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250506 PM Accelerated Material Qualification
	ML25129A088
Person / Time
Issue date:	03/06/2025
From:	Christian Araguas; NRC/RES/DE
To:	;
	Aditya Savara 4151049
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	Download: ML25129A088 (96)
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Public Meeting on Accelerated Material Qualification May 6, 2025 Christian Araguas, Director Division of Engineering Office of Regulatory Research 1

2 ADVANCE Act Section 401 Table 3 - potential action DD4 Develop guidance on accelerated material qualification Advanced Methods of Manufacturing and Construction for Nuclear Energy Projects (ML24292A171)

Meeting Objective Hear from the technical community on activities related to the near-and mid-term deployment of new materials for advanced reactor designs.

No licensing or regulatory decisions are being made at todays meeting.

3

Meeting Agenda, Early Afternoon Time Topic Speaker (and Affiliation) 1:00 PM Welcome and Introduction Meredith Neubauer (NRC) 1:05 PM Opening Remarks Christian Araguas (NRC) 1:10 PM AMMTs Perspectives on Accelerated Material Qualification for Advanced Reactors Meimei Li (DOE-NE) 1:30 PM Accelerating the Deployment of Materials and Advanced Manufacturing Methods for Nuclear Applications Marc Albert and Chris Wax (EPRI) 1:45 PM Material Qualification for the eVinci Microreactor Zefeng Yu (Westinghouse) 2:00 PM Kairos Power: An Iterative Approach for Reactor Materials Craig Gerardi (Kairos) 2:15 PM Break 4

Meeting Agenda, Late Afternoon 5

Time Topic Speaker (and Affiliation) 2:30 PM Aalo's Advanced Manufacturing and Qualification Approach for Intermediate Heat Exchangers Luke Andrew (Aalo) 2:45 PM Metallic Materials Development for the Natrium Advanced Reactor Bridgette Hannifin (TerraPower) 3:00 PM Qualification of Metallic Materials for Kaleidos Parker Buntin (Radiant Nuclear) 3:15 PM Discussion Moderator: NRC Discussion

Participants:

DOE, EPRI, Industry Representatives 4:40 PM Public Q&A Public 4:50 PM Closing Remarks NRC

Advanced Materials and Manufacturing Technologies (AMMT) Program Perspectives on Accelerated Material Qualification for Advanced Reactors Meimei Li, National Technical Director, Argonne National Laboratory Dirk Cairns-Gallimore, Federal Program Manager, DOE Office of Nuclear Energy NRC Public Meeting on Accelerated Material Qualification, May 6, 2025

AMMT Program: Mission, Vision, Goals Mission Accelerate the development, qualification, demonstration, and deployment of advanced materials and manufacturing technologies in support of U.S.

leadership in a broad range of nuclear energy applications.

Vision Expansion of reliable and economical nuclear energy enabled by advanced materials and manufacturing technologies.

Goals

Develop advanced materials &

manufacturing technologies.

Establish and demonstrate a rapid qualification framework.

Evaluate materials performance in nuclear environments.

Accelerate commercialization through technology maturation.

AMMT Program: Technical Areas Advanced Materials &

Manufacturing

Advanced Metallic Materials

Advanced Manufacturing Technologies

Traditional Manufacturing &

System Integration Rapid Qualification

Rapid Qualification Framework

High-temperature Materials Qualification

Advanced Manufacturing Qualification Technology Maturation

Component Fabrication &

Evaluation

Codes and Standards

Regulatory Acceptance &

Licensing Environmental Effects

Neutron Irradiation & Post-irradiation Examination

Accelerated Qualification for Radiation Effects

Corrosion Effects in Nuclear Environments AMMT supports the development of a broad range of reactor concepts:

Molten Salt Reactors (MSRs)

Sodium-cooled Fast Reactors (SFRs)

Gas-cooled Reactors (GCRs)

Lead-cooled Fast Reactors (LFRs)

Advanced Light Water Reactors (aLWRs)

AMMTs Perspective on Accelerated Material Qualification Material Qualification

Qualification refers to the entire process of transitioning materials from development to approval for nuclear applications.

Material qualification addresses temperature, stress, radiation, and corrosion effects.

Key aspects:

Baseline property testing and temperature effect evaluation

Performance testing in irradiation and corrosive environments

Predictive modeling of processing-structure-property-performance relationships

Development of Codes, Standards, and guidelines Accelerated Material Qualification

Goal: Faster, cost-effective qualification while maintaining the thoroughness and integrity of the qualification process.

Acceleration is achieved through innovative testing techniques, advanced characterization, modeling and simulation, and AI/ML, enabling

Reduced dependence on extensive engineering property data

Rapid assessment of long-term material behavior in nuclear environments

Large time extrapolation factors

Utilization of non-standard or subscale specimen data

Advanced Materials & Manufacturing Development Apply advanced manufacturing to existing reactor materials Transition non-nuclear commercial materials for nuclear applications Develop innovative new materials Our materials development strategy is to develop advanced materials through integration with manufacturing processes.

Fe-based alloys (316, Alloy 709, G91, G92)

Ni-based alloys (Alloys 617, 625, 244)

Refractory alloys (Mo, Nb alloys)

Innovative new materials (ODS, HEA, FGM)

Materials Advanced manufacturing (LPBF, DED, PM-HIP)

Traditional manufacturing Hybrid manufacturing Joining techniques Manufacturing Processes Advanced materials and manufacturing development lays the groundwork for qualification.

Use integrated experimental, modeling and data-driven tools Capitalize on the wealth of digital manufacturing data, integrated computational materials engineering (ICME) and machine learning/artificial intelligence (ML/AI) tools, and accelerated, high-throughput testing and characterization techniques.

Demonstrate accelerated qualification methods through qualifying LPBF 316H SS Laser powder bed fusion 316H stainless steel (LPBF 316H SS) serves as a test case for demonstration of a new qualification framework.

Establish Processing-Structure-Property-Performance relationships A P-S-P-P based qualification framework requires a fundamental understanding of processing-structure-property-performance relationship to enhance the prediction of material behavior, design allowables, and performance limits in nuclear reactor environments.

Incorporate in situ process monitoring data into the qualification process Monitor and analyze the printing process in real-time to ensure the quality and integrity of the fabricated part. Use in situ process monitoring data to detect defects and as a QA tool to assess part quality.

Integrate scientific understanding with engineering data to establish a physics-based, data-driven qualification methodology.

Rapid Qualification Framework

Rapid Qualification Approach Advanced Experimental Methods

Innovative testing methods and advanced characterization accelerate materials qualification by rapidly generating comprehensive datasets and providing detailed insights into material properties and performance.

Automated, fast NDE

Advanced characterization

Small-scale specimen testing

Accelerated testing tools In-situ Process Monitoring

In-situ process monitoring can play a crucial role in accelerating material qualification, particularly for advanced manufacturing techniques such as additive manufacturing.

Provide real-time insights

Improve quality control

Enable predictive modeling

Contribute to a digital thread Computational Tools

Computational tools accelerate materials qualification by providing predictive insights that complement experimental data.

Modeling Process-Structure-Property-Performance relationships

Extrapolation of long-term behavior

Sensitivity Analysis

Uncertainty Quantification

Rapid Qualification for Radiation Effects Neutron Irradiation

Provide critical performance data in nuclear reactor environments

Neutron irradiation and post irradiation examination (PIE)

In-reactor experiments including combined irradiation and corrosion effects

Ongoing and Planned Activities: ATR and HFIR irradiation and PIE of LPBF 316H and wrought Alloy 709.

Ion Irradiation

Use ion irradiation as an accelerated tool to provide complementary data to cover a wide parameter space

Metallurgical variables, e.g. heat variation, product form, heat treatment, etc.

Irradiation parameters, e.g. temperature, dose, dose rate, energy spectrum, transmutation, etc.

Modeling and Simulation

Understand the underlying physics and predict material performance beyond testing conditions.

Material surveillance technology to monitor material degradation in service to enhance predictions and reduce uncertainties.

Apply a science-driven licensing strategy, so called the Licensing Approach with Ions and Neutrons (LAIN) framework that combines neutron and ion irradiations with physics-based modeling to accelerate material qualification.

Courtesy of Andrea Jokisaari (INL) and Stephen Taller (ORNL) et al.

LAIN Framework

Evaluation of Corrosion Effects Research Focus

Understanding of corrosion processes in molten salt, liquid sodium, and helium environments.

Evaluate corrosion behavior of additively manufactured (AM) materials focusing on their unique characteristics.

Ongoing Activities

Testing in molten salts

316H, 709 SS, Alloys 625, 617, 244 Ni alloys (wrought and AM)

Evaluate corrosion and creep behavior in molten fluoride and chloride salts

Determine corrosion kinetics and speciation in molten NaCl-MgCl2

Characterize corrosion behavior of LPBF 316H in molten NaCl-MgCl2 and understand processing-structure-performance relationship

Testing in liquid sodium

Wrought Alloy 709 and LPBF 316H

Performing sodium exposure tests in forced-convection loops

Evaluate sodium compatibility and effects on microstructural evolution and mechanical properties Material interactions with coolants vary significantly across different reactor designs and environments, influenced by factors such as coolant chemistry and operating temperature.

Multi-Dimensional Data Correlation (MDDC) Platform Improve Performance, Reliability and Lifetime of Nuclear Components Toolkit Artificial Intelligence Machine Learning Data Analytics Process Models Materials Models Performance Models MDDC Twin 1 Twin 2 Twin 3

Twin n Feedstock Information Process Parameters In-Situ Data Manufacturing Post Processing Destructive Testing Non-Destructive Testing Material Characterization Digital Twin 8

2 1

3 5

6 4

9 AI Based Design Digitally Aided Qualification Demonstrations 10 years 5 years 3 years Digital Twins and MDDC Toolkit Accelerates Development Characterization Lifetime &

Performance Data Data Fusion Spatially Tracked Data

Accelerated Qualification Strategy Staged Approach: Begin with statistical-or equivalence-based qualification and progressively transition to an advanced, accelerated qualification methodology.

Application Demonstration: Use LPBF 316H SS as a case study to develop the accelerated qualification framework and demonstrate its applications to materials produced by various advanced and traditional manufacturing processes.

Codes and Standards Development

New standards, such as material specifications and testing methods.

LPBF 316H 100,000h Code Case in ASME Section III Division 5.

Alloy 709 longer-term Code Cases (300,000 h and 500,00 h) in ASME Section III Division 5.

Qualify additional product forms of Alloy 709, such as bar, pipe and forging.

Introduce new materials and manufacturing processes in ASME Section III Division 5.

Design Requirements for Environmental Effects

Provide data and insights to support the development of design guidelines that address the environmental effects of corrosion and irradiation.

Identify alternative pathways to accelerate the adoption of advanced materials and manufacturing technologies.

Summary Material qualification addresses temperature, stress, irradiation, and corrosion effects in nuclear reactors.

AMMT material qualification focus area

High temperature materials qualification

Advanced manufacturing qualification Rapid Qualification Framework Integrates engineering data with scientific understanding of Processing-Structure-Property-Performance relationships Leverage advanced characterization, high-throughput testing, modeling and simulation, and AI/ML Stakeholder Engagement Understand and address their needs, requirements and expectations.

Opportunities for further NRC guidance Acceptance of the rapid qualification framework Digital-driven qualification with lifecycle data integration to qualify AM components Incorporation of in-situ process monitoring data into the qualification process.

Rapid assessment of long-term material behavior in nuclear environments (e.g. LAIN framework)

Role of materials surveillance program in advanced reactors.

Utilization of non-standard or subscale specimen data Large time extrapolation factors

www.epri.com

www.epri.com w w w. e p r i. c o m Marc Albert Sr. Principal Team Lead - Advanced Manufacturing & Materials Qualification Chris Wax Sr. Principal Team Lead - Advanced Reactor Materials Reliability May 6, 2025 NRC Public Meeting on Guidance Development for Accelerated Material Qualification Accelerating Deployment of Advanced Reactor Materials and Manufacturing Methods

2 Materials Deployment for Advanced Reactors Can take a DECADE to fully qualify a new alloy Just because the material is Code Qualified doesnt mean it is approved for Nuclear Service Owner/Operator has the responsibility to demonstrate to regional regulator that the effects on structural failure modes are accounted for in their specific reactor design Irradiation Data Corrosion Data Thermal Performance Limited number of ASME Code Qualified alloys for high temperature service Code Qualification Environmental Effects Supply Chain Critical data and understanding required for informed fabrication and design of AR components Environmental Testing

3 Regulatory Approval?

What does it take to deploy a material for ANLWRs?

an example BPV III-Div. 5 code qualification up to 100,000 hrs of service BPV III-Div. 5 code qualification up to 300,000 hrs of service BPV III-Div. 5 code qualification up to 500,000 hrs of service Code Data Environmental Effects Corrosion - EA cracking in He Corrosion - EA cracking in salts Irradiation Assessment Data Irradiation Properties Fabrication Data Weldment Optimization Tensile, high temp, creep, thermal fatigue Feature Testing Cyclic Stress Relaxation Heat to Heat Variability ASME Approval (for 12 years Operation)

ASME Approval (for 24 years Operation)

Confidence in Supply and Operation Regulatory Approval?

?

ASME Approval (for 60 years Operation)

Combined Environmental Effects Corrosion - EA cracking in Na Corrosion - EA crackin in Pb Corrosion Rates in He Corrosion Rates in salts Corrosion Rates in Na Corrosion Rates in Pb Legend:

Needed Complete In-process Not Needed or N/A Multiple product forms Capable Suppliers and Fabricators

4 Reduction in Costly Experiments Regulatory agreement on key questions:

- How many experiments does it take to verify a property?

Need to ensure inflection points are covered

- What accuracy is needed to justify understanding of a property?

Increased conservatism until additional data is captured

- Increased Inspection & Monitoring

- Larger error bars (uncertainty)

- Fill in data gaps with modeling Target high-cost experiments?

5 Approaches for Accelerated Qualification of Materials

6 Approaches for Accelerated Qualification of Materials 3002029265 published November 2024 Assembled promising and most value-added methods Primer document outlining the advantages, disadvantages, and challenges of each approach Collaboration with Argonne National Lab Integrate numerous approaches into a qualification framework Pilot framework with multiple approaches on known material (e.g., 316 variants)

Continued collaboration with Argonne National Laboratory OBJECTIVE Qualification of new materials for nuclear applications is time consuming and expensive Particularly for high temp applications (up to 10 years)

Assess and develop accelerated qualification approaches Pilot the framework with codes &

standards and regulatory bodies STATUS NEXT STEPS Roadmap Strategic Gap Addressed:

1) Capture material data and close gaps necessary for deployment of Advanced Reactors

7 Phase I Activities Conducted survey to document methods that could potentially reduce ASME code qualification burden Collaboration with Argonne National Lab Various methods identified that might allow acceleration of the code process (primarily centered around long-term creep data)

Report published in late 2024 EPRI Report 3002029265, November 2024

8 Accelerating qualification: Reduce the time required to conduct testing, analyze data, and secure approval for a new material compared to conventional approaches Qualification by Analogy Physics-based Modeling Material Surveillance Staggered Qualification Limited Design Scope Alternate Code Classification Improved Empirical Models Potential Approaches to Accelerate Material Qualification

A B

9 Next Steps - Accelerating Materials Qualification Published Primer Document 3002029265

Provides a toolbox of approaches to accelerating qualification

Includes advantages, disadvantages, and specific research needed to deploy each given method

Integrate multiple approaches into a qualification framework

Continuing the collaboration with ANL Phase 2 Underway

Pilot framework with multiple approaches on known material (e.g., 316 variants)

Looking to leverage pilot towards potential future materials

10 EPRI Proposed Approach for High Temperature Stress Allowables for DED Additive Manufacturing

11 Gas Metal Arc-Directed Energy Deposition (GMA-DED)

Aka: wire arc additive manufacturing (WAAM), wire additive welding.

316LSi valve body, 1600 pounds (700 kg)

Collaborative effort between EPRI and Lincoln Electric Additive Solutions

12 Current Approach for GMA-DED within ASME Boiler and Pressure Vessel Code Section III Code Case nearing approval that builds off BPTCS/BNCS Special Committee on Use of Additive Manufacturing for Pressure Retaining Equipment Relies on bracketed qualification approach of AM process to permit use of design parameters from corresponding material for time-independent service No current actions specific to GMA-DED Recent focus has been on LPBF and PM-HIP for high temperature service Low temperature rules will likely mirror the Division 1 approach Extension to elevated temperatures is a gap (more on this later)

13 GMA-DED construction Conventional welded construction How are welds treated for high temperature applications?

316H weld material used in both cases, but no technical basis exists for high temperature GMA-DED designs rules 316H piping girth weld (DOE-EPRI-FE31562) 316H GMA-DED build Base metal design curves Knockdown strength reduction factors applied to base material design stresses for welded construction 316H Weld Material No existing design approach for high temperature nuclear service Treating DED as a new material will be very expensive + time consuming

14 EPRI proposal for stress allowables in DED-AM components ASME Section II Appendix 5 Challenges

- Section II Appendix 5 does not address AM processes and the possibility of different heat-treatments for the same material

- If treated as a new material, each material +

heat-treatment would require a prohibitive amount of long-term data for materials which are already well characterized in other product forms

- Bracketed qualifications are not considered

- Testing in multiple orientations not considered Important guidance

- Consideration for service experience

- Consideration for larger sample/feature testing (relevant data)

Alternative: AMSRF (Additive Manufacturing Strength Reduction Factor) Approach is Proposed Using a combination of past available creep data on weld metals and new creep data on DED builds, use an approach similar to the WSRFs that used today for weldments to create stress allowables based on the wrought equivalent materials Validate the approach using lab or field data on relevant components In order to allow early adoption and field demonstration, use conservative factors until longer-term data are made available Alternative approach will help accelerate acceptance of DED-AM processes requiring stress allowables in the time-dependent regime

15 On-going Expanded 316H GMA-DED Work for ASME Code on Austenitic Stainless Steel Focus on GMA-DED for Section III elevated temperature service Compile data relevant to ASME qualification in the time-dependent regime (ETT, creep, creep-fatigue)

Follow ASME time-independent qualification as much as possible to develop material for time-dependent testing and characterization Data package assembly and analysis for preliminary AM-SRF approach Extensive database of wrought 316H creep rupture data enables comparisons with conventional product forms

16 Summary Large scale DED has reached commercial maturity and offers an attractive processing route to complement conventional methods of manufacturing ASME Code status:

- Time-independent service: criteria have been established and are nearing adoption across multiple book sections. Qualification hinges on establishing material equivalency with wrought or cast products.

- Time-dependent service: work is needed to establish the technical basis and qualification approach. Possible opportunity to leverage an equivalency approach with knockdown factors on time-dependent design parameters similar to how welds are treated today.

On-going and future research activities are focused on two areas:

- Fundamental R&D to understand process-structure-property-performance linkages

- Applied R&D to establish and demonstrate a workable qualification approach

17 Materials Management Environmental Compatibility

18 Regulatory Guidance for Advanced Reactor Materials

Section III-5, HBB-1110(g) ASME Code rules do not provide methods to evaluate deterioration that may occur in service as a result of corrosion, mass transfer phenomena, radiation effects, or other material instabilitiesnon-LWR application to review applicable design requirements including environmental compatibility, qualification and monitoring programs for safety-significant structures, systems, and components (SSCs)

US Nuclear Regulatory Commission Interim Staff Guidance (DANU-ISG-2023-01)

High Temperature Materials Qualification Materials Compatibility in New Reactor Environments Materials Management Programs to Ensure Operational Integrity RIM

19 Materials Validation and Deployment Time Dependent Mechanical Properties Cyclic Properties Fatigue Life Cyclic / Curves Mechanical Properties, in Environment Stress Corrosion Cracking Stress vs Life, Crack Growth Rates Environmentally Affected Cyclic Deformation Response:

Stress Amplitude vs Life, Crack Growth Rates etc.

Irradiation Effects on Mechanical Properties Irradiation Effects on Creep :

Creep Rates, Creep Life Stress-Corrosion Cracking Behavior of Previously Irradiated Material Irradiation Effects on Microstructure Swelling, He Production, Matrix Hardening, Phase Changes Corrosion Behavior Weight Loss, IGA Attack Irradiation Effects on Lifing Parameters Mechanical Properties Environmental Effects Irradiation Effects In-reactor, In-environment Mechanical Response, Irradiation Assisted Stress Corrosion Cracking, Fatigue Materials deployment decisions are the culmination of numerous inputs Multi-Variable Performance Data Laboratory Test Data For Interacting Variables Prototype Performance Data Intermediate-Time Test Data For Simple Effects

20 Materials Management - Post Material Selection Identify applicable materials degradation for an AR environment Assess impact of degradation Can the degradation be designed out?

If not, then mitigate, monitor, or plan for replacement Operating experience available?

Research data available?

Can the mechanism be modelled?

Time-dependent or time-independent degradation?

Critical/Detrimental to design integrity?

Change geometries?

Change materials?

Change operating parameters/chemistry controls?

SSC change, in general?

Cladding Peening Overlay New/Novel Mitigations Continuous monitoring Inspections Surveillance Plan for replacement Design Phase Operational Programs Materials TAG Materials Degradation Matrices Degradation Mechanism Screening and Assessment Reactor developer decision making process

- reasonable assurance for material deployment In-service inspection, monitoring, or surveillance ASME Section XI, Division 2 - RIM

21 EPRI Advanced Reactor Materials Technical Advisory Group

22 AR Materials Technical Advisory Group (TAG)

Sodium Fast Reactors 3002016949 Molten Salt Reactors 3002010726 Lead Fast Reactors 3002016950 High-Temperature Gas Reactors 3002015815 Materials Gap Analyses Advanced Reactor Materials Development Roadmap 3002022979 Materials Degradation Matrices Materials, potential degradation mechanisms, and status of knowledge Molten Salt Reactors MDM Sodium Fast Reactors MDM High Temp Gas Reactors MDM Lead-cooled Reactors MDM Develop & Execute Test Plans Strategic direction setting and prioritization Advanced Reactor Materials Deployment Roadmap Stakeholder engagement and alignment on industry deployment needs Code Qualification and Data Gaps Environmental Compatibility In Progress Scoped Future Project AR Materials TAG Key stakeholders to assist in direction setting and prioritization of needs concerning AR materials qualification and testing

23 Advanced Ultra-supercritcal (A-USC) Coal Commercial Readiness Inconel 740H was the key enabling material for the U.S.

DOE/OCDO A-USC Program 2001: Material Selection 2005: Material Optimization and Fabrication 2011: ASME Section I Code Case 2015: Field Testing Completed 2016-2020: Supply Chain Development & Small Pilots 2020-2023: First Large-Scale Pilot (sCO2) and Full-Size Components Collaboration Across the Supply Chain is Critical

24 www.epri.com

www.epri.com w w w. e p r i. c o m TOGETHERSHAPING THE FUTURE OF ENERGY

1 eVinci Microreactor 1

Westinghouse Non-Proprietary Class 3

May 06, 2025 Material Qualification for the eVinci Microreactor eVinci is a trademark or registered trademark of Westinghouse Electric Company LLC, its affiliates and/or its subsidiaries in the United States of America and may be registered in other countries throughout the world. All rights reserved. Unauthorized use is strictly prohibited. Other names may be trademarks of their respective owners.

2 Agenda

eVinci Microreactor Design Overview

Overall Material Qualification Roadmap

Metallic Qualification and Challenges

Graphite Qualification and Challenges

Ongoing Testing Programs

eVinci Microreactor U.S. Nuclear Regulatory Commission (NRC) Pre-Application Engagement

3 eVinci Microreactor Design Safety through passive heat pipe technology, enabling a very low-pressure reactor Parameter eVinci Microreactor Power 15 MWt Fuel Cycle 8 years Fuel (Enrichment)

Tri-structural Isotropic (TRISO) (19.75%)

Coolant Heat Pipes Reactor Pressure

~1 atm Moderator Graphite Power Conversion Open-Air Brayton Efficiency 34%

Decay Heat Removal Radial Conduction Shutdown Rods Steel Canister Radial Reflector Control Drums Graphite Core Block Primary Heat Exchanger Shielding &

Bulkhead Heat Pipes

4 Identify Gaps (4) Design input to NTR through DOE Overall Material Qualification Roadmap (1) Qualification based on ASME Code + Reg Guide (2) Qualification of Existing Data from Literature

[1] ASME BPVC.III.A-2023

[2] Journal of Nuclear Materials l Vol 578, May 2023 l ScienceDirect.com by Elsevier

[3] Structural Materials for Generation IV Nuclear Reactors (Woodhead Publishing Series in Energy): Yvon, Pascal: 9780081009062: Amazon.com: Books

[4] Material Testing - Photron (3) Material Development +

Confirmatory Testing (6) Design input to Commercial Reactor

[2]

[3]

[4]

Baseline properties Aging effects Irradiation effects Oxidation effects Material combability (5) Additional material property assessment, identify gaps, and testing.

[1]

5 Metallic Qualification and Challenges

eVinci microreactor metallic qualification guided by:

ASME BPVC Section III Division 5 (Div. 5)

ASME NQA-1-2024

DANU-ISG-2023-01

RG 1.87

Use Div. 5 materials where possible based the allowable temperature ranges

Div. 5, App. HBB-Y provides guidance for metallic material development & testing Testing based on justified needs for design Testing partners with universities, national labs, commercial vendors, internal testing labs

Qualification of existing data based on NQA-1, Subpart 4.2.3 Qualification methods: quality assurance program equivalency, data corroboration, confirmatory testing, and peer review

6 Metallic Qualification and Challenges

Challenges:

Environmental effects (e.g., irradiation, oxidation, etc.) not explicitly addressed in Div. 5 for metals

Long-term high temperature testing to qualify new materials

Despite code permitting 3x or 5x extrapolation of creep data, several years of testing needed to obtain statistically significant creep data for new materials or to validate creep models

Ask:

Although Div. 5 HBB-Y rules are for qualification of new materials into ASME code, rules can be used to qualify materials

Request NRC endorse Div. 5 HBB-Y for material qualification

Endorsement represents agreement that approach is acceptable without needing materials added to code first

7 Graphite Qualification and Challenges

Div. 5, HHA-2200 provides guidance for graphite material qualification

Generate MDS including: 1) manufactured material properties, 2) irradiated material properties, and 3) oxidized material properties

Div. 5 does not list permissible graphite grades like it does for metallic components

Westinghouse has comprehensive testing program to acquire manufactured material properties

Gaps of irradiation data for graphite grades

Utilize DOE funded programs to access publicly available data on relevant graphite grades

Establish and implement statistical analysis methods to interpolate and extrapolate irradiated material behaviors

Ask:

In TLR-RES/DE/REB-2022-1, material properties or parameterization developed using the graphite degradation models (thermo-mechanical model and oxidation model) were specifically for IG-110

Beneficial for NRC to expand application of these models for other graphite grades and provide corresponding parameterizations

8 Ongoing Testing Programs

Heat Pipe Testing High Temperature Testing for time-independent and time-dependent material properties.

Graphite Testing Room and High Temperature (>1000

°C) Mechanical Testing Thermal Property Testing

Material Compatibility Testing Long term and high temperature sodium compatibility with heat pipe tubing and wick materials.

9 Current Status:

https://www.nrc.gov/reactors/new-reactors/advanced/who-were-working-with/pre-application-activities/evinci.html Topic Submittal Wave Topic Submittal Wave Topic Submittal Wave 1

Facility Level Design Description Submitted - 1 13 Advanced Logic System(ALS) v2 Submitted - 3 25 Inservice Inspection Program/Inservice Testing Program Submitted - 5 2

Principal Design Criteria Submitted - 1 14 Component Qualification Submitted-3 26 Post-Accident Monitoring System Submitted - 5 3

Safety and Accident Analysis Methodologies Submitted - 1 15 Emergency Plan Zone Sizing Methodology Submitted - 3 27 Equipment Qualification Submitted - 5 4

Licensing Modernization Project Implementation Submitted - 1 16 Physical Security Submitted - 3 28 Probabilistic Risk Assessment and Transportation Risk Assessment Submitted - 5 5

Regulatory Analysis Submitted - 2 17 Heat Pipe Design, Qualification, and Testing Submitted - 3 29 Fire Protection Submitted - 5 6

Deployment Model Submitted - 2 18 Nuclear Design Submitted - 3 30 Cyber Security Submitted - 5 7

Safeguards Information Plan Submitted - 2 19 U.S Transportation Strategy Submitted - 3 31 Radiation Protection and Contamination Methodology Submitted - 6 8

Test and Analysis Process Submitted - 2 20 Phenomena Identification and Ranking Table (PIRT)

Submitted - 4 9

Functional Containment and Mechanistic Source Term Submitted - 2 21 Integral Effects and Transient Testing Submitted - 4 10 Composite Material Qualification and Testing Submitted - 2 22 Refueling and Decommissioning Submitted - 4 11 Fuel Qualification and Testing Submitted - 3 23 Seismic Methodology Submitted - 4 12 Code Qualification Submitted - 3 24 Operations and Remote Monitoring Submitted - 4 Pre-Application Engagement - White Papers

10 Topical Reports Report Title Status 1

ALS v2 Platform Approved (Mar. 2025) 2 ALS v2 Development Process Approved (Mar. 2025) 3 Principal Design Criteria Approved (Jan. 2025) 4 ALS v2 Platform Elimination of Technical Specification Surveillance Requirements Submitted (Dec. 2023) 5 Nuclear Design Methodology Submitted (May 2024) 6 Westinghouse TRISO Fuel Design Methodology Submitted (Aug. 2024) 7 Composite Materials Qualification Methdology 8

Testing Program 9

Physical Security Design 10 Functional Containment and Mechanistic Source Term Methodology 11 Design Basis Analysis Methodology 12 Metallic Materials 13 Graphite Materials 14 Heat Pipe Qualification Criteria 15 Component Qualification Methodology 16 Inservice Inspection 17 Inservice Testing

Questions 11

12

KAIROS POWER: AN ITERATIVE APPROACH FOR REACTOR MATERIALS NRC PUBLIC MEETING: ADVANCE ACT - ADVANCED METHODS OF MANUFACTURING AND CONSTRUCTION FOR NUCLEAR ENERGY PROJECTS 6 MAY 2025

Kairos Powers mission is to enable the worlds transition to clean energy, with the ultimate goal of dramatically improving peoples quality of life while protecting the environment.

In order to achieve this mission, we must prioritize our efforts to focus on a clean energy technology that is affordable and safe.

2

=

Background===

KP-FHR Reactors operate 550-650ºC at low pressure 3

Key Points Reactor Description Pool-type, fluoride-salt cooled, high temperature reactor (FHR)

Core Configuration Pebble bed core, graphite reflector, and enriched Flibe molten salt coolant Primary Heat Transport System Flibe Salt, 550°C-650C, ~0.2 MPa, ~0.11-0.15 m/s Tmax < 750ºC Materials for Safety Related Structures 316H 16-8-2 Weld Filler Metal Possible 316H Autogenous EBW Lifetime 20 years for Power Reactor End of Life Irradiation of Reactor Vessel

<0.1 dpa

Kairos Power Path to Commercialization Successive Large-Scale Integrated Demonstrations Produces electricity and connected to grid Nuclear PLAN BUILD DESIGN TEST PLAN BUILD DESIGN TEST PLAN BUILD DESIGN TEST PLAN BUILD DESIGN TEST KP-X KP-X Commercial Demonstration Plant ETU 1.0 Engineering Test Unit Series (Non-Nuclear)

Hermes Hermes 2 Hermes Demonstration Reactor Series Commercial Fleet ETU 2.0 ETU 3.0 4

Hermes RX via GTAW

EBW possibly adopted sometime after Hermes

ü: completed

¹: in progress

ü ¹

¹

Topics of Interest to Kairos Power

Extension of 16-8-2 filler metal to higher temperatures in Sec. III Div 5 Wrapping up internal testing program to justify

Local vacuum electron beam welding Technical assessment complete Vetting test plan through ASME Allowable Stress Committee May 2025 May initiate materials testing in the near-future

Combined effects testing Utilizing MIT-R to assess molten salt + irradiation for graphite and 316H

New alloys 709 for improved creep resistance Hast-N type alloys for use in fluoride salts - in collaboration with ORNL (Dr. Murali Muralindharan)

Stainless steels that have increased resistance to helium embrittlement

Solid state welding for head & vessel penetrations

Additive manufacturing 316H PM and wire arc additive AM component performance in our Engineering Test Unit (ETU) 5

AALO'S ADVANCED MANUFACTURING AND QUALIFICATION APPROACH FOR INTERMEDIATE HEAT EXCHANGERS Luke Andrew, PE A a l o - X P r o g r a m T e c h n i c a l L e a d l Copyright© 2025 Aalo Atomics. All Rights Reser ved

1. Introduction to Aalo

2. Intermediate Heat Exchanger in Aalo Design a) Overview b) Manufacturing Processes c) PCHEs Role in Aalo-1 d) PCHE in Aalos Systematic Technology Maturation

Lower Confinement Passive Cooling Reactor Building Secondary Annex Upper Confinement Auxiliary Cooling Confinement Lower SC Module Upper SC Module Structurally Independent Secondary Annex Reactor Building Air-Based Cooling Auxiliary Cooling Passive Cooling Unit Overview l Copyright© 2025 Aalo Atomics. All Rights Reser ved

Safety Features Control Motor-driven control rod power reduction and scram Gravity-driven control rod scram Contain Low pressure primary system No penetrations in reactor vessel wall Guard vessel for secondary containment Cool Natural circulation within reactor Auxiliary air cooling through natural and forced circulation Passive air cooling through natural circulation always operational l Copyright© 2025 Aalo Atomics. All Rights Reser ved

IHX IN AALO-1 DESIGN Printed Circuit Heat Exchanger

Highly compact and efficient type of heat exchanger o Up to 85% smaller than equivalent shell & tube

Used in high-temperature, high-pressure applications o Pressure capability: up to 1,000 bar (14,500 psi) o Temperature range: -270°C (-454°F) to 900°C (1650°F)

Inherently robust design o High integrity plate type exchangers

MANUFACTURING PROCESS

1. Plate material a) 316 L

2. Photolithographic Masking, Chemical Etching, or Milling of flow channels

3. Plate Stacking

4. Diffusion Bonding a) Vacuum hot press furnace under large pressure, temperature, and time b) atomic diffusion occurs across the plate interfaces a) creating a solid-state weld that forms a monolithic block with no joints or seals l Copyright© 2025 Aalo Atomics. All Rights Reser ved

PCHE ROLE IN AALO-1 DESIGN a) Safety function for PCHE a) IHX isolates the secondary sodium used from the sodium in the primary system b) Leaks in the IHX would result in the transfer of Secondary sodium into the primary system b) Critical characteristics for PCHE a) Ensure postulated leakage across the IHX interface is within acceptable limits consistent with radionuclide release design limits b) Capable to transfer its design heat load during normal operation l Copyright© 2025 Aalo Atomics. All Rights Reser ved

PCHE IMPLEMENTATION AT AALO

Use ASME BPVC Section IX requirements for the qualification of Diffusion Welding (DFW) o Seeking Code Interpretation

Use 316L for PCHE Fabrication o Code Case 2577 allows use of 316L at elevated temperatures for Section VIII.1 (time independent properties)

SYSTEMATIC TECHNOLOGY MATURATION Aalo-0 Aalo Pod Aalo-X Non-nuclear Systems Prototype (Separate Effects and Integrated Effects Testing)

NRC Licensed Facility (Uses data and experience from Aalo-0 and Aalo-X)

PCHE PERFORMANCE EVALUATION AT AALO-0

Verify PCHE performs its intended functions.

Demonstrate the operability and performance of the heat exchanger as a component and within its system

Confirm structural and leak-tight integrity

PCHE PERFORMANCE EVALUATION AT AALO-X

Verification of PCHE operation during Aalo-X operation

potentially through temporary configurations to test different design conditions

Heat transfer capability

Flow rates and inlet/outlet temperatures

Structural and leak-tight integrity

SUBJECT TO DOE COOPERATIVE AGREEMENT NO. DE-NE0009054 Copyright © 2025 TerraPower, LLC. All Rights Reserved SUBJECT TO DOE COOPERATIVE AGREEMENT NO. DE-NE0009054 Copyright © 2025 TerraPower, LLC. All Rights Reserved Natrium reactor is a TerraPower & GE Hitachi technology Metallic Materials Development for the NATRIUM Advanced Reactor Bridgette Hannifin May 6, 2025

TerraPower Proprietary and Confidential - Subject to Confidentiality Agreement Rx Building Fuel Handling Building Rx Aux. Building Control Building Warehouse

Energy Storage Tanks Decoupling Boundary 2

730-1050°F (390-540°C) Reactor Coolant Operating temperature

98°C Melting Temperature

Operates near atmospheric pressure Molten Salt (60 NaNO3-40 KNO3)

Temperature range 460-1150 °F (238°C -

621°C)

Commonly used for heat storage is the same as used for solar plants 3

Reactor Aux. Building Int Sodium Hot Leg Int Sodium Cold Leg Reactor and Core IAC Head Access Area RAC / Reactor Cavity Reactor Building Fuel Handling Building RAC Ducts Used Fuel Water Pool Salt Piping to/from Thermal Storage System Sodium Int loop Sodium/Salt HXs

SUBJECT TO DOE COOPERATIVE AGREEMENT NO. DE-NE0009054 Copyright © 2025 TerraPower, LLC. All Rights Reserved Control Motor-driven control rod runback and scram follow Gravity-driven control rod scram Inherently stable with increased power or temperature Cool In-vessel primary sodium heat transport (limited penetrations)

Intermediate air cooling natural draft flow Reactor air cooling natural draft flow -

always on Contain Low primary and secondary pressure Sodium affinity for radionuclides Multiple radionuclides retention boundaries Natrium Reactor Safety Features Pool-type Metal Fuel SFR with Molten Salt Energy Island

- Metallic fuel and sodium have high compatibility

- No sodium-water reaction in steam generator

- Large thermal inertia enables simplified response to abnormal events Simplified Response to Abnormal Events

- Reliable reactor shutdown

- Transition to coolant natural circulation

- Indefinite passive emergency decay heat removal

- Low pressure functional containment

- No reliance on Energy Island for safety functions No Safety-Related Operator Actions or AC power Technology Based on U.S. SFR Experience

- EBR-I, EBR-II, FFTF, TREAT

- SFR inherent safety characteristics demonstrated through testing in EBR-II and FFTF 5

Control Cool

SUBJECT TO DOE COOPERATIVE AGREEMENT NO. DE-NE0009054 Copyright © 2025 TerraPower, LLC. All Rights Reserved SUBJECT TO DOE COOPERATIVE AGREEMENT NO.DE-NE0009054 Copyright © 2025 TerraPower, LLC. All Rights Reserved Natrium Program Roadmap Pre-Demo Phase U.S. legacy SFR experience, PRISM and TWR development Commercial Series II+

(Up to GWe scale)

Commercial Series I Benefits

+DU Breed-and-Burn

+Potential UNF Recycling

+Potential Pu Disposition

+Zero-Carbon Process Heat Natrium Demonstration Project (345 MWe 500 MWe)

Commercial Plant Economics

+Energy Storage & Peaking Capability Natrium Commercial Series I (345 MWe 500 MWe) 3 yr. Construction

+Energy Storage & Peaking Capability 1980s-2019 2021-2030 2030+

2040+

Product Natrium Reactor Technology TWR Qualification and testing of commercial technology occurs through advanced fuel and materials development using the Natrium reactor system as a platform.

Demo project start April 1st, 2021 6

Time-temperature gaps in the design properties for the six currently-qualified Class A materials

Section III, Div 5 covers 300,000 hrs. Code case required to extend to 500,000 hrs

Testing may be required to extend material properties to longer times and/or higher temps

US NRC endorsements and potential restrictions

NRC reviewed the rules of ASME Section III, Division 5, 2017 edition and identified a set of material specific restrictions on the currently-qualified materials that could be mandated by the NRC as a condition of their endorsement of the ASME design approach

The simplified design-by-elastic analysis rules for evaluating the Section III, Division 5 creep-fatigue and deformation limits criteria may have reduced accuracy in the temperature range where creep and plasticity become indistinguishable

Does not provide reference inelastic constitutive models for use with the design by inelastic analysis method for evaluating the creep-fatigue and deformation limits

The list of currently-qualified Class A and Class B materials may not be optimal for some advanced reactor concepts ASME BPVC Challenges for Section III Div 5 Messner et al. 2021. ANL-21/27 Identifying Limitations of ASME Section III Division 5 For Advanced SMR Designs 7

HBB-2800 stipulates a fatigue acceptance test on every lot of material

HBB-2800 specifies ASTM E 606

Sample geometry as shown below where d=0.25 in

>0.5 in of material is needed for the sample

Push-pull test - thin or subsize specimens may buckle

Potentially limits applications/geometries where 304/316 SS can be used Code Challenges: HBB-2800 8

SUBJECT TO DOE COOPERATIVE AGREEMENT NO. DE-NE0009054 Copyright © 2025 TerraPower, LLC. All Rights Reserved In-situ mechanical testing SoCCRaTes Loop being fabricated at Oregon State University Mechanical properties testing in sodium using a load frame Facility for in-situ testing of mechanical properties using a miniature bellows system (GELS)

Sodium exposure testing SMT-3 loop fabricated and running at ANL Primary goal is to develop carburization/decarburization curves for core assembly materials (HT9 and Grade 92) to match published curve for Grade 91 (ANL-ART-190)

Structural materials, welds, and coatings will be included Evaluations of mass loss, mass transfer, effects on mechanical properties, etc.

Environmental Testing in Sodium SoCCRaTes sodium loop for in-situ mechanical SMT-3 Loop at ANL

SUBJECT TO DOE COOPERATIVE AGREEMENT NO. DE-NE0009054 Copyright © 2025 TerraPower, LLC. All Rights Reserved Material Sample Type Target Dose Range 316 SS Metallography, Tensile, Bend Base, coated 0.6 - 2 dpa 316 H SS Metallography, Tensile, Bend, Fracture Toughness, Creep Base, coated, welded, cold-worked, sensitized 0.5 - 10 dpa Alloy 718 Metallography, Tensile, Bend, Fracture Toughness, Creep Base, coated 0.6 - 6 dpa Grade 22 Metallography, Tensile, Bend Base, coated 0.5 dpa Neutron Irradiations in HFIR at ORNL Four campaigns

Structural materials

Welds

Coatings and surface treatments

Advanced fuel cladding materials Environmental Testing-Neutron Irradiation Coated specimen of the type inserted into HFIR

The qualification process for new materials is long compared to design and construction timelines.

Neither nuclear nor industrial codes & standards address full environmental effects relevant to time-temperature dependent properties driving design of advanced reactors.

In-Service Inspection in-situ is limited in pool type reactors, leading to increased consideration of monitoring technologies.

Challenges in Developing Advanced Manufacturing for Metallics

SUBJECT TO DOE COOPERATIVE AGREEMENT NO. DE-NE0009054 Copyright © 2025 TerraPower, LLC. All Rights Reserved SUBJECT TO DOE COOPERATIVE AGREEMENT NO. DE-NE0009054 Copyright © 2025 TerraPower, LLC. All Rights Reserved Natrium reactor is a TerraPower & GE Hitachi technology THANK YOU To learn more, visit www.terrapower.com

Radiant Proprietary and Confidential Qualification of Metallic Materials for Kaleidos NRC Accelerated Material Qualification Meeting 5/6/2025 Parker Buntin

Radiant Proprietary and Confidential Kaleidos l Mass-Produced HTGR Microreactor A climate-friendly alternative to diesel generators, the Kaleidos microreactor will make nuclear portable, bringing clean energy to remote areas.

2 1 MW Powers microgrids, data centers, military bases, and emergency relief disaster areas.

~1.9 MW Thermal power byproduct can deliver facility heating water desalination.

48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months Delivery via truck, ship, or plane.

Requires no site excavation or water lines and achieves full power the next day.

Zero waste No permanent waste on-site.

Shipped backed after 5-year use period for refueling and spent core storage off-site.

Radiant Proprietary and Confidential Radiant Material Qualification 3

- Data Qualification Methods 1.

Quality Assurance Program Equivalency 2.

Data Corroboration 3.

Confirmatory Testing 4.

Peer Review

Existing Data, in order of preference:

1.

Established data (codes/standards, handbooks, databases, industry-wide sources) 2.

Data from heritage use in nuclear applications 3.

Literature data (test reports, journal articles)

Qualified Material: Sufficient technical basis for materials & components to fulfill design requirements for design life

Radiant Proprietary and Confidential 316H Stainless Steel Forging Material 4

Austenitic stainless steel with high carbon for improved creep and strength performance at elevated temperatures

Approved Class A material per BPVC III.5 HBB for elevated temperature service Data available to 700 °C+

Service conditions of applications vary but all within BPVC envelope

Material ordered per ASME standards Includes material test coupons for mechanical property testing in representative environments

Radiant Proprietary and Confidential A286 Bolting Material 5

Precipitation-hardened austenitic stainless steel (Alloy 660) with high strength and corrosion resistance

Approved Class A bolting material per BPVC III.5 HBA for low temperature service ( 427 °C)

Not approved for elevated temperature service ( 427 °C)

Approved bolting material for non-nuclear applications per BPVC VIII.1 up to 538 °C

Service conditions of applications bounded by 550 °C

Collaboration with MPR Associates to use NIMS1 database to prepare BPVC III.5 A286 bolting code case for service up to 100,000 hours0 days 0 hours 0 weeks 0 months & 550 °C 3 month from project start to code case submission for comment & review at ASME Code Week May 11 - 16 2025 1NIMS = National Institute for Materials Science, formerly National Research Institute for Metals (NRIM)

Radiant Proprietary and Confidential A625 Wrought & Welded Material 6

Solid-solution strengthened nickel-based superalloy with high strength and corrosion resistance (Low Co)

A625 material specifications in BPVC II-B, but not permitted in BPVC III.5 Many reactor developers are considering use of Alloy 625 in primary system applications for elevated temperature service (core supports, primary pressure boundary)

Collaboration with INL & ANL on white paper for gap analysis identify testing required Leverage ASME Code Committees to organize industry collaboration on an Alloy 625 code case(s)

Kickoff meeting attended by 2 national labs, ASME representatives, 5 reactor developers, 1 metal supplier, 1 nonprofit organization Reactor developers conduct test programs, determine the qualification envelope, and contribute to the technical basis for the code case National labs, suppliers, and industry partners have an opportunity to support and contribute industry developers Welded Pipe Welded Plate Test Specimen from Weld Coupon

Radiant Proprietary and Confidential How to Accelerate Material Qualification

Leverage existing codes and standards Metallic Materials Properties Development and Standardization (MMPDS)

European Creep Collaborative Committee (ECCC)

NIMS databases (Japan)

National Laboratory Technical Reports and Handbooks

Provide guidance and pathways to qualify many new materials at once, rather than one material at a time e.g. bulk acceptance of materials from existing codes, standards, and databases instead of code case submissions for individual materials

Reduce testing burden for developers Reduce material qualification testing overhead for first-of-a-kind units with shorter lifetimes but increased monitoring Encourage surveillance and monitoring of materials through non-destructive examination (NDE) 7 ADVANCE Act Title IV Sec. 401

Radiant Proprietary and Confidential 2028 Timeline 8

Finalize Design and Material Selection 2025 Material Qualification Testing Kaleidos Demonstration Unit at INL DOME Licensing & Code Cases 2026 2027 Kaleidos Commercial Units Surveillance &

Monitoring Data Analysis

Radiant Proprietary and Confidential Acknowledgements

This work was conducted (in part) using the Creep Data Sheets provided by the Materials Data Platform (MDPF) of the National Institute for Materials Science (NIMS), formerly National Research Institute for Metals (NRIM)."

9

Radiant Proprietary and Confidential Questions?

10

ML25129A088

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Participants:

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