ML22179A334
| ML22179A334 | |
| Person / Time | |
|---|---|
| Issue date: | 06/28/2022 |
| From: | Office of Nuclear Regulatory Research |
| To: | |
| M. Yoo | |
| References | |
| Download: ML22179A334 (35) | |
Text
NRC Public Meeting Advanced Manufacturing Technologies US NRC June 28, 2022
NRC Draft Guidelines Document Laser - Directed Energy Deposition Mark Yoo Office of Nuclear Regulatory Research June 28, 2022
Outline
- Overview of Laser-Directed Energy Deposition (L-DED)
- Technical Basis for L-DED Draft Guidelines Document (DGD)
- Tie to Draft AMT Review Guidelines (Table 1)
- L-DED Technical Assessment
- Table 2A: Material-generic Process Topics
- Table 2B: 316L Material-Specific Properties / Performance Topics
- Conclusions
Laser-Directed Energy Deposition
- Process:
- Wire or powder fed through nozzle into laser for melting
- Fundamentally welding using robotics/
computer controls
- Potential Applications 4
- Medium sized Class 1, 2, and 3 components
- Larger components than laser-powder bed fusion are possible due to faster production and greater build chamber volumes Schematic of DED process https://www.osti.gov/pages/servlets/purl/1437906
Draft AMT Review Guidelines
- Provides guidelines to assist NRC staff reviewing requests to use AMTs and identifies the range of information that could be necessary in a submittal
- General Review Philosophy:
- Sufficient: all important (i.e., safety-significant or safety-related) attributes for the specific application of an AMT are addressed in sufficient technical depth to justify its use.
- Flexible: a variety of both technical and regulatory approaches can be used to demonstrate that these important attributes are addressed.
- Minimize technical and regulatory burden: the level of detail in which a submittal must address the applicable requirements and technical basis may vary depending on the safety significance of the application and the maturity of the AMT.
Appendix A Process Flow Chart
- Describes an approach to qualification and performance considerations
- Quality Assurance
- Process Qualification
- Essential Variable Identification
- Qualification Testing
- Supplemental Testing
- As needed to demonstrate design requirements in applicable environmental conditions
- Production Process Control and Verification
- Performance Monitoring
- Could include inspection, aging management, post-service evaluation
Technical Basis for L-DED Guidelines
- DGD is based on two technical documents (ML21301A077)
- Technical letter report from Oak Ridge National Laboratory (ORNL)
- NRC staff technical assessment of L-DED
- DGD builds on the NRC technical assessment and provides guidelines, when finalized, to the NRC staff by identifying important considerations when reviewing a submittal requesting the use of L-DED Technical Letter Report LPBF Technical Letter Report L-DED Technical Letter Report Cold Spray AMT-Specific (Initial 5 AMTs)
Generic Technical (Subtask 1A)
Final Guidance for Initial AMTs Regulatory Guidelines (Subtask 2C)
Technical Letter Report PM-HIP Technical Letter Report EBW NRC Staff-developed Contractor-developed Legend Technical Assessment LPBF Draft Guidelines Document LPBF Draft Guidelines Document L-DED Technical Assessment L-DED Draft Guidelines Document Cold Spray Technical Assessment Cold Spray Draft Guidelines Document PM-HIP Technical Assessment PM-HIP Technical Assessment EBW Draft Guidelines Document EBW Expected to be developed later after DOE-EPRI demo project Subtask 2C Draft AMT Review Guidelines
L-DED Technical Basis Documents
- Technical letter report on L-DED from ORNL
- Documents the current state of L-DED with respect to material microstructures and properties relative to conventional manufacturing
- Identifies technical and codes and standards gaps in ensuring quality and sufficient properties and performance for L-DED-fabricated components
- NRC staff technical assessment
- Provides context to the gaps identified in the ORNL report from NRCs perspective
- Considers other relevant technical information, such as NRC regulatory and research experience, technical meetings and conferences, codes and standards activities, EPRI and DOE research products
- Highlights key technical information related to L-DED-fabricated components in nuclear applications 8
Use of the Term Safety Significance
- The safety significance of each identified difference/topic in the L-DED DGD refers to the impact on component performance.
- The overall impact to plant safety is a function of component performance and the specific component application (e.g., its intended safety function).
- The L-DED DGD and its supporting documents do not address the impact on plant safety, as such an assessment would not be possible without considering a specific component application.
- In addition to the technical review guidelines in the L-DED DGD, the NRC staff should consider the specific component application and the potential for secondary consequences, such as debris generation and associated impacts, when assessing the impact to overall plant safety.
9
Tie to Draft AMT Review Guidelines (Table 1)
Difference / Topic Process Qualification Supplemental Testing Production Process Control and Verification Performance Monitoring Process-Driven: L-DED machine process control, Powder feedstock quality, Wire feedstock quality, L-DED build process management and control, Witness specimens, Thermal post-processing, Weldability / Joining X
X Process and Properties: Local geometry impacts on component properties and performance, Heterogeneity and anisotropy in properties, Residual stress, Porosity, Surface finish*, Tensile properties, Initial fracture toughness X
X Performance under Aging: Thermal aging, SCC and corrosion resistance, Fatigue, Irradiation effects, High Temperature Time-Dependent Aging Effects, Weld integrity X
X 10 The applicable primary elements may vary on a case-by-case basis, depending on the licensees approach to demonstrating quality and safety.
Table 1 provides an example of applicable elements and reflects that not every element in Appendix A to the draft AMT review guidelines is applicable to every difference listed in Table 1.
- also ties to Production Process Control and Verification
Tables 2A and 2B
- Tables 2A and 2B provide the technical review guidelines
- Material-generic vs. material-specific
- Table 2A lists the generic differences / topics (generally process focused)
- Table 2B lists the material-specific (generally properties and performance focused) differences / topics for L-DED 316L stainless steel
- Differences identified in Table 2B involving material-specific properties and performance would likely need to be considered for any newly fabricated material (316L or not) using L-DED
- In general, material-specific data are important for any nuclear L-DED-fabricated component to ensure adequate component performance in the applicable environment 11
Content of Tables 2A and 2B
- Difference
- Lists the differences between L-DED and traditional manufacturing identified in the NRC technical assessment
- Key Technical Information
- Summarizes the key technical information documented in the NRC technical assessment for easy reference
- Technical Review Guidelines
- Provides additional guidelines related to the differences between L-DED and traditional manufacturing that the staff should consider when evaluating how a licensees or applicants submittal addresses the differences between L-DED and traditional manufacturing 12
DGD Example - Table 2A, Process-Driven
DGD Example - Table 2A, Process and Properties
DGD Example - Table 2A, Process and Properties
DGD Example - Table 2B, Process and Properties
DGD Example - Table 2B, Performance Under Aging
Conclusions
- L-DED DGD has been developed as a "draft not for use"
- The DGD builds on the ORNL technical letter report and NRC staff technical assessment to provide the technical review guidelines and associated key technical information
- The L-DED DGD is consistent with the draft AMT review guidelines and addresses the same primary elements
- Technology-specific DGDs are anticipated to be incorporated in some form into the final AMT guidance 18
References
- Draft AMT Review Guidelines
- ADAMS Accession No. ML21074A037
- L-DED Draft Guidelines Document
- ADAMS Accession No. ML22143A951
- L-DED Technical Letter Report and Technical Assessment
- ADAMS Accession No. ML21301A077
- NRC Public Site on AMTs
- https://www.nrc.gov/reactors/power/amts.html
Questions ?
NRC Draft Guidelines Document Cold Spray Bruce Lin Office of Nuclear Regulatory Research June 28, 2022
Outline
- Overview of Cold Spray (CS)
- Technical Basis for CS Draft Guidelines Document (DGD)
- Tie to Draft AMT Review Guidelines (Table 1)
- CS Technical Review Guidelines
- Conclusions
Cold Spray
- Process:
- Powder is sprayed at supersonic velocities onto a metal surface and forms a bond with the part
- This can be used to repair existing parts or as a mitigation process
- Potential Applications 23
- Mitigation or repair of potential chloride-induced stress corrosion cracking (CISCC) in spent fuel canisters
- Mitigation or repair of stress corrosion cracking (SCC) in reactor applications Schematic of CS process https://www.army.mil/article/148465/army_researchers_develop_cold_spray_system_transition_to_industry
Technical Basis for CS Guidelines
- DGD is based on two technical documents (ML21263A105)
- Technical letter report from Pacific Northwest National Laboratory (PNNL)
- NRC staff technical assessment of CS
- DGD builds on the NRC technical assessment and provides guidelines, when finalized, to the NRC staff by identifying important considerations when reviewing a submittal requesting the use of CS Technical Letter Report LPBF Technical Letter Report L-DED Technical Letter Report Cold Spray AMT-Specific (Initial 5 AMTs)
Generic Technical (Subtask 1A)
Final Guidance for Initial AMTs Regulatory Guidelines (Subtask 2C)
Technical Letter Report PM-HIP Technical Letter Report EBW NRC Staff-developed Contractor-developed Legend Technical Assessment LPBF Draft Guidelines Document LPBF Draft Guidelines Document L-DED Technical Assessment L-DED Draft Guidelines Document Cold Spray Technical Assessment Cold Spray Draft Guidelines Document PM-HIP Technical Assessment PM-HIP Technical Assessment EBW Draft Guidelines Document EBW Expected to be developed later after DOE-EPRI demo project Subtask 2C Draft AMT Review Guidelines
CS Technical Basis Documents
- Provides an overview of CS technology and highlights important considerations for qualification of CS process
- Identifies knowledge gaps associated with using CS for nuclear power applications
- NRC staff technical assessment
- Provides context to the gaps identified in the PNNL report from NRCs perspective
- Highlights key technical information related to the use of CS for nuclear applications
- Assesses the properties and performance characteristics of CS for both structural and nonstructural applications 25
Structural vs. Nonstructural
- Structural applications
- Likely to be thicker
- Credit the CS material for load-bearing capacity such that either the CS material entirely or the CS material in conjunction with the substrate meet the full structural strength requirements
- Nonstructural applications
- Likely to be thinner
- Do not credit the CS material for any load-bearing capacity
- Only credit the CS material for non-structural purposes, such as corrosion mitigation or wear resistance
- The determination of whether a particular application is structural or non-structural will largely be dependent on whether the CS material is needed to meet structural requirements 26
Tie to Draft AMT Review Guidelines (Table 1)
Topic Process Qualification Supplemental Testing Production Process Control and Verification Performance Monitoring Process-Driven: Factory/field application, Power quality and processing, Surface preparation, Process parameter and controls, Post-processing, Witness specimens, Non-destructive examination X
X Process and Properties: Local geometry impacts on component properties and performance*, Adhesion strength, Porosity, Edge effects, Tensile properties, Initial fracture toughness X
X Performance: Corrosion/Erosion resistance, Wear resistance, SCC resistance, Fatigue resistance, Irradiation effects, Thermal aging, High temperature time-dependent aging effects X
X 27 The applicable primary elements may vary on a case-by-case basis, depending on the licensees approach to demonstrating quality and safety.
Table 1 provides an example of applicable elements and reflects that not every element in Appendix A to the draft AMT review guidelines is applicable to every topic listed in Table 1.
- also ties to Production Process Control and Verification
CS Technical Review Guidelines
- Tables 2 and 3 provide the technical review guidelines
- Table 2 addresses CS process considerations
- Table 3 covers properties and performance characteristic for CS materials
- Topics identified in Tables 2 and 3 involving CS process and properties and performance would likely need to be considered for application of CS in nuclear component
- Not all topics identified in the tables need to be addressed but only those that are relevant for the particular application
- In general, application-specific data will need to be generated to demonstrate adequate CS performance to meet the intended function of the CS materials 28
Content of Tables 2 and 3
- Topic
- Identifies the key aspect of the CS process or property / performance characteristics
- Key Technical Information
- Summarizes the key technical information associate with the specific topic for use of CS in nuclear applications
- Technical Review Guidelines
- Provides additional guidelines to support the staffs evaluation of the proposed use of CS 29
DGD Example - Table 2 Process Consideration Topic Key Technical Information Technical Review Guidelines Surface Preparation Poor surface preparation results in poor adhesion, or bonding, to the substrate.
Failure to remove oxide layers from a substrate surface before CS application can negatively impact coating performance.
Surface preparation examples include grit blasting, abrasive pads, and wire brushes or wire wheels.
The surfaces to receive CS deposits should be cleaned to remove oil, grease, dirt, paint, oxides, and other foreign material that could affect CS adhesion.
Section 2.2.4 of the PNNL TLR discuss surface preparation and post cleaning in more detail.
Process Qualification Through process qualification, the applicant should identify the necessary surface conditions including the necessary surface roughness and cleanliness for achieving a good quality coating. Cleaning procedures should not cause any damage to the surfaces that are to be coated that may detrimentally affect CS adhesion or component performance.
Production Process Control and Verification During CS application, measures should be employed to protect the surface to be coated from dust, dirt, moisture, and other contaminants that may detrimentally affect CS adhesion.
The applicant can use a variety of post process quality testing such as adhesion testing and NDE to validate the adequacy of surface preparation practices and procedures.
DGD Example - Table 3 Properties and Performance Topic Key Technical Information Technical Review Guidelines Adhesion Strength Adhesion strength of 10-20 kilopounds per square inch (ksi) is common on a properly prepared surface, and adhesion strengths greater than 30 ksi are not uncommon for CS adhesion strength of higher strength alloys.
Thick oxides and surface contamination can significantly reduce the adhesion strength of the CS coating.
Adhesion strength may be limited by the bond strength of the epoxy when epoxy-based adhesion tests (ASTM-C633, ASTM-D4541) are used.
The triple-lug shear testing described in MIL-J-24445A can be used to reach adhesion values not limited to epoxy strength.
Process Qualification/Supplemental Testing/Performance Monitoring For process qualification and supplemental testing, the applicant should provide an analysis, supported by sufficient data in representative or bounding environments (e.g. temperature, chemistry, stress), to show adequate adhesion strength of the CS material to the substrate over the intended service life.
o The corresponding analysis can demonstrate acceptable performance using approaches such as the following:
demonstrating adequate adhesion strength by adhesion tests
experience from previous applications of CS in similar environments using similar process and material
NDE may be used to confirm adhesion quality.
DGD Example - Table 3 Process and Properties Topic Key Technical Information Technical Review Guidelines Corrosion /
Erosion Resistance For corrosion resistance, the most used coatings are forms of nickel, copper, aluminum, or titanium.
Short-term testing using ASTM standards may be used to screen corrosion and erosion resistance of material combinations in representative environments.
Corrosion testing using representative test conditions may be necessary to demonstrate the long-term behavior of CS protective coatings.
Supplemental Testing/Performance Monitoring Through supplemental testing and performance monitoring, the applicant should provide an analysis, supported by sufficient data in representative or bounding environments, to show adequate corrosion/erosion resistance for the intended function of the CS component over the intended service life.
o The corresponding analysis can demonstrate meeting design requirements by using approaches such as the following:
demonstrating equal or superior performance by comparison to corrosion / erosion performance for substrate materials (assuming similar in-service inspection frequency and methods)
addressing uncertainties in the data on corrosion / erosion and the implications to in-service performance through conservative design assumptions, additional margins in analyses, surveillance programs, in-service inspection, or additional performance monitoring as appropriate
Conclusions
- CS DGD has been developed as a "draft not for use"
- The DGD builds on the PNNL technical letter report and NRC staff technical assessment to provide the technical review guidelines and associated key technical information
- The CS DGD is consistent with the draft AMT review guidelines and addresses the same primary elements
- Technology-specific DGDs are anticipated to be incorporated in some form into the final AMT guidance 33
References
- CS Draft Guidelines Document
- ADAMS Accession No. ML22143A952
- CS Technical Letter Report and Technical Assessment
- ADAMS Accession No. ML21263A105
- NRC Public Site on AMTs
- https://www.nrc.gov/reactors/power/amts.html
Questions ?