RA-22-0157, Subsequent License Renewal Application First Annual Amendment to the License Renewal Application and Subsequent License Renewal Application Supplement 4

Subsequent License Renewal Application First Annual Amendment to the License Renewal Application and Subsequent License Renewal Application Supplement 4

ML22158A028
Person / Time
Site:	Oconee
Issue date:	06/07/2022
From:	Snider S Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RA-22-0157
Download: ML22158A028 (56)

Text

Steven M. Snider Vice President Oconee Nuclear Station

Duke Energy ON01VP l 7800 Rochester Hwy Seneca, SC 29672 o:864.873.3478 f: 864.873.5791 RA-22-0157 Steve.Snider@duke-energy.com June 7, 2022 10 CFR 50.4 10 CFR Part 54 10 CFR 54.21(b)

ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

Subject:

Duke Energy Carolinas, LLC (Duke Energy)

Oconee Nuclear Station (ONS), Units 1, 2, and 3 Docket Numbers 50-269, 50-270, 50-287 Renewed License Numbers DPR-38, DPR-47, DPR-55 Subsequent License Renewal Application First Annual Amendment To The License Renewal Application And Subsequent License Renewal Application Supplement 4

References:

1. Duke Energy Letter (RA-21-0132) dated June 7, 2021, Application for Subsequent Renewed Operating Licenses, (ADAMS Accession Number ML21158A193)

2. NRC Letter dated July 22, 2021, Oconee Nuclear Station, Units 1, 2, and 3 - Determination of Acceptability and Sufficiency for Docketing, Proposed Review Schedule, and Opportunity for a Hearing Regarding Duke Energy Carolinas Application for Subsequent License Renewal (ADAMS Accession Number ML21194A245)

3. NRC Letter dated July 23, 2021, Oconee Nuclear Station, Units 1, 2, and 3 - Aging Management Audit Plan Regarding the Subsequent License Renewal Application Review, (ADAMS Accession Number ML21196A076)

4. Duke Energy Letter (RA-21-0249) dated October 28, 2021, Subsequent License Renewal Application Supplement 1 (ADAMS Accession ML21302A208)

5. Duke Energy Letter (RA-21-0288) dated November 11, 2021, Subsequent License Renewal Application Supplement 2 (ADAMS Accession ML21315A012)

6. Duke Energy Letter (RA-21-0316) dated December 15, 2021, Subsequent License Renewal Application Supplement 3 (ADAMS Accession ML21349A005)

Ladies and Gentlemen:

By letter dated June 7, 2021 (Reference 1), Duke Energy Carolinas, LLC (Duke Energy) submitted an application for the subsequent license renewal of Renewed Facility Operating License Numbers DPR-38, DPR-47, and DPR-55 for the Oconee Nuclear Station (ONS), Units 1, 2, and 3 to the U.S. Nuclear Regulatory Commission (NRC). On July 22, 2021 (Reference 2), the NRC determined that ONS subsequent license renewal application (SLRA) was acceptable and sufficient for docketing.

10 CFR 54.21(b) requires Duke Energy to report changes to the Current Licensing Basis (CLB) that materially affect the contents of the SLRA, including the UFSAR supplement. These changes are required to be submitted each year and at least 3 months prior to the scheduled completion of NRC review of the SLRA.

U.S. Nuclear Regulatory Commission June 7, 2022 Page 2

Duke Energy has completed the annual review and concluded that there are three (3) changes that are considered to materially affect the contents of the Oconee SLRA. Enclosure 1 provides the descriptions of these CLB changes and the corresponding mark-ups to the portions of the SLRA affected by the changes, thereby supplementing the Oconee SLRA. For clarity, deletions are indicated by strikethrough and inserted text by underlined red font.

By letter dated July 23, 2021 (Reference 3), the NRC issued the regulatory audit plan for the aging management portion of the SLRA review. During the audit conducted July 26, 2021 - October 8, 2021, Duke Energy agreed to supplement the SLRA with new or clarifying information. SLRA Supplements 1, 2, and 3 are provided by References 4, 5 and 6, respectively. Enclosure 2 includes additional information and clarification of six (6) topics that require an SLRA supplement to assist the NRC staff in the development of the safety evaluation report and the corresponding mark-ups to the portions of the affected SLRA Sections. For clarity, deletions are indicated by strikethrough and inserted text by underlined red font.

This submittal contains revisions to Table A6.0-1, Commitment Numbers 24 and 33, Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components and Structures Monitoring programs, respectively.

Should you have any questions regarding this submittal, please contact Paul Guill at (704) 382-4753 or by email at paul.guill@duke-energy.com.

I declare under penalty of perjury that the foregoing is true and correct. Executed on June 7, 2022.

Sincerely,

Steven M. Snider Site Vice President Oconee Nuclear Station

Enclosures:

Current Licensing Basis Changes Impacting Subsequent License Renewal Application : Supplement 4

U.S. Nuclear Regulatory Commission June 7, 2022 Page 3

CC: W/O

Enclosures:

Laura A. Dudes Regional Administrator U.S. Nuclear Regulatory Commission - Region II Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, Georgia 30303-1257

Angela X. Wu, Project manager (by electronic mail only)

U.S. Nuclear Regulatory Commission Mail Stop 11 G3 11555 Rockville Pike Rockville, Maryland 20852

Shawn A. Williams, Project Manager (by electronic mail only)

U.S. Nuclear Regulatory Commission Mail Stop 8 B1A 11555 Rockville Pike Rockville, Maryland 20852

Jared Nadel (by electronic mail only)

NRC Senior Resident Inspector Oconee Nuclear Station

Anuradha Nair (by electronic mail only: naira@dhec.sc.gov)

Bureau Environmental Health Services Department of Health & Environmental Control 2600 Bull Street Columbia, South Carolina 29201

U.S. Nuclear Regulatory Commission June 7, 2022 Page 4

BCC: W/O

Enclosures:

T.P. Gillespie K. Henderson S.D. Capps T.M. Hamilton P.V. Fisk H.T. Grant D.A. Wilson M.C. Nolan S.M. Snider R.K. Nader G.D. Robison T.M. LeRoy P.F. Guill R.V. Gambrell File: (Corporate)

Electronic Licensing Library (ELL)

ENCLOSURE 1

OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 SUBSEQUENT LICENSE RENEWAL APPLICATION CURRENT LICENSING BASIS CHANGES IMPACTING SUBSEQUENT LICENSE RENEWAL APPLICATION

Introduction This enclosure contains the descriptions of the three changes that are being made to the Subsequent License Renewal Application (SLRA) as a result of 10 CFR 54.21(b) incorporating Current Licensing Basis (CLB) changes that materially affect the contents of the Oconee SLRA. For each item, the change is described and the affected page number(s) and portion(s) of the SLRA is provided. For clarity, deletions are indicated by strikethrough and inserted text by underlined red font. Revisions to SLRA tables and SLRA Sections are shown by providing only excerpts from the affected SLRA tables and affected text provided in the SLRA sections.

CLB CHANGES AFFECTING THE SLRA

Number Change Topic

1 Keowee Generator Air Cooler Tube Material

2 SSF RCS Letdown Line to Support SSF Operability

3 Auxiliary Building Door Plexiglass Cover

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, CLB Changes Impacting SLRA

Change Number 1: Keowee Generator Air Cooler Tube Material Description of Change As a result of a change to the design drawing for the Keowee generator air coolers, the tube material has been revised from 90-10 copper nickel to admiralty brass. Admiralty brass is an inhibited copper alloy with greater than 15% zinc. Consistent with NUREG-2191, copper alloy > 15% Zn is susceptible to cracking in air-indoor uncontrolled and raw water environments. The Open-Cycle Cooling Water System Program (B2.1.11) will manage cracking of the tubes in the raw water (internal) environment.

The Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components Program (B2.1.24) will be used in lieu of the recommended External Surfaces Monitoring of Mechanical Components Program for managing cracking of copper alloy > 15% Zn components in an air-indoor uncontrolled (external) environment. The alternative program is used since these air coolers are located within the generator casing and are not normally accessible for inspection except during the performance of maintenance. As a result of the addition of these components to the scope of the Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components Program, the program description in SLRA Section A2.24 and B2.1.24 is revised to include external surface inspections.

SLRA Markup Based on the above discussions, SLRA Table 3.3.1, Table 3.3.2-52, Appendix A2.24, Table A6.0-1, and Appendix B2.1.24 are supplemented.

SLRA Table 3.3.1 Item Number 3.3.1-132 (page 3-476) is revised as follows:

Table 3.3.1 Summary of Aging Management Programs for Auxiliary Systems Evaluated in Chapter VII of the GALL-SLR Report Item Component Aging Effect/ Aging Management Further Evaluation Discussion Number Mechanism Program Recommended

3.3.1-132 Insulated steel, copper Loss of material due to AMP XI.M36, External No Consistent with NUREG-2191.

alloy (>15% Zn or >8% general, pitting, crevice Surfaces Monitoring of,except that the Inspection of Al), piping, piping corrosion (steel only); Mechanical Components" Internal Surfaces in Miscellaneous components, tanks, cracking due to SCC or AMP XI.M29, "Outdoor Piping and Ducting Components tanks (within the scope (copper alloy (>15% Zn and Large Atmospheric (B2.1.24) is used for managing of AMP XI.M29, or >8% Al) only) Metallic Storage Tanks the external surfaces of the "Outdoor and Large Keowee Turbine Generator air Atmospheric Metallic cooler tubes since the air coolers Storage Tanks") are located inside of the exposed to air, generator.

condensation

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Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, CLB Changes Impacting SLRA

SLRA Table 3.3.2-52 (page 3-972) is revised as follows:

Table 3.3.2-52 Auxiliary Systems - Keowee Turbine Generator Cooling Water System - Aging Management Evaluation Component Intended Material Environment Aging Effect Aging Management NUREG-2191 NUREG-2192 Notes Type Function Program Item Table 1 Heat Heat Transfer Copper Alloy Air -Indoor Reduction of Inspection of Internal VII.C1.A-419 3.3.1- 096a A,2 Exchanger (> 15% Zn) Uncontrolled Heat Transfer Surfaces in (generator air (External) Miscellaneous Piping cooler) and Ducting Tubes Components (B2.1.24)

Raw Water Reduction of Open-Cycle Cooling VII.C1.AP-187 3.3.1- 042 B,2 (Internal) Heat Transfer Water System (B2.1.11)

Pressure Copper Alloy Air -Indoor None None VII.J.AP-144 3.3.1-114 C Boundary (> 15% Zn) Uncontrolled Cracking Inspection of Internal VII.I.A-405a 3.3.1-132 E,4 (External) Surfaces in Miscellaneous Piping and Ducting Components (B2.1.24)

Raw Water Cracking Open-Cycle Cooling VII.C1.A-473b 3.3.1-160 B,3 (Internal) Water System (B2.1.11)

Loss of Open-Cycle Cooling VII.C1.AP-179 3.3.1- 038 B,2 Material, Flow Water System (B2.1.11)

Blockage

SLRA Table 3.3.2-52, as amended by Duke Energy letter dated October 28, 2021, ADAMS Accession Number ML21302A208, (page 3-978) is revised as follows:

Table 3.3.2-52 Auxiliary Systems - Keowee Turbine Generator Cooling Water System - Aging Management Evaluation Plant Specific Notes:

2. Components constructed of Copper Alloy and Copper Alloy >15% Zn share common aging effects.

For Copper Alloy >15% Zn components, these common aging effects are managed by aligning to a GALL SLR item for Copper Alloy as a direct match. Unique aging effects applicable only to components constructed of Copper Alloy >15% Zn, are managed by aligning to a GALL SLR line item specific to Copper Alloy >15% Zn.

3. Material of construction is inhibited Brass which is not susceptible to selective leaching.

4. The external surface of the generator air cooler tubes is internal to the generator units.

SLRA Appendix A2.24 (page A-25) is revised as follows:

A2.24 Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components Program Description This program will consist of visual inspections of internal surfaces (or external surfaces of components located internal to other components such that the external surface is not normally accessible) of piping, piping components, ducting, heat exchanger components, polymeric and elastomeric components, and other mechanical components

2

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, CLB Changes Impacting SLRA

SLRA Table A6.0-1, Commitment Number 24, Commitment Column, as amended by Duke Energy Letter dated October 22, 2021 (ADAMS Accession Number ML21295A035), (page A-89) is revised as follows:

The Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components AMP is a new condition monitoring program that will manage loss of material and cracking of metallic components, as well as loss of material, cracking, blistering, hardening and loss of strength of polymeric and elastomeric materials. The program also manages loss of coating integrity for certain components that do not perform a pressure boundary intended function and where loss of coating integrity would not impact the intended functions of downstream components. Reduction of heat transfer and flow blockage will also be managed. This program will consist of visual inspections of all accessible internal surfaces (or external surfaces of components located internal to other components such that the external surface is not normally accessible) of piping, piping components, ducting, heat exchanger components, polymeric and elastomeric components, and other mechanical components. Periodic wall thickness measurements may be conducted in lieu of visual inspections for managing loss of coating integrity. Periodic visual (VT-1) or surface examinations will be performed to detect cracking of stainless steel components exposed to a diesel exhaust, potable raw water, and waste water and in copper alloys exposed to waste water.

SLRA Appendix B2.1.24 (page B-171) is revised as follows:

B2.1.24 INSPECTION OF INTERNAL SURFACES IN MISCELLANEOUS PIPING AND DUCTING COMPONENTS Program Description This program will consist of visual inspections of internal surfaces (or external surfaces of components located internal to other components such that the external surface is not normally accessible) of piping, piping components, ducting, heat exchanger components, polymeric and elastomeric components, and other mechanical components

3

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, CLB Changes Impacting SLRA

Change Number 2: SSF RCS Letdown Line to Support SSF Operability Description of Change:

A plant modification to all three Oconee units has been implemented that installed a new reactor coolant letdown line for use during design basis events. This letdown line allows operators to letdown reactor coolant inventory into either the spent fuel pool or the quench tank. This modification revised the intended functions for the High Pressure Injection, Reactor Coolant, Coolant Storage, Feedwater, and Spent Fuel Cooling systems. Most of the piping and components used in fulfilling this new function were included in the scope of SLR with a structural integrity function and will now have a pressure boundary function as they are relied upon for the mitigation of a design basis event. In addition, a system level function was added to the Spent Fuel Cooling System to utilize the BWST inventory to make up to the spent fuel pool during design basis events.

SLRA Markup:

Based on these modifications, SLRA sections 2.3.1.3, 2.3.2.3, 2.3.2.4, 2.3.3.2.2, 2.3.3.2.6, and 2.3.4.2 and tables 2.3.3.2-2, 2.3.3.2-6, 3.3.2-13, and 3.3.2-17 are modified as follows:

SLRA Section 2.3.1.3, (Page 2-58) is revised as follows:

2.3.1.3 Reactor Coolant System System Intended Functions Portions of the reactor coolant system are relied upon to provide core decay, latent and reactor coolant pump heat removal during normal operations, shutdown, and following a design basis event. Portions of the reactor coolant system provide the capability to letdown to the quench tank or the spent fuel pool during design basis events.

SLRA Section 2.3.2.3, (Pages 2-74 and 2-76) is revised as follows:

2.3.2.3 High Pressure Injection System System Intended Functions The standby shutdown facility reactor coolant makeup system also provides a flow path to letdown the reactor coolant system into the spent fuel pool.

Secondary Drawings :

OSLRD-104A-1.1 OSLRD-104A-3.1

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Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, CLB Changes Impacting SLRA

SLRA Section 2.3.2.4, (Page 2-78) is revised as follows:

2.3.2.4 Low Pressure Injection System System Intended Functions Portions of the low pressure injection system also provide borated water to the spent fuel pool and the high pressure injection and reactor building spray pumps during design basis events...

SLRA Section 2.3.3.2.2, (Pages 2-110, 2-111, and 2-112) is revised as follows:

2.3.3.2.2 Coolant Storage System

System Description

The coolant storage system is designed to accommodate the accumulated coolant bleed over a core cycle, including startup expansion and coolant letdown to storage for boric acid reduction. The coolant storage system is also designed to provide capability to letdown and store reactor coolant in the quench tank during emergency operations.

System Intended Functions Portions of the coolant storage system are relied upon for containment integrity. Portions of the coolant storage system also provide storage capability for reactor coolant letdown during emergency operations. Therefore, the coolant storage system is within the scope of SLR in accordance with the criteria of 10 CFR 54.4(a)(1).

Secondary Drawings OSLRD-100A-1.1 OSLRD-100A-1.3 OSLRD-100A-1.5 OSLRD-100A-2.1 OSLRD-100A-2.3 OSLRD-100A-2.5 OSLRD-100A-3.1 OSLRD-100A-3.3 OSLRD-100A-3.5 OSLRD-102A-1.3 OSLRD-102A-2.3 OSLRD-102A-3.3 OSLRD-121B-1.5 OSLRD-121B-2.3 OSLRD-121B-2.5 OSLRD-121B-3.3 OSLRD-121B-3.5

5

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, CLB Changes Impacting SLRA

SLRA Table 2.3.3.2-2, (Page 2-112) is revised as follows:

Table 2.3.3.2-2 Coolant Storage System Component/Commodity Group Intended Functions Expansion Joint Pressure Boundary

SLRA Table 2.3.3.2-2, (Page 2-113) is revised as follows:

Table 2.3.3.2-2 Coolant Storage System Component/Commodity Group Intended Functions Tank (quench) Pressure Boundary Structural Integrity

SLRA Section 2.3.3.2.6, (Page 2-121) is revised as follows:

2.3.3.2.6 Spent Fuel Cooling System System Intended Functions Portions of the spent fuel cooling system also provide a source of makeup water to the standby shutdown facility and letdown storage capability for reactor coolant system inventory, drain accumulated reactor building spray water (post actuation) from the fuel transfer canal, and provide emergency makeup to the spent fuel pool to maintain shutdown margin and shielding...

SLRA Table 2.3.3.2-6, (Page 2-123) is revised as follows:

Table 2.3.3.2-6 Spent Fuel Cooling System Component/Commodity Group Intended Functions Orifice Pressure Boundary Structural Integrity Pump Casing (borated water recirculation) Pressure Boundary Structural Integrity

SLRA Section 2.3.4.2, (Page 2-253) is revised as follows:

2.3.4.2 Feedwater System System Intended Functions Portions of the feedwater system are relied upon to maintain containment integrity. The feedwater system provides isolation of feedwater flow following a main steam line break, tube leak, or reactor shutdown. The feedwater system provides the capability to isolate steam generators during a turbine building flood.

6

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application Enclosure 1, CLB Changes Impacting SLRA

SLRA Table 3.3.2-13, (Page 3-598) is revised as follows:

Table 3.3.2-13 Auxiliary Systems - Coolant Storage System - Aging Management Evaluation Component Intended Material Environment Aging Effect Aging Management NUREG-2191 NUREG-2192 Notes Type Function Program Item Table 1

Expansion Joint Pressure Stainless Air - Indoor Cracking One-Time Inspection VII.C1.AP-209a 3.3.1- 004 A Boundary Steel Uncontrolled (B2.1.20)

(External)

Loss of One-Time Inspection VII.C1.AP-221a 3.3.1- 006 A Material (B2.1.20)

Air with Borated None None VII.J.AP-18 3.3.1-120 A Water Leakage (External)

Treated Borated Loss of Material One-Time Inspection VII.A2.AP-79 3.3.1-125 A Water (Internal) (B2.1.20)

Water Chemistry VII.A2.AP-79 3.3.1-125 A (B2.1.2)

Treated Borated Cracking One-Time Inspection VII.E1.AP-82 3.3.1- 028 A water (B2.1.20)

>60°C (>140°F)

(Internal) Water Chemistry VII.E1.AP-82 3.2.1- 028 A

(B2.1.2)

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Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application Enclosure 1, CLB Changes Impacting SLRA

SLRA Table 3.3.2-13, (Page 3-602) is revised as follows:

Table 3.3.2-13 Auxiliary Systems - Coolant Storage System - Aging Management Evaluation

Component Intended Material Environmental Aging Effect Aging Management NUREG-2191 NUREG-Notes Type Function Program Item 2192 Table 1 Piping Pressure Stainless Steel Treated Borated Loss of Material One-Time Inspection VII.A2.AP-79 3.3.1-125 A Boundary Water (Internal) (B2.1.20)

Water Chemistry VII.A2.AP-79 3.3.1-125 A (B2.1.2)

Treated Borated Cracking One-Time Inspection VII.E1.AP-82 3.3.1- 028 A water >60°C (>140°F) (B2.1.20)

(Internal)

Water Chemistry VII.E1.AP-82 3.3.1- 028 A (B2.1.2)

Treated Water Loss of Material One-Time Inspection VIII.G.SP-87 3.4.1- 085 A (Internal) (B2.1.20)

Water Chemistry VIII.G.SP-87 3.4.1- 085 A (B2.1.2)

Treated Water >60°C Cracking One-Time Inspection VIII.E.SP-88 3.4.1- 011 A

(>140°F) (Internal) (B2.1.20)

Water Chemistry VIII.E.SP-88 3.4.1- 011 A (B2.1.2)

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Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application Enclosure 1, CLB Changes Impacting SLRA

SLRA Table 3.3.2-13, (Page 3-603) is revised as follows:

Table 3.3.2-13 Auxiliary Systems - Coolant Storage System - Aging Management Evaluation Component Intended Aging NUREG-2191 NUREG-2192 Type Function Material Environment Aging Effect Management Item Table 1 Notes Program Piping and Pressure Stainless Treated Borated Cumulative Fatigue TLAA VII.E1.A-57 3.3.1- 002 A,3 Piping Boundary Steel water >60°C Damage Components (>140°F) (Internal)

Treated Water Cumulative Fatigue TLAA VII.E1.A-57 3.3.1- 002 A,3

>60°C (>140°F) Damage (Internal)

SLRA Table 3.3.2-13, (Page 3-603) is revised as follows:

Table 3.3.2-13 Auxiliary Systems - Coolant Storage System - Aging Management Evaluation Component Intended Aging NUREG-2191 NUREG-2192 Type Function Material Environment Aging Effect Management Item Table 1 Notes Program Piping and Pressure Treated Water Cumulative Fatigue Piping Boundary Steel >60°C (>140°F) Damage TLAA VII.E1.A-34 3.3.1- 002 A,3 Components (Internal)

SLRA Table 3.3.2-13,Columns Component type, and Intended Function (Page 3-610) is revised as follows:

Table 3.3.2-13 Auxiliary Systems - Coolant Storage System - Aging Management Evaluation Component Type Intended Function Tank (quench) Pressure Boundary Structural Integrity

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Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application Enclosure 1, CLB Changes Impacting SLRA

SLRA Table 3.3.2-13, (Page 3-611) is revised as follows:

Table 3.3.2-13 Auxiliary Systems - Coolant Storage System - Aging Management Evaluation

Component Intended Aging Management NUREG-2191 NUREG-Type Function Material Environment Aging Effect Program Item 2192 Notes Table 1 Valve Body Pressure Stainless Treated Borated Loss of Material Water Chemistry VII.A2.AP-79 3.3.1-125 A Boundary Steel Water (Internal) (B2.1.2)

Treated Borated Cracking One-Time Inspection VII.E1.AP-82 3.3.1- 028 A water >60°C (B2.1.20)

(>140°F) (Internal)

Water Chemistry VII.E1.AP-82 3.3.1- 028 A (B2.1.2)

Steel Air - Indoor Loss of Material External Surfaces VII.I.A-77 3.3.1- 078 A Uncontrolled Monitoring of (External) Mechanical Components (B2.1.23)

Air with Borated Loss of Material Boric Acid Corrosion VII.I.A-79 3.3.1- 009 A Water Leakage (B2.1.4)

(External)

Gas (Internal) None None VII.J.AP-6 3.3.1-121 A

Treated Water Long-Term Loss of One-Time Inspection VII.A3.A-439 3.3.1-193 A (Internal) Material (B2.1.20)

Loss of Material One-Time Inspection VIII.B1.SP-74 3.4.1-014 A (B2.1.20)

Water Chemistry VIII.B1.SP-74 3.4.1-014 A (B2.1.2)

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Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application Enclosure 1, CLB Changes Impacting SLRA

SLRA Table 3.3.2-17, (Page 3-641) is revised as follows:

Table 3.3.2-17 Auxiliary Systems - Spent Fuel Cooling System - Aging Management Evaluation Component Intended Aging Management NUREG-NUREG-2192 Type Function Material Environment Aging Effect Program 2191 Table 1 Notes Item Orifice Pressure Stainless Air - Indoor Cracking One-Time Inspection VII.C1.AP-209a 3.3.1- 004 A Boundary Steel Uncontrolled (B2.1.20)

(External)

Loss of Material One-Time Inspection VII.C1.AP-221a 3.3.1- 006 A (B2.1.20)

Air with Borated None None VII.J.AP-18 3.3.1-120 A Water Leakage (External)

Treated Borated Loss of Material One-Time Inspection VII.A2.AP-79 3.3.1-125 A Water (Internal) (B2.1.20)

Water Chemistry VII.A2.AP-79 3.3.1-125 A (B2.1.2)

Treated Borated Cracking One-Time Inspection VII.E1.AP-82 3.3.1- 028 A water >60°C (B2.1.20)

(>140°F) (Internal)

Water Chemistry VII.E1.AP-82 3.3.1- 028 A (B2.1.2)

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Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, CLB Changes Impacting SLRA

SLRA Table 3.3.2-17, Columns Component Type, and Intended Function (Pages 3-643 and 3-644) is revised as follows:

Table 3.3.2-17 Auxiliary Systems - Spent Fuel Cooling System - Aging Management Evaluation Component Type Intended Function Pump Casing (borated water recirculation) Pressure Boundary Structural Integrity

12

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, CLB Changes Impacting SLRA

Change Number 3: Auxiliary Building Door Plexiglass Cover Description of Change Plexiglass covers are installed above various doors in the Auxiliary Building. The plexiglass is credited for restricting the air flow in the Auxiliary Building for fire safe shudown. As a result, the plexiglass component type, which is made from a polymeric material, is added to SLRA Table 3.5.2-1: Auxiliary Building - Aging Management Evaluation. Consistent with NUREG-2191, polymeric material is susceptible to hardening, loss of strength, loss of material, and cracking in an air environment. The Structures Monitoring Program (B2.1.33) will be used in lieu of the recommended External Surfaces Monitoring of Mechanical Components Program (B2.1.23) to manage hardening or loss of strength, loss of material, and cracking or blistering of the plexiglass in the air environment. The alternate program is credited as the plexiglass is used for the structural purpose of directing air flow and does not perform a mechanical function. As a result of the addition of these components to the scope of the Structures Monitoring Program, the Structures Monitoring Program description is updated to include plexiglass inspections in addition to an enhancement being added to address degradation monitoring and acceptance criteria for the plexiglass. The Structures Monitoring Program description in SLRA Sections A2.33 and B2.1.33 is revised for these changes.

SLRA Markup Based on the above discussions, SLRA Section 2.4.1, Table 2.4.1-1, Table 3.3.1, Section 3.5.2.1.1, Table 3.5.2-1, Section A2.33, Table A6.0-1, and Section B2.1.33 are supplemented.

SLRA Section 2.4.1 (page 2-286) is revised as follows:

2.4.1 AUXILIARY BUILDING

System Description

The auxiliary buildings are comprised of structural components whose materials of construction are either reinforced concrete or steel. Fire barriers and lead shielding are structural components that are also within the evaluation boundary of the ONS auxiliary buildings. Fiber reinforced polymer exists on the exterior of the outside masonry block wall. Polymeric plexiglass covers exist over certain doors and direct air flow in the Auxiliary Building.

SLRA Section 2.4.1 (page 2-287) is revised as follows:

2.4.1 AUXILIARY BUILDING System Evaluation Boundary The evaluation boundary for the auxiliary building includes the foundation, internal structural members, external walls and roof. Also included are the spent fuel pool, spent fuel storage racks, battery racks, auxiliary building cranes, doors, metal siding, masonry block walls, plexiglass covers, and fiber reinforced polymer. The low pressure injection room sumps and cover plates, in addition to waste tanks stainless steel lined cover slabs, are within the evaluation boundary of the auxiliary building.

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Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, CLB Changes Impacting SLRA

SLRA Table 2.4.1-1 (page 2-289) is revised as follows:

Table 2.4.1-1 Auxiliary Building Structural Member Intended Functions

Plexiglass Cover Direct Flow

SLRA Table 3.3.1 (Page 3-503) is revised as follows:

Table 3.3.1 Summary of Aging Management Programs for Auxiliary Systems Evaluated in Chapter VII of the GALL-SLR Report Item Aging Effect/ Aging Management Further Number Component Mechanism Program Evaluation Discussion Recommended 3.3.1-263 Polymeric piping, piping Hardening or loss of AMP XI.M36, External No Consistent with NUREG-2191 components, ducting, strength due to polymeric Surfaces Monitoring of,except that the Structures ducting components, degradation; loss of Mechanical Components, or Monitoring Program (B2.1.33) is seals exposed to air, material due to peeling, AMP XI.M38, Inspection of used for managing plexiglass condensation, raw delamination, wear; Internal Surfaces in covers in the Auxiliary Building.

water, raw water cracking or blistering due Miscellaneous Piping and (potable), treated to exposure to ultraviolet Ducting Components water, waste water, light, ozone, radiation, or underground, concrete, chemical attack; flow soil blockage due to fouling

SLRA Section 3.5.2.1.1 (page 3-1263) is revised as follows:

3.5.2.1.1 Auxiliary Building Materials Polymeric

14

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, CLB Changes Impacting SLRA

SLRA Table 3.5.2-1 (page 3-1359) is revised as follows:

Table 3.5.2-1 Containments, Structures, and Component Supports - Auxiliary Building - Aging Management Evaluation

Component Intended Material Environment Aging Effect Aging Management NUREG-2191 NUREG-2192 Notes Type Function Program Item Table 1

Plexiglass DF Polymeric Air (External) Hardening or loss of Structures Monitoring VII.I.A-797a 3.3.1-263 E,4 Cover strength; loss of Program (B2.1.33) material; cracking or blistering

15

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, CLB Changes Impacting SLRA

SLRA Table 3.5.2-1, as amended by Duke Energy Letter dated November 11, 2021 (ADAMS Accession Number ML21315A012) and Duke Energy Letter dated December 15, 2021 (ADAMS Number ML21349A005), (page 3-1361) is revised as follows:

Table 3.5.2-1 Containments, Structures, and Component Supports - Auxiliary Building - Aging Management Evaluation Plant Specific Notes:

4. None In accordance with GALL-SLR Table IX.C, page IX C-6 flow blockage due to fouling need not be managed for polymeric materials exposed to air (external) and hardening need not be managed for rigid polymeric materials.

SLRA Appendix A2.33, as amended by Duke Energy Letter dated December 15, 2021 (ADAMS Accession Number ML21349A005) and Duke Energy Letter dated February 14, 2022 (ADAMS Accession Number ML22045A021), (page A-35) is revised as follows:

A2.33 Structures Monitoring Program Description Inspections also include seismic joint fillers, elastomeric materials, polymeric materials (plexiglass covers); and reinforcement of masonry walls, and periodic evaluation of groundwater chemistry and opportunistic inspections for the condition of below grade concrete.

Enhancements The Structures Monitoring AMP will be enhanced to:

2. Procedures will be revised to specify that structural components inspected include piping supports, line supports, structural bolting, anchor bolts and embedments, supports and bracings associated with masonry walls, pipe whip restraints and jet impingement shields, transmission towers, panels and other enclosures, racks, sliding surfaces, sump and pool liners, wear plates, electrical cable trays and conduits, tube tracks, electrical duct banks, manholes, louvers, aluminum components, liners, sump, drains/curbs, piles, unit vent, lead shield supports, doors, penetration seals, polymeric materials (plexiglass covers), and other elastomeric materials

SLRA Appendix A2.33, as amended by Duke Energy Letter dated December 15, 2021 (ADAMS Accession Number ML21349A005) and Duke Energy Letter dated February 14, 2022 (ADAMS Accession Number ML22045A021), (page A-38) is revised as follows:

A2.33 Structures Monitoring Enhancements The Structures Monitoring AMP will be enhanced to:

25. Expand the program to monitor polymeric materials for cracking or blistering, loss of material, and loss of strength. Establish acceptance criteria for polymeric material as no loss of material, cracking or blistering, and loss of strength that can lead to reduction or loss of function.

16

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, CLB Changes Impacting SLRA

SLRA Table A6.0-1, Commitment Column, Commitment Number 33, as amended by Duke Energy Letter December 15, 2021 (ADAMS Accession Number ML21349A005) and Duke Energy Letter dated February 14, 2022 (ADAMS Accession Number ML22045A021), (page A-98) is revised as follows:

2. Procedures will be revised to specify that structural components inspected include piping supports, line supports, structural bolting, anchor bolts and embedments, supports and bracings associated with masonry walls, pipe whip restraints and jet impingement shields, transmission towers, panels and other enclosures, racks, sliding surfaces, sump and pool liners, wear plates, electrical cable trays and conduits, tube tracks, electrical duct banks, manholes, louvers, aluminum components, liners, sump, drains/curbs, piles, unit vent, lead shield supports, doors, penetration seals, polymeric materials (plexiglass covers), and other elastomeric materials.

SLRA Table A6.0-1, Commitment Column, Commitment Number 33, as amended by Duke Energy Letter December 15, 2021 (ADAMS Accession Number ML21349A005) and Duke Energy Letter dated February 14, 2022 (ADAMS Accession Number ML22045A021), (page A-104) is revised as follows:

25. Expand the program to monitor polymeric materialsfor cracking or blistering, loss of material, and loss of strength. Establish acceptance criteria for polymeric material as no loss of material, cracking or blistering, and loss of strength that can lead to reduction or loss of function.

SLRA Appendix B2.1.33, as amended by Duke Energy Letter dated December 15, 2021 (ADAMS Accession Number ML21349A005) and Duke Energy Letter dated February 14, 2022 (ADAMS Accession Number ML22045A021), (pages B-222, B-223, and B-226) is revised as follows:

B2.1.33 STRUCTURES MONITORING Program Description Inspections also include seismic joint fillers, elastomeric materials; and fiber reinforced polymers and steel bracings associated with masonry walls. Polymeric materials (plexiglass covers) are inspected for cracking or blistering, loss of material and loss of strength.

Applicable components within the scope of this program include, but are not limited to: bolting, concrete anchors and embedments, concrete components, decking and siding, doors and door seals, ductbanks, external surfaces of bus enclosures (metallic ducting) and bus enclosure structural supports, expansion and seismic joints, foundations, hatches, hazard barriers, metal components such as louvers, miscellaneous steel, penetrations seals and sleeves, piles, pipe whip restraints and jet impingement shields, shielding, steel components, wear plates, steel liners, supports, panels, racks, cabinets, enclosures, cable trays, conduits, wire way gutters, plexiglass covers, and tubing track.

Applicable metallic materials within the scope of this program include: aluminum, carbon steel, ductile iron, galvanized steel, and stainless steel; applicable bolting materials include: carbon steel, galvanized steel, and stainless steel. Applicable non-metallic materials within the scope of this program include:

reinforced concrete, elastomer, polymeric materials, fiberglass reinforced polymer, grout, and Lubrite.

Applicable aging effects within the scope of this program include change in material properties/ loss of strength, cracking, blistering, hardening, loss of strength, loss of material, loss of mechanical function, loss of preload/ self-loosening, and loss of sealing.

17

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, CLB Changes Impacting SLRA

Enhancements

2. Procedures will be revised to specify that structural components inspected include piping supports, line supports, structural bolting, anchor bolts and embedments, supports and bracings associated with masonry walls, pipe whip restraints and jet impingement shields, transmission towers, panels and other enclosures, racks, sliding surfaces, sump and pool liners, wear plates, electrical cable trays and conduits, tube tracks, electrical duct banks, manholes, louvers, aluminum components, liners, sump, drains/curbs, piles, unit vent, lead shield supports, doors, penetration seals, polymeric materials (plexiglass covers) and other elastomeric materials. (Element 1)

25. Expand the program to monitor polymeric materials for cracking or blistering, loss of material, and loss of strength. Establish acceptance criteria for polymeric material as no loss of material, cracking or blistering, and loss of strength that can lead to reduction or loss of function. (Elements 3, 4 and 6)

18

ENCLOSURE 2

OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 SUBSEQUENT LICENSE RENEWAL APPLICATION SUPPLEMENT 4

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

Introduction This enclosure, Supplement 4, includes additional information and clarification of six topics that require an SLRA supplement to assist the NRC staff with their review of requests for information that were previously submitted. For each Supplement 4 topic, the change is described and the affected page number(s) and portion(s) of the SLRA is provided. For clarity, deletions are indicated by strikethrough and inserted text by underlined red font. Revisions to SLRA tables and SLRA Sections are shown by providing only excerpts from the affected SLRA tables and affected text provided in the SLRA sections.

SLRA SUPPLEMENT 4 TOPICS

Number Change Topic

1 Coatings for Reactor Building Cooling Units

2 Aging Effects Requiring Management for Aluminum Alloy 5052 Components

3 Fire Water System Aging Management Program

4 Materials and Environments for Closed Cycle Cooling Water Systems

5 Update to Aging Management Review of Internally Lined Steel Tanks in the Lube Oil System

6 Microwave House Structure Name Update to Site Assembly Siren Equipment House

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

Supplement 4 Change Number 1: Coatings for Reactor Building Cooling Units Affected SLRA Sections:

Sections 3.3.2.1.27, Appendix B2.1.27, Table 3.3.2-27 SLRA Page Numbers:

3-370, 3-371, 3-744, 3-745, 3-747, B-191 Description of Change:

Revised aging management review to include coatings as a material for the heads and tubes of the Reactor Building Cooling Units.

SLRA Update SLRA Section 3.3.2.1.27, (pages 3-370 and 3-371) is revised as follows:

3.3.2.1.27 Reactor Building Cooling and Ventilation Systems Materials

• Copper Alloy with Internal Coating/Lining

• Stainless Steel with Internal Coating/Lining Aging Effects Requiring Management

• Loss of Coating or Lining Integrity Aging Management Programs

• Internal Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, and Tanks (B2.1.27)

1

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Table 3.3.2-27, (page 3-744) is revised as follows:

Table 3.3.2-27 Auxiliary Systems - Reactor Building Cooling and Ventilation Systems - Aging Management Evaluation Component Intended Material Environment Aging Effect Aging Management NUREG-2191 NUREG-Notes Type Function Program Item 2192 Table 1 Cooling Coil Pressure Stainless Steel Air with Borated Water None None VII.J.AP-18 3.3.1-120 C (reactor building Boundary with Internal Leakage (External) cooling units) Head Coating/Lining Condensation Cracking One-Time Inspection VII.F1.A-781a 3.3.1- 094a A (External) (B2.1.20)

Loss of Material One-Time Inspection VII.F1.AP-99a 3.3.1- 094 A (B2.1.20)

Raw Water (Internal) Loss of Material, Flow Open-Cycle Cooling VII.C1.A-54 3.3.1- 040 D Blockage Water System (B2.1.11)

Loss of Coating or Internal VII.F3.A-416 3.3.1-138 B,2 Lining Integrity Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, and Tanks (B2.1.27)

Loss of Material Internal VII.F3.A-414 3.3.1-139 B,3 Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, and Tanks (B2.1.27)

2

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Table 3.3.2-27,(page 3-745) is revised as follows:

Table 3.3.2-27 Auxiliary Systems - Reactor Building Cooling and Ventilation Systems - Aging Management Evaluation

Component Intended Material Environment Aging Effect Aging Management NUREG-2191 NUREG-Notes Type Function Program Item 2192 Table 1

Cooling Coil Heat Transfer Copper Alloy with Condensation Reduction of Heat Inspection of Internal VII.C1.A-419 3.3.1- 096a A (reactor Internal (External) Transfer Surfaces in building Coating/Lining Miscellaneous Piping cooling units) and Ducting Tubes Components (B2.1.24)

Raw Water (Internal) Reduction of Heat Open-Cycle Cooling VII.C1.AP-187 3.3.1- 042 B Transfer Water System (B2.1.11)

Pressure Copper Alloy with Condensation None None VII.J.AP-144 3.3.1-114 C Boundary Internal (External)

Coating/Lining Raw Water (Internal) Loss of Material, Flow Open-Cycle Cooling VII.C1.AP-179 3.3.1- 038 B Blockage Water System (B2.1.11)

Loss of Coating or Internal VII.F3.A-416 3.3.1-138 B,2 Lining Integrity Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, and Tanks (B2.1.27)

Loss of Material Internal VII.F3.A-414 3.3.1-139 B Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, and Tanks (B2.1.27)

3

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Table 3.3.2-27, (page 3-747) is revised as follows:

Table 3.3.2-27 Auxiliary Systems - Reactor Building Cooling and Ventilation Systems - Aging Management Evaluation Plant Specific Notes:

2. The header and the first few inches of the tube internal surfaces are coated with Plastocor. Loss of material and cracking (i.e., for cementitious coatings) are not aging effects requiring management.

3. NUREG-2191 item cites loss of material due to general, pitting, crevice corrosion and MIC for any material with an internal coating/lining. Loss of material due to general corrosion is not applicable aging effect for stainless steel with internal coating/lining.

SLRA Section B2.1.27, (page B-191) is revised as follows:

B2.1.27 INTERNAL COATINGS/LININGS FOR IN-SCOPE PIPING, PIPING COMPONENTS, HEAT EXCHANGERS, AND TANKS Program Description The Internal Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, and Tanks AMP is a new condition monitoring program that includes visual inspections of internal coatings/linings of ductile iron, stainless steel, copper alloy and carbon steel piping, piping components, tanks, heat exchangers exposed to raw water, treated water, treated borated water, or lubricating oil.

4

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

Supplement 4 Change Number 2: Aging Effects Requiring Management for Aluminum Alloy 5052 Components Affected SLRA Sections:

Section 3.3.2.2.8, Tables 3.3.1, 3.3.2-12, 3.3.2-13 SLRA Page Numbers:

3-446, 3-495, 3-588, 3-608 Description of Change:

Removed cracking as an aging effect for components constructed of 5052 aluminum in an air-indoor uncontrolled environment.

SLRA Update SLRA Section 3.3.2.2.8, (page 3-446) is revised as follows:

3.3.2.2.8 Cracking Due to Stress Corrosion Cracking in Aluminum Alloys

[3.3.1-233] - The boric acid mixing tanks in the chemical addition system, and the concentrated boric acid tanks in the coolant storage system are constructed of 5052 alloy.. and considered to be potentiallyThese 5xxx series alloys contain less than 3.5% magnesium and are not susceptible to stress corrosion cracking. These tanks are exposed to a halide free air-indoor uncontrolled external environment in the auxiliary building, and a treated borated water internal environment. Both the boric acid mixing tanks and the concentrated boric acid tanks are insulated, and are heat traced such that condensation is not a concern. An OE review does not reflect that external surfaces of these tanks have been exposed to secondary sources of halides. Therefore, cracking due to SCC of insulated aluminum piping, piping components, and tanks exposed to air, condensation is not a concern for ONS. The One-Time Inspection program (B2.1.20) will be implemented to confirm that cracking due to stress corrosion cracking is not occurring on surfaces of aluminum tanks exposed to an air-indoor uncontrolled environment.

5

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Table 3.3.1, Item Number 3.3.1-233, (page 3-495) is revised as follows:

Table 3.3.1 Summary of Aging Management Programs for Auxiliary Systems Evaluated in Chapter VII of the GALL-SLR Report Item Aging Aging Management Further Number Component Effect/Mechanism Program Evaluation Discussion Recommended 3.3.1-233 Insulated aluminum piping, Cracking due to AMP XI.M29, Outdoor and Yes (SRP-SLR Consistent with NUREG-2191. The One-piping components, tanks stress Large Atmospheric Metallic Section 3.3.2.2.8) Time Inspection program (B2.1.20) will be exposed to air, condensation corrosion Storage Tanks, AMP implemented to confirm that the aging cracking XI.M32, One-Time effect is not occurring on insulated Inspection, AMP XI.M36, surfaces, or is occurring so slowly that it External Surfaces Monitoring will not affect the intended function of the of Mechanical Components, components during the SPEO. Not or AMP XI.M42, Internal applicable. The only components that Coatings/ Linings for In-align to this item are formed from a grade Scope Piping, Piping of aluminum that is not susceptible to Components, Heat cracking due to SCC. See further Exchangers, and Tanks evaluation in Section 3.3.2.2.8.

6

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Table 3.3.2-12, page (3-588) is revised as follows:

Table 3.3.2-12 Auxiliary Systems - Chemical Addition System - Aging Management Evaluation Component Intended Material Environment Aging Effect Aging Management NUREG-2191 NUREG-Notes Type Function Program Item 2192 Table 1 Tank (boric acid Structural Aluminum Air - Indoor Cracking One-Time Inspection VII.I.A-762b 3.3.1-233 A mixing) Integrity Uncontrolled (External) None (B2.1.20) I, 2 None

Loss of Material One-Time Inspection VII.I.A-774b 3.3.1-245 A (B2.1.20)

SLRA Table 3.3.2-13, page (3-608) is revised as follows:

Table 3.3.2-13 Auxiliary Systems - Coolant Storage System - Aging Management Evaluation Component Intended Material Environment Aging Effect Aging Management NUREG-2191 NUREG-Notes Type Function Program Item 2192 Table 1 Tank (concentrated Structural Aluminum Air - Indoor Cracking One-Time Inspection VII.I.A-762b 3.3.1-233 A boric acid) Integrity Uncontrolled (External) None (B2.1.20) I, 1 None

7

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

Supplement 4 Change Number 3: Fire Water System Aging Management Program Affected SLRA Sections:

Appendix A2.16, Appendix B2.16 SLRA Page Numbers:

A-17, B-123 Description of Change:

Removed cracking as an aging effect and made editorial changes to correct typographical errors.

SLRA Update SLRA Appendix A2.16, (page A-17) is revised as follows:

A2.16 Fire Water System Program Description The Fire Water System AMP is an existing condition monitoring program that manages the aging effects such as of loss of material, cracking, and flow blockage associated with water-based fire protection system components.

SLRA Appendix B2.1.16, (page B-123) is revised as follows:

B2.1.16 FIRE WATER SYSTEM Program Description The Fire Water System AMP is an existing condition monitoring program that manages loss of material and flow blockage for water-based fire protection systems that consist of sprinklers, nozzles, valve bodies, fire pump casings, hydrants, hose stations, standpipes, aboveground and underground piping and piping components, strainers, and the elevated water storage tank. The program also manages loss of coating integrity of the internal coating of the elevated water storage tank. This program relies on flow testing, visual inspections, and volumetric examination to ensure that loss of material due to due to general, pitting and crevice corrosion, or microbiologically influenced corrosion (MIC), or fouling, and flow blockage due to fouling is adequately managed.

8

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

Supplement 4 Change Number 4: Materials and Environments for Closed Cycle Cooling Water Systems Recirculating Cooling Water System:

Affected SLRA Sections: Section 3.3.2.1.21, Table 3.3.2-21, SLRA Page Numbers: 3-358, 3-359, 3-682, 3-690, 3-691 Description of Change:

Added copper alloy to the evaluation of materials for valve body components. Added elastomer to the evaluation of materials for expansion joint components. Updated listing of aging effects requiring management to reflect the additional materials. Updated listing of aging management programs to reflect the additional materials.

SLRA Update SLRA Section 3.3.2.1.21 (pages 3-358 and 3-359) is revised as follows:

3.3.2.1.21 Recirculating Cooling Water System Materials

• Copper Alloy

• Elastomer Aging Effects Requiring Management

• Hardening or Loss of Strength Aging Management Programs

• Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components (B2.1.24)

9

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

Revise SLRA Table 3.3.2-21 (page 3-682) is revised as follows:

Table 3.3.2-21 Auxiliary Systems - Recirculating Cooling Water System - Aging Management Evaluation

Intended Aging Management NUREG-2191 NUREG-Component Type Function Material Environment Aging Effect Program Item 2192 Notes Table 1 Hardening or Loss External Surfaces Monitoring of Strength of Mechanical Components VII.I.AP-102 3.3.1-076 A Air - Indoor (B2.1.23)

Pressure Uncontrolled (External) External Surfaces Monitoring Expansion Joint Boundary Elastomer Loss of Material of Mechanical Components VII.I.AP-113 3.3.1-082 A (B2.1.23)

Inspection of Internal Surfaces Closed-Cycle Cooling Hardening or Loss in Miscellaneous Piping and VII.C2.AP-259 3.3.1-085 A Water (Internal) of Strength Ducting Components (B2.1.24)

Revise SLRA Table 3.3.2-21 (page 3-690) is revised as follows:

Table 3.3.2-21 Auxiliary Systems - Recirculating Cooling Water System - Aging Management Evaluation Intended Aging Management NUREG-2191 NUREG-Component Type Function Material Environment Aging Effect Program Item 2192 Notes Table 1

Air - Indoor None None VII.J.AP-144 3.3.1-114 A Uncontrolled (External)

Valve Body Pressure Copper Alloy Closed-Cycle Cooling Loss of Material Closed Treated Water VII.C2.AP-199 3.3.1- 046 A Boundary Water (Internal) System (B2.1.12)

Air with Borated Water None None VII.J.AP-11 3.3.1-115 A Leakage (External)

10

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

Revise SLRA Table 3.3.2-21 (page 3-691) is revised as follows:

Table 3.3.2-21 Auxiliary Systems - Recirculating Cooling Water System - Aging Management Evaluation Intended Aging Management NUREG-2191 NUREG-Component Type Function Material Environment Aging Effect Program Item 2192 Notes Table 1

Air - Indoor None None VII.J.AP-144 3.3.1-114 A Structural Uncontrolled (External)

Valve Body Integrity Copper Alloy Closed-Cycle Cooling Loss of Material Closed Treated Water VII.C2.AP-199 3.3.1- 046 A Water (Internal) System (B2.1.12)

11

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

Chilled Water (Vital Loads) System:

Affected SLRA Sections: Section 3.3.2.1.23, Section 3.3.2.2.4, Table 3.3.1, Table 3.3.2-23 SLRA Page Numbers: Page 3-362, Page 3-438, Page 3-481, Pages 3-709, 3-710, 3-711 Description of Change:

Added copper alloy (>15% Zn), nickel alloy, and PVC to the materials of construction of the Chilled Water (Vital Loads) System. Added nickel alloy to the evaluation of materials for piping and piping components in the further evaluation discussion. Added copper alloy (>15% Zn), gray cast iron, nickel alloy, and PVC to the evaluation of valve body components and resultant plant-specific notes.

SLRA Update SLRA Section 3.3.2.1.23 (page 3-362) is revised as follows:

3.3.2.1.23 Chilled Water (Vital Loads) System Materials

• Copper Alloy (>15% Zn)

• Nickel Alloy

• PVC

SLRA Section 3.3.2.2.4 (page 3-438) is revised as follows:

3.3.2.2.4 Loss of Material Due to Pitting and Crevice Corrosion in Stainless Steel and Nickel Alloys Evaluation:

[3.3.1-232] - The One-Time Inspection program (B2.1.20) will be implemented to confirm that pitting and crevice corrosion of insulated stainless steel and nickel alloy piping and piping components exposed to air or condensation environments is not occurring.

12

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Table 3.3.1 (page 3-481) is revised as follows:

Table 3.3.1 Summary of Aging Management Programs for Auxiliary Systems Evaluated in Chapter VII of the GALL-SLR Report

Item Component Aging Effect/ Aging Management Program Further Evaluation Discussion Number Mechanism Recommended

3.3.1-147 Nickel alloy, nickel alloy Loss of material due AMP XIM21A, Closed No Not applicable. ONS has no nickel alloy, cladding piping, piping to pitting, crevice Treated Water Systems nickel alloy cladding piping, piping components exposed to corrosion, MIC components exposed to closed-cycle closed-cycle cooling water cooling water in the scope of SLR in auxiliary systems. The associated NUREG-2191 aging items are not used.

Consistent with NUREG-2191.

SLRA Table 3.3.2-23 (page 3-709) is revised as follows:

Table 3.3.2-23 Auxiliary Systems - Chilled Water (Vital Loads) System - Aging Management Evaluation

Component Type Intended Material Environment Aging Effect Aging Management NUREG-2191 NUREG-Notes Function Program Item 2192 Table 1 Valve Body Pressure Copper Alloy Condensation Cracking External Surfaces VII.I.A-405a 3.3.1-132 A Boundary (>15% Zn) (External) Monitoring of Mechanical Components (B2.1.23)

Closed-Cycle Cooling Cracking Closed Treated Water VII.C2.A-473a 3.3.1-160 A Water (Internal) System (B2.1.12)

Loss of Material Closed Treated Water VII.C2.AP-199 3.3.1- 046 A, 4 System (B2.1.12)

Selective Leaching VII.C2.AP-43 3.3.1- 072 B (B2.1.21)

13

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Table 3.3.2-23 (page 3-709) is revised as follows:

Table 3.3.2-23 Auxiliary Systems - Chilled Water (Vital Loads) System - Aging Management Evaluation Component Type Intended Material Environment Aging Effect Aging Management NUREG-2191 NUREG-Notes Function Program Item 2192 Table 1 Valve Body Pressure Gray Cast Iron Condensation Loss of Material External Surfaces VII.I.A-405a 3.3.1-132 A Boundary (External) Monitoring of Mechanical Components (B2.1.23)

Air with Borated Water Loss of Material Boric Acid Corrosion VII.I.A-79 3.3.1- 009 A Leakage (External) (B2.1.4)

Closed-Cycle Cooling Loss of Material Closed Treated Water VII.C2.AP-202 3.3.1- 045 A Water (Internal) System (B2.1.12)

Selective Leaching VII.C2.A-50 3.3.1- 072 B (B2.1.21)

14

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Table 3.3.2-23 (page 3-709) is revised as follows:

Table 3.3.2-23 Auxiliary Systems - Chilled Water (Vital Loads) System - Aging Management Evaluation Component Type Intended Material Environment Aging Effect Aging Management NUREG-2191 NUREG-Notes Function Program Item 2192 Table 1 Valve Body Pressure Nickel Alloy Air with Borated Water None None VII.J.AP-260 3.3.1-119 A, 5 Boundary Leakage (External)

Closed-Cycle Cooling Loss of Material Closed Treated Water VII.C2.A-471 3.3.1-147 A, 5 Water (Internal) System (B2.1.12)

Condensation Loss of Material One-Time Inspection VII.I.A-761b 3.3.1-232 A, 5 (External) (B2.1.20)

SLRA Table 3.3.2-23 (page 3-709) is revised as follows:

Table 3.3.2-23 Auxiliary Systems - Chilled Water (Vital Loads) System - Aging Management Evaluation Component Type Intended Material Environment Aging Effect Aging Management NUREG-2191 NUREG-Notes Function Program Item 2192 Table 1 Valve Body Pressure PVC Condensation None None VII.J.AP-269 3.3.1-119 A Boundary (External)

Closed-Cycle Cooling None None None None G, 6 Water (Internal)

15

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Table 3.3.2-23 (page 3-710) is revised as follows:

Table 3.3.2-23 Auxiliary Systems - Chilled Water (Vital Loads) System - Aging Management Evaluation Component Type Intended Material Environment Aging Effect Aging Management NUREG-2191 NUREG-Notes Function Program Item 2192 Table 1 Valve Body Structural Copper Alloy Condensation Cracking External Surfaces VII.I.A-405a 3.3.1-132 A Integrity (>15% Zn) (External) Monitoring of Mechanical Components (B2.1.23)

Closed-Cycle Cooling Cracking Closed Treated Water VII.C2.A-473a 3.3.1-160 A Water (Internal) System (B2.1.12)

Loss of Material Closed Treated Water VII.C2.AP-199 3.3.1- 046 A, 4 System (B2.1.12)

Selective Leaching VII.C2.AP-43 3.3.1- 072 B (B2.1.21)

SLRA Table 3.3.2-23 (page 3-711) is revised as follows:

Table 3.3.2-23 Auxiliary Systems - Chilled Water (Vital Loads) System - Aging Management Evaluation Plant Specific Notes:

4. Components constructed of Copper Alloy and Copper Alloy >15%Zn share common aging effects. For Copper Alloy >15% Zn components, these common aging effects are managed by aligning to a GALL SLR item for Copper Alloy as a direct match. Unique aging effects applicable only to components constructed of Copper Alloy >15%Zn, are managed by aligning to a GALL SLR line item specific to Copper Alloy >15%Zn.

5. Subject component is a nickel alloy plated brass valve body.

6. PVC piping components in a closed-cycle cooling water environment are not evaluated in NUREG-2191. A Note G is used. The aging effects/mechanisms are evaluated based on the NUREG-2191 raw water (potable) environment (item VII.J.AP-269). For Oconee these environments are equivalent since the Plant Drinking Water System is the makeup source for the Chilled Water (Vital Loads) System.

16

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

Alternate Chilled Water System:

Affected SLRA Sections:

Table 3.3.2-18 SLRA Page Numbers:

Page 3-659 Description of Change:

Added missing environments for copper alloy valve body components.

SLRA Update:

Revise SLRA Table 3.3.2-18 (page 3-659) is revised as follows:

Table 3.3.2-18 Auxiliary Systems - Alternate Chilled Water System - Aging Management Evaluation

Component Type Intended Material Environment Aging Effect Aging Management NUREG-2191 NUREG-Notes Function Program Item 2192 Table 1 Valve Body Pressure Copper Alloy Air - Indoor None None VII.J.AP-144 3.3.1-114 A Boundary Uncontrolled (External)

Air - Outdoor None None VII.J.AP-144 3.3.1-114 A (External)

Air with Borated Water None None VII.J.AP-11 3.3.1-115 A Leakage (External)

Closed-Cycle Cooling Loss of Material Closed Treated Water VII.C2.AP-199 3.3.1-046 A Water (Internal) System (B2.1.12)

17

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

Sample Cooling Water System:

Affected SLRA Sections:

Table 3.3.2-22 SLRA Page Numbers:

Page 3-696 Description of Change:

Added external environment for copper alloy (>15% Zn) valve body components.

SLRA Update Revise SLRA Table 3.3.2-22 (page 3-696) is revised as follows:

Table 3.3.2-22 Auxiliary Systems - Sample Cooling Water System - Aging Management Evaluation Component Type Intended Material Environment Aging Effect Aging Management NUREG-2191 NUREG-Notes Function Program Item 2192 Table 1 Valve Body Structural Copper Alloy Air - Indoor Cracking External Surfaces VII.I.A-405a 3.3.1-132 A Integrity (>15% Zn) Uncontrolled (External) Monitoring of Mechanical Components (B2.1.23)

18

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

Supplement 4 Change Number 5: Update to Aging Management Review of Internally Lined Steel Tanks in the Lube Oil System Affected SLRA Section:

Tables 3.3.1 and Section 3.3.2-30 SLRA Page Numbers:

3-479, 3-806, 3-807 Description of Change:

For internally lined steel tanks in the Lube Oil System, the same aging management program that manages loss of coating or lining integrity is also credited for managing loss of material in SLRA Table 3.3.2-30. Table 3.3.1 item 3.3.1-139 discussion is updated for the change to SLRA Table 3.3.2-30.

19

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Update SLRA Table 3.3.1, as amended by Duke Letter dated October 22, 2021, ADAMS Accession Number ML21295A035, (page 3-479) is revised as follows:

Table 3.3.1 Summary of Aging Management Programs for Auxiliary Systems Evaluated in Chapter VII of the GALL-SLR Report Item Component Aging Effect / Aging Management Further Discussion Number Mechanism Program Evaluation Recommended 3.3.1-139 Any material piping, piping Loss of material due AMP XI. M42, Internal No Consistent with NUREG-2191 with components, heat to general, pitting, Coatings/Linings for In-Scope exceptions, and a different program is exchangers, tanks with crevice corrosion, Piping, Piping Components, credited for some components. Aging internal coatings/linings MIC Heat Exchangers, and Tanks effects for the Elevated Water Storage exposed to closed-cycle Tank are managed by the Fire Water cooling water, raw water, System (B2.1.16) program. Aging effects raw water (potable), treated for components in the Plant Drinking water, treated borated Water System, and Ventilation Systems water, fuel oil, lubricating oil, and Lube Oil System are managed by waste water. air-dry, air, the Inspection of Internal Surfaces of condensation Miscellaneous Piping and Ducting Components (B2.1.24) program.

Aging effects for components in the Condensate System are managed by the Open-Cycle Cooling Water System (B2.1.11).

Exceptions apply to the NUREG-2191 recommendations for the Internal Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, and Tanks (B2.1.27) program implementation.

20

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Table 3.3.2-30, (page 3-806) is revised as follows:

Table 3.3.2-30 Auxiliary Systems - Lube Oil System - Aging Management Evaluation Component Intended Material Environment Aging Effect Aging Management NUREG-2191 NUREG-Notes Type Function Program Item 2192 Table 1 Tank (emergency Pressure Steel with Lubricating Oil Loss of Coating or Internal VII.G.A-416 3.3.1-138 D feedwater pump Boundary Internal (Internal) Lining Integrity Coatings/Linings for In-turbine oil) Coating/Lining Scope Piping, Piping Components, Heat Exchangers, and Tanks (B2.1.27)

Loss of Material Lubricating Oil Analysis VII.E1.AP-127 3.3.1- 097 C,3 (B2.1.25)

Internal VII.G.A-414 3.3.1-139 D Coatings/Linings for In-Scope Piping, Piping Components, Heat Exchangers, and Tanks (B2.1.27)

Tank (feedwater Structural Steel with Air - Indoor Loss of Material External Surfaces VII.I.A-77 3.3.1- 078 A pump turbine oil) Integrity Internal Uncontrolled (External) Monitoring of Coating/Lining Mechanical Components (B2.1.23)

Lubricating Oil Loss of Coating or Inspection of Internal VII.G.A-416 3.3.1-138 E (Internal) Lining Integrity Surfaces in Miscellaneous Piping and Ducting Components (B2.1.24)

Loss of Material Lubricating Oil Analysis VII.E1.AP-127 3.3.1- 097 C (B2.1.25)

Inspection of Internal VII.G.A-414 3.3.1-139 E Surfaces in Miscellaneous Piping and Ducting Components (B2.1.24)

21

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Table 3.3.2-30, (page 3-807) is revised as follows:

Table 3.3.2-30 Auxiliary Systems - Lube Oil System - Aging Management Evaluation Component Intended Material Environment Aging Effect Aging Management NUREG-2191 NUREG-Notes Type Function Program Item 2192 Table 1 Tank (main turbine Structural Steel with Lubricating Oil Loss of Material Lubricating Oil Analysis VII.E1.AP-127 3.3.1- 097 C oil) Integrity Internal (Internal) (B2.1.25)

Coating/Lining Inspection of Internal VII.G.A-414 3.3.1-139 E Surfaces in Miscellaneous Piping and Ducting Components (B2.1.24)

22

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4 Supplement 4 Change Number 6: Microwave House Structure Name Update to Site Assembly Siren Equipment House Affected SLRA Sections:

Table of Contents, Tables 2.2-2, 2.3.3.1-4, Section 2.4.7.11, Table 2.4.7-11, Sections 2.4.7.12, 2.4.7.15, 2.4.8.2, Table 3.3.2-4, Sections 3.5.2, 3.5.2.1.17, Table 3.5.2-17, Appendix A2.33, Table A6.0-1, Appendix B2.1.33 SLRA Page Numbers:

vi, xi, xvii, xxii, 2-45, 2-90, 2-327, 2-328, 2-329, 2-334, 2-340, 3-529, 3-1262, 3-1293, 3-1294, 3-1429, 3-1430, 3-1431, 3-1432, A-35, A-98, B-223 Description of Change:

The microwave tower at Oconee was demolished under a site engineering change. As part of the engineering change, the name of the equipment house that remains at the base of the tower was changed from the Microwave Tower to the Site Assembly Siren Equipment House and the Site Assembly Siren & Pole was erected at the microwave tower location. In addition, the name of the air tank (0IA-TK0002) located inside the Site Assembly Siren Equipment House changed from Tank (evacuation air horn instrument air) to Tank (elevated water storage tank instrument air). This supplement addresses these name changes in the SLRA.

This supplement also provides an editorial correction to the scoping determination statement in SLRA Section 2.4.7.12 (under System Intended Functions) to cite manholes instead of the microwave house structure as within the scope of SLR.

SLRA Update SLRA Table of Contents Section 2.4.7.11, (page vi) is revised as follows:

2.4.7.11 Site Assembly Siren Equipment House Microwave House Structure 2-327

SLRA Table of Contents Section 3.5.2.1.17, (page xi) is revised as follows:

3.5.2.1.17 Site Assembly Siren Equipment House Microwave House Structure 3-1293

SLRA Table of Contents Table 2.4.7-11, (page xvii) is revised as follows:

Table 2.4.7-11 Site Assembly Siren Equipment House Microwave House Structure 2-328

SLRA Table of Contents Table 3.5.2-17, (page xxii) is revised as follows:

Table 3.5.2-17 Containments, Structures, and Component Supports - Site Assembly Siren Equipment House Microwave House Structure - Aging Management Evaluation 3-1429

23 Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Table 2.2-2, (page 2-45) is revised as follows:

Table 2.2-2 Plant Level Scoping Results for Structures In-Scope for System, Structure, or Commodity Group License Reference Renewal

Site Assembly Siren & Pole NO Not Applicable Microwave and Meteorological Tower Site Assembly Siren Equipment House YES Section 2.4.7.11 Microwave House Structure

SLRA Table 2.3.3.1-4, (page 2-90) is revised as follows:

Table 2.3.3.1-4 Instrument Air System Component/Commodity Group Intended Functions

Tank (evacuation air horn instrument air) (Elevated Water Pressure Boundary Storage Tank Instrument Air)

SLRA Section 2.4.7.11, (page 2-327 and 2-328) is revised as follows:

2.4.7.11 Site Assembly Siren Equipment House Microwave House Structure

System Description

The Oconee Site Assembly Siren Equipment House microwave house structure is a small (16' X 10') building located approximately 100 yards northwest of the elevated water storage tank., at the base of the microwave tower superstructure and situated inside the microwave tower footings. The Site Assembly Siren Equipment House microwave house structure consists of aluminum sheet metal walls over a tube steel frame, supported by a concrete foundation. The roof has steel deck, covered with built up roofing. A single steel door provides access to the building.

System Intended Functions Portions of the Site Assembly Siren Equipment House microwave house structure are relied upon for compliance with regulations for fire protection (10 CFR 50.48). Therefore, the Site Assembly Siren Equipment House microwave house structure is within the scope of SLR in accordance with the criteria of 10 CFR 54.4(a)(3).

UFSAR References Additional details for the Site Assembly Siren Equipment House microwave house structure can be found in UFSAR Sections 2.3.3. 3.2, and 3.8.5.

System Evaluation Boundaries The evaluation boundary for the Site Assembly Siren Equipment House microwave house structure includes the foundation, external walls, and roof. There are no internal walls in the building. The evaluation boundary does not include the microwave tower, tower footings, tower bolting, etc. Building insulation and heating ventilation and air conditioning are considered to perform no intended function. Equipment pads/ supports, 24 Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

piping supports, instrument supports, cable tray and conduit supports, and electrical enclosures are addressed as bulk commodities in Section 2.4.8.

Subsequent License Renewal Boundary Drawing The SLR boundary drawing for the Site Assembly Siren Equipment House microwave house structure is listed below:

Components Subject to Aging Management Review The component types subject to AMR are indicated in Table 2.4.7-11, Site Assembly Siren Equipment House Microwave House Structure.

SLRA Table 2.4.7-11, (pages 2-328 and 2-329) title of table is revised as follows:

Table 2.4.7-11 Site Assembly Siren Equipment House Microwave House Structure

SLRA Section 2.4.7-11, (page 2-329 after Table 2.4.7-11) is revised as follows:

The AMR results for these component types are indicated in Table 3.5.2-17, Containments, Structures, and Component Supports - Site Assembly Siren Equipment House Microwave House Structure - Aging Management Evaluation.

SLRA Section 2.4.7.12, (page 2-329) is revised as follows:

2.4.7.12 Manholes

System Description

The yard contains manholes that perform an intended function and are in the scope of SLR. Manhole 7 is a new manhole, installed by the protected service water project, on the electrical path from the protected service water building to the Unit 3 auxiliary building. Manhole CMH-S1 is situated at the 100 kV switchyard before the cables from CT-5 go into the trench towards the auxiliary building. Manholes MCH-C3, CMH-C4, CMH-C5 and CMH-C6 are on the electrical path from the administration building to the Site Assembly Siren Equipment House microwave house. The cable routed through these manholes powers the air compressor for the elevated water storage tank level transmitter.

System Intended Functions Portions of the manholes are relied upon for compliance with regulations for fire protection (10 CFR 50.48) and SBO (10 CFR 50.63). Therefore, the Manholes microwave house structure is are within the scope of SLR in accordance with the criteria of 10 CFR 54.4(a)(3).

25 Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Section 2.4.7.15, (page 2-334) is revised as follows:

2.4.7.15 Administration Building

System Description

The administration building is located on the north side of the site adjacent to the security building. The administration building supports the electrical panel that provides electrical power to the air compressor for the elevated water storage tank level transmitter located in the Site Assembly Siren Equipment House microwave house, which serves a fire protection intended function. The administration building provides structural support for the electrical panel located on a masonry block wall, supported by a concrete foundation.

SLRA Section 2.4.8.2, (page 2-340) is revised as follows:

2.4.8.2 Miscellaneous Structural Commodities

System Description

The concrete elements consist of the foundations for the borated water storage tank superstructure, elevated water storage tank, Site Assembly Siren Equipment House microwave building, transformer pads for the Keowee main step-up transformer and ONS CT1, CT2 and CT3 transformers, the Unit 3 6.9 kV switchgear and condenser circulating water valve pits (yard foundations, valve pits, and transformer equipment pads).

SLRA Section 3.5.2, (page 3-1262) is revised as follows:

3.5.2 RESULTS Table 3.5.2-17, Containments, Structures, and Component Supports - Site Assembly Siren Equipment House Microwave House Structure - Aging Management Evaluation

26 Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Table 3.3.2-4, (page 3-529) is revised as follows:

Table 3.3.2-4 Auxiliary Systems - Instrument Air System - Aging Management Evaluation Component Intended Material Environment Aging Effect Aging Management NUREG-2191 NUREG-Notes Type Function Program Item 2192 Table 1 Tank (evacuation air Pressure Steel Air - Indoor Loss of Material External Surfaces VII.I.A-77 3.3.1- 078 A horn instrument air) Boundary Uncontrolled (External) Monitoring of Mechanical (Elevated Water Components (B2.1.23)

Storage Tank Instrument Air) Condensation (Internal) Loss of Material Inspection of Internal VII.D.A-26 3.3.1- 055 A Surfaces in Miscellaneous Piping and Ducting Components (B2.1.24)

27

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Section 3.5.2.1.17, (page 3-1293 and 3-1294) is revised as follows:

3.5.2.1.17 Site Assembly Siren Equipment House Microwave House Structure Materials Components in the Site Assembly Siren Equipment House Microwave House Structure are constructed of the following materials:

Environments Components in the Site Assembly Siren Equipment House Microwave House Structure are exposed to the following environments:

Aging Effects Requiring Management Components in the Site Assembly Siren Equipment House Microwave House Structure require aging management to address the following aging effects:

Aging Management Programs The aging effects for components in the Site Assembly Siren Equipment House Microwave House Structure are managed by the following AMPs:

SLRA Table 3.5.2-17, (pages 3-1429 through 3-1432), the table title is revised as follows:

Table 3.5.2-17 Containments, Structures, and Component Supports - Site Assembly Siren Equipment House Microwave House Structure - Aging Management Evaluation

SLRA Section A2.33,( page A-35) is revised as follows:

A2.33 Structures Monitoring Enhancements The Structures Monitoring AMP will be enhanced to:

1. Add the following structures to the scope of the program:

a. Site Assembly Siren Equipment House Microwave House Structure

28 Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Table A6.0-1, as amended by Duke Letter dated December 15, 2021, ADAMS Accession Number ML21349A005, (page A-98) is revised as follows:

Table A6.0-1: Subsequent License Renewal Commitments

1. Program Commitment AMP Implementation

33 Structures Monitoring The Structures Monitoring AMP is an existing program that will be B2.1.33 Program enhancements for program enhanced to: SLR will be implemented no

1. Add the following structures to the scope of the program: later than 6 months prior to a) Microwave House Structure the SPEO.

a) Site Assembly Siren Equipment House b) Technical Support Building Cable Vault c) 100 kV Structure d) Protected Service Water Building e) Protected Service Water Duct Banks f) Borated Water Storage Tank Superstructure g) HP Office Building h) Administration Building i) Keowee Breaker Vault

29

Oconee Nuclear Station, Units 1, 2, and 3 Subsequent License Renewal Application, SLRA Supplement 4

SLRA Section B2.1.33, as amended by Duke Letter dated December 15, 2021, ADAMS Accession Number ML21349A005 (page B-223) is revised as follows:

B2.1.33 STRUCTURES MONITORING Enhancements The following enhancements will be implemented in the following program elements: Scope of Program (Element 1), Preventive Actions (Element 2), Parameters Monitored/Inspected (Element 3), Detection of Aging Effects (Element 4), Monitor and Trending (Element 5), and Acceptance Criteria (Element 6).

1. Add the following structures to the scope of the program (Element 1):

a) Microwave house structure a) Site Assembly Siren Equipment House b) Technical Support Building cable vault c) 100kv Structure d) Protected Service Water Building e) Protected Service Water Duct Banks f) Borated Water Storage Tank Superstructure g) Health Physics Office Building h) Administration Building i) Keowee Breaker Vault

30