ML24311A123

– Report for the Aging Management Audit Regarding the License Renewal Application Review

ML24311A123
Person / Time
Site:	Diablo Canyon
Issue date:	11/14/2024
From:	Harris B Office of Nuclear Reactor Regulation
To:	Peck A Pacific Gas & Electric Co
Shared Package
ML24311A122	List: ML24311A123
References
EPID L-2023-RNW-0022
Download: ML24311A123 (98)

Text

November 14, 2024 Mr. Adam Peck Senior Vice President, Generation and Chief Nuclear Officer Pacific Gas and Electric Company Diablo Canyon Nuclear Power Plant P.O. Box 56 Mail Code 104/6/605 Avila Beach, CA 93424

SUBJECT:

DIABLO CANYON POWER PLANT, UNITS 1 AND 2 - REPORT FOR THE AGING MANAGEMENT AUDIT REGARDING THE LICENSE RENEWAL APPLICATION REVIEW (EPID NO. L-2023-RNW-0022)

Dear Mr. Peck:

By letter dated November 7, 2023 (Agencywide Documents Access and Management System Accession No. ML23311A154), as supplemented by letters dated October 14, 2024 (ML24289A118), Pacific Gas and Electric Company (PG&E) submitted an application for the renewal of Facility Operating License Nos. DPR-80 and DPR-82 for Diablo Canyon Nuclear Power Plant (DCPP), Units 1 and 2 to the U.S. Nuclear Regulatory Commission (NRC). PG&E 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 license renewal.

The NRC staff completed its aging management audit from February 12, 2024 - August 20, 2024, in accordance with the audit plan (ML24002B180). The audit report is enclosed.

A. Peck If you have any questions, please contact me by email at Brian.Harris2@nrc.gov.

Sincerely,

/RA/

Brian Harris, Senior Project Manager License Renewal Projects Branch Division of New and Renewed Licenses Office of Nuclear Reactor Regulation Docket Nos. 50-275 and 50-323

Enclosure:

Audit Report cc w/encl.: Listserv

Pkg: ML24311A122 Letter: ML24311A123 via email NRR-106 OFFICE PM:NLRP:DNRL LA:NLRP:DNRL BC:NPHP:DNRL BC:NCSG:DNRL BC:NVIB:DNRL NAME BHarris KBratcher MMitchell SBloom ABuford DATE 10/17/24 10/25/24 08/06/24 08/29/24 10/30/24 OFFICE BC:ESEB:DEX BC:ELTB:DEX BC:SCPB:DSS BC:NLRP:DNRL PM:NLRP:DNRL NAME ITseng JPaige MValentin LGibson BHarris DATE 10/30/24 09/05/24 08/14/24 11/14/24 11/14/24

Enclosure AUDIT REPORT Aging Management Audit Diablo Canyon Nuclear Power Plant, Units 1 and 2 License Renewal Application February 12, 2024 - August 20, 2024 Division of New and Renewed Licenses Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission

U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR REACTOR REGULATION DIVISION OF NEW AND RENEWED LICENSES Docket Nos:

50-275 and 50-323 License No:

DPR-80 and DPR-82 Licensee:

Pacific Gas and Electric Company Facility:

Diablo Canyon Nuclear Power Plant, Units 1 and 2 Locations:

Rockville, Maryland Avila Beach, California Dates:

February 12, 2024 - August 20, 2024 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 Lauren K. Gibson, Chief License Renewal Projects Branch Division of New and Renewed Licenses Matthew A. Mitchell, Chief Piping and Head Penetrations Branch Division of New and Renewed Licenses Jason Paige, Chief Long-Term Operations and Modernization Branch Division of Engineering and External Hazards Milton Valentin, Chief Containment and Plant Systems Branch Division of Safety Systems Ian Tseng, Chief Structural, Civil, Geotech Engineering Branch B Division of Engineering and External Hazards Reviewers:

Name Organization Naeem Iqbal PRA Licensing Branch B (APLB)/Division of Risk Assessment (DRA)

Adakou Foli Electrical Engineering Branch/Division of Engineering and External Hazards (DEX)

Jorge Cintron-Rivera Long-Term Operations and Modernization Branch (ELTB)/DEX Brian Correll ELTB/DEX Matthew McConnell ELTB/DEX Liliana Ramadan ELTB/DEX Dan Hoang Structural, Civil, Geotech Branch (ESEB)/DEX Se-Kwon Jung ESEB/DEX Shaohua Lai ESEB/DEX George Thomas ESEB/DEX George Wang ESEB/DEX Yi-Lun Chu ESEB/DEX Brian Allik Corrosion and Steam Generator Branch (NCSG)/Division of New and Renewed Licenses (DNRL)

Lydiana Alvarado NCSG/DNRL Miranda Ross NCSG/DNRL Reena Boruk NCSG/DNRL Tony Gardner NCSG/DNRL James Gavula NCSG/DNRL Joel Jenkins NCSG/DNRL Andy Johnson NCSG/DNRL Paul Klein NCSG/DNRL Greg Makar NCSG/DNRL Devendra Ray NCSG/DNRL Leslie Terry NCSG/DNRL Matthew Yoder NCSG/DNRL Karen Sida Piping and Head Penetrations Branch (NPHP)/DNRL Jay Collins NPHP/DNRL Bart Fu NPHP/DNRL Varoujan Kalikian NPHP/DNRL Seung Min NPHP/DNRL Ali Rezai NPHP/DNRL Karen Sida NPHP/DNRL Steven Levitus Vessels and Internals Branch (NVIB)/DNRL David Dijamco NVIB/DNRL Carol Moyer NVIB/DNRL Carolyn Fairbanks NVIB/DNRL Emma Haywood NVIB/DNRL Eric Palmer NVIB/DNRL Cory Parker NVIB/DNRL John Tsao NVIB/DNRL On Yee NVIB/DNRL Brian Lee Containment and Plant Systems Branch (SCPB)/Division of Safety Systems (DSS)

David Nold SCPB/DSS

Hanry Wagage SCPB/DSS Justin Donohoe SCPB/DSS Noushin Amini Nuclear Systems Performance Branch (SNSB)/Division of Safety Systems (DSS)

Santosh Bhatt SNSB/DSS Bill Rogers NLRP/DNRL Chris Tyree NLRP/DNRL

TABLE OF CONTENTS AUDIT REPORT......................................................................................................................

TABLE OF CONTENTS...........................................................................................................

ACRONYMS............................................................................................................................

1.

Introduction............................................................................................................................ 9

2.

Audit Activities..................................................................................................................... 10 LRA Section 2.1, Scoping and Screening Methodology.......................................................... 10 LRA AMP B.2.2.1, Fatigue Monitoring.................................................................................... 18 LRA AMP B.2.2.2, Environmental Qualification of Electric Components................................ 20 LRA AMP B.2.3.1, ASME Section XI Inservice Inspection, Subsections IWB, IWC, and IWD 21 LRA AMP B.2.3.2, Water Chemistry....................................................................................... 22 LRA AMP B.2.3.3, Reactor Head Closure Stud Bolting.......................................................... 23 LRA AMP B.2.3.4, Boric Acid Corrosion................................................................................. 24 LRA AMP B.2.3.5, Cracking of Nickel-Alloy Components and Loss of Material Due to Boric Acid-Induced Corrosion in Reactor Coolant Pressure Boundary Components................... 25 LRA AMP B.2.3.6, Thermal Aging Embrittlement of Cast Austenitic Stainless-Steel (CASS). 28 LRA AMP B.2.3.7, PWR Vessel Internals............................................................................... 29 LRA AMP B.2.3.8, Flow-Accelerated Corrosion...................................................................... 31 LRA AMP B.2.3.9, Bolting Integrity......................................................................................... 32 LRA AMP B.2.3.10, Steam Generators................................................................................... 33 LRA AMP B.2.3.11, Open-Cycle Cooling Water System........................................................ 34 LRA AMP B.2.3.12, Closed Treated Water Systems.............................................................. 35 LRA AMP B.2.3.13, Inspection of Overhead Heavy Load and Light Load (Related to Refueling) Handling Systems.............................................................................................. 36 LRA AMP B.2.3.14, Fire Protection......................................................................................... 37 LRA AMP B.2.3.15, Fire Water System.................................................................................. 39 LRA AMP B.2.3.16, Aboveground Metallic Tanks................................................................... 41 LRA AMP B.2.3.17, Fuel Oil Chemistry................................................................................... 42 LRA AMP B.2.3.18,Reactor Vessel Surveillance.................................................................... 43 LRA AMP B.2.3.19, One-Time Inspection............................................................................... 43 LRA AMP B.2.3.20, Selective Leaching.................................................................................. 44 LRA AMP B.2.3.21, One-Time Inspection of ASME Code Class 1 Small-Bore Piping........... 45 LRA AMP B.2.3.22, External Surfaces Monitoring of Mechanical Components...................... 46 LRA AMP B.2.3.23, Flux Thimble Tube Inspection................................................................. 47 LRA AMP B.2.3.24, Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components........................................................................................................................ 48 LRA AMP B.2.3.25, Lube Oil Analysis.................................................................................... 48 LRA AMP B.2.3.26, Buried and Underground Piping and Tanks............................................ 49 LRA AMP B.2.3.27, Internal Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, and Tanks....................................................................................................... 51 LRA AMP B.2.3.28, ASME Section XI, Subsection IWE......................................................... 52 LRA AMP B.2.3.29, ASME Section XI, Subsection IWL......................................................... 55 LRA AMP B.2.3.30, ASME Section XI, Subsection IWF......................................................... 56 LRA AMP B.2.3.31, 10 CFR Part 50, Appendix J................................................................... 59 LRA AMP B.2.3.32, Masonry Walls......................................................................................... 59 LRA AMP B.2.3.33, Structures Monitoring.............................................................................. 60

LRA AMP B.2.3.34, RG 1.127, Inspection of Water-Control Structures Associated with Nuclear Power Plants.......................................................................................................... 64 LRA AMP B.2.3.35, Protective Coating Monitoring and Maintenance.................................... 65 LRA AMP B.2.3.36, Insulation Material for Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements.................................................. 66 LRA AMP B.2.3.37, Insulation Material for Electrical Cables and Connections Not Subject to 10 CFR 50.49 EQ Requirements Used in Instrumentation Circuits..................................... 68 LRA AMP B.2.3.38, Inaccessible Power Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements................................................................................................. 69 LRA AMP B.2.3.39, Metal Enclosed Bus................................................................................ 71 LRA AMP B.2.3.40, Electrical Cable Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements................................................................................................. 72 LRA AMP B.2.3.41, Periodic Inspections for Selective Leaching............................................ 73 LRA AMP B.2.3.42, Transmission Conductor and Connections, Insulators, and Switchyard Bus and Connections.......................................................................................................... 74 LRA TLAA Section 4.1, Identification of Time-Limited Aging Analyses................................... 75 LRA TLAA Section 4.2.2 through 4.2.4................................................................................... 76 LRA TLAA Section 4.3.1 DCPP Transient Monitoring and Projections................................... 78 LRA TLAA Section 4.3.2 ASME Section III, Class A Fatigue Analyses.................................. 80 LRA TLAA Section 4.3.3 Fatigue Analyses of the Reactor Pressure Vessel Internals........... 83 LRA TLAA Section 4.3.4, Environmentally-Assisted Fatigue.................................................. 84 LRA TLAA Section 4.3.5, Assumed Thermal Cycle Count for Allowable Secondary Stress Range Reduction Factor in ANSI B31.1 Piping................................................................... 86 LRA TLAA Section 4.3.6, Fatigue Design and Analysis of Class 1E Electrical Raceway Support Angle Fittings for Seismic Events.......................................................................... 87 LRA TLAA Section 4.4, Environmental Qualification of Electrical Equipment......................... 88 LRA TLAA Section 4.6.1, Containment Concrete, Liner, and Penetrations Analyses............. 90 LRA TLAA Section 4.7.1, Crane Load Cycle Limits................................................................ 91 LRA TLAA Section 4.7.4, Reactor Coolant Pump Flywheel Fatigue Crack Growth Analysis.. 92

3.

Audit Questions Provided to PG&E..................................................................................... 93

4.

Applicant Personnel Contacted During the Audit................................................................. 94

5.

Exit Meeting......................................................................................................................... 95

ACRONYMS ADAMS Agencywide Documents Access and Management System AMP aging management program AMR aging management review ASME American Society of Mechanical Engineers CAP corrective action program CASS cast austenitic stainless-steel CFR Code of Federal Regulations CLB current licensing basis CRDM control rod drive mechanism CRGT control rod guide tube CUF cumulative usage factor CUFen environmentally-adjusted cumulative usage factor DBD design-basis document DBE design-basis event EAF environmentally-assisted fatigue EI&C electrical and instrumentation and controls EPRI Electric Power Research Institute EQ electrical qualification ERR electronic reading room FAC flow-accelerated corrosion FSAR final safety analysis report GALL-LR generic aging lessons learned for license renewal HELB high energy line break I&C instrumentation and control IASCC irradiation-assisted stress corrosion cracking IPA integrated plant assessment ISG Interim Staff Guidance ISI inservice inspection Kv kilo Volt LAR license amendment request LRA license renewal application LR license renewal LTOP low temperature overpressure protection

MRP materials reliability program NDE nondestructive examination NEI Nuclear Energy Institute NRC U.S. Nuclear Regulatory Commission OE operating experience PG&E Pacific Gas and Electric Company PTLR pressure-temperature limits report PWR pressurized-water reactor PWROG Pressurized-Water Reactor Owners Group PWRVI pressurized-water reactor vessel internals PWRVIP pressurized-water reactor vessel internals program PWSCC primary water stress corrosion cracking RAI request for additional information RCI request for confirmation of information RCP reactor coolant pump RCS reactor coolant system RG Regulatory Guide RHR residual heat removal RIS regulatory issue summary RPV reactor pressure vessel RV reactor vessel RVI reactor vessel internal SC structures and components SE safety evaluation SG steam generator SRP Standard Review Plan TLAA Time-limited aging analyses UFSAR Updated Final Safety Analysis Report QA quality assurance

9 Report for the Aging Management Audit Diablo Canyon Nuclear Power Plant, Units 1 and 2 License Renewal Application

1. Introduction The U.S. Nuclear Regulatory Commission (NRC) staff conducted an aging management audit of Pacific Gas and Electric Company (PG&E or the applicant) (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 (TLAA) and associated bases and documentation as applicable (AMP and TLAA Portion) for the LR of Renewed Facility Operating License Nos. DPR-80 and DPR-82 for Diablo Canyon Nuclear Power Plant (DCPP, Diablo Canyon, or the applicant).

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. PG&E searched their OE database and provided the results for the associated AMPs and TLAAs for NRC staff review.

Additional word searches were performed by PG&E 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 license renewal application (LRA), implementing procedures, reports, and drawings, such that the NRC staff:

Obtains 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.

Has 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:

Examine PG&Es AMPs, AMR items, and TLAAs for Diablo Canyon; Verify PG&Es claims of consistency with the corresponding NUREG-1801, Generic Aging Lessons Learned for License Renewal (GALL) Report, (GALL-LR Report) issued in December 2010, AMPs, and AMR items; and 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

10 also considered the guidance contained in NUREG-1800, Standard Review Plan for Review of License Renewal Applications for Nuclear Power Plants (SRP-LR), dated December 2010, and NUREG-1801. The SRP-LR allows an applicant to reference in its LRA the AMPs described in the GALL-LR Report. By referencing the GALL-LR Report AMPs, the applicant concludes that its AMPs correspond to those AMPs reviewed and approved in the GALL-LR Report and that no further staff review is required. If an applicant credits an AMP for being consistent with a GALL-LR Report program, it is incumbent on the applicant to ensure that the plant program contains all of the elements of the referenced GALL-LR Report program. The applicant should document this determination in an auditable form and maintain the documentation on-site.

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 LRA states that every AMP in the LRA is consistent with the program elements of the GALL-LR Report. To verify this claim of consistency, the staff audited each AMP, including any enhancements or exceptions associated with an AMP.

The LRA discusses each time-limited aging analyses, 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 LRA is consistent with the further evaluation information in the SRP-LR.

Furthermore, the staff audited the FSAR descriptions for each AMP and TLAA for consistency with the SRP-LR. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the LRA 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 LRA 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 LRA areas reviewed by the staff.

LRA Section 2.1, Scoping and Screening Methodology Summary of Information in the Application. LRA Section 2.1, Scoping and Screening Methodology, described the process for identifying and determining the DCPP SSCs that are included within the scope of LR. 10 CFR 54.21, Contents of Application - Technical Information, requires that each application for LR contain an integrated plant assessment (IPA).

11 which lists, for SSCs within the scope of LR, the structures and components (SCs) that are subject to an AMR. Section 10 CFR 54.4(a), Scope, provides the criteria for inclusion of SSCs within the scope of LR and 10 CFR 54.21(a)(1) requires that SCs within the scope of license, that are determined to be passive and not periodically replaced (long-lived), are subject to an AMR. The staff conducted an on-site scoping and screening methodology audit, from February 27-29, 2024, to review the scoping and screening methodology, administrative controls governing implementation of the methodology, and the scoping and screening results for selected plant SSCs.

Audit Activities.

A. Scoping Methodology Staff Review of Information Sources, Implementing Documents, and Scoping Methodology The audit team reviewed the methodology used by the applicant to identify mechanical, structural, and electrical SSCs within the scope of LR (scoping). In addition, the audit team reviewed documentation pertinent to the scoping process. The audit team assessed whether the scoping methodology outlined in the LRA and implementing procedures was consistent with the requirements of 10 CFR Part 54.

The staff confirmed that the applicants detailed LR program guidelines specified the use of the current licensing basis (CLB) source information in developing scoping evaluations. The staff reviewed pertinent information sources used by the applicant including the component database, the Final Safety Analysis Report (FSAR), maintenance rule basis documents, design-basis documents (DBD), LR drawings and station drawings.

The staff discussed the applicants administrative controls for the component database and the other information sources used to verify system information. These controls are described and implemented by plant procedures. Based on a review of the administrative controls and on a sample of the system classification information contained in the applicable documentation, the staff determined that the applicant has established adequate measures to control the integrity and reliability of system identification and safety classification data; therefore, the staff determined that the information sources used by the applicant during the scoping and screening process provided a controlled source of system and component data to support scoping and screening evaluations.

The staff reviewed the implementing procedures and results reports used to support identification of SSCs that the applicant relied on to demonstrate compliance with the requirements of 10 CFR 54.4(a). The applicants LR program guidelines provided a listing of documents used to support scoping evaluations. The staff determined that the design documentation sources, required to be used by the applicants implementing procedures, provided sufficient information to ensure that the applicant identified SSCs to be included within the scope of LR consistent with the plants CLB.

During the audit, the applicant stated that it evaluated the types of events listed in Nuclear Energy Institute (NEI) 95-10 (anticipated operational occurrences, design-basis accidents, external events, and natural phenomena) that were applicable to DCPP. The staff reviewed the applicants basis documents, which described design-basis conditions in the CLB, and addressed events defined by 10 CFR 50.49(b)(1) and 10 CFR 54.4(a)(1). The FSAR and basis documents discussed events, such as internal and external flooding, tornados, and missiles.

12 The staff determined that the applicants evaluation of design-basis events (DBEs) was consistent with the SRP-LR.

The staff determined that the applicants LR project personnel performed the scoping activities, in accordance with the applicable implementing documents, as follows:

Mechanical scoping: The applicant used information contained in the plant component database to develop a list of plant systems and used CLB information, DBD, maintenance rule basis documents, and station drawings to identify system intended functions. The intended functions were evaluated using the criteria of 10 CFR 54.4(a) to identify those systems to be included within the scope of LR.

Structural scoping: The applicant used CLB information, DBD, and station drawings to develop a structures list and to identify structural intended functions. The intended functions were evaluated using the criteria of 10 CFR 54.4(a) to identify those systems to be included within the scope of LR.

Electrical scoping: The applicant used a bounding approach for plant electrical and instrumentation and control (EI&C) systems and included all EI&C systems, like EI&C components contained in mechanical systems, within the scope of LR by default. The screening of electrical I&C components in electrical I&C and mechanical systems used a bounding approach as described in NEI 95-10 and electrical I&C components for in-scope systems were assigned to commodity groups.

B. Screening Methodology The audit team reviewed the methodology used by the applicant to determine if mechanical, structural, and electrical SCs within the scope of LR would be subject to an AMR (screening) and the applicant provided a discussion indicating the processes used for each discipline.

The staff determined that the applicants LR project personnel performed the screening activities, in accordance with the applicable implementing documents as follows:

Mechanical components were subject to AMR if they met the criteria of being passive and long-lived and the components supported a system intended function, which required the system to be included within the scope of LR. The applicant had identified the component level intended functions (e.g., pressure boundary, heat transfer), which supported a system intended function and highlighted the in-scope components that were subject to AMR on the LR drawings. Mechanical components that were included within the scope in accordance with 10 CFR 54.4(a)(2) and subject to AMR were also identified on the LR drawings.

Structural components had been determined by the applicant to be inherently passive and long-lived and were grouped by common structural intended functions (e.g., support, enclosure protection, fire barrier, flood barrier, pressure boundary). The components were treated as bulk commodities based on material of construction for the purposes for the AMR.

13 Electrical and instrumentation and control components, which were included within the scope of renewal in accordance with the bounding method used for EI&C, were evaluated in accordance with the guidance contained in NEI 95-10 to identify the passive and long-lived components subject to AMR. The remaining passive electrical commodities are reviewed to determine if the commodity performs a LR intended function. If an electrical commodity does not perform a LR intended function, it is not considered further and, therefore, is not subject to an AMR.

The audit team noted that the applicants screening process was performed in accordance with its written requirements and was consistent with the guidance provided in the SRP-LR and NEI 95-10. The audit team determined that the screening methodology was consistent with the requirements of 10 CFR Part 54 for the identification of SSCs that meet the screening criteria of 10 CFR 54.21(a)(1).

C. Staff Verification of Scoping and Screening Results for Sampled Systems and Components The staff performed a sampling review of the results of the applicants implementation of the scoping and screening methodology to confirm that the results were in conformance with the applicable implementing documents and the requirements of 10 CFR Part 54.

The staff reviewed a sample of the scoping and screening implementation and performed walkdowns for portions of various systems, focusing on nonsafety-related SSCs in proximity to SR SSCs. The staff reviewed applicable portions of the FSAR, scoping and screening reports, and LR drawings and performed walkdowns to confirm information contained in the LRA.

The staff performed a site walkdown to observe those buildings that were included within the scope of LR, determined to be subject to an AMR, and were included in AMPs. The staff walkdowns included the exteriors and interiors (as appropriate) of the turbine, emergency diesel generators, switchgear, auxiliary, and containment structures.

D. Aging Management Program Quality Assurance Attributes The audit team reviewed the AMP quality assurance (QA) elements to verify consistency with the staffs guidance described in SRP-LR, Appendix A, Branch Technical Positions, Section A.2, Quality Assurance for Aging Management Programs (Branch Technical Position IQMB-1).

The AMP QA elements are corrective action, confirmation process, and administrative controls.

The applicant described the AMP QA elements in LRA Appendix A, Final Safety Analysis Report Supplement, Section A.1.3, Quality Assurance Program and Administrative Controls, and LRA Appendix B, Aging Management Programs, Section B.1.3, Quality Assurance Program and Administrative Controls, and the individual AMPs.

LRA Appendix A.1.3 stated that the QA Program for DCPP implements the requirements of 10 CFR Part 50, Appendix B, and will be consistent with the summary in Appendix A.2, Quality Assurance for Aging Management Programs (Branch Technical Position IQMB-1), of NUREG-1800. The QA Program includes the elements of corrective action, confirmation process, and administrative controls, and is applicable to nuclear safety-related SSCs. DCPP will enhance the QA Program to include nonsafety-related SSCs that are subject to AMR for LR.

LRA Section B.1.3 also stated that the DCPP QA Program implements the requirements of 10 CFR Part 50, Appendix B, Quality Assurance Requirements for Nuclear Power Plants and Fuel

14 Reprocessing Plants and is consistent with the summary in Appendix A.2 of NUREG-1800. The DCPP QA Program includes the elements of corrective action, confirmation process, and administrative controls, and is applicable to safety-related and nonsafety-related SSCs that are subject to aging management activities.

Based on the audit teams evaluation, review of the AMPs and information contained in the LRA Sections Appendix A.1.3 and Appendix B.1.3, the staff determined that the AMP QA elements are consistent with the staffs position regarding QA for aging management.

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

Document Title Revision /

Date Report No.

PGEDCROLI00007-REPT-001 10 CFR 54(a)(1) Scoping Evaluation, FLOC Screening, and Modification Review Revision 0 Report No.

PGEDCROLI00007-REPT-002 10 CFR 54(a)(2) Methodology System and Structure Scoping Revision 0 Report Nos.

PGEDCROLO0000 7-REPT-003 10 CFR 54.4(a)(3) Scoping Update Revision 0 Report Nos.

PGEDCROLO0000 7-REPT-004 Final Plant Scoping Revision 1 Boundary Drawing LR-STRUCT-01 Plot Plan Revision 2 Summary of Information in the Application. During the audit, the staff reviewed plant scoping and screening documentation associated with the following LRA sections:

LRA SECTION 2.3.3 AUXILIARY SYSTEMS 2.3.3.21 Secondary Sampling System (ID 28) 2.3.3.22 Service Cooling Water System (ID 15) 2.3.3.23 Solid Radwaste System (ID 78) 2.3.3.24 Turbine Generator Associated System (ID 22) 2.3.3.25 Oily Water and Turbine Sump (ID 27)

LRA SECTION 2.3.4 STEAM AND POWER CONVERSION SYSTEMS 2.3.4.1 Turbine Steam Supply System (ID 04) 2.3.4.2 Auxiliary Steam System (ID 06) 2.3.4.3 Main Feedwater System (ID 03) 2.3.4.4 Condensate System (ID 02) 2.3.4.5 Auxiliary Feedwater System (ID 03)

Audit Activities. The table below lists documents that were reviewed by the staff and were found relevant to the LRA Sections 2.3.3 and 2.3.4. The staff will document its review of this information in the SE.

15 Document Title Revision / Date Updated Final Safety Analysis Report (UFSAR)*

Chapter 3.0 Design Of Structures, Components, Equipment, And Systems Chapter 6.0 Engineered Safety Features Chapter 9.0 Auxiliary Systems Chapter 10.0 Steam And Power Conversion System Chapter 11.0 Radioactive Waste Management

• Sections Reviewed as listed in the LRA Sections Listed Above Revision 27 May 2023 License Renewal Drawings Drawing Numbers as listed in the LRA Sections Reviewed Above and posted to the Diablo Canyon electronic portal.

Various - as Posted for Relevance by the Applicant Safety Audit View - NRC / Audit Action Tracker - Phase 2 Applicant written responses for discussion as posted to the Diablo Canyon electronic portal. - Applicant posts on the electronic portal were in response to the Breakout Questions presented from the Staffs audit review of the LRA sections listed above.

Various dates - as the Applicant made the responses available for review. -

Actual Breakout Discussions with Applicant Occurred on June 27 and July 8, 9 & 15, 2024.

During the audit, the staff presented 28 issues to the Applicant during the breakout session for the ten LRA sections listed above. The applicants written responses to these issues furthered the staffs understanding of the scoping methodologies employed and eliminated any perception of inconsistency in the LRAs substance. The written responses were of good quality (i.e.,

comprehensive, and sufficient) such that follow-up discussions were not necessary to resolve any issue. As the audit closed of the 28 issues presented, seven issues remain as open items pending the applicants issuing an LRA Supplement. The applicant for these seven open items intends to make these changes in the first voluntary LRA supplement to DCNPP LRA.

A brief synopsis of the resolution (i.e. LRA Supplement) of Open Items is as follows:

1) LRA Section 2.3.3.21 Secondary Sampling System - Question #1 Residual Issue: The following LBRDs contain no Secondary Sampling System components that are subject to aging management. However:

a. LR-DCPP-02-106702-08 and LR-DCPP-02-107702 do contain components subject to aging management but are Condensate System components (LRA Section 2.3.4.4).

b. LR-DCPP-04-106704-05 and LR-DCPP-04-106704 Both contain components subject to aging management but are Turbine Steam Supply System components (LRA Section 2.3.4.1).

In its first voluntary supplement, Applicant will remove these four (4) LRBDs from the list in LRA Section 2.3.3.21.

2) LRA Section 2.3.3.22 Service Water Cooling - Question #1

16 Issue: Table 2.3.3 Service Cooling Water System Components Subject to Aging Management Review contains Component Type Pump Casing (Sample Circ Pump) with Component Intended Function of Leakage Boundary (Spatial). This component type does not appear in the four LRBDs listed in LRA Section 2.3.3.22 Service Cooling Water.

The applicant responded that:

The Sample Circ Pump is no longer installed in the plant. This pump was scoped into License Renewal during the original LRA development in 2009. However, removal of the pump in the 2009/2010 timeframe was not identified during the first annual update and this was carried forward to the new LRA.

In the applicants first voluntary LRA supplement, LRA Table 2.3.3-22 and Table 3.3.2-22 will remove this component type.

3) LRA Section 2.3.4.1 Turbine Steam Supply System - Question #3 Issue: The staff requested clarification about the abandoned in place status of the subject components [i.e., Heat Exchanger (Abandoned Steam Purity Analyzer Sample Cooler) and Heat Exchanger (Abandoned Steam Purity Analyzer Sample Cooler) Tube Side Component] and the specifics of how the Leakage Boundary (Spatial) intended function will be maintained during the period of extended plant operations.

The applicant responded that:

The steam purity analyzer sample cooler heat exchanger is abandoned in-place, but it has not been drained and completely isolated from the TSS system. LRA Table 3.4.2-1 currently shows this heat exchanger being managed by the Water Chemistry and One-Time-Inspection AMPs; however, these are not appropriate for the heat exchangers since the water chemistry is not active in this abandoned portion of the system.

In the applicants first voluntary LRA supplement, LRA Table 3.4.2-1 will be revised to credit the Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components AMP for managing the Heat Exchanger (Abandoned Steam Purity Analyzer Sample Cooler) Shell Side and Heat Exchanger (Abandoned Steam Purity Analyzer Sample Cooler) Tube Side components.

4) LRA Section 2.3.4.2 Auxiliary Steam System - Question #4 Issue: The staff requested verification that all the component types in the subject sample lines displayed on LR-DCPP-28-106728-02 and LRBD LR-DCPP-06-106706-05 will be adequately managed for aging during the period of extended operations per the requirements of 10 CFR 54.4(a)(2).

The applicant responded in part:

LR-DCPP-28-106728-02 was omitted from LRA Section 2.3.4.2, but all of the components indicated in the drawing as being in-scope for license renewal are

17 covered in the AMR tables for their corresponding systems in the LRA. LR-DCPP-28-106728-02 is listed as an LRBD in LRA Section 2.3.3.21.

During the breakout Issue discussion, the Applicant indicated their intent to revise LRA Section 2.3.4.2 to include LR-DCPP-28-106728-02.

5) LRA Section 2.3.4.3 Main Feedwater System - Question #2 Issue: The staff observed that the six LRBDs listed in LRA 2.3.4.3 contain at least 12 flow elements all parallel-connected to flow transmitters/indicators. In contrast, on these same LRBDs there are many non-instrumented restricting orifices evaluated per 10 CFR 54.4(a)(2) (i.e., leakage boundary or structural integrity concerns) that may have a Throttle intended function but not listed as such in Table 2.3.4-3. The staff asked whether any of the restricting orifices evaluated/identified as being within the domain of 10 CFR 54.4(a)(2) (i.e.,

leakage boundary or structural integrity concerns), have a component level intended function of restricting flow for overall 10 CFR 54.4(a)(2) system performance.

The applicant responded in part:

This convention of including orifices as a flow element component type was done consistently throughout the LRA with the exception of the use of an orifice component type in the Component Cooling Water System (LRA Tables 2.3.3-4 and 3.3.2-4). Therefore, in the first voluntary LRA supplement, PG&E will revise Tables 2.3.3-4 and 3.3.2-4 to reflect "orifice" as a "flow element" component type to be consistent with rest of the LRA.

6) LRA Section 2.3.4.3 Main Feedwater System - Question #4 Issue: The staff could not identify Component Types such as Heat Exchanger (Sample Cooler) Shell Side Components and Pump Casing (Generic Secondary Water Pumps),

as listed in LRA Table 3.4.2-3, on the six LRBDs listed in LRA section 2.3.4.3.

The applicant responded that:

Pump Casing (Generic Secondary Water Pumps): This component represents a generic component. A review of the LRBDs and supporting P&IDs do not show any pumps associated with main feedwater system other than the main feedwater pumps; therefore, this generic component designation is not needed for the main feedwater system.

In the first voluntary LRA supplement, PG&E will remove the Pump Casing (Generic Secondary Water Pumps) from Tables 2.3.4-3 and 3.4.2-

3.

7) LRA Section 2.3.4.4 Condensate System - Question #3 Issue: LRBD LR-DCPP-02-106702-05 and LRBD LR-DCPP-02-107702-05 both display Piping and Piping Components to the Abandoned in Place SEA WATER EVAPORATOR. The valves and piping segments to this evaporator are

18 evaluated as being within the scope of license renewal as evaluated per 10 CFR 54.4(a)(2) and subject to AMR. The staff requested that the applicant provide additional information as to how the subject Abandoned in Place piping components (e.g., structural integrity) will be adequately managed for aging during the period of extended plant operations.

The applicant responded:

The abandoned piping in question is in scope under 10 CFR 54.4(a)(2). The abandoned piping will be managed by the External Surfaces Monitoring of Mechanical Components (B.2.3.22) AMP and the internal surface will be managed by the Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components (B.2.3.24) AMP.

In PG&E's first voluntary LRA supplement, LRA Table 3.4.2-4 will be revised to credit the Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components AMP for managing all internal surfaces of abandoned piping and components.

LRA AMP B.2.2.1, Fatigue Monitoring Summary of Information in the Application. The LRA states that AMP B.2.2.1, Fatigue Monitoring, is an existing program with enhancements that is consistent with the program elements in GALL Report (Revision 2) 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. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the LRA 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 LRA 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 PGEDCROLI00007-REPT-005 License Renewal - Aging Effects DCPP Operating Experience Report Revision 1 October 9, 2023 N/A NRC Keywords Search Results August 2023 DCM T-43 Diablo Canyon Aging Management Program Evaluation Report B.2.2.1 - Fatigue Monitoring Revision 3

19 During the audit, the staff audited the applicants claim that the scope of program, detection of aging effects, parameters monitored or inspected, monitoring and trending, and corrective actions program elements of the LRA AMP are consistent with the corresponding elements of the GALL Report AMP or will be consistent after implementation of the identified enhancements.

The staff found that, for the preventive actions and acceptance criteria program elements, sufficient information was not available to verify whether they were consistent with the corresponding program elements of the GALL 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 Report AMP.

During the audit, the staff made the following observation. Enhancement 3 of the Fatigue Monitoring AMP indicates that the plant procedures will be enhanced to include acceptance criteria for transient definitions, cycle count action limits, and cumulative usage factor (CUF) action limits, which will invoke appropriate corrective actions if a component reaches a cycle count action limit or a CUF action limit. However, the following items related to Enhancement 3 are not clear to the staff: (1) whether the enhancement will specify the action limit for environmentally-adjusted CUF (CUFen); and (2) the approach for specifying the action limits for the transient cycle, CUF and CUFen and the action limits for these time-dependent parameters.

SAPN 50593843 2014 LRA Annual Update December 13, 2013 SAPN 50455240 RIS 11-14 Metal Fatigue Analysis Performed By Computer Software January 31, 2012 Westinghouse InfoGram IG-12-1 NRC Regulatory Issue Summary 2011 Metal Fatigue Analysis Performed By Computer Software January 16, 2012 Procedure P-51 Procedure for Fatigue Monitoring and Transient Cycle Counting Diablo Canyon Units 1 and 2 Revision 0 July 9,1998 STP M-55 Recording of Cyclic Fatigue or Transients Revision 20A SAPN 50700200 NRC IN 2015-04 Fatigue in Branch Connection Welds April 30, 2015 N/A Review of Time-Limited Aging Analyses (TLAAs) for Diablo Canyon Power Plant, Units 1 and 2 Revision 4 11/6/2023 ML11153A103 Safety Evaluation Report Related to the License Renewal of Diablo Canyon Nuclear Power Plant, Units 1 and 2 July 2011 PG&E Letter DCL 015 Request to Withdraw the Diablo Canyon Power Plant License Renewal Application March 7, 2018 SAPN 50134887 RIS 08-30 Fatigue Analysis of Nuclear Power Plant Components December 22, 2008 SAPN 51027947 EPRI MRP 2019 Guidance Thermal Fatigue April 18, 2019

20 The staff also audited the description of the LRA AMP provided in the Updated Final Safety Analysis Report supplement. The staff verified this description is consistent with the guidance in SRP-LR (Revision 2) Section 3.1.2.5.

LRA AMP B.2.2.2, Environmental Qualification of Electric Components Summary of Information in the Application. The LRA notes that AMP B.2.2.2, Environmental Qualification (EQ) of Electric Components, is an existing program that is consistent with the program elements in GALL-LR Report AMP X.E1, Environmental Qualification (EQ) of Electric Components.

Audit Activities. An on-site audit was performed June 4th to 6th, 2024.

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 DCM T-43 License Renewal Appendix B Diablo Canyon Aging Management Program Evaluation Report B.2.2.2 - Environmental Qualification of Electrical Components (NUREG 1801 Program X.E1)

Revision 3 CF3.DC1 Diablo Canyon Power Plant Departmental Administrative Procedure Maintenance and Surveillance of Electrical Environmentally Qualified (EQ) Equip Revision 5 CF3-DC3 Diablo Canyon Power Plant Departmental Administrative Procedure Maintenance of EQ Equipment: I&C Revision 1 MP E-57.8A Diablo Canyon Power Plant Electrical Maintenance Procedure Temperature Monitoring Revision 11 CF3-ID3 Environmental Qualification (EQ) Program Revision 10 DCM No. T-20 Environmental Qualification Revision 12 SAPN 508135547 1-FCV-749 EQ Splice Unsat at J-box Applicant print date: July 21, 2023 SAPN 50960226 EA: SA: EVAL T-drain on FCV-95 Applicant print date: July 21, 2023 SAPN 50986202 2018 DBA EQ: Outage scope add U1 SV-455C Applicant print date: July 21, 2023 SAPN 50986203 2018 DBA EQ: Outage scope add U1 SV-474 Applicant print date: July 21, 2023 SAPN 50986204 2018 DBA EQ: Outage scope add U2 SV-276 Applicant print date: July 21, 2023 SAPN 51241490 EQ: EH22 Activation Energy Basis Created on: May 30, 2024 SAPN 51241491 EQ: IH09 Activation Energy Basis Created on: May 30, 2024 EQ File IH-14 Reference #31 Electro-Hydraulic Actuator Temperature Datalogger Summary Revision 16

21 Document Title Revision /

Date DCM T-20 Appendix A Environmental Qualification November 17, 2000 CF3.ID4 Attachment 4 (SAP Calculation No.

9000013922)

Environmental Qualification Requirements September 23, 2020 90000007927-016-00 IH14 Revision 16 90000008405-008-00 IH49 Revision 8 EQ File IH49 Reference

1. 33 Five-Year Unit 1 Containment Average Temperature Study -

August 2015 to September 2020 October 2023 90000007450-010-00 EH20 Revision 10 90000007462-013-00 EH21 Revision 13 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, parameters monitored/inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the LRA AMP are consistent with the corresponding elements of the GALL-LR Report AMP.

The staff also audited the description of the LRA EQ of Electric Components provided in the FSAR supplement. The staff verified that the description is consistent with the acceptance criteria provided in SRP-LR Section 4.4.3.2.

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

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

For the OE review, the applicant provided a presentation on the process used to identify and evaluate the pertinent OE. Afterwards, the staff conducted its review of the applicants methodology and evaluated the OE by reviewing documentation contained in the LRA and ePortal. The staff performed a search of the operating experience file using keywords: fatigue cracking, thermal fatigue, stress corrosion, PWSCC, reactor coolant leak, and weld crack.

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.

22 Document Title Revision /

Date AD5.ID2 Diablo Canyon Power Plant Interdepartmental Administrative Procedure - Inservice Inspection Program Revision 15 12/14/2022 MA1.ID13 ASME Section XI Repair/Replacement Program Implementation - DCPP Interdepartmental Administrative Procedure Revision 18A 04/05/2023 DOC 0607.1420 Diablo Canyon Power Plant Units 1 & 2 Inservice Inspection Procedure - Additional, Supplemental and Successive Inspections Revision 7 06/22/2017 PG&E Letter DCL-19-049 Diablo Canyon Unit 1 - Owners Activity Report for Unit 1 Twenty-First Refueling Outage Revision 0 07/13/2019 PG&E Letter DCL-21-008 Diablo Canyon Unit 1 - Owners Activity Report for Unit 1 Twenty-Second Refueling Outage Revision 0 01/27/2021 PPG&E Letter DCL-22-060 Diablo Canyon Unit 1 - Owners Activity Report for Unit 1 Twenty-Third Refueling Outage Revision 0 07/21/2022 PG&E Letter DCL-24-014 Diablo Canyon Unit 1 - Owners Activity Report for Unit 1 Twenty-Third Refueling Outage Revision 1 02/12/2024 PG&E Letter DCL-18-048 Diablo Canyon Unit 2 - Owners Activity Report for Unit 2 Twentieth Refueling Outage Revision 0 06/19/2018 PG&E Letter DCL-20-011 Diablo Canyon Unit 2 - Owners Activity Report for Unit 2 Twenty-First Refueling Outage Revision 0 03/04/2020 PG&E Letter DCL-21-055 Diablo Canyon Unit 2 - Owners Activity Report for Unit 2 Twenty-Second Refueling Outage Revision 0 07/19/2021 PG&E Letter DCL-23-009 Diablo Canyon Unit 2 - Owners Activity Report for Unit 2 Twenty-Third Refueling Outage Revision 0 02/22/2023 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 LRA AMP are consistent with the corresponding elements of the GALL-LR Report AMP.

During the audit, the staff also noted that the applicant performed the re-examination of Unit 1 Pressurizer Spray Line Pipe Weld WIB-378 during the 24th refueling outage. This completed the third successive examination of the subject weld, which was the subject of the applicants enhancement. During the audit, the applicant indicated that the LRA will be updated accordingly by a subsequent revision of the LRA.

The staff also audited the description of the LRA AMP ASME Section XI Inservice Inspection, Subsections IWB, IWC, and IWD, provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

LRA AMP B.2.3.2, Water Chemistry Summary of Information in the Application. The LRA states that AMP B.2.3.2, Water Chemistry, is an existing program that is consistent with the program elements in GALL Report AMP XI.M2, Water Chemistry.

23 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 DCM T-43 Diablo Canyon Aging Management Program Evaluation Report B.2.3.2-Water Chemistry (NUREG 1801 Program XI.M2)

Revision 3 OP F-5: I Chemical Control Limits and Action Guidelines for the Primary Systems Revision 51 OP F-5: II Chemistry Control Limits and Action Guidelines for the Secondary Systems Revision 55 N/A EPRI Pressurized-Water Reactor Primary Chemistry Guidelines:

Revision 8 Strategic Primary Water Chemistry Plan Revision 8 CAP A-1 Primary Sampling and Analysis Schedules Revision 27 N/A DCPP Secondary Chemistry Strategic Plan-Revision 13 Revision 13 CAP A-2 Secondary Cycle Sampling Schedule Revision 26 CAP A-3 Technical Specifications Sampling Schedule Revision 16A SAPN 50608728 AFW Hydrazine Injection Pump Not Pumping February 10, 2014 SAPN 50863342 U2 PRT Oxygen Trending Towards Limit July 19, 2016 SAPN 51022555 U1 RCS Silica Higher than Expected March 13, 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 LRA AMP are consistent with the corresponding elements of the GALL Report AMP.

The staff also audited the description of the LRA AMP Water Chemistry program provided in the UFSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

LRA AMP B.2.3.3, Reactor Head Closure Stud Bolting Summary of Information in the Application. The LRA states that AMP B.2.3.3, Reactor Head Closure Stud Bolting is an existing program with an enhancement and an exception that is consistent with the program elements in GALL--LR Report AMP XI.M3, Reactor Head Closure Stud Bolting.

Audit Activities. In addition to the OE documentation contained in the LRA and ePortal, the staff observed the applicants search of its operating experience database.

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.

24 Document Title Revision / Date N/A Diablo Canyon License Renewal Application November 7, 2023 DCM T-43 Diablo Canyon Aging Management Program Evaluation Report B.2.3.3 - Reactor Head Closure Stud Bolting Rev 3 50811952 RPV stud 34 has surface imperfection October 16, 2015 51049681 Pitting on #4 reactor head nut October 07, 2019 AD5.ID2 Inservice Inspection Program Rev 15 PGEDCROLI00007-REPT-005 License Renewal - Aging Effects DCPP Operating Experience Report Rev 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, corrective actions, and acceptance criteria, program elements of the LRA AMP are consistent with the corresponding elements of the GALL-LR Report AMP after implementation of the identified enhancements.

The staff also verified the applicants claim that aspects of the preventive actions program elements not associated with the exception identified in the LRA or by the staff during the audit are consistent with the corresponding program elements inthe GALL-LR 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, meant to avoid SCC.

Procurement procedures have been updated to require that all newly procured studs have a yield strength less than 150 ksi.

The applicant stated that they will ensure the use of molybdenum disulfide (MoS2) as a lubricant for reactor vessel closure studs is prohibited.

The applicant stated that two ISI incidents have been reported over the 10-year OE review period, one concerning pitting on a nut, the other on a stud having surface imperfection.

o No additional reports of cracking or reportable indications were discovered in OE search.

The staff also audited the description of the LRA Reactor Head Closure Stud Bolting provided in the UFSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

LRA AMP B.2.3.4, Boric Acid Corrosion Summary of Information in the Application. The LRA states that AMP B.2.3.4, Boric Acid Corrosion, is an existing program that is consistent with the program elements in GALL-LR Report AMP XI.M10, Boric Acid Corrosion.

25 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 DCM T-43, Appendix B, Section B.2.3.4 Diablo Canyon Aging Management Program Evaluation Report - Boric Acid Corrosion Revision 3 AD4.ID2 Plant Leakage Evaluation Revision 14 ER1.ID2 Boric Acid Corrosion Control Program Revision 7 STP R-8A Reactor Coolant System Leakage Test Revision 17 STP R-8C Containment Walkdown for Evidence of Boric Acid Leakage Revision 11 SAPN 50537893 U2 Rx HL Nozzle Boric Acid February 5, 2013 SAPN 50817922 CVCS-1-92 WET BA Packing Reg Room 1R20 November 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 and trending, acceptance criteria, and corrective actions program elements of the LRA AMP are consistent with the corresponding elements of the GALL-LR Report AMP.

The staff also audited the description of the LRA Boric Acid Corrosion program provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

LRA AMP B.2.3.5, Cracking of Nickel-Alloy Components and Loss of Material Due to Boric Acid-Induced Corrosion in Reactor Coolant Pressure Boundary Components Summary of Information in the Application. The LRA states that AMP B.2.3.5, Cracking of Nickel-Alloy Components and Loss of Material Due to Boric Acid-Induced Corrosion in Reactor Coolant Pressure Boundary Components, is an existing program that is consistent with the program elements in GALL-LR Report AMP XI.M11B, Cracking of Nickel-Alloy Components and Loss of Material Due to Boric Acid-induced Corrosion in Reactor Coolant Pressure Boundary Components. To verify this claim of consistency, the staff audited the LRA AMP.

Audit Activities. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the LRA 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. The staff conducted its review of the applicants methodology and OE by reviewing documentation contained in the LRA 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.

26 Document Title Revision /

Date DCM T-43 Diablo Canyon Aging Management Program Evaluation Report B.2.3.5 - Cracking of Nickel-Alloy Components and Loss of Material due to Boric Acid-Induced Corrosion in Reactor Coolant Pressure Boundary Components Revision 3 TS1.ID9 Reactor Coolant System Alloy 600 Program Revision 1 / July 19, 2021 ISI X-CRDM Reactor Vessel Top and Bottom Head Visual Inspections This report referenced the applicants awareness of NRC Regulatory Issued Summary (RIS) 2018-06, Clarification of the Requirements for Reactor Pressure Vessel Upper Head Bare Metal Visual Examinations, dated December 2018 Revision 8 /

October 12, 2022 TS1.ID10 Reactor Coolant System Materials Degradation Management Program Revision 9 / July 14, 2021 DCL-21-055 Owners Activity Report for Unit 1 Twenty-Second Refueling Outage This report contains results of the successive examinations performed on the Diablo Canyon, Unit 2 Alloy 600 dissimilar metal (DM) welds of the pressurizer surge, spray, pressure operated relief valve (PORV), and safety valve nozzles that were mitigated by Alloy 690 full structural weld overlay in 2008. No changes were identified in characteristics of the existing flaws July 19, 2021 AD5.ID2 Inservice Program Inservice Inspection Program This report contains discussions on fabrication-related laminar indications identified in the Diablo Canyon, Unit 2 pressurizer overlaid DM welds of safety nozzles A, B, and C and spray nozzle in the 2013 refueling outage December 14, 2022 Additional Information NRC RIS 2015-10, Applicability of ASME Code Case N-770-1 as Conditioned in 10 CFR 50.55a, Codes and Standards, to Branch Connection Butt Welds 2024 Additional Information Additional Information on Electric Power Research Institute (EPRI) Reports as Required by Nuclear Energy Institute (NEI) 03-08, Guideline for the Management of Materials Issues 2024 Additional Information Additional Information on the DCPP Unit 2 Pressurizer Structural Weld Overlays 2024 Additional Information Oversight of Nondestructive Examination Activities - Procedure Classification: Quality Related Revision 5 Additional Information Nondestructive Examination Planning and Execution Revision 2 During the audit, the staff verified 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 LRA AMP are consistent with the corresponding elements of the GALL-LR Report AMP.

During the audit, the staff made the following observations:

27 The original Diablo Canyon, Units 1 and 2 Alloy 600/82/182 reactor vessel closure head were replaced by a head made with Alloy 690/52/152 materials in October 2010 and October 2009, respectively.

The original Diablo Canyon, Units 1 and 2 Alloy 600 steam generators (SG) were replaced by SGs made with Alloy 690 tubing in 2008 and 2009, respectively.

Diablo Canyon, Unit 2 pressurizer surge, spray, PORV and safety valve nozzles DM butt welds were mitigated by preemptive Alloy 690 structural weld overlays (SWOL) in 2008.

The licensees analysis showed that the crack growth due to fatigue and primary water stress corrosion cracking (PWSCC) will remain within the ASME Code acceptance limits throughout and beyond the extended period of operation from the date of installation.

NRC SE dated October 14, 2014 (ML14255A232) authorized the fabrication-related laminar indications, identified in the Diablo Canyon, Unit 2 pressurizer overlaid DM welds of safety nozzles A, B, and C and spray nozzle in the 2013 refueling outage, to remain in service for the life of the overlays (i.e., through August 26, 2045, 20 years beyond the initial license which will end on August 26, 2025).

The applicant provided additional information in the Portal, in which it confirmed that:

o It has reviewed NRC RIS 2015-10 for applicability to Diablo Canyon.

o It reviewed the industry guidance in EPRI Report 3002000091, Nondestructive Evaluation: Guideline for Conducting Ultrasonic Examinations of Dissimilar Metal Welds, Revision 1, and EPRI Report 3002000041, Nondestructive Evaluation Improvement Focus Group Extent of Condition Actions in Response to North Anna Dissimilar Metal Weld Operating Experience, Revision 1, as required under NEI 03-08 implementation criteria, and incorporated the needed and good practice elements of these guidance in its inservice inspection (ISI) program.

o It will incorporate the industry guidance recommendations in EPRI Report 3002017288, Materials Reliability Program: Guideline for Nondestructive Examination of Reactor Vessel Upper Head Penetrations, Revision 1 (MRP-384), as required under NEI 03-08 implementation criteria, into its ISI program prior to the next scheduled reactor vessel upper head penetration examinations in the period of extended operation. There will not be any reactor vessel upper head penetration examinations in the remainder of current operating license of Unit 1 that is scheduled to end in 2024 and Unit 2 that is scheduled to end in 2025.

o It reviewed the industry guidance in EPRI Report 3002012244, Revision 3, Nondestructive Evaluation: Guideline for Conducting Ultrasonic Examinations of Dissimilar Metal Welds, as required under NEI 03-08 implementation criteria, and revised its procedure ISI examination plan to reflect the changes to the needed and good practice elements from this updated report.

o The applicant confirmed that the requirement in Note 10 of applicable revision to ASME Code Case 770, Alternative Examination Requirements and Acceptance Standards for Class 1 PWR Piping and Vessel Nozzle Butt Welds Fabricated

28 with UNS N06082 or UNS W86182 Weld Filler Material with or without Application of Listed Mitigation Activities,Section XI, has been met.

The applicant confirmed that it reviewed NRC RIS 2018-06, Clarification of the Requirements for Reactor Pressure Vessel Upper Head Bare Metal Visual Examinations, dated December 2018. The applicant incorporated relevant information from RIS 2018-06 into its ISI program.

The staff also audited the description of the LRA Cracking of Nickel-Alloy Components and Loss of Material Due to Boric Acid-induced Corrosion in Reactor Coolant Pressure Boundary Components provided in the UFSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

LRA AMP B.2.3.6, Thermal Aging Embrittlement of Cast Austenitic Stainless-Steel (CASS)

Summary of Information in the Application. The LRA states that AMP B.2.3.6, Thermal Aging Embrittlement of Cast Austenitic Stainless Steel (CASS), is a new program that is consistent with the program elements in GALL-LR Report AMP XI.M12, Thermal Aging Embrittlement of Cast Austenitic Stainless Steel (CASS). To verify this claim of consistency, the staff audited the LRA AMP.

Audit Activities. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the LRA 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. The staff conducted its review of the applicants methodology and OE by reviewing documentation contained in the LRA 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 DCM T-43 Thermal Aging Embrittlement of CASS Basis Document Revision 3 NRC NUREG/CR-4513 Estimation of Fracture Toughness of Cast Stainless Steels during Thermal Aging in LWR Systems (ML16145A082)

Revision 2 March 15, 2021 Additional Information:

WCAP-18892-P Flaw Tolerance Evaluation for Susceptible Reactor Coolant Loop Cast Austenitic Stainless Steel Piping Components for Diablo Canyon Units 1 and 2 60 Year License Renewal Revision 0 Additional Information CASS AMP WCAP-1889-P Question.pdf July 2024 During the audit, the staff verified 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 LRA AMP are consistent with the corresponding elements of the GALL-LR Report AMP.

During the audit, the staff made the following observations:

29 The applicant identified that the reactor coolant loop elbow fittings of Units 1 and 2 are constructed from CASS SA-351 Grade CF8M. The applicant determined that these CASS fittings are susceptible to thermal aging embrittlement based on the casting method, molybdenum content, and ferrite content.

The applicant identified that the straight piping of Units 1 and 2 are constructed from centrifugally cast materials. The applicant screened the subject piping out as not susceptible to thermal aging embrittlement solely based on the casting method. The staff requested the applicant to clarify its technical basis and to provide ferrite content for the subject piping. During a breakout session, the applicant acknowledged the issue in WCAP 18892-P report, Revision 0, confirmed that the straight piping of Units 1 and 2 are mistakenly identified as centrifugally cast, and confirmed to revise the WCAP to correct the mistake.

The applicant utilized NRC NUREG-4513, Revision 2, Estimation of Fracture Toughness of Cast Stainless Steels during Thermal Aging in LWR Systems, with errata issued on March 15, 2021 (ML16145A082).

The staff also audited the description of the LRA Thermal Aging Embrittlement of CASS provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the GALL-LR Report.

LRA AMP B.2.3.7, PWR Vessel Internals Summary of Information in the Application. LRA Section B.2.3.7, PWR Vessel Internals, is a new program that will be consistent with the program elements in GALL Report AMP XI.M16A, PWR Vessel Internals, as modified by SLR-ISG-2021-01-PWRVI and supplemental guidance issued under the NEI 03-08 initiative.

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

30 Document Title Revision / Date Design Criteria Memorandum T-43 Appendix B Diablo Canyon Aging Management Program Evaluation Report; B.2.3.7 - PWR Vessel Internals (NUREG 1801 Program XI.M16A)

Revision 3 TS1.ID11 Diablo Canyon Power Plant Interdepartmental Administrative Procedure Reactor Internals Aging Management Program Revision 2 July 14, 2021 OG-21-160 PWROG NEI 03-08 Needed Guidance: PWR Lower Radial Support Clevis Insert X-750 Bolt Inspection Requirements September 1, 2021 NSAL-16-1 Nuclear Safety Advisory Letter: Baffle-Former Bolts Revision 1 August 1, 2016 NSAL-17-1 Nuclear Safety Advisory Letter: Guide Tube Card Wear Attributed to Ion Nitride Rod Cluster Control Assembly January 16, 2017 NSAL-20-1 Nuclear Safety Advisory Letter: Reactor Vessel Head Control Rod Drive Mechanism Penetration Thermal Sleeve Cross-Sectional Failure Revision 1 September 23, 2021 MRP 2019-009 Transmittal of NEI-03-08 Good Practice Interim Guidance Regarding MRP-227-A and MRP-227, Revision 1 PWR Core Barrel and Core Support Barrel Inspection Requirements July 17, 2019 SAPN 51225767 MRP 2024-004: Supplement to MRP 2023-005 February 16, 2024 TB 19-5 Westinghouse NSSS PWR Thermal Shield Degradation Revision 0 October 9, 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 LRA AMP are consistent with the corresponding elements of the GALL Report AMP as modified by SLR-ISG-2021-01-PWRVI and including supplemental guidance in accordance with NEI 03-08.

During the audit, the staff made the following observations:

Section 2.4 of MRP-227 Revision 1-A contains a set of general assumptions about plant operation that should be met for the guidelines of MRP-227 Revision 1-A to be applicable for use at a plant. The applicants procedure TS1-ID11 contains instructions to verify those assumptions when the new PWR Vessel Internals AMP is implemented.

Aging management of the clevis insert bolts - Item Number W14 of Table 4-9 of MRP-227 Revision 1-A - was supplemented by the guidance of PWROG Letter OG-21-160. The applicant has responded to the industry guidance of PWROG Letter OG-21-160 regarding degradation of clevis insert bolts by performing ultrasonic inspections.

Aging management of the baffle-former bolting - Item Number W6 of Table 4-3 of MRP-227 Revision 1-A - was supplemented by the guidance of Westinghouse Letter NSAL-16-1. Diablo Canyon Units 1 and 2 are Tier 1 and Tier 3 units, respectively. The full population of baffle-former bolts in Unit 1 were volumetrically inspected during the 2017 outage (1R20). One indication was found, and 61 bolts were replaced with bolts made from a material less susceptible to irradiation-assisted stress corrosion cracking

31 (IASCC). The baseline volumetric examinations for the Unit 2 baffle-former bolts are scheduled for 2025 (outage 2R25).

Aging management of the control rod guide tube (CRGT) guide plates (cards) - Item Number W1 of Table 4-3 of MRP-227 Revision 1-A - was supplemented by the guidance of Westinghouse Letter NSAL 17-1. Baseline inspections for the full population of CRGT guide cards at Diablo Canyon Units 1 and 2 were completed during 2017 (outage 1R20) and 2016 (outage 2R19), respectively. Both units contained assemblies that required mitigating actions. Because of the required mitigation, the applicant plans reinspection activities for both units during the period of extended operation in accordance with the guidance of NSAL 17-1.

Aging management of the thermal sleeve flanges was supplemented by the guidance of Westinghouse Letter NSAL-20-01. The applicant reviewed this guidance and determined it is not applicable to Diablo Canyon Units 1 and 2 because neither unit has thermal sleeve collar regions in their reactor vessel heads.

Aging management of the core support barrel - Item Numbers W3 and W4 of Tables 4-3 and 4-6 of MRP-227 Revision 1-A - was supplemented by the guidance of EPRI Letters MRP 2019-009 and MRP 2023-005 as supplemented by MRP 2024-004. The applicant has noted that they will incorporate this guidance into the inspection schedules of the relevant welds.

Aging management of the thermal shield support block bolts - Item Number W9 of Table 5-3 of MRP-227 Revision 1-A - was supplemented by Westinghouse Letter TB 19-5.

The applicant has reviewed the guidance and determined it only applies to Diablo Canyon Unit 1. Guidance from revision 0 of TB 19-5 is incorporated into site procedures.

The applicant is currently evaluating the updated guidance issued in revision 1 of TB 19-5.

The staff also audited the description of the LRA AMP PWR Vessel Internals provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the GALL Report as modified by SLR-ISG-2021-01-PWRVI.

LRA AMP B.2.3.8, Flow-Accelerated Corrosion Summary of Information in the Application. The LRA states that AMP B.2.3.8, Flow-Accelerated Corrosion, is an existing program with enhancements and an exception that will be consistent with the program elements in GALL-LR Report AMP XI.M17, Flow-Accelerated Corrosion as revised by LR-ISG-2012-01, Wall Thinning Due to Erosion Mechanisms. 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 description of the enhancements in the LRA and 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.

32 Document Title Revision / Date TS1.NE1 Flow Accelerated Corrosion (FAC) Monitoring Program Revision 8 DCM T-43 License Renewal Appendix B Section B.2.3.8 Flow Accel Corrosion AMP Basis Doc Revision 3 DCPP PAC Program Statistics Post - 2R22 Update FAC Stats thru 2R22 August 2, 2021 2R20 FAC Program Outage Report DCPP FAC Monitoring Program 2R20 Summary Report March 22, 2018 1R22 FAC Program Outage Report DCPP FAC Monitoring Program 1R22 Summary Report December 17, 2020 1R24 FAC Program Outage Report DCPP FAC Monitoring Program 1R24 Summary Report March 11, 2024 2R21 FAC Program Outage Report DCPP FAC Monitoring Program 2R21 Summary Report January 1, 2020 2R22 FAC Program Outage Report DCPP FAC Monitoring Program 2R22 Summary Report April 28, 2021 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 LRA AMP are consistent with the corresponding elements in the GALL-LR Report AMP as amended by LR-ISG-2012-01, or will be consistent after implementation of the enhancements identified in the LRA.

The staff also reviewed the FSAR supplement in LRA Section A.2.2.8, Flow-Accelerated Corrosion Program. The staff verified this description is consistent with the description provided in the SRP-LR Table 3.0-1, as revised by LR-ISG-2012-01.

LRA AMP B.2.3.9, Bolting Integrity Summary of Information in the Application. The LRA states that AMP B.2.3.9, Bolting Integrity, is an existing program with exemptions and enhancements for consistency with the program elements in GALL-LR Report AMP XI.M18, Bolting Integrity. To verify this claim of consistency, the staff audited the LRA AMP. During the audit, the staff reviewed the exemption and enhancements associated with this AMP. The staff will document its review of the enhancements in the SE.

Audit Activities. During its audit, the NRC staff met with the applicants staff and reviewed documentation contained in the LRA and provided by the applicant via the ePortal.

From June 4 through June 6, 2024, the staff participated in an on-site audit at DCPP in Avila Beach, CA to gain a general overview of current conditions of the structures compared to the provided OE. While onsite, the staff engaged with the applicant staff, conducted walkdowns, and reviewed documents provided by the applicant.

For the OE review, the staff conducted its review of the applicants methodology and operating experience by reviewing documentation contained in the LRA and ePortal.

33 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 DCM T-43 Diablo Canyon Aging Management Program Evaluation Report B.2.3.9 - Bolting Integrity Revision3 MP M54.1 Bolt Fabrication and Tensioning Revision 26 CAP 51154489 DA-DEG 2-3 cap screws as-found torque low.

May 24, 2022 CAP 51124262 DA-DEG 2-3 fuel leak June 28, 2021 CAP 50993794 Fire piping flange bolting corrosion August 21, 2018 CAP 50562548 XS-2-299 Leaking around valve body May 16, 2013 CAP 50700977 SW-1-302 inlet flange bolts corroded May 5, 2015 AD5.ID2 Inservice Inspection 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 LRA AMP are consistent with the corresponding elements of the GALL-LR Report AMP or will be consistent after implementation of the identified enhancements. During the audit, the staff relayed its expressed concerns with an exception to Element 3, parameters monitored/inspected. The applicant will submit a supplement to the LRA to remove this exception.

During the on-site audit, the staff performed walkdowns of the Auxiliary Building including the Spent Fuel Pool areas, Turbine Building, Condenser Pit, Intake Structure, Discharge Structures and Rad-Waste Building, and Yard Structures.

The staff also audited the description of the LRA AMP provided in the FSAR supplement in section A.2.2.9, Bolting Integrity. The staff verified that this description is consistent with the description provided in the GALL-LR.

LRA AMP B.2.3.10, Steam Generators Summary of Information in the Application. The LRA states that AMP B.2.3.10, Steam Generators, is an existing program with exceptions that is consistent with the program elements in GALL Report AMP XI.M19, Steam Generators, as modified by LR-ISG-2016-01.

To verify this claim of consistency, the staff audited the LRA AMP. During the audit, the staff also reviewed the exceptions associated with this AMP. The staff will document its review of the exceptions to the GALL Report AMP in the SE.

Audit Activities. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the LRA and provided by the applicant through its 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 LRA 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.

34 Document Title Revision / Date DCM T-43 License Renewal, Appendix B, Diablo Canyon Aging Management Program Evaluation Report, B.2.3.10-Steam Generators (NUREG 1801 Program XI.M19)

Revision 3 PGEDCROLI00007-REPT-005 License Renewal - Aging Effect Operating Experience Report Revision 1 TS1.ID3 Steam Generator Management Program Revision 15 TS1.ID10 Reactor Coolant System Materials Degradation Management Program Revision 9 TS1.NE3 Steam Generator Secondary Side Integrity Program Revision 11 STP M-SGTI Steam Generator Tube Inspection Revision 25 SG-CDMP-20-22 Diablo Canyon Unit 1 1R22 Condition Monitoring and Operational Assessment Revision 1 SG-CDMP-23-16 Diablo Canyon Unit 1 1R24 Condition Monitoring and Operational Assessment Revision 0 SG-CDMP-19-15 Diablo Canyon Unit 2 2R21 Condition Monitoring and Operational Assessment Revision 0 N/A DCPP LRA Appendix B Comparison.docx January 31, 2024 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, monitoring and trending, and corrective actions program elements of the LRA AMP are consistent with the corresponding elements of the GALL Report AMP. The staff also verified the applicants claims that aspects of the parameters monitored or inspected, detection of aging effects, and acceptance criteria program elements identified in the LRA are consistent with the corresponding elements in the GALL Report AMP.

The staff also audited the description of the LRA SG Program provided in the UFSAR supplement. The staff verified this description is consistent with the description provided in the GALL Report.

LRA AMP B.2.3.11, Open-Cycle Cooling Water System Summary of Information in the Application. The LRA states that AMP B.2.3.11, Open-Cycle Cooling Water System, is an existing program that is consistent with the program elements in GALL-LR Report AMP XI.M20, "Open-Cycle Cooling Water System," as modified by LR-ISG-2012-02.

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.

35 Document Title Revision / Date DCM T-43 Program Basis Document - Open-Cycle Cooling Water System Revision 3 OP F-5 III Chemistry Control Limits and Action Guidelines for the Plant Support Systems Revision 32 MA1.ID20 Testing Inspections for Aux Saltwater System NRC Generic Letter 89-13 Compliance Revision 7 STP I-1C U1 Routine Weekly Checks Required by Licenses Revision 131 ECG 17.2 Auxiliary Saltwater Continuous Chlorination System Revision 3 TS1.ID4 Saltwater Systems Aging Management Program Revision 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 LRA AMP are consistent with the corresponding elements of the GALL-LR Report AMP.

The staff also audited the description of the LRA AMP for the Open-Cycle Cooling Water System provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

LRA AMP B.2.3.12, Closed Treated Water Systems Summary of Information in the Application. The LRA states that AMP M21A, Closed Treated Water Systems, is an existing program with enhancements and exceptions that will be consistent with the program elements in GALL-LR Report AMP XI.M21A, Closed Treated Water Systems as modified by OE provided in LR-ISG-2012-02 and SLR-ISG-2021 MECHANICAL.

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 DCM T-43 Closed Treated Water AMP Basis Doc Revision 3 CF3.ID13 Replacement Part Evaluation and CITI Revision 32 OP-F5 III Chemistry Control Limits and Action Guidelines for the Plant Support Systems Revision 32 1007820 Closed Cooling Water Chemistry Guidelines Revision 1 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, monitoring and trending, and corrective actions program elements of the LRA AMP will be consistent with the corresponding elements of the GALL-LR Report AMP after implementation of the identified enhancements.

36 The staff also verified the applicants claim that aspects of the parameters monitored or inspected, detection of aging effects, and acceptance criteria, program elements not associated with the exceptions identified in the LRA or by the staff during the audit are consistent with the corresponding program elements inthe GALL-LR Report AMP.

The staff also audited the description of the LRA AMP M21A, Closed Treated Water Systems, provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

LRA 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 LRA 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-LR Report AMP XI.M23, Inspection of Overhead Heavy Load and Light Load (Related to Refueling Handling Systems. To verify this claim of consistency, the staff audited the LRA AMP. During the audit, the staff also reviewed the enhancements associated with this AMP. The staff will document its review of the enhancements in the SE.

Audit Activities. During its audit, the NRC staff met with the applicants staff and reviewed documentation contained in the LRA and provided by the applicant via the ePortal.

From June 4 through June 6, 2024, the staff participated in an on-site audit at DCPP in Avila Beach, CA to gain a general overview of current conditions of the structures compared to the provided operating experience (OE). While onsite, the staff engaged with the applicant staff, conducted walkdowns, and reviewed documents provided by the applicant.

For the OE review, the staff conducted its review of the applicants methodology and operating experience by reviewing documentation contained in the LRA 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 DCM T-43 Diablo Canyon Aging Management Program Evaluation Report -

Inspection of Overhead Heavy Load and Light Load (Related to Refueling Handling Systems Revision 3 SAPN 51076593 Corroded bolting on Intake Trolley motor May 26, 2020 SAPN 50921827 U2 Turbine Building Crane Noise (2 gap on east side crane rail) May 23, 2017 SAPN 50886770 Intake crane aux hoist monorail corrosion December 22, 2016 NUREG-0612 Control of Heavy Loads at Nuclear Power Plants July 1980 ASME NOG-1 Rules for Construction of Overhead and Gantry Cranes (Top Running Bridge, Multiple Girder) 2004 ASME B30.2 Overhead and Gantry Cranes (Top Running Bridge, Single or Multiple Girder, Top Running Trolley Hoist) 2005 Drawing 442845 Turbine Building Structural Steel Exterior Crane Girder Details June 15, 1972 Drawing 439507 Typical Sections and Details Crane Support Structure - Auxiliary Building Crane Areas J & K October 29, 2009 DCM No. S-42B Design Criteria Memorandum S-42B, Appendix C, Fuel Handling Building Crane (Single-Failure-Proof Crane)

Revision 7B

37 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 LRA AMP are consistent with the corresponding elements of the GALL-LR Report AMP or will be consistent after implementation of the identified enhancements.

During the on-site audit, the staff performed walkdowns of the Auxiliary Building including the Spent Fuel Pool areas, Turbine Building, Intake Structure, and Rad-Waste Building.

The staff also audited the description of the LRA AMP provided in the FSAR supplement in section A.2.2.13, Inspection of Overhead Heavy Load and Light Load (Related to Refueling Handling Systems. The staff verified that this description is consistent with the description provided in the GALL-LR.

LRA AMP B.2.3.14, Fire Protection Summary of Information in the Application. The LRA states that AMP B.2.3.14, Fire Protection, is an existing program with one exception and one enhancement that will be consistent with the program elements in GALL-LR Report AMP XI.M26, Fire Protection. To verify this claim of consistency, the staff audited the LRA AMP. 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 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/Description Revision /

Date DCM T-43, Appendix B Diablo Canyon Aging Management Program Evaluation Report Revision 3 OM8 Fire Protection Program Revision 7B STP M-70D Inspection of Rated Fire Assemblies, Except Penetration Seals, Dampers, & Doors Revision 30 STP M-70A Inspection of Fire Barrier and HELB Penetration Seals Revision 13 STP M-70B Inspection and Testing of Fire Dampers Revision 23 STP M-39A1 Routine Test of Diesel Generator 1-1 or 2-1 Room CO2 Fire System Operation Revision 25A STP M-39B Routine Test of Cable Spreading Room CO2 Fire System Operation Revision 40 STP M-39C Routine Test of Turbine Lube Oil Room CO2 Fire System Operation Revision 26 STP M-39D Routine Surveillance Test of Carbon Dioxide Hose Reels Revision 19 STP M-39E Routine Test of Turbine Generator Bearing No. 10 CO2 Fire System Operation Revision 22

38 Document Title/Description Revision /

Date STP M-39 F Routine Test of Circulating Water Pump High Pressure CO2 Fire System Operation Revision 14 STP M-70.CRD Control Room ECG Door Inspection Revision 6 STP M-70-ROL Inspection of ECG Roll-up Doors and Doors on Rollers Revision 3 STP M-70.SWG Inspection of ECG Swing Type Doors Revision 14 SAPN 50611014 Cable Tray ENDB Fire Barrier Damage February 19, 2014 SAPN 50659771 Fire Door 245 Unable to Operate September 27, 2014 SAPN 50700082 Equipment Failure Associated with Smoke Damper April 29, 2015 SAPN 50888756 Degraded Pyrocrete January 3, 2017 SAPN 51140823 Missing Screws in Sheet Metal Junction Box January 11, 2022 SAPN 51142043 Fire Damper Drop Failure January 26, 2022 SAPN 51182651 Corroded Hinges on ECG Fire Door March 1, 2023 SAPN 50971906 Failed CO2 System Test March 20, 2018 N/A Full DCPP OE (1 or more keywords) Part 1 N/A N/A Full DCPP OE (1 or more keywords) Part 2 N/A N/A Full DCPP OE (1 or more keywords) Part 3 N/A N/A Full DCPP OE (1 or more keywords) Part 4 N/A During the audit, the staff verified the applicants claim that the preventive actions, acceptance criteria, and corrective actions program elements are consistent with the corresponding program elements in the GALL-LR Report AMP.

The staff also verified the applicants claim that aspects of the detection of aging effects program element not associated with the exception identified in the LRA will be consistent with the corresponding program element inthe GALL-LRReport AMP after implementation of the identified enhancement.

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

39 necessary to verify whether the program elements are consistent with the corresponding program elements of the GALL-LR Report AMP.

During the audit of the operating experience 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 LRA Fire Protection program provided in the FSAR supplement. The staff verified this descriptionisconsistent with the description provided in the SRP-LR.

LRA AMP B.2.3.15, Fire Water System Summary of Information in the Application. The LRA states that AMP B.2.3.15, Fire Water System, is an existing program with exceptions and enhancements that will be consistent with the program elements in GALL-LR Report AMP XI.M27, Fire Water System. To verify this claim of consistency, the staff audited the LRA AMP. 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 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/Description Revision /

Date DCM T-43, Appendix B Diablo Canyon Aging Management Program Evaluation Report, Fire Water System Revision 3 STP M-63E Fire Water System Yard Loop Flush Revision 9A STP M-63F Yard Loop Fire Water System Hydrant Flush Revision 11 STP M-66A Deluge System Nozzle Proof Test Startup Transformers Revision 9 STP M-66B Deluge System Nozzle Proof Test Main and Auxiliary Transformers Revision 13 STP M-63B Fire Water Deluge System Flow Test Revision 6 STP M-71 Firewater System Flow Test Revision 13 STP M-80B Indoor Fire Hose Operability Test Revision 24 STP M-80D Fire Hose Hydrostatic Testing Revision 8A STP M-65 Sprinkler/Deluge System Visual Verification Revision 23 STP M-79 Indoor Fire Hose Inspection Revision 22 MP 13743 FWT1: Firewater Tank Internal Insp N/A

40 Document Title/Description Revision /

Date STP P-FPP-B02 Fire Pump 0-2 Routine Surveillance Revision 15 STP M-63C Fire Water System Functional Test of the Fuel Handling and Radwaste Buildings Revision 5B STP M-63D Fire Water Main System Functional Test of the Turbine Buildings Revision 8A STP M-67B2 Containment Fire Hose Reel Station Inspection Revision 8 STP M-64 Deluge System Functional Test Revision 12B MP M-18.4 Firewater System Flush Through RCP Sprinkler Heads Revision 4 SAPN 51051185 Deluge Nozzles Blocked October 16, 2019 SAPN 51049099 Paint on Fire Sprinkler October 3, 2019 SAPN 51171520 Sprinkler Pipe with Moderate Pitting Corrosion and Loss of Coating November 14, 2022 SAPN 51162277 Sprinkler Head Leakage August 26, 2022 SAPN 51121875 Rust Corrosion on Fire Water Piping June 4, 2021 SAPN 50584537 Minor Fire Water Leak September 23, 2019 SAPN 50585945 Localized Pit Close to TW October 10, 2013 N/A Full DCPP OE (1 or more keywords) Part 1 N/A N/A Full DCPP OE (1 or more keywords) Part 2 N/A N/A Full DCPP OE (1 or more keywords) Part 3 N/A N/A Full DCPP OE (1 or more keywords) Part 4 N/A During the audit, the staff verified that for the program element that the applicant declared was consistent, the preventive actions program element of the LRA AMP is consistent with the corresponding element of the GALL-LR Report AMP.

The staff also verified the applicants claim that aspects of the acceptance criteria and corrective actions program elements not associated with the exceptions identified in the LRA will be consistent with the corresponding program elements in the GALL-LR Report AMP after implementation of the identified enhancements.

In addition, the staff found that for the scope of the program, parameters monitored or inspected, detection of aging effects, and monitoring and trending program elements, sufficient information was not available to determine whether they are consistent with the

41 corresponding program elements of the GALL-LR 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-LR Report AMP.

During the audit of the operating experience 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 LRA Fire Water System program provided in the FSAR supplement. The staff verified this descriptionisconsistent with the description provided in the SRP-LR.

LRA AMP B.2.3.16, Aboveground Metallic Tanks Summary of Information in the Application. The LRA states that AMP B.2.3.1.6, Aboveground Metallic Tanks, is a new program with exceptions that will be consistent with the program elements in GALL-SLR Report AMP XI.M30, Aboveground Metallic Tanks.

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 operating experience by reviewing documentation contained in the LRA and ePortal.

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

Document Title Revision /

Date DCM T-43 License Renewal Appendix B Diablo Canyon Aging Management Program Evaluation Report B.2.3.16 Aboveground Metallic Tanks (Nureg 1801 Program XI.M29)

Revision 1 DA IN-2013-18 RWST Degradation September 24, 2013 NRC Information Notice 2013-18 Refueling Water Storage Tank Degradation September 13, 2013 Drawing 463987 Diesel Fire Pump Fuel Oil Storage Tank February 10, 2014 Order 60000326 U1 OWST Concrete Repairs December 13, 2000 Order 60000327 Implement OWST Concrete Repairs January 3, 2001 Order 60000309 Civil Maintenance Rule Monitoring of Outdoor September 24, 2008 During the audit, the staff verified the applicants claim that the scope of program, preventive actions, monitoring and trending, acceptance criteria, corrective actions and confirmation process program elements program elements of the LRA AMP are consistent with the corresponding elements of the GALL-SLR Report AMP.

42 During the audit, the staff verified applicants claim that the parameters monitored or inspected and detection of aging effects program elements of the LRA AMP will be consistent after implementation of the identified exceptions with the corresponding elements of the GALL-LR Report AMP.

The staff also audited the description of the LRA Aboveground Metallic Tanks provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR Report.

LRA AMP B.2.3.17, Fuel Oil Chemistry Summary of Information in the Application. The LRA states that AMP B.2.3.17, 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.M31, Fuel Oil Chemistry. 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. During its audit, the staff reviewed documentation contained in the LRA 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 operating experience by reviewing documentation contained in the LRA and ePortal.

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 Chemical Analysis Procedure Water and Sediment Revision 6 License Renewal Appendix B Diablo Canyon Aging Management Program Evaluation Report Revision 3 Surveillance Test Procedure Diesel Fuel Oil Testing Program Revision 21 Surveillance Test Procedure Emergency Diesel Fuel Oil Storage Tanks Analysis Revision 13 Surveillance Test Procedure New Fuel Oil Shipments Analysis Revision 14 Order 64003505 Diesel Fuel Oil Storage Tanks Inspections and Cleaning January 31, 2009 Order 60059792 ISI Support for STP M-91A May 4, 2023 During the audit, the staff verified the applicants claim that the scope of program, detection of aging effects, monitoring and trending, acceptance criteria and corrective actions program elements of the LRA AMP are consistent with the corresponding elements of the GALL-LRReport AMP.

43 During the audit, the staff verified applicants claim that the preventive actions and parameters monitored or inspected program elements of the LRA AMP will be consistent after implementation of the identified exceptions with the corresponding elements of the GALL-LR Report AMP.

The staff also audited the description of the LRA AMP provided in the UFSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

LRA AMP B.2.3.18,Reactor Vessel Surveillance Summary of Information in the Application. The LRA states that AMP B.2.3.18, Reactor Vessel Surveillance, is an existing program with an exception that is be consistent with the program elements in GALL-LR Report AMP XI.M31, Reactor Vessel Surveillance.

Audit Activities. In addition to the OE documentation contained in the LRA and ePortal, the staff observed the applicants search of its operating experience database using the keyword:

(embrittle, fluence).

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 DCM T-43 Diablo Canyon Aging Management Program Evaluation Report -

B.2.3.18 - Reactor Vessel Surveillance Revision 3 WCAP-17315-NP Diablo Canyon Units 1 and 2 Pressurized Thermal Shock and Upper-Shelf Energy Evaluations Revision 0 Final Safety Analysis Report Diablo Canyon Power Plant Units 1 and 2 - Final Safety Analysis Report Update Revision 26 September 2021 ML23199A312 Diablo Canyon Nuclear Power Plant, Unit 1 - Revision to the Reactor Vessel Material Surveillance Capsule Withdrawal Schedule (EPID L-2023-LLL-0012)

July 20, 2023 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 LRA AMP are consistent with the corresponding elements of the GALL-LR Report AMP.

The staff also verified the applicants claim that aspects of the detection of aging effects, program element not associated with the exception identified in the LRA or by the staff during the audit are consistent with the corresponding program elements inthe GALL-LR Report AMP.

The staff also audited the description of the LRA AMP B.2.3.18, Reactor Vessel Surveillance, provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

LRA AMP B.2.3.19, One-Time Inspection Summary of Information in the Application. The LRA states that AMP B.2.3.19 One-Time Inspection, is a new program that will be consistent with the program elements in GALL-LR Report AMP XI.M32, One-Time Inspection. At the time of the audit, the applicant

44 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.

The staff will address issues identified but not resolved in this audit report in the SE.

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 DCM T-43 Diablo Canyon Aging Management Program Evaluation Report B.2.3.19 - One-Time Inspection (NUREG-1801 Program XI.M32) Revision 3 TS1.DC3 Diablo Canyon Power Plant Departmental Administrative Procedure - One-Time Inspection Program Revision 1 June 13, 2023 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 LRA AMP will be consistent with the corresponding elements of the GALL-LR Report AMP.

The staff also audited the description of the LRA One-Time Inspection program provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

LRA AMP B.2.3.20, Selective Leaching Summary of Information in the Application. The LRA states that AMP B.2.3.20, Selective Leaching, is a new program that will be consistent with the program elements in GALL-LR Report AMP XI.M33, Selective Leaching, as modified by LR-ISG-2015-01, Changes to Buried and Underground Piping and Tank Recommendations. 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 DCM T-43 License Renewal Appendix B Diablo Canyon Aging Management Program Evaluation Report B.2.3.20 - Selective Leaching Revision 3 DN50123904 Fire Water Line Break at SU Trans. 2-1 December 17, 2008 DN50581755 FP-2-FP-30: d/s Piping Condition September 9, 2013 DN50581757 FP-2-FP-30 Material Condition September 9, 2013 During the audit, the staff verified the applicants claim that the preventive actions, parameters monitored or inspected, detection of aging effects, monitoring and trending,

45 acceptance criteria, and corrective actions program elements of the LRA AMP are consistent with the corresponding elements of the GALL-LR Report AMP.

In addition, the staff found that for the scope of program program element, sufficient information was not available to verify whether it was consistent with the corresponding program element of the GALL-LR Report AMP. The staff will consider issuing an RAI in order to obtain the information necessary to verify whether this program element is consistent with the corresponding program element of the GALL-LR Report AMP.

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

LRA AMP B.2.3.21, One-Time Inspection of ASME Code Class 1 Small-Bore Piping Summary of Information in the Application. The LRA states that AMP B.2.3.21, One-Time Inspection of ASME Code Class 1 Small-Bore Piping is a new condition monitoring program that will be consistent with the program elements in GALL Report AMP XI.M35, One-Time Inspection of ASME Code Class 1 Small-Bore Piping. To verify this claim of consistency, the staff audited the LRA AMP.

Audit Activities. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the LRA and documentation 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. The staff conducted its review of the applicants methodology and OE by reviewing the documentation contained in the LRA and ePortal. The staff performed a search of the operating experience file using keywords: fatigue, high cycle, fatigue cracking, thermal fatigue, stress corrosion, SCC, socket weld, and small bore, small-bore, RCS leak, weld crack, 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 DCM-T43 Diablo Canyon Aging Management Program Evaluation Report Basis Document - One-Time Inspection of ASME Code Class 1 Small-Bore Piping Revision 3 July 9, 2022 OTI-Small-Bore Question 1 - Response Program Implementation March 26, 2024 OTI-Small-Bore Question 2 - Response OE Search Results March 26, 2024 OTI-Small-Bore Question 1 - Enclosure OE Search Results Enclosure March 26, 2024 NRC IN 2014-02 Failure to Properly Pressure Test Reactor Vessel Flange Leak-off Lines February 25, 2014 NRC IN 2015-04 Fatigue in Branch Connection Welds April 24, 2015

46 Document Title Revision /

Date MRP-146 Management of Thermal Fatigue in Normally Stagnant Non-Isolable Reactor Coolant System Branch Lines Revision 0 April 20, 2010 AR-A0505979 Cracked Weld Found on Coupling on Capillary Line for LT-459 June 8, 2000 AR-A064034064034Excess Letdown HX Inlet Line Probable Leak November 23, 2005 DCL-13-085 Licensee Event Report 1-2013-005-00, Both Trains of Residual Heat Removal Inoperable Due to Circumferential Crack on a Socket Weld August 22, 2013 DCL-16-021 Licensee Event Report 1-2015-001-01, Both Trains of Residual Heat Removal Inoperable Due to Circumferential Crack on a Socket Weld February 11, 2016 TS1.DC3 One-Time Inspection Program Revision 1 June 13, 2023 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 LRA AMP are consistent with the corresponding elements of the GALL Report AMP.

The staff also audited the description of the LRA AMP provided in the FSAR supplement. The staff verified that this description is consistent with the description provided in the SRP-LR.

LRA AMP B.2.3.22, External Surfaces Monitoring of Mechanical Components Summary of Information in the Application. The LRA states that AMP B.2.3.22, External Surfaces Monitoring of Mechanical Components, is a new program that will be consistent with the program elements in GALL-LR Report AMP XI.M36 External Surfaces Monitoring of Mechanical Components, as modified by LR-ISG-2012-02 (ML13227A361).

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 DCM-T43 Diablo Canyon Aging Management Program Evaluation Report, External Surfaces Monitoring of Mechanical Components

((NUREG-1801 Program XI.M36)

Revision 4 CAP 51082639 Leak on Auxiliary Feedwater Piping After LCV-111 July 23, 2020 SAPN 51083213 Root Cause Evaluation, Leak on Auxiliary Feedwater Piping After LCV-111 Revision 0 CAP 51084933 Component Cooling Water CCW-2-698 and TCV-1429 Corrosion August 12, 2020 CAP 51112352 Steam Generator Blowdown Tank Corrosion Under Insulation March 25, 2021 CAP 51169747 Unit 2 Steam Generator Blowdown Tank - Shell Is Below T-minimum November 3, 2022 CAP 51171499 Recommend Replace -Steam Generator Blowdown Tank 2-1 November 14, 2022

47 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 LRA AMP are consistent with the corresponding program elements of the GALL-LR Report AMP XI.M36, as modified by LR-ISG-2012-02.

The staff also reviewed the FSAR supplement in LRA Section A.2.2.22, External Surfaces Monitoring of Mechanical Components. The staff verified this description is consistent with the description provided in the SRP-LR, Table 3.0-1, as revised by LR-ISG-2012-02.

LRA AMP B.2.3.23, Flux Thimble Tube Inspection Summary of Information in the Application. The LRA states that AMP XI.M37, Flux Thimble Tube Inspection, is an existing program that is consistent with the program elements in GALL--LR Report AMP XI.M37, Flux Thimble Tube Inspection.

Audit Activities. In addition to the OE documentation contained in the LRA and ePortal, the staff observed the applicants search of its operating experience database.

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 N/A Diablo Canyon License Renewal Application November 7, 2023 DCM T-43 Diablo Canyon Aging Management Program Evaluation Report, B.2.3.23 - Flux Thimble Tube Inspection Revision 4 STP R-22 Thimble Tube Inspection Program Revision 18 50812934 Tube G-12 is capped at the seal table October 20, 2015 50848480 MIDS Thimble Tube Cleaning during 2R19 May 01, 2016 50863266 Replace 13 Flux Thimble Tubes 2R20 July 19, 2016 PGEDCROLI00007-REPT-005 License Renewal - Aging Effects DCPP Operating Experience Report 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 LRA AMP are consistent with the corresponding elements of the GALL-LR Report AMP.

During the audit, the staff made the following observations:

All flux thimble tubes are inspected, per the application and procedures, during each refueling outage, with wall thickness measurements trended for wear to the next outage.

The applicant has employed capping, moving, and replacing flux thimble tubes to reduce wear or prevent it in the case of the acceptance criteria being exceeded.

48 The staff also audited the description of the LRA Flux Thimble Tube Inspection Program provided in the UFSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

LRA AMP B.2.3.24, Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components Summary of Information in the Application. The LRA states that AMP B.2.3.24, Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components, is a new program with exceptions that will be consistent with the program elements in GALL-LR Report AMP XI.M38, Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components, as modified by LR-ISG-2012-02.

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 DCM T-43 Diablo Canyon Aging Management Program Evaluation Report B.2.3.24 - Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components (NUREG 1801 Program XI.M38)

Revision 3 CAP Report 51008158 Trend analysis of copper alloy piping in the domestic water piping system December 13, 2018 CAP Report 50848012 License renewal commitment to replace copper alloy piping in the domestic water piping system April 28, 2016 During the audit, the staff verified the applicants claim that the preventive actions, monitoring and trending, acceptance criteria, and corrective actions program elements of the LRA AMP will be consistent with the corresponding elements of the GALL-LR Report AMP.

The staff also verified the applicants claim that aspects of the scope of program, parameters monitored or inspected, and detection of aging effects program elements not associated with the exceptions identified in the LRA are consistent with the corresponding program elements inthe GALL-LR Report AMP.

The staff also audited the description of the Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components AMP in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

LRA AMP B.2.3.25, Lube Oil Analysis Summary of Information in the Application. The LRA states that AMP B.2.3.25, Lubricating Oil Analysis, is an existing program with enhancements that will be consistent with the program elements in GALL-LR Report AMP XI.M40, Lubricating Oil Analysis. 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.

Activities. During its audit, the staff reviewed documentation contained in the LRA and provided by the applicant via the ePortal. For the OE review, the applicant made a presentation on the

49 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 LRA and ePortal. 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 operating experience in the SE.

Document Title Revision / Date DCM No. T-43 Appendix B Lubricating Oil Analysis Program Revision 3 Order: 60049469 Outboard Seal Leak July 20, 2015 Procedure TS5.ID8 Predictive Maintenance Revision 3 Procedure CF5.ID11 Lubricant Control Revision 9D Procedure MP M-56.7 Lubricant Sampling Revision 11 Procedure TS5.ID8 Predictive Maintenance Revision 3 Procedure MA1.ID27 Preventive Maintenance Program Revision 11 Order: 64058015 Sample/Change Oil, Clean & Inspection December 11, 2013 During the audit, the staff verified applicants claim that the scope of program, preventive actions, parameters monitored or inspected, monitoring and trending, detection of aging effects, acceptance criteria, and corrective actions program elements of the LRA AMP is consistent with the corresponding elements of the GALL-LR Report AMP after implementation of the identified enhancements.

The staff also audited the description of the LRA AMP Lubricating Oil Analysis program provided in the UFSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR Report.

LRA AMP B.2.3.26, Buried and Underground Piping and Tanks Summary of Information in the Application. The LRA states that AMP B.2.3.26, Buried and Underground Piping and Tanks, is an existing program with enhancements and exceptions that will be consistent with the program elements in GALL-LR Report AMP XI.M41, "Buried and Underground Piping and Tanks," as modified by LR-ISG-2015-01, Changes to Buried and Underground Piping and Tank Recommendations. 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.

50 Document Title Revision / Date PGEDCROLI00007-REPT-078 License Renewal Aging Management Program Basis Document Buried and Underground Piping and Tanks Revision 1 Drawing 438145, Sheet 1 Civil Plan Firewater System Power Block Perimeter Diablo Canyon Power Plant Revision 40 PEP 72.1 Annual Survey of ASW Pipe Cathodic Protection Revision 0 MIP C-15.0 Excavation and Backfill Revision 3 PEP M-21A Diesel Fuel Oil Storage Tanks Inspection and Cleaning Revision 0 TS5.ID3 Buried Piping and Tanks Program Revision 8 STP M-71 Firewater System Flow Test Revision 13 STP M-122 Diesel Fuel Oil Underground Storage Tanks (DFOUST) 0-1 and 0-2 Interstitial Test and Enhanced Leak Detection Test Revision 7 Calculation Number 9000041674 Buried Piping and Tanks Program Asset Management Plan Revision 3 DN50595631 Inspect U1 ASW Discharge Buried Piping November 20, 2013 DN50805534 Diesel F.O. Vault 0-1 Coatings September 15, 2015 DN50865731 Inspect DFO System Piping Per TS5.ID3 August 3, 2016 DN50915722 ASW Line 713 Corrosion on Bolting April 27, 2017 DN51086178 CP Anode ECPOC is Discharging No Current August 25, 2020 DA50513038 Firewater Line Break W of Main Warehouse September 15, 2012 DN50313969 Piping Corrosion in DFO Vault 0-2 May 4, 2010 DN51050775 Water Leak on Unpaved Road to 30K Tank October 13, 2019 N/A 2017 Diabo Canyon Soil Corrosivity Analysis April 30, 2017 8831R Specification for Construction of Buildings and Related Structures for Diablo Canyon Site June 3, 1969 Drawing No. 066632 Civil Underground ASW Bypass Piping Installation Specification Diablo Canyon Power Plant Revision 1 Drawing No. 438165 Civil Emergency Diesel Generator Fuel Oil System Diablo Canyon Power Plant Revision 14 Drawing No. 438145 Plan Firewater System Diablo Canyon Revision 21 Drawing No. 449202-1 Unit 1 Piping Design Review Isometric Vacuum Relief of Auxiliary Saltwater Lines Revision 7 Drawing No. 449204-1 Unit 2 Piping Design Review Isometric Vacuum Relief of Auxiliary Salt Water Lines Revision 9

51 During the audit, the staff verified the applicants claim that the scope of program, monitoring and trending, and corrective actions program elements of the LRA AMP will be consistent with the corresponding elements of the GALL-LR Report AMP after implementation of the identified enhancements.

In addition, the staff found that for the preventive actions, parameters monitored or inspected, detection of aging effects, and acceptance criteria program elements, sufficient information was not available to determine whether they were consistent with the corresponding program elements of the GALL-LR 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-LR Report AMP.

During the audit, the staff made the following observations:

The staff reviewed drawings 449202-1 and 449204-1 and noted lines 5198 and 5199 are specified to be externally coated with two coats of Devtar 247. In addition, the staff noted that Devtar 247 is a high build epoxy mastic coating.

The staff reviewed drawing 438145 (Revision 21) and noted the exterior surfaces of cast iron fittings shall be coated with PPG Coal Cat. UC 40101.

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

LRA AMP B.2.3.27, Internal Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, and Tanks Summary of Information in the Application. The LRA states that AMP B.2.3.27, Internal Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, and Tanks, is a new program with exceptions that will be consistent with the program elements in GALL-LR Report AMP XI.M42, Internal Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers and Tanks, as amended by LR-ISG-2013-01, Aging Management of Loss of Coating or Lining Integrity for Internal Coatings/Linings on In-Scope Piping, Piping Components, Heat Exchangers 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 DCM T-43, Appendix B, Section B.2.3.27 Diablo Canyon Aging Management Program Evaluation Report - Internal Coatings/Linings on In-Scope Piping, Piping Components, Heat Exchangers, and Tanks Revision 2 AWP E-054 Inspections: Internal Coatings/Linings of Piping/Components, Heat Exchgs & Tanks Revision 0

52 2R16 ASW Piping Inspection Report (No.

420DC-11.22)

Remote Visual Inspection of the Diablo Canyon Power Plant, Unit 2, Auxiliary Salt Water Piping Train 2-1 and 2-2, During the 2R16 Refueling Outage June 2011 2R17 ASW Piping Inspection Report (No.

420DC-13.12)

Remote Visual Inspection of the Diablo Canyon Power Plant, Unit 2, Auxiliary Salt Water Piping, Train 2-1 CCW/HX Outlet to Discharge During the 2R17 Refueling Outage March 2013 1R20 ASW Piping Inspection Report (No.

413.61-17.86)

Remote Visual Inspection of the Diablo Canyon Power Plant, Unit 1, Auxiliary Salt Water Piping Train 1-1 and 1-2, During the 2R16 Refueling Outage May 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 LRA AMP will be consistent with the corresponding elements of the GALL-LR Report AMP.

During the audit, the staff made the following observation:

1) Although the LRA stated that the plant-specific OE search did not identify any plant-specific OE related to AMP B.2.3.27, staff made the following observation. Applicant inspections of Auxiliary Salt Water (ASW) piping in the current licensing period, as documented in DCM T-43, Appendix B, Section B.2.3.27, revealed holidays (discontinuities) in the internal coating/lining, but DCM T-43 states that there are no degrading trends in the base material thickness. During the breakout response period, the applicant provided additional information to justify the applicants claim that there are no degrading trends.

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

The staff verified this description is consistent with the description provided in the SRP-LR.

LRA AMP B.2.3.28, ASME Section XI, Subsection IWE Summary of Information in the Application. The LRA states that AMP B.2.3.28, ASME Section XI, Subsection IWE, is an existing program with enhancements that will be consistent with the program elements in GALL Report AMP XI.S1, ASME Section XI, Subsection IWE.

Audit Activities. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the LRA 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 operating experience by reviewing documentation contained in the LRA 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.

53 Document Title Revision / Date DCM No. T-43 License Renewal Appendix B, Diablo Canyon Aging Management Program Evaluation Report, B.2.3.28 - ASME Section XI, Subsection IWE (NUREG-1801 Program XI.S1)

Revision 3 PGEDCROLI00007-REPT-005 License Renewal - Aging Effects Operating Experience Report Revision 1 N/A Evaluated Filtered DCPP OE 5 or more keywords (1918 records)_portrait.pdf August 28, 2023 AD5.ID2 Inservice Inspection Program, Interdepartmental Administrative Procedure, DCPP Revision 15 December 14, 2022 N/A Containment Inservice Inspection Program (ASME Section XI, Subsections IWE and IWL), Third Ten-Year Inspection Interval (Start date 5/9/2018), DCPP Units 1 and 2 Revision 0, April 4, 2019 NDE VT GEN General Visual Examination of Containment Liner, DCPP Nondestructive Examination Procedure Revision 0 NDE VT1-1 Visual Examination of Component Surfaces, DCPP Nondestructive Examination Procedure Revision 3 ISI DATA Dispositioning of Recorded NDE Examination Data, DCPP Inservice Inspection Procedure Revision 5 ISI DATA SUCCESS Additional, Supplemental and Successive Inspections, DCPP Inservice Inspection Procedure Revision 7 MP M-54.1 Bolt Fabrication and Tensioning, DCPP Mechanical Maintenance Procedure Revision 26 April 27, 2021 50921421 Equipment Hatch Bolt: Degraded Condition May 22, 2017 Work Order (WO) 60101082 Equipment Hatch Bolt; Degraded Condition MP67: Replace Equipment Hatch Bolt/Nut, DCPP Unit 1 July 31, 2017 50419948 IN 11-15: Calculation Steel Containment Degradation - License Renewal August 8, 2011 50628122-2 DA-IN 2014 Containment Leak-Chase Channel May 8, 2014 A/R A0554957 Unit 1 Containment Liner Bulge May 10, 2002 50325017 Industry OE31490 - Bulges in RB Liner Require Further Evaluation (Crystal River 30)

July 1, 2010 50354177 U-1 Containment Liner Bulging (from initial construction)

October 24, 2010 DCPP Form 69-22232 General Containment Visual Examination Report, Unit 2, 2R22 March 30, 2021 DCPP Form 69-22232 General Containment Visual Examination Report, Unit 1, 1R22, including photographs October 20, 2020 thru October 26, 2020 DCPP Form 69-22232 General Containment Visual Examination Report, Unit 1, 1R24, including photographs and UT measurements October 18, 2023 thru November 9, 2023 51210857 Industry OE: DA-N-Mod for Caulking Should Have Been Identified October 24, 2023 50851403 RIS 2016-07: Containment Shell/Liner Inspection May 13, 2016

54 51210689 LR Revise NDE VT GEN October 23, 2023 51210819 Revise ISI Program for Moisture Barrier October 24, 2023 N/A Technical Data Sheet - Loctite LB N-5000 High Purity Anti-Seize Lubricant (nickel-based)

June 2016 N/A Technical Data Sheet - Loctite N-7000 Metal Free, High Purity Anti-Seize Lubricant April 2010 ML101690321 NRC Audit Report Regarding the Diablo Canyon Power Plant License Renewal Application (TAC NOS. ME2896 AND ME2897)

August 11, 2010 During the audit, the staff verified the applicants claim that the scope of program, parameters monitored or inspected, monitoring and trending, and acceptance criteria and corrective actions program elements of the LRA AMP are consistent with the corresponding elements of the GALL Report AMP In addition, the staff found that for the preventive actions, 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 Report AMP. The staff will use a voluntary LRA supplement offered by the applicant or consider issuing RAIs to obtain the information necessary to verify whether these program elements are consistent with the corresponding program elements of the GALL-LR Report AMP.

During the audit, the staff made the following observations:

The staff reviewed the program basis document and the LRA with respect to the program enhancements and noted that the language of program enhancements 1 and 3 to the preventive actions element regarding structural bolting and enhancement 6 to the detection of aging effects element regarding one-time supplemental examination to confirm absence of SCC in the original LRA needed additional clarification or revision in the LRA to make the LRA AMP consistent or adequate to manage the aging effects.

These issues are indicated in the breakout questions.

The staffs review of the OE description of LRA B.2.3.28 noted that the plant-specific OE in the LRA did not include a description of the extent of condition, evaluation and disposition of significant containment liner bulging present in both Unit 1 and Unit 2.

The staffs review of LRA Table 3.5-1, item 3.5-1, 027 noted that the non-applicability claim for the AMR item was not adequately justified considering penetration components with dissimilar metal welds and stainless-steel fuel transfer tube/bellows exist for which there is no CLB fatigue analyses.

The staff reviewed the LRA description of industry OE and noted that the applicability of RIS 2016-07 regarding inspection of moisture barriers to DCPP was being re-evaluated and it was unclear what the outcome of the applicants re-evaluation.

The staff will consider issuing RAI(s) or use a voluntary LRA supplement offered by the applicant to address the issues in the above observations.

The staff also audited the description of the LRA AMP ASME Section XI, Subsection IWE provided in the FSAR supplement A.2.2.28. The staff found that sufficient information was not

55 available to determine whether the description provided in the FSAR supplement was an adequate description of the LRA AMP ASME Section XI, Subsection IWE. The staff will consider issuing an RAI or use a voluntary LRA supplement to obtain the information necessary to verify the sufficiency of the FSAR supplement program description.

LRA AMP B.2.3.29, ASME Section XI, Subsection IWL Summary of Information in the Application. The LRA states that AMP B.2.3.29, ASME Section XI, Subsection IWL, is an existing program with enhancements that will be consistent with the program elements in GALL-LR Report AMP XI.S2, ASME Section XI, Subsection IWL.

Audit Activities. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the LRA and provided by the applicant via the ePortal. An on-site audit was performed from 6/3/24 to 6/7/24.

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 operating experience by reviewing documentation contained in the LRA 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 NDE VT 3C-1 Diablo Canyon Power Plant Nondestructive Examination Procedure, Units 1 & 2 Revision 7 DCM No. T-43 Diablo Canyon Aging Management Program Evaluation Report, B.2.3.29 - ASME Section XI, Subsection IWL Revision 3 AD5.ID2 Diablo Canyon Power Plant Interdepartmental Administrative Procedure Revision 15 VL_15016_110516 Diablo Canyon Power Plant Test and Analysis of Structural Concrete, Unit 2 IWL November 5, 2016 VL_16010_022217 Diablo Canyon Power Plant Test and Analysis of Structural Concrete, Unit 1 IWL February 22, 2017 VL_20007_0051322_Unit_1Diablo Canyon Power Plant Test and Analysis of Structural Concrete, Unit 1 IWL May 13, 2022 VL_20007_051722_Unit_2 Diablo Canyon Power Plant Test and Analysis of Structural Concrete, Unit 2 IWL May 17, 2022 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 element(s) of the LRA AMP will be consistent with the corresponding elements of the GALL-LRReport AMP after implementation of the identified enhancements.

The staff also audited the description of the LRA ASME Section XI, Subsection IWL AMP provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

56 LRA AMP B.2.3.30, ASME Section XI, Subsection IWF Summary of Information in the Application. The LRA states that AMP B.2.3.30 ASME Section XI, Subsection IWF, is an existing program, with enhancements when implemented, will be consistent with an exception with the program elements in GALL-LR Report, Revision 2, AMP XI.S3, ASME Section XI, Subsection IWF.

Audit Activities. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the LRA and 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 LRA 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.

57 Document Title Revision / Date DCM No. T-43 License Renewal Appendix B, Diablo Canyon Aging Management Program Evaluation Report, B.2.3.30 - ASME Section XI, Subsection IWF (NUREG-1801 Program XI.S3)

Revision 3 PGEDCROLI00007-REPT-005 License Renewal - Aging Effects Operating Experience Report Revision 1 N/A Evaluated Filtered DCPP OE 5 or more keywords (1918 records) portrait.pdf August 28, 2023 AD5.ID2 Inservice Inspection Program, Interdepartmental Administrative Procedure, DCPP Revision 15 December 14, 2022 OM7.ID13 Technical Evaluations, Interdepartmental Administrative Procedure, DCPP Revision 11 ISI SCHED ISI Program Interval Four Examinations, DCPP ISI Procedure, Unit 2 Revision 5 August 22, 2017 NDE VT3-1 Visual Examination of Component and Piping Supports, DCPP Nondestructive Examination Procedure Revision 3 ISI DATA Dispositioning of Recorded NDE Examination Data, DCPP Inservice Inspection Procedure, Units 1 and 2 Revision 5 April 25, 2017 ISI DATA SUCCESS Additional, Supplemental and Successive Inspections, DCPP Inservice Inspection Procedure Revision 7 MP M-54.1 Bolt Fabrication and Tensioning, DCPP Mechanical Maintenance Procedure Revision 26 April 27, 2021 51091807 U1 AFW Support Degraded 3-41R-loss of material, general corrosion; significantly corroded; removed and cleaned to bare metal for Engineering inspection October 10, 2020 51091806 U1 AFW Pipe Support Degraded 3-40R -wall thinning, general corrosion; significantly corroded - removed and cleaned to bare metal for Engg inspection; October 10, 2020 51086232 U-2 Pipe Support 404-25R Corrosion August 26, 2020 51084912 U-2 Support 36-50R Corrosion August 12, 2020 51169826 U-2 Hanger # 414-665R Out-of-Tolerance November 4, 2022 51232542 (OA-14)

U-2 2R24 LR Insp: Inspect Spring Can on Chrg Ln (DC-2-08-P-PSL-15-12V) with attachments April 10,2024 DCPP Form 69-22136 (OA-

13)

Report of Visual Examination of Support for Piping or Component

- Section XI: Reactor Vessel 1-1; 4 supports (2 hot-leg and 2 cold leg); with pictures attached April 15, 2022 DCPP Form 69-22136 (OA-

13)

Report of Visual Examination of Support for Piping or Component

- Section XI: Reactor Vessel 2-1; 4 supports; picture attached November 6, 2022 N/A Technical Data Sheet - Loctite LB N-5000 High Purity Anti-Seize Lubricant (nickel-based)

June 2016 N/A Technical Data Sheet - Loctite N-7000 Metal Free, High Purity Anti-Seize Lubricant April 2010 ML101690321 NRC Audit Report Regarding the Diablo Canyon Power Plant License Renewal Application (TAC NOS. ME2896 AND ME2897)

August 11, 2010 51232596 Unit 2 Support 25-1V CCW to Surge Tank Corroded (Task # 3 Support Eng. Evaluation)

April 10, 2024

58 51055056 Unit 2 ASW Support 28-60R ISI VT-3 Unacceptable (Task # 6 Examine adjacent supports)

November 13, 2019 During the audit, the staff verified the applicants claim that the parameters monitored or inspected, detection of aging effects, monitoring and trending, acceptance criteria, and corrective actions program elements of the LRA AMP are consistent with the corresponding elements of the GALL-LR Report AMP XI.S3 after implementation of the identified enhancements.

In addition, the staff found that for the scope of program and preventive actions program elements, sufficient information was not available to determine whether they were consistent with the corresponding program elements of the GALL-LR Report AMP. The staff will consider issuing RAIs or use a voluntary LRA supplement to obtain the information necessary to verify whether these program elements are consistent with the corresponding program elements of the GALL-LR Report.

During the audit, the staff made the following observations:

The staff reviewed technical data sheets for the Loctite LB N-5000, and N-7000 lubricants that will continue to be used at DCPP and noted that it is formulated with high purity raw materials and contains only trace levels of sulfur (less than 100 ppm), and that during operation the high purity prevents stress corrosion.

The staff reviewed Procedure NDE VT 3-1, R3, and noted that paragraph 6.1.11 requires, when any unacceptable condition is identified, examination of one additional support on each direction of the affected support where such support exists.

The staff noted from the LRA that sufficient information was not provided in the LRA as justification for the exception taken to the preventive actions program element for the staff to determine adequacy of the AMP to manage related aging effects with the exception.

The staff noted from review of the LRA that regarding AMR line item 3.5-1, 084 with generic note E, sufficient information was not provided to justify the adequacy of the alternate AMP being used in lieu of the GALL-LR recommended AMP.

The staff reviewed LRA AMR item 3.5-1, 068 and noted lack of clarity regarding the classes of component supports that used high strength bolting greater than 1-inch nominal diameter that would be subject to volumetric examination during the period of extended operation.

The staff will consider issuing RAIs or use a voluntary LRA supplement to obtain the information necessary to make its finding regarding the issues in the latter three observations above.

The staff also audited the description of the LRA AMP ASME Section XI, Subsection IWF provided in the FSAR supplement Section A.2.2.30. The staff verified this description is consistent with the general description provided in the SRP-LR.

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

Audit Activities. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the LRA 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 operating experience by reviewing documentation contained in the LRA 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 AD13.DC5 Diablo Canyon Power Plant Departmental Administrative Procedure Revision 15 DCM No. T-43 Diablo Canyon Aging Management Program Evaluation Report, B.2.3.31 - 10 CFR 50, Appendix J Revision 3 STP M-8F2 Pacific Gas and Electric Company Diablo Canyon Power Plant PLTM Leak Rate Testing of Personnel Air Lock Seals Revision 8 50539596 High Leakage on NSS-2-0355A LLRT February 13, 2013 N/A Appendix J Program Health Metric Report - 2R23 January 18, 2023 N/A Appendix J Program Health Metric Report - 1R23 June 27, 2022 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 LRA AMP are consistent with the corresponding elements of the GALL-LRReport AMP.

The staff also audited the description of the LRA 10 CFR Part 50, Appendix J AMP provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

LRA AMP B.2.3.32, Masonry Walls Summary of Information in the Application. The LRA 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-LR Report AMP XI.S5, Masonry Walls.

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

60 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 operating experience by reviewing documentation contained in the LRA 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 AWP E-016 Diablo Canyon Power Plant Departmental Administrative Procedure Revision 12 DCM No. T-43 Diablo Canyon Aging Management Program Evaluation Report, B.2.3.32 - Masonry Walls Revision 3 MA1.NE1 Diablo Canyon Power Plant Departmental Administrative Procedure Maintenance Rule Monitoring Program - Civil Implementation Revision 7 50841979 Barrier Discrepancy U2 480V SWGR to HSDP March 16, 2023 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 LRA AMP are consistent with the corresponding elements of the GALL-LRReport AMP after implementation of the identified enhancements.

The staff also audited the description of the LRA Masonry Walls AMP provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

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

Audit Activities. In addition to the OE documentation contained in the LRA and ePortal, the staff observed the applicants search of its operating experience database using the keywords. An on-site audit was performed from April 30, 2024, to May 2, 2024.

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 DCM No. T-43 Diablo Canyon Aging Management Program Basis Document -

Structures Monitoring Revision 3 MIP C-15.0 Diablo Canyon Power Plant Modification Installation Procedure:

Excavation and Backfill Revision 3 MAI.NEI Diablo Canyon Power Plant Department Administrative Procedure: Maintenance Rule Monitoring Program - Civil Implementation Revision 7

61 AWPE-016 Diablo Canyon Power Plant Administrative Work Procedure:

Inspection Guide - Maintenance Rule Structural Monitoring Programs -Civil Revision 12 TSI.1D4 Diablo Canyon Power Plant Interdepartmental Administrative Procedure: Saltwater Systems Aging Management Program Revision 4 MPM-54.1 Diablo Canyon Power Plant Mechanical Maintenance Procedure:

Bolt Fabrication and Tensioning Revision 26 MIP C-6.0 Diablo Canyon Power Plant Modification Installation Procedure:

Fabrication and Erection of Structural Steel (DCP-201)

Revision 5A MAI.ID 17 Diablo Canyon Power Plant Interdepartmental Administrative Procedure: Maintenance Rule Monitoring Program Revision 34 Drawing No. 522196 Civil Electrical Pull Box Layout Plan Revision 16 LR-DCPP-STRUC-512297 Architectural Site Development Plan - Structural Boundary Drawing Revision 23 EPRI 3002007348 2016 Technical Report: Aging Management for Leaking Spent Fuel Pool December 2016 N/A Unit 1 & Unit 2 Spent Fuel Pool Tell-Tale Drain Graphical Analysis N/A Notification 51221629 Unit 1 Spent Fuel Pool Tell-Tales Rod Out January 11, 2024 Notification 51241254 Unit 1 Spent Fuel Pool Tell-Tales Rod Out Results and Recommendations May 28, 2024 Notification 51221710 Unit 2 Spent Fuel Pool Tell-Tales Rod Out January 11, 2024 Notification 51241316 Unit 2 Spent Fuel Pool Tell-Tales Rod Out Results and Recommendations May 29, 2024 CAP E-17 Diablo Canyon Power Plant Chemical Analysis Procedure: Units 1 and 2 Sampling and Analyses of the Spent Fuel Pool Leak Detection Valves Revision 16 STP I-1C Diablo Canyon Power Plant Surveillance Test Procedure: Unit 1 Routine Weekly Checks Required by Licenses Revision 131 STP I-1C Diablo Canyon Power Plant Surveillance Test Procedure: Unit 2 Routine Weekly Checks Required by Licenses Revision 105 Notification 51206054 Reactor Cavity Open Pipe Boric Acid Deposit October 1, 2033 Notification 51167547 Unit 2 Refueling Water Storage Tank Concrete Crack on Roof Dome October 19, 2022 N/A Diablo Canyon Breakwater Petrographic Examination of Tribar Concrete June 8,1982 C-2123-91 Diablo Canyon Power Plant Sixth Diesel Generator Analyses of Coarse Aggregate and Portland Cement May 17, 1991 CMR-2.2 Diablo Canyon Power Plant Units 1 and 2 Auxiliary Building -

Maintenance Rule Monitoring per 10 CFR 50.65 August 9, 2022

62 CMR-2.4 Diablo Canyon Power Plant Units 1 and 2 Turbine Building -

Maintenance Rule Monitoring per 10 CFR 50.65 January 13, 2022 CMR-2.5 Diablo Canyon Power Plant Units 1 and 2 Intake Structure and Intake Control Building - Maintenance Rule Monitoring per 10 CFR 50.65 June 28, 2022 CMR-2.6 Diablo Canyon Power Plant Units 1 and 2 Discharge Structure and Circulating Water Discharge Tunnels - Maintenance Rule Monitoring per 10 CFR 50.65 July 7, 2022 CMR-2.7 Diablo Canyon Power Plant Units 1 and 2 Pipeway Structure -

Maintenance Rule Monitoring per 10 CFR 50.65 July 21, 2022 CMR-6.2 Diablo Canyon Power Plant Units 1 and 2 Miscellaneous Outdoor SSCs -Civil Works August 11, 2022 Notification 51216311 Concrete Delamination Unit 1 Intake Structure November 28, 2023 Notification 51216267 Unit 2 Intake Structure Elevation 17.5 feet Concrete Indications November 18, 2023 Notification 50442417 IN 11-20 Concrete Degradation Alkali-Silica Reaction November 28, 2011 Notification 50442417 Unit 1 License Renewal Onsite Audit: Bottom Spring Can Not Align June 6, 2024 During the audit, the staff verified the applicants claim that the monitoring and trending, acceptance criteria, and corrective actions program elements of the LRA AMP are consistent with the corresponding elements of the GALL-LR Report AMP. In addition, the staff found that for the scope of program, preventive actions, parameters monitored or inspected, and detection of aging effect program elements, sufficient information was not available to determine whether they were consistent with the corresponding program elements of the GALL--LR 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-LR Report AMP.

During the audit, the staff made the following observations:

The staff noted that the inspection of in-scope pull box shall be included in the enhancement to the Detection of Aging Effects program element instead of the Scope of Program program element. In addition, the staff noted that LRA lacks the information of scoping and screening results and Tables 1 and 2 AMR items for the in-scope pull box.

For the Preventive Actions program element, the staff noted that AMPs enhancement for ensuring structural bolting integrity is inconsistent with GALL-LR XI.S6 AMP.

For the Parameters Monitored or Inspected program element, the staff noted that the applicant only provides an enhancement to conduct a one-time video inspection of the Unit 2 spent fuel pool leak-chase within one year prior to August 26, 2025. Based on OE audit, the staff determined that the applicants one-time video inspection is not sufficient, and the plant-specific AMP or enhancements to the Structures Monitoring AMP are

63 required to manage effects of aging for the boric acid attack on the reinforced concrete in the Spent Fuel Pool, the Transfer Canal, and the Refueling Cavity during the period of extended operation. The applicant needs to follow guidelines in the EPRI 3002007348 report, which is consistent with the guidance in the Branch Technical Position RLSB-1 of the SRP-LR Appendix A.1.

For the Parameters Monitored or Inspected program element, the staff noted that the applicant may need an enhancement for structural sealants to be consistent with GALL-LR XI.S6 AMP.

During the review of LRA Table 3.5.2-10, the staff noted the component of aluminum hatches and plugs exposed to encased in concrete environment and finds that LRA does not make clear how aging effects of the embedded aluminum can be adequately managed by the DCPP Structures Monitoring AMP during the PEO.

During the on-site audit, the staff performed walkdowns of the Reactor Building (exterior),

Radwaste Storage Facilities (exterior), Administration Building (exterior), Elevated Walkway, Turbine Building, Auxiliary Building, Pipeway Structure, Fuel Handling Building, Intake Structure, Discharge Structure, and breakwaters. The staff made the following observations during walkdowns:

During the walkdown of the Fuel Handling Building, the staff noted the slight increases in leakage of the spent fuel pool at Unit 2. The staff discussed with the applicant about the function of the leak-chase channel and EPRI 3002007348 report regarding managing aging effects of boric attack on the reinforced concrete in the SFP, the Transfer Canal, and the Refueling Cavity. The applicant agreed to follow the EPRI guidance and provide enhancements to the Structures Monitoring AMP as necessary for ensuring adequate aging management of boric attack on the reinforced concrete during the PEO.

During the walkdown of the pull boxes, the staff noted that those in-scope pull boxes are reinforced concrete structures, which are directly buried in soil and potentially exposed to adverse localized environment caused by significant moisture. The staff notified the applicant that LRA Sections 2.2, 2.4, and 3.5 lack the information of aging management for the pull boxes.

During the walkdown of the Auxiliary Building, the staff noted pattern cracking on the interior and exterior surfaces of concrete walls. The staff discussed with the applicant about visual indications of aggregate reactions and potential cracking due to expansion and reaction with aggregates. The applicant was requested to evaluate whether these pattern cracking are related to ASR.

During the walkdown of the Intake Structure, the staff noted that cathodic protect system installed at concrete deck of the intake structure. The staff observed some minor cracks on the concrete floor deck and noted some cracks and more concrete spalling and deterioration towards the waterfront. The staff also noted pipe leakage to the concrete floor, the staff requested the applicant to evaluate whether chemicals from the leaked fluid will accelerate deterioration of the concrete floor and the applicant will take proper corrective actions if necessary.

64 During the walkdown of the Turbine Building, the Administration building, and the Elevated Walkway, the staff noted extensive exterior metal siding corrosion on the Administration Building and the Elevated Walkway. The staff also note exterior metal siding corrosion on the southwest corner of the Turbine Building.

During the walkdown of the Turbine Building, the staff noted minor vertical and diagonal cracks on the interior concrete walls at different locations. The staff also noted one offset pipe support at elevation 104 feet and notified the applicant for actions.

The staff also audited the description of the LRA Structures Monitoring program provided in the UFSAR supplement. The staff verified this description is consistent with the description provided in the GALL-LR Report.

LRA AMP B.2.3.34, RG 1.127, Inspection of Water-Control Structures Associated with Nuclear Power Plants Summary of Information in the Application. The LRA 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-LR Report AMP XI.S7, Inspection of Water-Control Structures Associated with Nuclear Power Plants. To verify this claim of consistency, the staff audited the LRA AMP. During the audit, the staff also reviewed the enhancements associated with this AMP. The staff will document its review of the enhancements in the SE.

Audit Activities. During its audit, the NRC staff met with the applicants staff and reviewed documentation contained in the LRA and provided by the applicant via the ePortal.

From June 4 through June 6, 2024, the staff participated in an on-site audit at DCPP in Avila Beach, CA to gain a general overview of current conditions of the structures compared to the provided operating experience (OE). While onsite, the staff engaged with the applicant staff, conducted walkdowns, and reviewed documents provided by the applicant.

For the OE review, the staff conducted its review of the applicants methodology and operating experience by reviewing documentation contained in the LRA 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 DCM T-43 Diablo Canyon Aging Management Program Evaluation Report -

RG 1.127, Inspection of Water-Control Structures Associated with Nuclear Power Plants Revision 3 MA1.NEI Maintenance Rule Monitoring Program - Civil Implementation Revision 7 CAP Report 51035993 Shallow crack 12-18 inches length caused by delamination July 2019 CAP Report 50916439 Crack in the intake structure deck near traveling screens May 2017 CAP Report 50620709 Concrete spalling on the ocean side of the east breakwater 2014 CAP Report 50633704 U2 ASW vault: corrosion and blistering of coating on the Unistrut 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 LRA AMP are

65 consistent with the corresponding elements of the GALL-LR Report AMP, or will be consistent after implementation of the identified enhancements.

During the on-site audit, the staff performed walkdowns of the Intake Structure, Discharge Structures, Service Water Reservoirs, and Circulating Water Pump areas.

The staff also audited the description of the LRA AMP provided in the FSAR supplement in Section A.2.2.34, Inspection of Water-Control Structures Associated with Nuclear Power Plants. The staff verified that this description is consistent with the description provided in the GALL-LR.

LRA AMP B.2.3.35, Protective Coating Monitoring and Maintenance Summary of Information in the Application. The LRA states that AMP B2.3.35, Protective Coating Monitoring and Maintenance, is an existing program that, with enhancement, will be consistent with NUREG-1801,Section XI.S8, Protective Coating Monitoring and Maintenance.

To verify this claim of consistency, the staff audited the LRA AMP.

Audit Activities. The table below lists the documents that were reviewed by the staff and were found relevant to the Protective Coating Monitoring and Maintenance Program. These documents were provided by the applicant and identified in the staffs search of the applicants OE database. The staff will document its review of relevant OE in the SE.

Document Title Revision /

Date DCM T-43 Protective Coating AMP Basis Document Revision 3 MIP CT-2.0 Coating Quality Monitoring Program Revision 5 DCA 9000007010-015-00 Design Calculation Summary Unit 1 Revision 15 DCA 9000007041-013-00 Design Calculation Summary Unit 2 Revision 13 TQ1-NQ5 Qualification and Certification of Quality Control Inspectors Revision 8A SAPN 51018395 Corrective Action Program Report February 21, 2019 SAPN 51018587 Corrective Action Program Report February 23, 2019 SAPN 50967568 Corrective Action Program Report February 28, 2018 SAPN 5085077 Corrective Action Program Report May 11, 2016 MIP CT-1.0 Modification Installation Procedure Revision 15 1R23 Coating Report Unit 1 Containment Coatings Monitoring and Maintenance Program Report June 1, 2022 2R23 Coating Report Unit 2 Containment Coatings Monitoring and Maintenance Program Report February 13, 2023

66 Document Title Revision /

Date Order 60117151 Work Order February 28, 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, acceptance criteria, and corrective actions program elements of the LRA AMP are consistent with the corresponding elements of the GALL-LR Report AMP.

The staff also verified the applicants claim that aspects of the monitoring and trending program element not associated with the enhancement identified in the LRA are consistent with the corresponding program element inthe GALL-LR Report AMP.

During the audit of the operating experience 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 any identified plant-specific OE in the SE.

The staff also audited the description of the LRA AMP Protective Coating Monitoring and Maintenance program provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the GALL-LR Report.

LRA AMP B.2.3.36, Insulation Material for Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Summary of Information in the Application. The LRA notes that AMP B.2.3.36, Insulation Material for Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements, is a new program that will be consistent with the program elements in GALL-LR Report AMP XI.E1, Insulation Material for Electrical Cable 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 new program, and the staffs audit only addressed the applicants basis document, available procedures, and referenced documents.

Audit Activities. An on-site audit was performed June 4 to June 6, 2024.

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 DCM T-43 License Renewal Appendix B Diablo Canyon Aging Management Program Evaluation Report B.2.3.36-Electrical Cables and Connections Not Subject to 10CFR 50.49 EQ Requirements Revision 3 OM5 Quality Assurance Program Revision14 OM7 Corrective Action Program Revision 8 OM4.ID3 Operating Experience Program Revision 35

67 AD1 Administrative Controls Program Revision17B SAND96-0344 Aging Management Guideline for Commercial Nuclear Power Plants-Electrical Cable and Terminations Printed September 1996 AWP E-037 Electrical Cable and Connections Aging Management Program Revision 0 SAPN 51168826 H2DP1 mtr leads overheated Printed April 10, 2023 Order 60148640 H2DP1 mtr leads overheated MVT: Test Run H2DP1 Printed August 07, 2023 SAPN 50943930 Found Broken Connection on Heater Printed December 13, 2023 SAPN 50944006 Found broken connection on heater 36kw Printed December 13, 2023 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 LRA AMP are consistent with the corresponding elements of the GALL-LR Report AMP.

The staff also audited the description of the LRA Insulation Material for Electrical Cables and Connections Not Subject to 10 CFR 50.49 EQ Requirements provided in the FSAR supplement.

The staff verified this description is consistent with the description provided in the SRP-LR.

The staff made the following observations during walkdowns:

The staff interviewed the applicants staff and performed walkdowns of the DCPP.

Specifically, the staff conducted on-site walkdowns of the cable raceways and electrical manholes.

The staff observed hydraulic oil mist being drawn into a ventilation system and depositing oil on cables in the direct current (DC) switchgear rooms for both units. The oil is coming from exhaust damper VAC-1-FD-5 and has existed for an extended period of time (actual onset of this condition is unknown). The condition has been reported in several SAPNs (51161487, 50077678, 50307520, 50576969, 51162301). The source of the oil is the main turbine lube oil de-mister system exhaust and its proximity to the intake of the Switchgear Ventilation System supply fans 1S-43 and 1S-44. This condition and its impact on the cables in cable trays and to the electrical equipment in these rooms has been previously evaluated by the applicant in SAPN 51162301 Task 10. This evaluation determined that there is no impact to the cable functionality because the XLPE, EPR, and Hypalon materials used in the cable construction makes it oil resistant.

As noted in the SAPN Task 10, the cables should be routinely (periodicity undefined) wiped off with a towel and with no use of solvents.

However, EPRI TR 3002010641 Low-Voltage and I&C Cable Aging Management Guide, Revision 1, recommends that cables subjected to oil or hydraulic fluid contamination should be cleaned and evaluated for any effects on longevity. The document goes on to state that long exposures may lead to softening or swelling of jacket and insulation materials. If significant swelling or softening of a jacket is observed, removal of the jacket may be necessary to determine the effect on the insulation. Replacement/repair of the jacket material may be

68 allowed, but if insulation is significantly degraded, the affected section of cable should be replaced.

SAPN 51205737 documented a walkdown of the affected cable locations and only observed/inspected the cables from below the cable trays. During this observation/inspection of cables, the oil was not cleaned off nor was a thorough observation of the cables performed.

The SAPN stated only accessible portions of the cable trays that could be seen from below were inspected. While there were several areas where oily residue could be seen on the cables, none of the cables observed showed any signs of adverse aging. During a breakout session, the applicant acknowledged that it needed to submit a supplement to further explain how the cables subjected to the oil mist will be appropriately age managed during the period of extended operation (e.g., detailed 360-degree visual inspection of the cables, testing, and defined periodicity for removing oil from the cables, etc.).

LRA AMP B.2.3.37, Insulation Material for Electrical Cables and Connections Not Subject to 10 CFR 50.49 EQ Requirements Used in Instrumentation Circuits Summary of Information in the Application. The LRA notes that AMP B.2.3.37, Insulation Material 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-LR Report AMP XI.E2, Insulation Material 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 DCM T-43 Appendix B Diablo Canyon Aging Management Program Evaluation Report B.2.3.37-Electrical Cables and Connections Not Subject to 10 CFR 50.49 EQ Requirements Used in Instrumentation Circuits Revision 3 DCM T-43 Appendix B TR-11DC-Electrical Component Aging Evaluation License Renewal Topical Report Revision 1 STP I-39-R44A.B Containment Ventilation Exhaust RM-44A Radiation Monitor Calibration Revision 15 STP I-39-R44B.B Containment Ventilation Exhaust RM-44B Radiation Monitor Calibration Revision 15 STP I-119B Calibration of Fuel Handling Building Area Radiation Monitors RM-58 and RM59 Revision 6A STP I-118B Calibration of Control Room Pressurization Rad Monitors RM-51, 52, 53, & 54 Revision 2 SAPN 50609159 U1 NE-43 requires replacement Printed 12/13/2023 SAPN 51051574 U-2 N-36 possibly under-compensated Printed 12/13/2023 SAPN 50539987 Unexpected N42 Sig A Cable Test Results Printed 06/01/2023

69 SAPN 51078002 2-N35, HV cable outer shield anomaly Printed 06/01/2023 SAPN 51052955 U-2 N-36 ind HIGH for current condition Printed 06/01/2023 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 LRA AMP will be consistent with the corresponding elements of the GALL-LR Report AMP after implementation of the identified enhancements.

The staff also audited the description of the LRA Insulation Material for Electrical Cables and Connections Not Subject to 10 CFR 50.49 EQ Requirements Used in Instrumentation Circuits provided in the FSAR supplement. The staff verified this description is consistent with the description provided in SRP-LR.

LRA AMP B.2.3.38, Inaccessible Power Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Summary of Information in the Application. The LRA notes that AMP B.2.3.38, Inaccessible Power Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements, is an existing program with enhancements and exceptions that will be consistent with the program elements in GALL--LR Report AMP XI.E3, Inaccessible Power Cables 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. An on-site audit was performed June 4 to June 6, 2024.

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.

70 Document Title Revision / Date DCM T-43 License Renewal Appendix B Diablo Canyon Aging Management Program Evaluation Report B.2.3.38 - Inaccessible Power Cables Not Subject to 10 CFR 50.49 EQ Requirements Revision 3 MP 12814 Unit 1 Intake Pull Box Inspection and Cleaning N/A MP 18790 Unit 2 Intake Pull Box Inspection and Cleaning N/A MP 12289 MHSP 1-1: Motor and Level Switch Test N/A MP 18434 MHSP 2-1: Motor and Level Switch Test N/A MP 12291 PBSP 1-1: Motor and Level Switch Test N/A MP 18436 PBSP 2-1: Motor and Level Switch Test N/A SAPN 51178804 Momentary Ground on ASW 2-2 Vault Fan Printed August 7, 2023 SAPN 51242056 U1 PBSP Light on POSPS1 Printed August 5, 2024 SAPN 51242057 Missing BPZ44 Cable Supports Printed August 7, 2024 SAPN 50448441 AWP E-016 Pullbox Inspect Guideline Printed May 31, 2023 SAPN 51205737 Oil Misting on Tray RPAE Printed June 4, 2024 TS1.ID5 Cable Aging Management Revision 1 PGEDCROLI00007-REPT-049 Project Report Cover Sheet License Renewal Scoping, Screening and Aging Management Review Results Electrical Commodities Revision 1 Drawing 57683 General Arrangement of Electrical Pull Boxes and Duct Runs Revision 16 Drawing 57682 General Arrangement of Electrical Pull Boxes and Duct Runs Revision 22 Drawing 500820 Electrical Pull Boxes & Duct Runs Revision 11 N/A Pullbox Layout Drawings N/A 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 LRA AMP will be consistent with the corresponding elements of the GALL-LR Report AMP after implementation of the identified enhancements.

The staff also verified the applicants claim that the aspects of the preventive actions program element not associated with the exceptions identified in the LRA or by the staff during the audit are consistent with the corresponding program element in the GALL-LR Report AMP.

71 The staff also audited the description of the LRA Inaccessible Power Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

The staff made the following observations during walkdowns:

During on-site discussions with the applicant, photos of various manhole internals were audited by the audit staff. The staff inquired into intake structure pullbox BPZ40-44 which had cables with tie-wraps. The staff questioned whether these cables were safety-related and if the tie-wraps were being credited as supports. The applicant identified these cables to be safety-related and initiated condition report SAPN 51242057 to address the operational and structural aspects of this condition. The applicant determined that cable supports were missing from this manhole and that the cable tie-wraps were only used during construction to keep the cables orderly (i.e., not as structural supports).

During an in-plant walkdown, the staff observed a pullbox sump alarm panel in the Turbine Building 85-foot elevation level that had an active annunciator indicating that the sump level was high. The staff questioned how this annunciator is monitored. The applicant initially stated that the panel is monitored on operator rounds but since have concluded that operator rounds do not check the status of this annunciator. The applicant has initiated condition report SAPN 51242056 for this condition to ensure that the pullbox sump alarm panel is routinely monitored to ensure that appropriate corrective actions are taken to prevent cables in the scope of LR from being submerged in water.

During on-site discussions the applicant presented an issue where oil mist is being drawn into the ventilation system and oil is collecting and dripping onto Unit 1 and 2 cable trays in their respective DC Switchgear rooms. The fire contribution of the oil on the cables has been assessed by the applicant, but aging management for long-term oil collection on the cables needs to be established for the period of extended operation. In the interim, the applicant created a follow-up action to condition reports SAPN 51205737-7 (Unit 1) and SAPN 51222709 (Unit 2) to establish a routine preventive maintenance activity to clean the oil off the cables. During a breakout session, the applicant agreed to submit a supplement to address this adverse localized environment to ensure that the affected cables are appropriately age managed during the period of extended operation.

LRA AMP B.2.3.39, Metal Enclosed Bus Summary of Information in the Application. The LRA notes that AMP B.2.3.39, Metal Enclosed Bus, is an existing program with enhancements and an exception that will be consistent with the program elements in GALL-LR 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. An on-site audit was performed June 4 to June 6, 2024.

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.

72 Document Title Revision / Date DCM T-43 License Renewal Appendix B Diablo Canyon Aging Management Program Evaluation Report B.2.3.39 - Metal Enclosed Bus Revision 3 AWP E-039 Metal Enclosed Bus Aging Management Revision 2 SAPN 50811150 ISO-Phase bus grids 16/17 not done Printed August 7, 2023 SAPN 51153981 Degraded Bus Ducting on Aux XFMR 2-2 Printed August 7, 2023 SAPN 51017453 U1: Iso Phase Bus MOD phase C flex link Printed August 7, 2023 SAPN 50604468 U2 THA22 Peeling Paint on 4kV Bus Duct Printed August 7, 2023 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 LRA AMP will be consistent with the corresponding elements of the GALL-LR Report AMP after implementation of the identified enhancements.

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 LRA or by the staff during the audit are consistent with the corresponding program elements inthe GALL-LR Report AMP.

The staff also audited the description of the LRA Metal Enclosed Bus provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

The staff made the following observation during walkdowns:

The staff interviewed the applicants staff and performed walkdowns of the Diablo Canyon Nuclear Power Plant. Specifically, the staff conducted on-site walkdowns of the Non-segregated Metal Enclosed Bus (480V, 4.16 kV and 13.8kV) and iso-phase bus (25 kV). The conditions of the Metal Enclosed Bus that were observed did not show significant signs of age-related degradation.

LRA AMP B.2.3.40, Electrical Cable Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Summary of Information in the Application. The LRA notes that AMP B.2.3.40, Electrical Cable Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements, is a new program that will be consistent with the program elements in GALL-LR Report AMP 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 new program, and the staffs audit addressed only addressed the applicants basis document and referenced documents.

Audit Activities. An on-site audit was performed June 4 to June 6, 2024.

73 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 DCM T-43 License Renewal Appendix B Diablo Canyon Aging Management Program Evaluation Report B.2.3.40 - Electrical Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Revision 3 SAPN 51121658 Elevated Temp. on Linestarter Cable Printed August 7, 2023 SAPN 51121657 Elevated Temp. on Linestarter Cable Printed August 7, 2023 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 LRA AMP are consistent with the corresponding elements of the GALL-LR Report AMP.

The staff also audited the description of the LRA Electrical Cable Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

The staff made the following observation during walkdowns:

The staff interviewed the applicants staff and performed walkdowns of the Diablo Canyon Nuclear Power Plant. Specifically, the staff observed numerous electrical cable connections. The conditions of the electrical cable connections that was observed did not show significant signs of age-related degradation.

LRA AMP B.2.3.41, Periodic Inspections for Selective Leaching Summary of Information in the Application. The LRA states that AMP B.2.3.41, Periodic Inspections for Selective Leaching, is a new plant-specific aging management program. 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 DCM T-43 License Renewal Appendix B Diablo Canyon Aging Management Program Evaluation Report B.2.3.41 - Periodic Inspections for Selective Leaching Revision 0 DN50123904 Fire Water Line Break at SU Trans. 2-1 December 17, 2008 DN50581755 FP-2-FP-30: d/s Piping Condition September 9, 2013 DN50581757 FP-2-FP-30 Material Condition September 9, 2013 AR A0431200 SW-1-303 - Failed STP V-18 Inspection May 1, 1997

74 AR A0438773 SW-2-303: Dealloying of Bonnet Gasket Seating Area July 2, 1997 DN50416947 Fire Water Line Break Near Building 201 July 23, 2011 During the audit, the staff verified that the applicant addressed the guidance in GALL-SLR Report AMP XI.M33 for the scope of program, parameters monitored or inspected, monitoring and trending, acceptance criteria, and corrective actions program elements of the LRA AMP. In addition, the staff found that additional information may be needed and will consider issuing RAIs for the preventive actions and detection of aging effects program elements.

The staff also audited the description of the LRA Periodic Inspections for Selective Leaching program provided in the UFSAR supplement. The staff found that sufficient information was not available to determine whether the description provided in the UFSAR supplement was an adequate description of the LRA Periodic Inspections for Selective Leaching program. The staff will consider issuing an RAI in order to obtain the information necessary to verify the sufficiency of the UFSAR supplement program description.

LRA AMP B.2.3.42, Transmission Conductor and Connections, Insulators, and Switchyard Bus and Connections Summary of Information in the Application. The LRA notes that AMP Transmission Conductor and Connections, Switchyard Bus and Connections, and High-Voltage Insulators, is an existing plant-specific aging management program with enhancements.

Audit Activities. An on-site audit was performed June 4 to June 6, 2024.

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 DCM T-43 License Renewal Appendix B B.2.3.42 - Transmission Conductor and Connections, Insulators, and Switchyard Bus and Connections Revision 3 SAPN 50573497 Arcing on insulator Phase B 500 kV Tower Printed August 13, 2023 SAPN 50604402 U1 500-kV Swyd Insulator Corrosion Printed August 12, 2023 SAPN 51134194 Arcing: A Phase MBT Stand-off Insulators Printed August 13, 2023 Drawing 57483 General Arrangement Outdoors 230KV and 500KV Switchyards Revision 5 During the audit, the staff verified that the applicant addressed the guidance in SRP-LR Section A.1.2.3 for 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 LRA AMP.

The staff also audited the description of the LRA Transmission Conductor and Connections, Switchyard Bus and Connections, and High-Voltage Insulators provided in the FSAR

75 supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

The staff made the following observation during walkdowns:

The staff interviewed the applicants staff and performed walkdowns of the DCPP switchyard and other areas of the plant. Specifically, the staff observed transmission conductor and connections, the switchyard bus and connections, and high-voltage insulators in the station blackout recovery path that were within scope of LR. The staff did not identify any adverse or abnormal age-related degradation of equipment associated with this AMP during the walkdowns.

LRA TLAA Section 4.1, Identification of Time-Limited Aging Analyses Summary of Information in the Application. LRA section 4.1, Identification of Time-Limited Aging Analyses, discusses the methodology for the identifying of TLAAs in the LRA. To verify the implementation of the applicants methodology to identify TLAAs in accordance with 10 CFR Part 54, the staff performed an audit. Issues identified but not resolved in this report will be addressed in the SE.

Audit Activities. During the audit, the staff reviewed documentation contained in the LRA and provided by the applicant via the ePortal. The table below lists documents that were review by the staff and found relevant to the program. The staff will document its review of this information in the SE.

Document Title Revision /

Date DCPP TLAA Report Review of Time-Limited Aging Analyses (TLAAs) for Diablo Canyon Power Plant, Units 1 and 2 Revision 4 PG&E Letter DCL-23-117 (ML23298A107)

Pacific Gas and Electric Company Nuclear Power Generation Diablo Canyon Power Plant Pressure and Temperature Limit Report Revision 16A WCAP-14040-NP-A (ML15324A233)

Methodology Used to Develop Cold Overpressure Mitigating System Setpoints and RCS Heatup and Cooldown Limit Curves Revision 2 N/A Review of Time-Limited Aging Analyses (TLAAs) for Diablo Canyon, Units 1 and 2 Negative Screening Results Revision 0 N/A Diablo Canyon Power Plant License Renewal Application Update Work Guideline Revision 5 N/A 2015-2022 TLAA Search Results (Excel spreadsheet uploaded to Portal) 2024 During the audit, the staff verified that the applicant has provided its basis and methodology for identifying TLAAs, as defined in 10 CFR 54.3(a), in accordance with 10 CFR 54.21(c)(1).

During the audit, the staff made the following observations:

The staff reviewed the DCPP TLAA Report and confirmed that CLB and design-basis documentation were searched to identify potential TLAAs. The staff noted that specific key words were used during this search that would identify potential TLAAs. The staff noted that the key words searched were reasonable and include, but not limited to the following: cycles, design life, license term, fluence, and wear. The staff noted that

76 several others were used by the applicant to create a comprehensive list for the key word search.

The staff reviewed the DCPP TLAA Report 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 period of extended operation.

o The staff noted that the applicant performed a gap analysis from the prior LRA submittal (ML093340116) to the current LRA submittal (ML23311A154).

o As part of the gap analysis, the staff also noted that the applicant did a search on revisions of plant-specific calculations and that no additional TLAAs were identified.

The staff reviewed the DCPP TLAA Report and confirmed that a search of docketed licensing correspondence, the operating license, and the UFSAR identified the active exemptions currently in effect pursuant to 10 CFR 50.12.

The staff reviewed the DCPP TLAA Report and confirmed that these exemptions were then reviewed to determine whether the exemption was based on a TLAA, and that the applicant stated there was one 10 CFR 50.12 exemption identified that is currently in effect that is based upon a TLAA.

o The staff noted that the 10 CFR 50.12 exemption identified by the applicant is no longer in effect and that it has been superseded by the PTLR process. The staff will consider issuing an RAI.

LRA TLAA Section 4.2.2 through 4.2.4 Summary of Information in the Application. The staffs audit addresses the following TLAAs collectively due to their relationship in analyzing the reactor vessel neutron embrittlement:

LRA Section 4.2.2, Pressurized Thermal Shock, discusses the analysis for pressurized thermal shock of the reactor pressure vessel. The applicant dispositioned the TLAAs in accordance with 10 CFR54.21(c)(1)(ii).

LRA Section 4.2.3, Upper-Shelf Energy, discusses the analysis the decrease in upper-shelf energy of the reactor pressure vessel. The applicant dispositioned the TLAAs in accordance with 10 CFR54.21(c)(1)(ii).

LRA Section 4.2.4, Pressure-Temperature Limits and LTOP Analysis, discusses the analyses related to the pressure-temperature limits, Low temperature overpressure protection (LTOP) enables temperature setpoint and the power operated relief valve (PORV) pressure setpoint intended to project the reactor pressure vessel from brittle fracture. The applicant dispositioned the TLAAs in accordance with 10 CFR54.21(c)(1)(iii).

Audit Activities. In addition to the OE documentation contained in the LRA and ePortal, the staff observed the applicants search of its operating experience database using the keyword:

(embrittlement, brittle, fracture)

77 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 WCAP-17315-NP Diablo Canyon Units 1 and 2 Pressurized Thermal Shock and Upper-Shelf Energy Evaluations Revision 0 Final Safety Analysis Report Diablo Canyon Power Plant Units 1 and 2 - Final Safety Analysis Report Update Revision 26 September 2021 ML23199A312 Diablo Canyon Nuclear Power Plant, Unit 1 - Revision to the Reactor Vessel Material Surveillance Capsule Withdrawal Schedule (EPID L-2023-LLL-0012)

July 20, 2023 ML18092A231 WCAP 10492, Analysis of Capsule T, Salem 2 Surveillance Program March 1984 ML12242A156 WCAP-11554 Analysis of Capsule U from the Public Service Electric and Gas Company Salem Unit 2 Reactor Vessel Radiation Surveillance Program September 1987 ML12242A157 WCAP-13366 Analysis of Capsule X from the Public Service Electric and Gas Company Salem Unit 2 Reactor Vessel Radiation Surveillance Program June 1992 ML012910321 WCAP-15692 Analysis of Capsule Y from the Public Service Electric and Gas Company Salem Unit 2 Reactor Vessel Radiation Surveillance Program Revision 0 ML010180432 WCAP-15423, Revision 0, Analysis of Capsule V from Pacific Gas and Electric Company Diablo Canyon Unit 2 Reactor Vessel Radiation Surveillance Program Revision 0 ML16341D574 Evaluation of Diablo Canyon Power Plant Reactor Vessel Materials by the NRC Pressurized Thermal Shock Screening Criteria January 13, 1986 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 its TLAAs related to pressurized thermal shock and upper-shelf energy, and 10 CFR 54.21(c)(1)(iii) for its TLAA related to P-T limits and LTOP setpoints.

During the audit, the staff made the following observations:

The staff verified that the material information (e.g., initial RTNDT, %Cu, %Ni, initial USE, margin values) for the materials identified as Reactor Vessel Beltline for Unit 1 and Unit 2 contained in the applicants LRA Tables (Unit 1 - Tables 4.2.2-1 and 4.2.3-1; Unit 2 -

Tables 4.2.2-2 and 4.2.3-2) are consistent with the applicants CLB (e.g., UFSAR, PTLR and other official correspondence with the staff). Additionally, based on this verification, the staff observed that the appropriate margin value consistent with Regulatory Guide 1.99, Rev. 2, were applied for each Unit 1 and Unit 2 reactor vessel material identified as Reactor Vessel Beltline for the purposes of addressing pressurized thermal shock.

The staff verified that the material information (e.g., initial RTNDT, %Cu, %Ni, initial USE) for the materials identified as Reactor Vessel Extended Beltline for Unit 1 contained in LRA Tables 4.2.2-1 and 4.2.3-1 were based on information from the applicants CLB documents (i.e., UFSAR and other official correspondence with the NRC staff).

Additionally, based on this verification, the staff observed that the appropriate margin value consistent with 10 CFR 50.61, were applied for each Unit 1 reactor vessel material for the purposes of addressing pressurized thermal shock.

78 The staff verified that the material information (e.g., initial RTNDT, %Cu, %Ni, initial USE) for the materials identified as Reactor Vessel Extended Beltline for Unit 2 contained in LRA Tables 4.2.2-2 and 4.2.3-2 were based on information from the applicants CLB documents (i.e., UFSAR and other official correspondence with the staff), except for the

%Cu and %Ni values for the Upper Shell Long. Weld 1-201A, B and C (Heat No.

21935/12008). Additionally, based on this verification, the staff observed that the appropriate margin value consistent with 10 CFR 50.61, were applied for each reactor vessel material for the purposes of addressing pressurized thermal shock.

o With respect to %Cu and %Ni values for the Upper Shell Long. Weld 1-201A, B and C (Heat No. 21935/12008) the staff confirmed they were based on best estimate chemical compositions from relevant (i.e., heat-to-heat match of the RPV material) publicly available material data. The staffs review of this information will be documented in the SE.

The staff noted that surveillance data (i.e., WCAP 10492, WCAP-11554, WCAP-13366 and WCAP-15692) from another plant with a heat-to-heat match for a Unit 1 RPV material (i.e., Weld Heat No. 13253) was considered. The staffs review of this information will be documented in the SE.

The staff also audited the description of the LRA TLAAs for pressurized thermal shock, upper-shelf energy, and P-T limits and LTOP setpoints provided in the respective UFSAR supplement.

The staff verified this description is consistent with the description provided in the SRP-LR.

LRA TLAA Section 4.3.1 DCPP Transient Monitoring and Projections Summary of Information in the Application. LRA Section 4.3.1, DCPP Transient Monitoring and Projections, discusses the TLAA on transient monitoring and cycle projections for 60 years of operation. The applicant dispositioned the TLAA in accordance with 10 CFR54.21(c)(1)(iii).

Audit Activities. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the LRA 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 LRA and ePortal.

The table below lists documents that were reviewed by the staff and were found relevant to LRA Section 4.3.1 addressing transient monitoring and cycle projections. The staff will document its review of this information in the SE.

79 Document Title Revision /

Date PGEDCROLI00007-REPT-005 License Renewal - Aging Effects DCPP Operating Experience Report Revision 1 October 9, 2023 N/A NRC Keywords Search Results August 2023 Procedure P-51 Procedure for Fatigue Monitoring and Transient Cycle Counting Diablo Canyon Units 1 and 2 Revision 0 July 9, 1998 STP M-55 Recording of Cyclic Fatigue or Transients Revision 20A N/A Review of Time-Limited Aging Analyses (TLAAs) for Diablo Canyon Power Plant, Units 1 and 2 Revision 4 June 18, 2023 Structural Integrity Associates (SIA) FP-DCPP-330 Diablo Canyon Power Plant SI:FatiguePro 4 Baseline Automated Cycle Counting (ACC) Analysis and 60-Year Projections Revision 2 October 11, 2023 During the audit of the TLAA, the staff verified that the applicant has provided its basis that supports its disposition. 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.

LRA Table 4.3-1 indicates that the 60-year projected cycles of the loss of charging with prompt return to service (loop 4/3) transient exceed the limiting (lowest) cycles analyzed in the fatigue analyses in relation to the transient cycles for the loop 4 of DCPP Units 1 and 2. For the Unit 1 loop 4, the number of the 60-year projected cycles is 92 in comparison with the limiting analyzed cycles, 25. For the Unit 2 loop 4, the number of the 60-year projected cycles of the transient is 87 in comparison with the limiting analyzed cycles, 25. LRA Table 4.3-1 also indicates that the 60-year projected cycles of the Unit 2 step load decrease of 10% of full power transient and Unit 2 partial loss of flow (1 RCP [reactor coolant pump]) transient cycles are slightly greater than the limiting analyzed cycles, respectively.

In comparison, the applicant dispositioned the fatigue TLAAs for the following components associated with the replacement reactor vessel closure heads (RRVCHs) in accordance with 10 CFR54.21(c)(1)(i): (1) RRVCHs; (2) control rod drive mechanism (CRDM) pressure housings; (3) core exit thermocouple nozzle assemblies (CETNAs); and (4) thermocouple nozzles. The applicant also dispositioned the fatigue TLAAs for the pressurizer relief valve support bracket fillet weld (Unit 2 only) and replacement steam generator components in accordance with 10 CFR54.21(c)(1)(i). In addition, the applicant dispositioned the fatigue TLAA for the reactor vessel thermocouple column in accordance with 10 CFR54.21(c)(1)(ii).

Given the TLAA dispositions for the components discussed above in accordance with 10 CFR54.21(c)(i) or (ii) (i.e., not using the Fatigue Monitoring AMP), the staff needs clarification on whether the 60-year projected cycles of the Units 1 and 2 loss of charging with prompt

80 return to service (loop 4/3) transient, Unit 2 step load decrease of 10% of full power transient and Unit 2 "partial loss of flow (1 RCP) transient, which exceed the limiting analyzed cycles, can affect the validity of the TLAA dispositions (e.g., resulting in the 60-year CUF values of these components exceeding the design limit, 1.0).

In addition, the LRA does not clearly discuss whether the 60-year projected cycles, which exceed the limiting (lowest) analyzed cycles for the fatigue analyses in LRA Section 4.3 and its subsections, can increase the 60-year projected CUF and environmentally-adjusted CUF (CUFen) values above 1.0 in such a manner to affect the effectiveness of the Fatigue Monitoring AMP and the timeliness of corrective actions of the AMP.

The staff also audited the description of the LRA TLAA on transient monitoring and cycle projections provided in the UFSAR supplement. The staff verified this description is consistent with the guidance in SRP-LR (Revision 2) Section 3.1.2.5.

LRA TLAA Section 4.3.2 ASME Section III, Class A Fatigue Analyses Summary of Information in the Application. LRA Section 4.3.2, ASME Section III, Class A Fatigue Analyses discusses the fatigue analysis for ASME Code Section III Class A piping and components for 60 years of operation.

The applicant dispositioned the fatigue TLAAs for the following components associated with the RRVCHs in accordance with 10 CFR54.21(c)(1)(i): (1) RRVCHs; (2) CRDM pressure housings; (3) CETNAs; and (4) thermocouple nozzles. The applicant also dispositioned the fatigue TLAAs for the pressurizer relief valve support bracket fillet weld (Unit 2 only) and replacement SG in accordance with 10 CFR54.21(c)(1)(i). In addition, the applicant dispositioned the fatigue TLAAs for the RRVCH thermocouple columns in accordance with 10 CFR54.21(c)(1)(ii). The applicant further dispositioned the fatigue TLAAs for the other Class A piping and components in accordance with 10 CFR54.21(c)(1)(iii).

Audit Activities. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the LRA 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 LRA and ePortal.

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

Document Title Revision /

Date PGEDCROLI00007-REPT-005 License Renewal - Aging Effects DCPP Operating Experience Report Revision 1 October 9, 2023 N/A NRC Keywords Search Results August 2023 N/A Review of Time-Limited Aging Analyses (TLAAs) for Diablo Canyon Power Plant, Units 1 and 2 Revision 4 June 18, 2023

81 WCAP-16985-P Diablo Canyon Units 1 and 2 Tavg and Tfeed Ranges Program NSSS Engineering Report Revision 1 March 2009 AREVA Specification 18-9029935 Reactor Vessel Closure Head Replacements, Control Rod Drive Replacements, and Integrated Head Assemblies Diablo Canyon Units 1 & 2 Loading Specification and Design Transients Revision 9 September 8, 2016 WCAP-17103-P Diablo Canyon Unit 1 Insurge/Outsurge and Environmental Fatigue Evaluations Revision 4 May 2013 WCAP-17104-P Diablo Canyon Unit 2 Insurge/Outsurge and Environmental Fatigue Evaluations Revision 0 July 2009 WCAP-18129-P Diablo Canyon Power Plant Units 1 and 2 NSSS Structural and Licensing Review Project Engineering Report Revision 0 September 2016 WCAP-18177-P Reactor Coolant Pump Pressure Boundary Summary Stress Report Diablo Canyon Power Plant Units 1 & 2 Revision 0 September 2016 Design Specification 418A86 Diablo Canyon Units 1 and 2 Delta 54 Replacement Steam Generator Revision 9 September 29, 2016 CN-NCE-DCPPRSG-3 Delta 54 Replacement Steam Generator Primary Manway Analysis Revision 2 September 29, 2016 CN-NCE-DCPPRSG-8 Delta 54 Replacement Steam Generator 6-Inch Handhole Analysis Revision 3 September 29, 2016 CN-NCE-DCPPRSG-9 Delta 54 Replacement Steam Generator 2,5-Inch Inspection Port Analysis Revision 2 September 29, 2016 WCAP-12415 Evaluation of Thermal Stratification for the Diablo Canyon Units 1 and 2 Pressurizer Surge Line November 1989 WCAP-12415, Addendum 1 Evaluation of Thermal Stratification for the Diablo Canyon Units 1 and 2 Pressurizer Surge Line Revision 0 September 2015 PG&E Letter DCL 050 Evaluation Documents in Support of Structural Weld Overlay, REP-RHR-SWOL, Unit 2 September 11, 2018 N/A NRC Bulletin 88-08 Thermal Stresses in Piping Connected to Reactor Coolant Systems (TAC Nos. 69623 an 69624)

November 4, 1991

82 During the audit of the TLAAs, the staff verified that the applicant has provided its basis that supports its dispositions. However, the staff found that sufficient information was not available to complete its review of the applicants basis for its TLAA dispositions. In order to obtain the necessary information, the staff will consider issuing RAIs.

During the audit, the staff made the following observations:

LRA Section 4.3.2.2 addresses the fatigue TLAAs for the reactor vessel closure heads and associated components. LRA Section 4.3.2.2 explains that the RRVCHs, CRDM pressure housings, CETNAs and thermocouple nozzles have been analyzed for a 50-year design life from the date of replacement (i.e., in 2010 for Unit 1 and in 2009 for Unit 2). The LRA also explains that the 50-year design life will extend beyond the period of extended operation.

The applicant dispositioned the fatigue TLAA for the components in accordance with 10 CFR 54.21(c)(1)(i) (i.e., validation of the existing analyses for the period of extended operation). However, the LRA section does not describe the CUF values for these components for the 50-year design life.

LRA Section 4.3.2.3 addresses the fatigue TLAA for the reactor coolant pump (RCP) pressure boundary components. The LRA section indicates that some of the RCP components were evaluated for fatigue waiver in accordance with the fatigue waiver provisions in ASME Code Section III. LRA Section 4.3.2.3 explains that the transient cycles used in the fatigue waiver analysis are consistent with a subset of those identified in UFSAR Table 5.2-4 except for using a lower number of (1) plant heatup and cooldown transient cycles and (2) primary side leak test transient cycles. LRA Section 4.3.2.3 also indicates that the Fatigue Monitoring AMP incorporates the lower, more conservative number of transients to determine an action limit and will monitor transient cycles used in the RCP fatigue analyses and waivers to ensure that corrective actions are taken if any of the actual cycles approach their analyzed numbers.

However, LRA Section 4.3.2.3 does not clearly address the following items related to the fatigue waiver analysis: (1) the RCP components evaluated in the fatigue waiver analysis; (2) the lower cycles of the plant heatup and cooldown and primary side leak test transient cycles evaluated in the fatigue waiver in comparison with the 60-year projected cycles; and (3) whether the incorporation of the lower number of transients into the fatigue monitoring is a program enhancement to the Fatigue Monitoring AMP or has been already completed.

LRA Section 4.3.2.4 addresses the fatigue TLAA for the pressurizer and pressurizer nozzle components. LRA Section 4.3.2.4 explains that, using transient cycles consistent with UFSAR Table 5.2-4, all of the locations that were analyzed to incorporate the effects of insurge-outsurge transients demonstrated a CUF of less than 1.0, except for the Unit 1 heater penetration. The LRA also indicates that, to meet the Code requirement, the fatigue analysis for the Unit 1 heater penetration was performed using the 60-year projected number of transients and that the results for the Unit 1 pressurizer lower head heater penetration demonstrated that the CUF for 60 years is less than 1.0. However, LRA Section 4.3.2.4 does not describe the revised CUF value of the Unit 1 lower head heater penetration.

LRA Section 4.3.2.4 also discusses the fatigue analysis for the Unit 2 pressurizer relief valve support bracket fillet weld. LRA Section 4.3.2.4 indicates that the fatigue usage factor due to the loads required by the design specification is much less than 0.1 and maintaining the CUF below 1.0 is controlled by the permitted number of valve operating cycles. However,

83 the LRA does not clearly discuss the following items: (1) the transients and their cycles evaluated in the CUF calculation due to the loads of the design specification; and (2) the 60-year projected cycles related to the loads of the design specification.

LRA Section 4.3.2.5 addresses the fatigue TLAAs for the replacement steam generator components and feedwater nozzle fatigue analyses. The LRA section also discusses the fatigue qualification tests for the following components: (1) primary manway drain hole; (2) primary manway studs; (3) 6-inch handhole studs; (4) 2.5-inch inspection port gasket seal bolts; and (5) diaphragm seal bolts. The LRA section explains that these components were qualified by fatigue tests in accordance with ASME Code Section III for the number of cycles required by the design specification.

However, the LRA does not clearly describe specific Code provisions and approaches of ASME Code Section III that are used for the qualification by performing fatigue tests. In addition, the LRA does not clearly describe the transients and cycles evaluated in the tests in comparison with the corresponding 60-year projected cycles to confirm that the evaluated cycles are bounding for the 60-year projected cycles.

LRA Section 4.3.2.11 addresses the absence of a cumulative fatigue usage factor TLAA to determine high energy line break (HELB) locations. In comparison, UFSAR Section 3.6.1.6 indicates that the postulation of HELB locations other than the reactor coolant line is in part, based on the allowable stress range for expansion stress (SA), consistent with Branch Technical Position MEB 3-1 (ML052340555). SA may need to be adjusted by a stress range reduction factor that is determined by the number of thermal cycles, as addressed in the implicit fatigue analysis in LRA Section 4.3.5. However, LRA Sections 4.3.2.11 and 4.3.5 and the associated UFSAR supplement do not clearly discuss whether the HELB location postulation for the piping other than the reactor coolant line, which involves SA, is a basis for identifying the HELB analysis as a TLAA.

LRA Section A.3.2.1.6 addresses the UFSAR supplement for the fatigue TLAA for the reactor coolant pressure boundary piping. Similarly, LRA Section A.3.2.1.8 addresses the UFSAR supplement for the fatigue TLAA for the CASS reactor coolant pumps. In addition, LRA Section A.3.2.1.9 addresses the UFSAR supplement for the fatigue crack growth analysis for the leak-before-break elimination of dynamic effects of primary loop piping failures. However, these UFSAR supplements do not clearly describe whether the action limits for the fatigue monitoring and initiation of corrective actions will be established to ensure the validity of the fatigue and fatigue crack growth analyses.

The staff also audited the description of the fatigue TLAAs for the Class A piping and components provided in the UFSAR supplement. The staff found that sufficient information was not available to determine whether the description provided in the UFSAR supplement was an adequate description of the fatigue TLAAs. The staff will consider issuing an RAI in order to obtain the information necessary to verify the sufficiency of the fatigue TLAAs.

LRA TLAA Section 4.3.3 Fatigue Analyses of the Reactor Pressure Vessel Internals Summary of Information in the Application. LRA Section 4.3.3, Fatigue Analyses of the Reactor Pressure Vessel Internals discusses the fatigue analyses for reactor vessel internal (RVI) components for 60 years of operation. The applicant dispositioned the fatigue TLAAs in accordance with 10 CFR54.21(c)(1)(iii).

84 Audit Activities. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the LRA 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 LRA and ePortal.

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

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 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 observation. The RVI CUF values based on the 50-year design transient cycles are less than the fatigue design limit (1.0).

The staff also audited the description of the fatigue TLAAs for the RVI components provided in the UFSAR supplement. The staff verified this description is consistent with the guidance in SRP-LR (Revision 2) Section 3.1.2.5.

LRA TLAA Section 4.3.4, Environmentally-Assisted Fatigue Summary of Information in the Application. LRA Section 4.3.4, Environmentally-Assisted Fatigue discusses the environmentally-assisted fatigue (EAF) TLAAs for ASME Section III Class 1 (reactor coolant pressure boundary) components and piping for 60 years of operation.

The applicant dispositioned the fatigue TLAAs in accordance with 10 CFR54.21(c)(1)(iii).

Audit Activities. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the LRA 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 LRA and ePortal.

Document Title Revision /

Date PGEDCROLI00007-REPT-005 License Renewal - Aging Effects DCPP Operating Experience Report Revision 1 October 9, 2023 N/A NRC Keywords Search Results August 2023 N/A Review of Time-Limited Aging Analyses (TLAAs) for Diablo Canyon Power Plant, Units 1 and 2 Revision 4 June 18, 2023 WCAP-18129-P Diablo Canyon Power Plant Units 1 and 2 NSSS Structural and Licensing Review Project Engineering Report Revision 0 September 2016

85 The table below lists documents that were reviewed by the staff and were found relevant to the ASME Section III, Class A fatigue analyses. The staff will document its review of this information in the SE.

During the audit of the TLAAs, 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.

LRA Section 4.3.4 indicates that the applicant commits to perform an additional review to determine whether there are more limiting locations than the NUREG/CR-6260 components for DCPP (LRA Commitment 1, item (a) as described in LRA Table A-3). The commitment is also identified as Enhancement 1 of the Fatigue Monitoring AMP. However, the LRA section does not clearly discuss whether the screening CUFen values are refined after the screening evaluation in relation to Commitment 1, item (a) (i.e., determination of the potentially more limiting locations than the NUREG/CR-6260 locations) and, if so, how the screening CUFen values are refined to reduce the conservatisms associated with the screening CUFen values.

LRA Section 4.3.4 also indicates that the maximum service temperature is used in the screening evaluation for EAF. However, the LRA does not clearly discuss whether the maximum service temperature is the component-specific maximum service temperature or the generic maximum temperature bounding for all the components evaluated in the EAF analysis.

Document Title Revision /

Date PGEDCROLI00007-REPT-005 License Renewal - Aging Effects DCPP Operating Experience Report Revision 1 October 9, 2023 N/A NRC Keywords Search Results August 2023 N/A Review of Time-Limited Aging Analyses (TLAAs) for Diablo Canyon Power Plant, Units 1 and 2 Revision 4 June 18, 2023 SIA 0800389.311 RHR-Accumulator Tee Fatigue Analysis Revision 0 November 7, 2008 SIA 0800389.321 Charging Nozzle Environmentally-Assisted Fatigue (EAF Analysis Using Bounding Projected 60-Year Number of Cycles Revision 0 July 24 2009 SIA 0800389.322 Hot Leg Surge Nozzle Environmentally-Assisted Fatigue (EAF)

Analysis Using Bounding Projected 60-Year Numbers of Cycles Revision 0 July 24, 2009 SIA 0800389.323 Safety Injection Nozzle Environmentally-Assisted Fatigue (EAF Analysis Using Bounding Projected 60-Year Number of Cycles Revision 0 July 24, 2009 PGE-127-301P Diablo Canyon Environmentally-Assisted Fatigue (EAF Analysis Revision 4 July 24, 2009

86 LRA Table 4.3.4-1 summarizes the CUFen values for the NUREG/CR-6260 locations applicable to DCPP Units 1 and 2 before the refinement of the CUFen values (e.g.,

refinement using the more realistic strain rates). However, the LRA does not clearly discuss whether the calculations of the CUFen values in LRA Table 4.3.4-1 are based on the 60-year projected cycles or based on the 50-year design cycles.

LRA Section 4.3.4 and Table 4.3.4-2 indicate that the 60-year CUFen value of the hot-leg surge nozzle safe-end is greater than 1.0. The LRA explains that the aging effect of EAF in this component will be managed by performing repair, replacement or augmented periodic inspections. However, the LRA does not clearly discuss the following: (1) which specific activity of aging management the applicant will use to manage the aging effects of EAF for the hot-leg surge nozzle safe-end; and (2) what the associated technical basis for the aging management activity is (e.g., if periodic inspections are performed on the component, what the inspection frequency is and what the associated technical basis for the inspection frequency is).

The staff also audited the description of the EAF TLAAs for the Class 1 components and piping provided in the UFSAR supplement. The staff verified this description is consistent with the guidance in SRP-LR (Revision 2) Section 3.1.2.5.

LRA TLAA Section 4.3.5, Assumed Thermal Cycle Count for Allowable Secondary Stress Range Reduction Factor in ANSI B31.1 Piping Summary of Information in the Application. LRA Section 4.3.5, Assumed Thermal Cycle Count for Allowable Secondary Stress Range Reduction Factor in ANSI B31.1 Piping discusses the TLAA on the allowable secondary stresses associated with the thermal expansion for the ANSI B31.1 piping. The applicant dispositioned the TLAA in accordance with 10 CFR54.21(c)(1)(i).

Audit Activities. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the LRA 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 LRA and ePortal.

The table below lists documents that were reviewed by the staff and were found relevant to the TLAA on the allowable stresses for the ANSI B31.1 piping. The staff will document its review of this information in the SE.

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 Document Title Revision /

Date PGEDCROLI00007-REPT-005 License Renewal - Aging Effects DCPP Operating Experience Report Revision 1 October 9, 2023 N/A NRC Keywords Search Results August 2023 N/A Review of Time-Limited Aging Analyses (TLAAs) for Diablo Canyon Power Plant, Units 1 and 2 Revision 4 June 18, 2023

87 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.

The applicant indicated that the thermal cycles for the piping lines are not more than 3 cycles per week so that the total cycle number is less than 7000 cycles for 60 years of operation. However, the staff needed clarification on whether the applicants discussion is intended to mean the weekly thermal cycles are not more than 2 cycles per week rather than 3 cycles per week because 2 cycles per week result in approximately 6240 cycles for 60 years and the 3 cycles per week result in approximately 9360 cycles for 60 years exceeding the 7000 cycle threshold. The staff also needs clarification on how the applicant determined the weekly cycles for the piping lines (e.g., by using piping design information, transient definitions, plant operation data, operation procedures, test requirements, UFSAR information, and specific system-level knowledge).

For the piping lines affected by the reactor coolant system (RCS) transients, the applicant explained that the total count of all DBEs (UFSAR Table 5.2-4) is estimated as 4665 cycles and that this is a reliable indication of the number of thermal cycles for most in-scope balance-of-plant support systems, as well as the chemical volume control system (CVCS) and emergency core cooling system (ECCS) piping more directly connected to the RCS.

However, the LRA does not clearly discuss the following items: (1) specific in-scope balance-of-plant support systems, for which the cycle estimation based on the design transient cycles is applicable; and (2) whether piping-specific transients need to be added to the cycle estimation that is based on the RCS design transients and, if not, the technical basis for why piping-specific transient cycles do not need to be considered in the total cycle estimation.

The staff also audited the description of the TLAA on the allowable stress for the ANSI B31.1 piping in the UFSAR supplement. The staff verified this description is consistent with the guidance in SRP-LR (Revision 2) Section 3.1.2.5.

LRA TLAA Section 4.3.6, Fatigue Design and Analysis of Class 1E Electrical Raceway Support Angle Fittings for Seismic Events Summary of Information in the Application. LRA Section 4.3.6, Fatigue Design and Analysis of Class 1E Electrical Raceway Support Angle Fittings for Seismic Events discusses the fatigue TLAA for the Class 1E electrical raceway support angle fittings subject to seismic events. The applicant dispositioned the fatigue TLAAs in accordance with 10 CFR54.21(c)(1)(i).

Audit Activities. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the LRA 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 LRA and ePortal.

The table below lists documents that were reviewed by the staff and were found relevant to the fatigue analysis for the Class 1E electrical raceway support angle fittings. The staff will document its review of this information in the SE.

88 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 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).

The staff also audited the description of the fatigue TLAAs for the Class 1E electrical raceway support angle fittings subject to seismic events in the UFSAR supplement. The staff verified this description is consistent with the guidance in SRP-LR (Revision 2) Section 3.1.2.5.

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

Audit Activities. An on-site audit was performed June 4th to 6th, 2024.

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 PGEDCROLI00007-REPT-005 License Renewal - Aging Effects DCPP Operating Experience Report Revision 1 October 9, 2023 N/A NRC Keywords Search Results August 2023 N/A Review of Time-Limited Aging Analyses (TLAAs) for Diablo Canyon Power Plant, Units 1 and 2 Revision 4 June 18, 2023 IEEE 344-1975 IEEE Recommended Practices for Seismic Qualification of Class 1E Equipment for Nuclear Power Generating Stations December 20, 1974 N/A UFSAR Section 3.10.3.12, Raceway Supports Revision 24 September 2018

89 Document Title Revision /

Date DCM T-43 License Renewal Appendix B Diablo Canyon Aging Management Program Evaluation Report B.2.2.2 - Environmental Qualification of Electrical Components (NUREG 1801 Program X.E1)

Revision 3 CF3.DC1 Diablo Canyon Power Plant Departmental Administrative Procedure Maintenance and Surveillance of Electrical Environmentally Qualified (EQ) Equip Revision 5 CF3-DC3 Diablo Canyon Power Plant Departmental Administrative Procedure Maintenance of EQ Equipment: I&C Revision 1 MP E-57.8A Diablo Canyon Power Plant Electrical Maintenance Procedure Temperature Monitoring Revision 11 CF3-ID3 Environmental Qualification (EQ) Program Revision 10 DCM No. T-20 Environmental Qualification Revision 12 SAPN 508135547 1-FCV-749 EQ Splice Unsat at J-box Applicant print date:

July 21, 2023 SAPN 50960226 EA: SA: EVAL T-drain on FCV-95 Applicant print date:

July 21, 2023 SAPN 50986202 2018 DBA EQ: Outage scope add U1 SV-455C Applicant print date:

July 21, 2023 SAPN 50986203 2018 DBA EQ: Outage scope add U1 SV-474 Applicant print date:

July 21, 2023 SAPN 50986204 2018 DBA EQ: Outage scope add U2 SV-276 Applicant print date:

July 21, 2023 SAPN 51241490 EQ: EH22 Activation Energy Basis Created on:

May 30, 2024 SAPN 51241491 EQ: IH09 Activation Energy Basis Created on:

May 30, 2024 EQ File IH-14 Reference #31 Electro-Hydraulic Actuator Temperature Datalogger Summary Revision 16 DCM T-20 Appendix A Environmental Qualification November 17, 2000 CF3.ID4 Attachment 4 (SAP Calculation No.

9000013922)

Environmental Qualification Requirements September 23, 2020 90000007927-016-00 IH14 Revision 16 90000008405-008-00 IH49 Revision 8 EQ File IH49 Reference

1. 33 Five-Year Unit 1 Containment Average Temperature Study -

August 2015 to September 2020 October 2023 90000007450-010-00 EH20 Revision 10

90 Document Title Revision /

Date 90000007462-013-00 EH21 Revision 13 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).

The staff also audited the description of the LRA Environmental Qualification of Electrical Equipment provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-LR.

LRA TLAA Section 4.6.1, Containment Concrete, Liner, and Penetrations Analyses Summary of Information in the Application. LRA Sections 4.6.1 Absence of a TLAA for Containment Concrete and Liner Plate and 4.6.2, Design Cycles for Containment Penetrations, discuss the absence of TLAAs for the containment concrete and liner plate and fatigue analyses of containment penetrations (i.e., airlocks and equipment hatches, containment penetration sleeves and end plates, and flued heads), respectively. The applicant dispositioned the TLAAs for containment penetrations in accordance with 10 CFR 54.21(c)(1)(i) for the steam generator blowdown lines flued heads and 10 CFR 54.21(c)(1)(iii) for the other containment penetration components.

Audit Activities. During its audit, the staff interviewed the applicants staff and reviewed documentation contained in the LRA and provided by the applicant via the electronic reading room (ERR).

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 operating experience by reviewing documentation contained in the LRA and ERR.

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 N/A Review of Time Limited Aging Analyses (TLAAs for Diablo Canyon Power Plant (DCPP), Units 1 and 2)

Revision 4 November 6, 2023 DCM T-1D Design Criteria Memorandum (DCM) T-1D Containment Liner Plate, DCPP Units 1 and 2 (Proprietary)

Revision 6 March 23, 2017 N/A Fatigue Design Waiver Evaluation Report: Penetration Sleeves, End Plate, Emergency Airlock, and Personnel Access Hatch, DCPP Calculation June 2009 Calculation FP-DCPP-330 Diablo Canyon Power Plant SI: FatiguePro4 Baseline Automated Cycle Counting (ACC) Analysis and 60-Year Projections, Structural Integrity Associates Inc (SIA)

Revision 2 October 10, 2023 During the audit of the TLAAs, the staff verified that the applicant has provided its basis that supports its disposition of 10 CFR 54.21(c)(1)(i) and 10 CFR 54.21(c)(1)(iii).

91 During the audit, the staff made the following observations:

The staff reviewed the DCPP Calculation Fatigue Design Waiver Evaluation Report:

Penetration Sleeves, End Plate, Emergency Airlock, and Personnel Access Hatch, and verified that the six fatigue waiver criteria of Subparagraph N-415.1, "Vessels Not Requiring Analysis for Cyclic Operation," of the ASME Code,Section III, 1968 Edition were satisfied for the carbon steel containment airlocks and equipment hatches, penetration sleeves and end plates, as stated in LRA Section 4.6.2.

The staff reviewed the 2023 LRA (ML23311A154) Section 4.6.1 and compared it to the corresponding Section 4.6.1 of the 2009 LRA (ML093340086) and noted that the description and evaluation of absence of TLAA for Containment Concrete, Liner and Liner attachments and supporting documents are essentially consistent between the 2023 and 2009 LRA submittals.

The staff reviewed the 2023 LRA ML23311A154) Section A.3.4 (including subsection A.3.4.1) and compared it to the corresponding Section A.3.4 of the 2009 LRA ML093340086 and noted that the FSAR summary description for Containment Concrete, Liner and Penetrations [Fatigue] Analyses TLAAs are essentially consistent between the 2023 and 2009 LRA submittals.

The staff also audited the description of the LRA TLAA provided in the FSAR supplement in LRA Section A.3.4 Containment Concrete, Liner, and Penetrations Analyses, including LRA Section A.3.4.1, Design Cycles for Containment Penetrations. The staff verified this description is consistent with the description provided in the SRP-LR.

LRA TLAA Section 4.7.1, Crane Load Cycle Limits Summary of Information in the Application. LRA Section 4.7.1, Crane Load Cycle Limits, discusses the 60-year limits for each evaluated crane, where the total number of projected load cycles is less than the maximum design allowable 2,000,000 cycles for the Category 1, Service Class F cranes. Therefore, the load cycle analyses remain valid for the subsequent period of extended operation. 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 TLAA. The staff will document its review of this information in the SE.

Document Title Revision /

Date Association of Iron and Steel Engineers (AISE)

Standard No. 6, Specification for Electric Overhead Traveling Crane for Steel Mill Service May 1, 1969 DCPP DCM S-42B Fuel Handling Cranes & Storage Racks, Appendix D, Spent Fuel Pool Bridge Crane.

Revision 6. July 13, 2020 CMAA Specification # 70 Specifications for Electric Overhead Traveling Cranes Revised 1975 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).

92 The staff also audited the description of the Crane Load Cycle Limits TLAA provided in the FSAR supplement. The staff verified this description is consistent with the description provided in the SRP-SLR.

LRA TLAA Section 4.7.4, Reactor Coolant Pump Flywheel Fatigue Crack Growth Analysis Summary of Information in the Application. LRA Section TLAA 4.7.4, Reactor Coolant Pump Flywheel Fatigue Crack Growth Analysis, discusses the fatigue crack growth analyses for the reactor coolant pump flywheel. The applicant dispositioned the TLAA in accordance with 10 CFR 54.21(c)(1)(i). To verify that the applicant provided an acceptable technical basis to support its disposition of the TLAA, the staff audited the TLAA.

Audit Activities. A search of the applicants OE database was conducted using keywords:

cycle, transient, flywheel, design cycle, fatigue cracking, CUF, usage factor, start/stop, and starts and stops. No significant plant-specific OE associated with the LRA TLAA 4.7.4, was noted by the staff during its review.

During its audit, the staff interviewed the applicants staff and reviewed documentation provided by the applicant. The staff reviewed the following relevant documents.

Document Title Revision /

Date Diablo Canyon LRA Section 4.7.4. Reactor Coolant Pump Flywheel Fatigue Crack Growth Analysis Revision 0 US NRC letter From Jennie K. Rankin, Project Manager, Plant Licensing Branch IV, Division of Operating Reactor Licensing, Office of Nuclear Reactor Regulation; to Mr. Edward D. Halpin, Senior Vice President and Chief Nuclear Officer, DCPP. "Diablo Canyon Power Plant, Unit Nos. 1 and 2 - Issuance of Amendments Re: Revision to Technical Specification 5.5.7, Reactor Coolant Pump Flywheel Inspection Program, in Accordance with TSTF-421-A, Revision 1 (TAC NOS. ME9566 and ME9567)." (ML13178A005)

September 5, 2013 Westinghouse Topical Report WCAP-15666-A, Revision 1, P.L. Strauch et al. "Extension of Reactor Coolant Pump Motor Flywheel Examination."

Pittsburgh: Westinghouse, October 2003 (ML18303A413)

October 2023 Diablo Canyon Units 1 and 2 Updated Final Safety Analysis Report (UFSAR) Chapter 5 Revision 23 December 2016 Diablo Canyon Units 1 and 2 Technical Specifications Section 5.5.7 Amendments 216 and 218 for Units 1 and 2, respectively Westinghouse Topical Report WCAP-14535A, Topical Report on Reactor Coolant Pump Flywheel Inspection Elimination, (ML18312A151)

November 1996 During the audit of the TLAA, the staff verified that the applicant has provided its technical basis that supports its disposition of 10 CFR 54.21(c)(1)(i). The staff found that sufficient information was available to complete its review of TLAA Section 4.7.4.

93 During the audit of the OE associated with the TLAA, the staff independently searched the plant-specific database to identify any previously unknown or recurring aging effects. The staff did not identify any additional aging effects that would have an impact on the evaluation of the TLAA.

The staff observed that LRA Section 4.3.1, Table 4.3-1, provides 250 cycles for heat up, 250 cycles for cooldown, and 500 cycles for reactor trip. These cycles are applicable to the fatigue crack growth calculation of the RCP flywheel.

The staff also audited the summary description of the TLAA for the Reactor Coolant Pump Flywheel Fatigue Crack Growth Analyses provided in Section A.3.5.3 of the Appendix A UFSAR supplement of the LRA. The staff verified this summary description is consistent with the generic description provided in the SRP-SLR.

3. Audit Questions Provided to PG&E Over the course of the audit, the NRC staff provided audit questions to PG&E to facilitate the audit discussions (ML24281A149).

Subject Area Meeting Date Onsite Audit 6/3/23 - 6/6/23 Breakout Session: Scoping of Service Cooling Water System 6/27/24 Breakout Session: Water Chemistry AMP 6/27/24 Breakout Session: Internal Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchanger, and Tanks AMP 7/2/24 Breakout Session: Neutron Fluence Projections TLAA 7/8/24 Breakout Session: Scoping of Auxiliary System 7/8/24 Breakout Session: Pressurized Thermal Shock TLAA 7/9/24 Breakout Session: Upper-Shelf Energy TLAA 7/9/24 Breakout Session: Upper-Shelf Energy TLAA 7/9/24 Breakout Session: Upper-Shelf Energy TLAA 7/9/24 Breakout Session: Scoping of Main Feedwater System 7/9/24 Breakout Session: PWR Vessel Internals 7/10/24 Breakout Session: Fuse Holders 7/10/24 Breakout Session: Non-metallic 7/11/24 Breakout Session: Steel-other 7/11/24 Breakout Session: Scoping of Auxiliary Feedwater System 7/15/24 Breakout Session: Scoping of Auxiliary Steam System 7/15/24 Breakout Session: Transient Monitoring and Projections 7/15/24 Breakout Session: Bolting Integrity AMP 7/16/24 Breakout Session: Stainless Steel 7/16/24 Breakout Session: Fire Protection 7/17/24 Breakout Session: Fire Water System AMP 7/17/24 Breakout Session: Fatigue Monitoring AMP 7/17/24 Breakout Session: Selective Leaching AMP 7/18/24 Breakout Session: Buried and Underground Piping and Tanks AMP 7/18/24 Breakout Session: ASME Section III, Class A Fatigue Analysis TLAA 7/22/24 Breakout Session: Fatigue Analyses of the Reactor Pressure Vessel Internals TLAA 7/22/24 Breakout Session: Environmentally Assisted Fatigue TLAA 7/22/24 Breakout Session: ASME Section XI, Subsection IWE AMP 7/25/24 Breakout Session: Corrosion - Structural 7/25/24 Breakout Session: ASME Section XI, Subsection IWF AMP 7/25/24

94 Subject Area Meeting Date Breakout Session: RG 1.127, Inspection of Water-Control Structures Associated with Nuclear Power Plants 7/25/24 Breakout Session: Structures Monitoring AMP 7/26/24 Breakout Session: Concrete 7/26/24 Breakout Session: Inaccessible Areas 7/26/24 Breakout Session: Settlement 7/26/24 Breakout Session: Thermal Aging and Neutron Irradiation Embrittlement of CASS 7/30/24 Breakout Session: Periodic Inspections of Selective Leaching AMP 7/31/24 Breakout Session: Buried and Underground Piping and Tanks AMP 7/31/24 Breakout Session: Inaccessible Power Cables Not Subject to 10 CFR 50.49 EQ Requirements 8/20/24 Breakout Session: Insulation Material for Electrical Cables-Connections Not Subject to 10 CFR 50.49 EQ Requirements AMP 8/20/24

4. Applicant Personnel Contacted During the Audit Name Affiliation Brandy Lopez PG&E Michelle Olsofsky PG&E Philippe Soenen PG&E Robbie Thorson PG&E Steve Baker PG&E Jaclyn Canova PG&E Sean Dunlap PG&E Josh Harrison PG&E Jeff Larson PG&E Carlos Lopez PG&E Garrett Passmore PG&E Steve Toney PG&E Michael Wright PG&E John Fonturbel PG&E Steven Goschke PG&E Brian Leasburg PG&E Scott Maze PG&E Ariel Montoya PG&E Mike Moren PG&E Dustin Platt PG&E Scott Stern PG&E Rob OSullivan PG&E Do Vo PG&E

95 Issa Zakaria PG&E Gary Adkins Enercon Jacob Barnes Enercon Latoya Bennett Enercon Marv Engen Enercon Reene Gambrell Enercon Jeff Gromatzky Enercon Aaron Halstrom Enercon Jim Hamlin Enercon Michael Hernandez Enercon Allison Hoke Enercon Chris Hudson Enercon Tristen Hunnewell Enercon Karl Karch Enercon Mitch McFarland Enercon George Mermigas Enercon Ian Miller Enercon Min Noh Enercon Ken Putnam Enercon Molly OSullivan Enercon Fred Polaski Enercon Laura Swenzinski Enercon Dave Gerber Structural Integrity Associates Tim Gilman Structural Integrity Associates Terry Hermann Structural Integrity Associates Kevin Wong Structural Integrity Associates Thomas Voss Voss Laboratories Nick DeDominicis Westinghouse Andrew Hawk Westinghouse Don McNutt Westinghouse Tim Nowicki Westinghouse Derek Simpson Westinghouse

5. Exit Meeting An exit meeting was held with the applicant on July 31, 2024, 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 LRA review.