.6.1-022 and Table 3.6.2-1 plant-specific Note 1 indicated that there are no aging effects to be managed for the insulation materials of the in-scope fuse holders (not part of active equipment) at MNGP, but the evaluation in SLRA Section 3.6.2.3.1 appears not to address aging effects/mechanisms on the insulation materials of the MNGP in-scope fuse holders. In response to a staff breakout question, the applicant stated that the insulation materials for the in-scope fuse holders were not subject to the aging effects/mechanisms identified in the NUREG-2192 Table 3.6-1 because these insulation materials are not located in an ALE, which would be the same environment for the in-scope fuse holders metallic clamps discussed in SLRA Section 3.6.2.3.1. In SLRA Section 3.6.2.3.1, the applicant stated that the electrical boxes containing the in-scope fuse holders located in the turbine and reactor buildings areas are in a mild environment.

The applicant noted that it will supplement SLRA Section 3.6.2.3.1 with information that clarifies the AMR of the in-scope fuse holders insulation materials.

  • Table 3.6-1 listed two Items 3.6.1-022 and 3.6.1-008 for fuse holders insulation materials with different evaluations in the discussion column, but no explanation was provided for the difference. The applicant explained that Item 3.6.1-008 is not applicable to the in-scope fuse holders insulation since it was determined that none of the in-scope fuse holders were identified as having exposure to moisture, heat, or radiation that would qualify as an ALE. The applicant noted that it will revise the SLRA Table 3.6-1 Items and Table 3.6.2-1 Note 1 to indicate the in-scope fuse holders insulation materials do not require an AMP.
  • There was no OE associated with the 48 in-scope fuse holders in the OE documents provided in the applicants ePortal.

SLRA AMR Evaluation 3.6.2.3.2, High-Voltage Electrical Insulators Summary of Information in the Application. GALL-SLR Report AMP XI.E7, High-Voltage Insulators, as modified by SLR-ISG-2021-04-ELECTRICAL, Updated Aging Management Criteria for Electrical Portions of the Subsequent License Renewal Guidance, contains the program elements for high-voltage (HV) insulators. The SLRA states that HV insulators are subject to AMR if they are necessary for restoration of offsite power following a station blackout (SBO) event. The HV insulators evaluated for MNGP SLR are located in the offsite power source circuits and the alternate AC source for the SBO. The in-scope insulators include 345 kilovolt (kV), 115 kV, and 13.8 kV post insulators in offsite source paths and 115 kV strain insulators in offsite source paths.

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HV insulators are evaluated for reduced insulation resistance due to presence of any salt deposits and surface contamination, and loss of material due to mechanical wear caused by significant wind blowing on transmission conductors. During the audit, the staff reviewed plant documentation associated with the AMR discussed in SLRA Section 3.6.2.3.2 and the following:

  • SLRA Table 3.6-1, Summary of Aging Management Evaluations for Electrical Commodities, Item Number 3.6-1,002-High-Voltage electrical insulators composed of porcelain; malleable iron; aluminum; galvanized steel; cement, toughened glass; polymers silicone rubber; fiberglass, aluminum alloy exposed to air-outdoor.
  • SLRA Table 3.6-1, Item Number 3.6-1,003-High-Voltage electrical insulators composed of porcelain; malleable iron; aluminum; galvanized steel; cement, toughened glass; polymers silicone rubber; fiberglass, aluminum alloy exposed to air-outdoor.

The SLRA notes that HV insulators surface contamination is not a significant aging effect for MNGP. The aging effects of surface contamination from salt, dust, fog, cooling tower plume, foreign debris, and industrial effluents are not applicable to MNGP for the subsequent period of extended operation and therefore no aging management activity is required for the HV insulators due to airborne contamination. The applicant considers its current inspection process as adequate.

Audit Activities. The table below lists documents that were reviewed by the staff and found relevant to the AMR of reduced insulation resistance due to presence of cracks, foreign debris, salt dust, cooling tower plume or industrial effluent contamination; peeling of silicone rubber sleeves for polymer insulators; or degradation of glazing on porcelain insulators. The staff will document its review of this information in the SE.

Document Title Revision / Date XCELMO00017-REPT- Subsequent License Renewal Aging Screening And Aging Revision 1 041 Management Review Results - Electrical Systems The staff also conducted an onsite audit where the staff interviewed the applicants staff and performed walkdowns of the MNGP switchyard. Specifically, the staff observed HV insulators associated with the SLRA. The staff did not identify any adverse or abnormal conditions with HV insulators during the walkdowns.

During the audit, the staff made the following observations:

The MNGP switchyard has both porcelain and polymer type of HV insulators; the SLRA did not identify any adverse events documented via the CAP for a period of 9 years.

The staff notes that the applicant concluded that the periodic inspections and the absence of plant specific OE verifies that this aging effect is not significant for polymer or porcelain type of HV insulators associated with the offsite power system required for recovery from an SBO event and no updates to existing maintenance programs or plant licensing documents is required.

3. Supplements to the SLRA By letters dated April 3, 2023 (ML23094A136), June 26, 2023 (ML23177A218), July 13, 2023 (ML23193B025), July 18, 2023 (ML23177A218) and August 28, 2023 (ML23240A695), NSPM

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voluntarily submitted Supplements 2, 3, 4 and 5 to the SLRA resulting from discussions held during the audit.

4. Audit Questions Provided to NSPM Over the course of the audit, the NRC staff provided audit questions to NSPM to facilitate the audit discussions (ML23214A242 and ML23214A240), for the non-proprietary and proprietary versions, respectively.

Subject Area Meeting Date Breakout Session: Neutron Fluence 4/7/2023 Breakout Session: Scoping and Screening Sections 2.4.6 and 2.3.3.9 4/19/2023 Breakout Session: BWR Vessel ID Welds 4/24/2023 Breakout Session: Internal Coatings / Lining 4/25/2023 Breakout Session: Fatigue Monitoring Program, GALL X.M1 and Metal Fatigue, 4/25/2023 TLAA 4.3 Breakout Session: Selective Leaching 4/26/2023 Breakout Session: Metal Fatigue of Class 1 Components, Metal Fatigue of Non-4/26/2023 Class 1 Components and High Energy Line Break Analyses Breakout Session: High Energy Line Break Analyses 4/26/2023 Breakout Session: Cycle-dependent Fracture Mechanics or Flaw Evaluations, Cycle-dependent Fatigue Waivers, Environmentally-Assisted Fatigue and 4/27/2023 Condensate Backwash Receiving Tank Fatigue Analysis Breakout Session: Buried and Underground Piping and Tanks 4/28/2023 Breakout Session: BWR Vessel Internals 5/1/2023 Breakout Session: EQ of Electric Equipment Program, GALL X.E1 5/2/2023 Breakout Session: Inspection of Internal Surfaces in Misc Piping and Ducting 5/2/2023 Components Breakout Session: SS Nickel Alloy Aluminum Alloy Further Evaluations and 5/3/2023 Water Chemistry Breakout Session: ASME XI - ISI (IWB,IWC,IWD) and ASME Code Class 1 5/4/2023 Small-Bore Piping Breakout Session: Reactor Vessel Neutron Embrittlement Analyses, TLAA 4.2 5/4/2023 and RV Material Surveillance

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Subject Area Meeting Date Breakout Session: Inaccessible Medium Voltage Cables, Inaccessible Instrument and Control Cables, Inaccessible Low Voltage Cables and Fuse 5/5/2023 Holders Breakout Session: Fire Protection 5/8/2023 Breakout Session: Environmentally-Assisted Fatigue and Condensate 5/8/2023 Backwash Receiving Tank Fatigue Analysis Breakout Session: ASME Section XI, Subsection IWF 5/9/2023 Breakout Session: Scoping and Screening Sections 2.3.3.10 and 2.3.3.17 5/9/2023 Breakout Session: Fire Water System 5/10/2023 Breakout Session: Open-Cycle Cooling Water System and Flow-Accelerated 5/10/2023 Corrosion Breakout Session: Bolting Integrity, 10 CFR Part 50, Appendix J, Masonry Wall 5/12/2023 Program and Corrosion-Structural Breakout Session: ASME Section XI, Subsection IWE 5/12/2023 Breakout Session: Scoping and Screening Sections 2.3.3.8, 2.3.3.14, 2.3.3.15 5/15/2023 and 2.3.3.16 Breakout Session: Scoping and Screening Sections 2.3.3.6 and 2.3.4.6 5/15/2023 Breakout Session: External Surfaces Monitoring of Mechanical Components 5/16/2023 Breakout Session: Buried and Underground Piping and Tanks and Selective 5/19/2023 Leaching Breakout Session: Inspection of Overhead Heavy Load and Light Load (Related to Refueling) Handling Systems and Fatigue Analysis of Cranes (crane cycle 5/19/2023 limits)

Breakout Session: Water Chemistry 5/22/2023 5/22/2023 Breakout Session: Structures Monitoring 5/24/2023 Breakout Session: Neutron Fluence 5/23/2023 5/23/2023 Breakout Session: Irradiation-Structural 5/24/2023 5/25/2023 Breakout Session: RG 1.127, Inspection of Water-Control Structures 5/23/2023 Associated with Nuclear Power Plants and Concrete

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Subject Area Meeting Date Breakout Session: Containment Liner Plate, Metal Containments, and Penetrations Fatigue Analyses, TLAA 4.6 and Fatigue Analyses of High 5/24/2023 Pressure Coolant Injection and Reactor Core isolation Breakout Session: TRP 1 - ASME XI - ISI 5/25/2023

5. Applicant Personnel Contacted During Audit Name Affiliation Taryn Barber Xcel Energy Toutseng Hawj Xcel Energy Max Smith Xcel Energy Jolynn Oquist Xcel Energy Adam Roehl Xcel Energy Matthew Sears Xcel Energy Stephen Sollom Xcel Energy Jason Tribe Xcel Energy Leah Whiteker Xcel Energy Paul Young Xcel Energy Latoya Bennett Enercon Ila Collins Enercon Ben Delaney Enercon Marven Engen Enercon Reene Gambrell Enercon Jeff Gromatzky Enercon Aaron Halstrom Enercon Ron Hepp Enercon Allison Hoke Enercon Tristan Hunnewell Enercon Tanton Mattson Enercon Mitch McFarland Enercon Ian Miller Enercon Mark Miller Enercon Molly O Sullivan Enercon Kenneth Putnam Enercon Caleb Trainor Enercon Mark Winsor Enercon Livia Costa Mello Structural Integrity Associates Shari Day Structural Integrity Associates

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Name Affiliation Dan Denis Structural Integrity Associates Keith Evon Structural Integrity Associates Scott Tradup Kinectrics Derek Warner Kinectrics Dean Jones TransWare

6. Exit Meeting An exit meeting was held with the applicant on May 25, 2023, to discuss the results of the regulatory audit. The staff is considering the issuance of RAIs and RCIs to support the completion of the staffs SLRA review.

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