ML25238A024

Notification of Inspection and Request for Information

ML25238A024
Person / Time
Site:	Oconee
Issue date:	08/15/2025
From:	David Strickland NRC/RGN-II
To:	Boyce L Duke Energy
References
Download: ML25238A024 (1)

Text

From:

David Strickland To:

Laura.Boyce@duke-energy.com

Subject:

Oconee Nuclear Station Unit 2: Notification of Inspection and Request for Information Date:

Friday, August 15, 2025 11:15:00 AM Attachments:

2025 ONS Unit 2 ISI and SGISI RFI.pdf Good morning Ms. Boyce,

From November 10 to November 21, 2025, the Nuclear Regulatory Commission (NRC) is scheduled to perform the baseline in-service inspection at Oconee Nuclear Station Unit 2, in accordance with NRC inspection procedure IP 71111.08, Inservice Inspection Activities.

Please see the attached request for information (RFI), which provides a list of documents needed for the inspection. Section A of the RFI identifies information needed to support inspection preparation (i.e., inspection scope, sample selection, logistics, etc.) and should be provided to the lead inspector no later than October 24, 2025. Section B of the attached RFI identifies additional information the inspector(s) will need upon arrival at the site.

Please confirm receipt of this request and let me know if you have any initial questions about the inspection. Additionally, to ensure we remain aligned on the scope and schedule of the inspection, please inform us as soon as possible of any significant changes to the outage schedule or scope of outage activities. We would also appreciate any feedback on the best time to perform the inspection.

Regards,

David Strickland Senior Reactor Inspector 404-997-4440

NRC REGION II - ENGINEERING BRANCH 3 ISI REQUEST FOR INFORMATION - PWR Site:

Oconee Nuclear Station Unit 2 Docket No.:

50-270 Inspection Dates:

November 10 - November 14, 2025 (ISI Inspection)

November 17 - November 21, 2025 (Steam Generator Inspection)

Inspection Procedure:

IP 71111.08, Inservice Inspection Activities, Dated January 1, 2024 Inspector(s):

David Strickland, Sr. Reactor Inspector (ISI Lead Inspector)

Steven Downey, Sr. Reactor Inspector (SG Inservice Inspector)

Unless explicitly stated otherwise, all documents provided in response to this information request should correspond to the Unit for which the inspection will be performed. The information can be provided in either hard copy or electronic format, with a preference for electronic format (e.g., compact disk or web-based document management system). In cases where the requested information does not apply to the site (i.e. activities outside the scope of the upcoming refueling outage), a response of not applicable is appropriate.

In order to minimize the impact on your onsite resources, the inspectors have attempted to identify only those items not previously submitted to the agency. For those documents, the NRC staff will locate the most recent copy stored within the NRC's Agencywide Document Access and Management System (ADAMS). The inspectors will work with you and your staff to confirm that the material located is, in fact, full and complete as well as reflects your current license basis.

If there are any questions regarding this inspection, or the material requested, please contact the lead inspector or the Engineering Branch 3 Chief using the contact information provided.

A.

Information requested for the In-Office Preparation Week Please provide the information requested in this section to the NRC Region II Office in care of the lead inspector by October 24, 2025, in order to facilitate the selection of specific items that will be reviewed during the onsite inspection week(s).

A.1 Non-destructive Examination and Welding Activities

a.

A detailed schedule (including preliminary dates) of nondestructive examinations (NDEs) planned for the structures, systems, and components (SSCs) listed below as part of the Inservice Inspection (ISI) Program required by the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC),Section XI, as incorporated by reference in 10 CFR 50.55a, and other augmented in-service inspection activities:

x ASME Code Class 1, 2, and 3 components and supports (including Risk-Informed ISI Program) x ASME Code Class MC and metallic liners of Class CC components (e.g. reactor building containment liner)

2 x

ASME Code Class CC components x

ASME Code Class MC supports x

Alloy 82/182/600 components (ASME Code Cases N-722 and N-770) x Reactor vessel internals (e.g. Electric Power Research Institute (EPRI) MRP-227 Program) x Other components to be inspected through NDE in accordance with industry initiatives or requirements (e.g. Flow Accelerated Corrosion Program)

b.

A detailed schedule (including preliminary dates) of welding activities to be completed on ASME Code Class 1, 2, or 3 components and supports during the upcoming refueling outage.

c.

A list of NDE reports (ultrasonic, radiographic, magnetic particle, and liquid penetrant) addressing surface or volumetric indications that were analytically evaluated and accepted for continued service in ASME Code Class 1, 2, and 3 components since the beginning of the last refueling outage. This list should also include any evaluations for continuous service performed as a result of Section XI pressure test(s) conducted during start up from the last refueling outage.

d.

A list of the welds in ASME Code Class 1, 2, and 3 systems that have been fabricated due to component repair/replacement activities since the beginning of the last refueling outage. Please include a brief description of the welds such as system, material, pipe size, weld number, and NDEs performed. Additionally, please indicate which of those welds are risk-significant.

e.

If NDE of pressure retaining welds in the reactor vessel shell required by the ASME BPVC,Section XI, Subsection IWB (also known as 10-year Reactor Vessel ISI) are scheduled to occur during the upcoming outage, provide a detailed description of the welds to be examined and the extent of the planned examination. Please include reference numbers for applicable procedures that will be used to conduct these examinations.

f.

A list of temporary Code or temporary non-Code repairs installed in ASME Code Class components (e.g., pinhole leaks or mechanical clamping devices).

g.

A copy of the most recent program self-assessments addressing the ISI Program and welding activities.

h.

If peening is scheduled to occur during the upcoming outage, provide a detailed description of the components and/or welds that will be subjected to peening.

i.

If the mechanical stress improvement process (MSIP) is scheduled to occur during the upcoming outage, provide a detailed description of the welds that will be subjected to MSIP.

A.2 Reactor Pressure Vessel Upper Head Penetration Inspection Activities

a.

Information on compliance with ASME Code Case N-729, including:

x N-729 examination requirements (by Item Number) that currently apply to the reactor vessel upper head

3 x

Outage and date(s) of last bare metal visual examination of the reactor vessel upper head x

Outage and date(s) of last volumetric or surface examination of the reactor vessel upper head NOTE: The remaining information request items in Section A.2 are applicable only if NDE of the reactor vessel upper head will occur during the upcoming refueling outage

b.

A detailed schedule (including preliminary dates) of NDEs planned for the reactor pressure vessel upper head penetrations (VUHPs) to meet the requirements of ASME Code Case N-729, as incorporated by reference in 10 CFR 50.55a.

c.

A detailed scope of the planned NDEs for the reactor pressure VUHPs. Please identify the types of NDE methods to be used on each specific part of the vessel upper head to meet the augmented inspection requirements of ASME Code Case N-729, as incorporated by reference in 10 CFR 50.55a.

A.3 Boric Acid Corrosion Control Program Inspection Activities

a.

A copy of the procedures governing the implementation of the boric acid corrosion control program (BACCP), including procedures required to identify boric acid leakage and perform boric acid leakage/corrosion evaluations.

b.

A list of leaks in ASME Code Class components which have been identified since the last refueling outage, including reference to the associated corrective action program documentation. For each leak, please describe how the leak was classified in accordance with your BACCP and whether an engineering evaluation was performed.

c.

If the Unit was shut down during the last cycle, please provide documentation of containment walk-down inspections performed as part of the BACCP.

d.

Copy of the most recent self-assessment performed for the BACCP.

A.4 Steam Generator Tube Inspection Activities

a.

Provide one of the following:

i.

A detailed schedule of steam generator (SG) tube inspection, eddy current data analyses, tube in-situ pressure testing, tube repairs, and SG secondary side inspection activities for the upcoming refueling outage, OR ii.

If no SG tube inspections are planned, then provide a copy of the document(s) verifying that no SG tube inspections are required during the upcoming outage (i.e. skipped cycle assessment)

b.

A copy of the current version of the following documents:

x SG ISI Inspection Program and Plan x

Condition Monitoring Assessment x

Operational Assessment

c.

Confirmation of whether SG primary-to-secondary leakage was identified and quantified during the previous operating cycle. If primary-to-secondary leakage was identified,

4 please provide documentation describing the affected SG and corrective actions completed, or planned for this condition.

NOTE: The remaining information request items in Section A.4 are applicable only if eddy current examination of the SG tubes will occur during the upcoming refueling outage.

d.

A copy of the most recent Degradation Assessment.

e.

A copy of the Eddy Current Examination Plan describing the scope of SG tube examinations, including examination methods such as bobbin, rotating, or array probes, and the percentage of tubes to be examined. Do not provide this information separately if it is already included in other documentation requested.

f.

A copy of the SG plant-specific degradation history provided to the vendor performing eddy current examination of the SG tubes during the upcoming outage. Please include information on issues pertaining to the secondary side of the steam generators (including items such as loose parts, fouling, top of tube sheet condition, and crud removal amounts, etc.). Do not provide this information separately if it is already included in other documentation requested.

g.

A copy of the following documents, as applicable:

x SG Eddy Current Data Analyst Guidelines x

Site Validated Eddy Current Techniques x

Eddy Current Technique Qualification Records per EPRI Appendix H or I

h.

A copy of the most recent program self-assessments for SG tube integrity, loose parts monitoring, and secondary side water chemistry control.

i.

The location of the primary, secondary, and resolution analysis teams.

A.5 Other Information Related to All ISI Activities

a.

A list with a brief description of ISI-related issues entered into the corrective action program for all operating Units since the beginning of the last refueling outage, including issues related to the SG tube inspections and the BACCP. For example, provide a list of condition reports based upon database searches using keywords related to piping, vessels, and SG tube degradation such as: ISI, ASME Code,Section XI, NDE, welding, SG tube, reactor vessel, steam generator, reactor coolant system, crack, wear, thinning, leakage, thru-wall, rust, corrosion, boric acid, or errors in piping/SG tube examinations.

b.

Names and contact information for the following program leads:

x ISI Program (examination, planning) x Reactor Containment Building ISI Program x

Alloy 600 Program x

VUHP Inspection Program x

Snubbers and Supports Inspection Program x

Repair and Replacement Program x

Licensing x

Site Welding

5 x

Boric Acid Corrosion Control Program x

SG Inspection Program (site lead and vendor contact) x Reactor Vessel Internals Program x

Flow Accelerated Corrosion Program

c.

Current outage and ISI program information including:

x Current edition and addendum of the ASME Code being used for inspection, NDE, welding and repair/replacement activities x

Current edition and addendum of the ASME Code being used for containment inspections x

Outage name (e.g. U3R20) x Current ISI interval number, period within the interval, outage within the period and total number of outages overall for the interval (e.g. the first outage of the third period in the fourth interval of the ISI inspection program, and the fifth outage for the interval B.

Information Requested for the Onsite Inspection Week(s)

Please provide the information requested in this Section on the first day of the inspection, if available. Prior to the onsite inspection, the inspector(s) will select some inspection samples from the information provided in Section A and may request additional information. Some inspection samples requiring direct observation (e.g.,

planned NDEs) may not be selected until the inspector(s) arrive onsite and confirm the current schedule of refueling outage activities.

B.1 Non-destructive Examination Activities, Welding Activities, and Schedule Information

a.

Updated schedules for the planned NDE and welding activities described in the response to items A.1.a and A.1.b of this enclosure.

b.

For the NDEs selected by the inspector(s) from item A.1.a of this enclosure, please provide a copy of the NDE procedures used to perform the examinations (including calibration and flaw characterization/sizing procedures). For ultrasonic examination procedures qualified in accordance with ASME Code,Section XI, Appendix VIII, please provide documentation supporting the procedure qualification (e.g., the EPRI performance demonstration qualification summary sheets). Please include documentation of the specific equipment to be used (e.g., ultrasonic unit, cables, and transducers including serial numbers) and NDE personnel qualification records.

c.

For the NDE reports with relevant indications on ASME Code Class 1, 2, and 3 components selected by the inspector(s) from item A.1.c of this enclosure, please provide a copy of the examination records, NDE qualification records, and associated corrective action documents, including technical evaluations supporting the acceptability of the indications for continuous service.

d.

For the ASME Code Class 1, 2, and 3 welds selected by the inspector(s) from item A.1.d of this enclosure, please provide copies of the following documentation for each subject weld:

x weld data sheet (traveler) x weld configuration and supporting drawings (e.g. ISI isometric drawings)

6 x

Weld Procedure Specification (WPS) used to fabricate the welds x

Procedure Qualification Records (PQRs) supporting the WPS x

mechanical test reports supporting the applicable PQRs x

welder performance qualifications records, including documentation that welder maintained proficiency in the applicable welding processes specified in the WPS x

examination records for the NDEs performed during weld fabrication x

preservice NDE records x

personnel qualification records for both fabrication and preservice NDEs x

nonconformance reports for the selected welds (if applicable)

B.2 Reactor Pressure Vessel Upper Head Penetration Inspection Activities

a.

A copy of NDE reports from the last visual and non-visual VUHP examinations.

b.

If visual and/or non-visual NDEs of the VUHPs are planned for the upcoming refueling outage, please provide the following:

x a copy of the procedures governing the implementation of NDEs x

drawings showing the configuration of the VUHPs within the scope of the examinations (e.g. upper head insulation configuration, fabrication drawings of the nozzle attachments, geometrical limitations, etc.)

x documentation demonstrating that the scope of the NDEs will meet the minimum coverage required by ASME Code Case N-729, as modified by 10 CFR 50.55a x

documentation demonstrating the detection capability and qualification of the NDE personnel, procedures, and equipment in accordance with 10 CFR 50.55a x

identify any changes in equipment configurations used for the VUHPs examinations that differ from that used in the vendor qualification or demonstration report(s)

B.3 Boric Acid Corrosion Control Program Inspection Activities

a.

Inspection results for boric acid walk-downs, including an updated list of boric acid leaks identified during the current refueling outage with associated corrective action documentation, and overall status of planned boric acid inspections.

b.

A list of engineering evaluations completed for boric acid leaks identified since the end of the last refueling outage. Please include a status of corrective actions to repair and/or clean these boric acid leaks. Please specify which known leaks, if any, have remained in service, or will remain in service, as active leaks.

c.

In accordance with NRC inspection procedure 71111.08, the inspector(s) would like to conduct an independent boric acid walk-down of the Reactor Building Containment early in the inspection week. Please have knowledgeable BACCP staff available to accompany the inspector(s) during the walk-down.

B.4 Steam Generator Tube Inspection Activities (if applicable)

NOTE: The information request items in Section B.4 are applicable only if eddy current examination of the SG tubes will occur during the upcoming refueling outage

a.

An updated schedule of SG tube inspection activities, including potential in-situ pressure tests, tube repairs, and secondary side inspections.

7

b.

A copy of the Eddy Current Examination Technique Specification Sheets from the EPRI Performance Demonstration Database that are applicable to the scheduled examinations of SG tubes.

c.

A copy of the eddy current examination procedures governing the SG tube examination activities. Specifically, provide the procedures for calibration, flaw detection, and flaw sizing.

d.

Access to the training and qualification records of personnel performing eddy current data analysis, including training material and test results for any site-specific training provided to the data analysts.

e.

Access to the certification records of eddy current equipment (i.e. eddy current instruments, probes, and calibration standards).

f.

A copy of the procedures to be followed if a loose part or foreign material is identified in the steam generators.

g.

Documentation demonstrating that the in-situ pressure test screening criteria are in accordance with the applicable EPRI Guidelines. Please have knowledgeable staff available to discuss the analytical method used to determine the in-situ pressure test screening criteria.

h.

A list of corrective action documents generated by the vendor with respect to SG tube inspection activities during the current refueling outage.

B.5 Other Information Related To All ISI Activities

a.

For the ISI-related corrective action issues selected by the inspector(s) from item A.5.a of this enclosure, please provide copies of the corrective action documents and supporting documentation (e.g. cause evaluations, work orders, corrective action plan, etc.).

b.

An updated list of ISI-related issues entered into the corrective action program for the current refueling outage, including issues related to the steam generator tube inspections and Boric Acid Corrosion Control Program.

c.

A copy of or ready access to:

x a current revision of the ISI Program Manual and Plan for the current interval PAPERWORK REDUCTION ACT STATEMENT This letter does not contain new or amended information collection requirements subject to the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.). Existing information collection requirements were approved by the Office of Management and Budget, control number 3150-0011.

PUBLIC PROTECTION NOTIFICATION The NRC may not conduct or sponsor, and a person is not required to respond to, a request for information or an information collection requirement unless the requesting document displays a currently valid Office of Management and Budget control number.

8 Contact Information:

David Strickland (Lead Inspector)

Sr. Reactor Inspector Engineering Branch 1 Division of Operating Reactor Safety David.Strickland@nrc.gov 404-997-4440 Mailing Address:

US NRC Region II Attn: David Strickland 245 Peachtree Center Avenue, Suite 1200 Atlanta, GA 30303 Louis J. McKown Branch Chief Engineering Branch 3 Division of Operating Reactor Safety Louis.McKown@nrc.gov 404-997-4545 Approving Branch Chief:

Date:

Louis J. McKown Chief, Engineering Branch 3 LOUIS MCKOWN Digitally signed by LOUIS MCKOWN Date: 2025.08.15 08:00:41

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