Text

20250327-Hatch-Pre-Application - Updated
	ML25100A081
Person / Time
Site:	Hatch
Issue date:	03/27/2025
From:	; Southern Nuclear Operating Co
To:	Harris B;
Shared Package
ML25100A079	List: ML25100A080; ML25100A081;
References
	Download: ML25100A081 (1)
	v • d • e

Pre-Application Meeting #2 March 27, 2025 Hatch Nuclear Plant Subsequent License Renewal

Hatch SLR Project Team

Hatch SLRA Project Update

Topic of Interest Buried and Underground Piping and Tanks

Questions Agenda Application information is considered preliminary and subject to change

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Hatch SLR Project Team

SNC Team:

Brad Deen - Engineering Manager Brad Creek - Electrical Lead Adam Wilcher - Civil Lead Michael Todd - Mechanical Lead Amy Aughtman - Licensing & Environmental Manager DeLisa Pournaras - Safety Licensing Lead

Supplemental Team:

ENERCON - Jeff Head, Safety Lead Steve Franzone - Consulting Engineer

Vendors

ENERCON, General Electric, Transware, Structural Integrity 3

4 Hatch Background

Located near Baxley, GA, Hatch is jointly owned by Georgia Power, Oglethorpe Power Corporation, Municipal Electrical Authority of Georgia, and Dalton Utilities, and operated by SNC, the licensee and applicant

The Hatch site is approximately 2,244 acres, located in Appling and Toombs County, GA

Unit 1 and Unit 2 are General Electric Type 4 BWRs

Hatch Background

Original license renewal application approved in 2002

- Current license expiration dates: 8/6/2034 Unit 1, 6/13/2038 Unit 2

- Based on pre-GALL

- IP 71003 Phase IV completed May 2023

- Entered PEO in 2014 (U1) and 2018 (U2)

- Latest NEI 14-12 AMP effectiveness review completed first quarter 2023

Core Power History

- 2436 MWt, Initial

- 2558 MWt, Power Uprate (1994)

- 2763 MWt, EPU Power Uprate (1998)

- 2804 MWt, MUR Power Uprate (2003)

Unit 1 and Unit 2 are on a 24-month refueling cycle 5

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General Topics

Submittal Schedule Second Quarter of 2025 - on track

ePortal Folder Structure Use Enercon Certrec ePortal for general SLRA documents Use SNC Certrec ePortal for designated Proprietary Documents

Incorporation of Draft GALL-SLR guidance Application based on July 2023 Draft guidance 6

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Approach to Application - Aging Management Programs 7

AMPs with Exceptions Fire Water Water Chemistry Buried and Underground Piping and Tanks Reactor Head Closure Stud Bolting Masonry Walls BWR Vessel ID Attachment Welds Structures Monitoring Fire Protection New AMPs Electrical Cable Connections ASME Code Class 1 Small-Bore Piping Neutron Fluence Monitoring High Voltage Insulators External Surfaces Monitoring of Mechanical Components Reactor Head Closure Stud Bolting Fuse Holders Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components Thermal Aging Embrittlement of CASS Lube Oil Analysis Internal Coatings/Linings for In-Scope Piping Compressed Air Monitoring BWR Penetrations Electrical Insulation for Inaccessible Instrument and Control Cables One-Time Inspection Electrical Insulation for Inaccessible Low-Voltage Power Cables Selective Leaching

8 Topic of Interest Buried and Underground Piping and Tanks Application information is considered preliminary and subject to change

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Hatch Buried Pipe and Tanks AMP

Introduction

- The Hatch Buried and Underground Piping and Tanks AMP, with enhancements, such as the installation of Cathodic Protection (CP) and increased periodic inspections, will provide reasonable assurance that the effects of aging will be managed so that the intended function(s) of components within the scope of the AMP will be maintained consistent with the current licensing basis during SPEO.

Construction

- CP not included in original design

- System materials consist of Carbon Steel (CS), Stainless Steel (SS), Copper Alloy, Ductile Iron, and Gray Cast Iron

- Coatings consist of Coal-Tar Enamel, Wraps, and Asphaltic 9

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Hatch Buried Pipe and Tanks AMP

Current Program

- Ensures the integrity of buried pipes by monitoring their condition, conducting preventive maintenance, and identifying and addressing potential issues before they impact the intended function. Aspects of the program include:

Regular inspections, testing, and analysis of the pipes and tanks o Site procedure requires qualified personnel to inspect the condition of the protective coating upon excavation or when uncovered for any reason and results documented o Holiday testing prior to placing backfill Replacement of in-scope CS piping with 304 SS piping 10

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Hatch Buried Pipe and Tanks AMP

Exceptions to NUREG-2191 The Hatch Buried and Underground Piping and Tanks AMP includes the following exceptions to the NUREG-2191 guidance:

Exception 1. Element 2, Preventive Actions Cathodic protection is not installed at HNP as recommended in NUREG-2191, Table XI.M41-1.

Exception 2. Element 2, Preventive Actions The diesel fuel oil storage tanks and a portion of stainless steel PSW piping are not coated as recommended in NUREG-2191, Table XI.M41-1.

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Hatch Buried Pipe and Tanks AMP

Notable Enhancements Installation of Cathodic Protection on the Diesel Fuel Oil Storage Tanks prior to SPEO Update the program to include the plant specific inspection quantities for SLR Require that newly installed, buried stainless steel piping is coated in accordance with Table 1 of NACE SP0169-2007 or Section 3.4 of NACE RP0285-2002.

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Hatch Buried Pipe and Tanks AMP

Historical Buried Asset Program Activities Soil Analyses - Results generally Mild to Non-Corrosive (2010, 2012) 13 locations tested for six chemistry parameters 2022 comprehensive review of program Included review of approximately 115 inspections performed at the site between 2008 to 2021.

Of the systems within the scope of SLR, RHR and PSW were the only systems with adverse inspection results.

This inspection history is used to inform prioritization of future inspections.

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Hatch Buried Pipe and Tanks AMP

2024 Soil Sampling and Analysis

- The analysis included a review of the soil sample data from 2010, 2012, 2023, and 2024.

Included 51 historical samples and 13 new samples for analysis

- The analysis determined that the soil surrounding HNPs in-scope piping was generally mild to moderately corrosive.

- Additional testing was performed included native structure-to-soil potential, native continuity, and soil resistivity.

- The results of this analysis are used to inform the SLRA and included in Appendix B (Table B.2.3.27-1: Site Inspection Locations and Priorities).

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SLR In-Scope Buried Pipe and Tanks Plant Service Water Emergency Diesel Generators Fire Protection Standby Gas Treatment High Pressure Coolant Injection Reactor Core Isolation Cooling Residual Heat Removal

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Soil Sampling Map 16

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Site Inspection Locations and Priorities 17 The Table on the next slide shows site inspection locations and priorities Inspection Priorities are group by material (e.g. CS for Carbon Steel) and ranked from Highest (1) to Lowest (4).

Priorities considered the following:

Number of previous inspections

Site OE

System Risk Rank (per current program)

Use of preventive actions (e.g., PSW uncoated SS)

Conservative approach to soil conditions based on corrosivity rating per EPRI Technical Report 3002005294 Inspections in soil of highest corrosivity rating will be performed prior to SPEO and will be trended to ensure the system's intended functions are maintained throughout the SPEO based on projected rate and extent of degradation.

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Site Inspection Locations and Priorities 18 Inspection Priority Previous Inspections/Operating Experience Soil Conditions Material System CS 3 Piping: Five inspections performed in 2013. All inspections SAT. Tanks: All five tanks inspected from 2013 to 2016. All inspections SAT.

Moderately corrosive Carbon steel Emergency Diesel Generator (EDG)

CS 4B No adverse OE identified.

Moderately to appreciably corrosive Carbon steel Fire Protection (FP)

CA 1 No adverse OE identified.

Unknown Copper alloy CS 4C No adverse OE identified.

Moderately to appreciably corrosive Ductile iron CS 4A System pressure perturbations have led to mechanical failures. These failures are not believed to be related to external corrosion.

Mildly to moderately corrosive Gray cast iron SS 1 One inspection performed in 2010. No adverse OE identified.

Moderately to severely corrosive Stainless steel High Pressure Coolant Injection (HPCI)

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Site Inspection Locations and Priorities 19 Inspection Priority Previous Inspections/Operating Experience Soil Conditions Material System CS 1B 39 inspections from 2010 to 2020. Several UNSAT results due to both internal and external degradation.

Moderately to appreciably corrosive Carbon steel Plant Service Water (PSW)

USS 1 No previous inspections or OE identified. Uncoated stainless steel PSW piping was installed in 2014.

Moderately to severely corrosive Stainless Steel (uncoated)

SS 2 Four inspections from 2010 to 2013.

No adverse OE identified.

Moderately to severely corrosive Stainless Steel Reactor Core Isolation Cooling (RCIC)

CS 1A 17 inspections from 2010 to 2021. Several UNSAT results, mostly related to internal corrosion.

Through wall leak in 2020.

Moderately to appreciably corrosive Carbon steel Residual Heat Removal (RHR)

CS 2 Three inspections from 2010 to 2013.

All inspections SAT.

Moderately to appreciably corrosive Carbon steel Standby Gas Treatment (SBGT)

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Hatch Buried Pipe and Tanks AMP

Summary Hatch is taking necessary action to provide reasonable assurance that the program will continue to manage aging effects so that the intended function(s) of components within the scope of the program will be maintained. Examples include:

Installation of targeted CP at the Diesel Fuel Oil Storage Tanks Increased inspection frequency Performance of higher priority inspections prior to SPEO Adoption of additional enhancements per the GALL-SLR Continued soil sampling, analysis and evaluations Using previous and continued inspections to inform future actions 20

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Acronyms 22