NOFO_DE-FOA-0003623_HORNIG_Modification 01.pdf

Questions about this NOFO? Check the Frequently Asked Questions available at https://arpa-e.energy.gov/faqs. For questions that have not already been answered, email ARPA-E-CO@hq.doe.gov (with NOFO name and number in subject line). Problems with ARPA-E eXCHANGE? Email ExchangeHelp@hq.doe.gov (with NOFO name and number in subject line).

FINANCIAL ASSISTANCE

NOTICE OF FUNDING OPPORTUNITY

ADVANCED RESEARCH PROJECTS AGENCY—ENERGY (ARPA-E)

U.S. DEPARTMENT OF ENERGY

HIGH-PERFORMANCE OPTIMIZED RECYCLED

NUCLEAR ISOTOPES FOR GEN IV REACTORS

(HORNIG)

Announcement Type: Initial Announcement Modification 01 Notice of Funding Opportunity No. DE-FOA-0003623

Assistance Listing Number 81.135

Mod. No. Date Description of Modifications 01 July 7, 2026 • Inserted certain deadlines and updated dates, including the deadlines for submitting questions and Full Applications (Basic Information, Section IV.C).

*All modifications to the Notice of Funding Opportunity (NOFO) are highlighted in yellow in the body of the NOFO.

NOFOs are posted on ARPA-E eXCHANGE (https://arpa-e-foa.energy.gov/), Grants.gov (http://www.grants.gov/), and FedConnect (https://www.fedconnect.net/FedConnect/). Any modifications to the NOFO are also posted to these websites. You can receive an e-mail when a modification is posted by registering with FedConnect as an interested party for this NOFO. It is recommended that you register as soon as possible after release of the NOFO to ensure that you receive timely notice of any modifications or other announcements.

https://arpa-e.energy.gov/faqs mailto:ARPA-E-CO@hq.doe.gov mailto:ExchangeHelp@hq.doe.gov https://arpa-e-foa.energy.gov/ http://www.grants.gov/ https://www.fedconnect.net/FedConnect/

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AR-311-05.25

TABLE OF CONTENTS

BASIC INFORMATION.......................................................................................................... - 6 - I. FUNDING OPPORTUNITY DESCRIPTION .............................................................. - 8 -

A. AGENCY OVERVIEW ........................................................................................................ - 8 - B. PROGRAM OVERVIEW ................................................................................................... - 10 -

1. TECHNICAL DESCRIPTION ....................................................................................... - 10 -

2. TECHNICAL NEEDS ................................................................................................. - 11 -

C. PROGRAM OBJECTIVES ................................................................................................. - 12 - D. TECHNICAL CATEGORIES OF INTEREST ....................................................................... - 12 -

1. CATEGORY A: FUELS .............................................................................................. - 13 -

1. FUEL DESIGN .......................................................................................................... - 13 -

2. FUEL FABRICATION ................................................................................................. - 14 -

3. TESTING AND CHARACTERIZATION OF FUEL MICROSTRUCTURE, PROPERTIES, AND

PERFORMANCE ............................................................................................................... - 15 -

4. FUEL PERFORMANCE MODELING ............................................................................ - 16 -

5. FUEL QUALIFICATION PLAN .................................................................................... - 16 -

2. CATEGORY B: CAPABILITIES ................................................................................... - 17 -

3. TECHNOLOGY-TO-MARKET CONSIDERATIONS ........................................................ - 18 -

4. CATEGORY, PROJECT, AND TEAM LOGISTICS .......................................................... - 18 -

5. DATA STORAGE PLAN .............................................................................................. - 20 -

E. TECHNICAL PERFORMANCE TARGETS ......................................................................... - 20 -

1. CATEGORY A: FUELS .............................................................................................. - 20 -

1. FABRICATION: ......................................................................................................... - 20 -

2. EXPERIMENTAL DATA: ............................................................................................ - 21 -

3. MODELING AND SIMULATION: ................................................................................. - 21 -

2. CATEGORY B: CAPABILITIES ................................................................................... - 22 - F. STATEMENT OF SUBSTANTIAL INVOLVEMENT ............................................................. - 23 - G. FUNDING RESTRICTIONS ............................................................................................... - 24 -

1. ALLOWABLE COSTS ................................................................................................. - 24 -

2. PRE-AWARD COSTS ................................................................................................. - 24 -

3. PATENT COSTS ........................................................................................................ - 24 -

4. CONSTRUCTION ....................................................................................................... - 24 -

5. FOREIGN TRAVEL .................................................................................................... - 24 -

6. PERFORMANCE OF WORK IN THE UNITED STATES.................................................. - 25 -

7. PURCHASE OF NEW EQUIPMENT ............................................................................. - 25 -

8. TECHNOLOGY TRANSFER AND OUTREACH .............................................................. - 25 -

9. LOBBYING................................................................................................................ - 25 -

10. CONFERENCE SPENDING ......................................................................................... - 26 -

11. INDEPENDENT RESEARCH AND DEVELOPMENT COSTS ........................................... - 26 -

12. BUY AMERICA REQUIREMENT FOR PUBLIC INFRASTRUCTURE PROJECTS .............. - 27 -

13. REQUIREMENT FOR FINANCIAL PERSONNEL .......................................................... - 27 -

14. PARTICIPANTS, COLLABORATING ORGANIZATIONS, AND CURRENT AND PENDING

SUPPORT ............................................................................................................................ - 27 -

II. ELIGIBILITY INFORMATION .................................................................................. - 29 -

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A. ELIGIBLE APPLICANTS .................................................................................................. - 29 -

1. INDIVIDUALS ........................................................................................................... - 29 -

2. DOMESTIC ENTITIES ............................................................................................... - 29 -

3. CONSORTIA.............................................................................................................. - 30 -

4. FOREIGN PARTICIPATION CONSIDERATIONS .......................................................... - 30 -

5. ENTITY OF CONCERN PROHIBITION ........................................................................ - 30 -

6. PROHIBITION RELATED TO MALIGN FOREIGN TALENT RECRUITMENT PROGRAMS- 31 -

B. COMPLIANCE AND RESPONSIVENESS ............................................................................ - 31 - C. LIMITATION ON NUMBER OF SUBMISSIONS .................................................................. - 31 - D. COST SHARING .............................................................................................................. - 32 -

1. BASE COST SHARE REQUIREMENT .......................................................................... - 32 -

2. INCREASED COST SHARE ........................................................................................ - 32 -

3. REDUCED COST SHARE REQUIREMENT .................................................................. - 32 -

4. LEGAL RESPONSIBILITY .......................................................................................... - 33 -

5. COST SHARE ALLOCATION ...................................................................................... - 33 -

6. COST SHARE TYPES AND ALLOWABILITY ................................................................ - 33 -

7. COST SHARE CONTRIBUTIONS BY FFRDCS AND GOGOS ...................................... - 34 -

8. COST SHARE VERIFICATION.................................................................................... - 34 -

III. APPLICATION CONTENTS AND FORMAT ........................................................... - 35 - A. GENERAL APPLICATION CONTENT REQUIREMENTS ................................................... - 35 -

1. MARKING OF CONFIDENTIAL INFORMATION .......................................................... - 35 -

2. EXPORT CONTROL INFORMATION ........................................................................... - 35 -

B. CONCEPT PAPERS .......................................................................................................... - 36 -

1. FIRST COMPONENT: CONCEPT PAPER .................................................................... - 36 -

2. SECOND COMPONENT: SUMMARY SLIDE ................................................................ - 36 -

C. FULL APPLICATIONS ..................................................................................................... - 37 -

1. FIRST COMPONENT: TECHNICAL VOLUME ............................................................. - 37 -

2. SECOND COMPONENT: SF-424 ............................................................................... - 38 -

3. THIRD COMPONENT: BUDGET JUSTIFICATION WORKBOOK/SF-424A .................... - 38 -

4. FOURTH COMPONENT: SUMMARY FOR PUBLIC RELEASE ....................................... - 39 -

5. FIFTH COMPONENT: SUMMARY SLIDE ................................................................... - 39 -

6. SIXTH COMPONENT: BUSINESS ASSURANCES & DISCLOSURES FORM ................... - 39 -

7. SEVENTH COMPONENT: BIOGRAPHICAL SKETCHES (BIOSKETCH) ......................... - 40 -

8. EIGHTH COMPONENT: CURRENT, PENDING, AND PAST SUPPORT .......................... - 40 -

9. NINTH COMPONENT: TRANSPARENCY OF FOREIGN CONNECTIONS ........................ - 42 -

10. TENTH COMPONENT: LETTER OF INTENT ............................................................... - 42 -

D. REPLIES TO REVIEWER COMMENTS ............................................................................. - 43 - IV. SUBMISSION REQUIREMENTS AND DEADLINES.............................................. - 44 -

A. UNIQUE ENTITY IDENTIFIER AND SAM REGISTRATION ............................................. - 44 - B. USE OF ARPA-E EXCHANGE .................................................................................... - 44 - C. REQUIRED DOCUMENTS CHECKLIST AND DEADLINES ................................................ - 46 - D. COMPLIANCE ................................................................................................................. - 47 - E. ARTIFICIAL INTELLIGENCE (AI) APPLICATION USE ................................................... - 47 - F. INTERGOVERNMENTAL REVIEW ................................................................................... - 48 -

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V. APPLICATION REVIEW INFORMATION .............................................................. - 49 - A. RESPONSIVENESS ........................................................................................................... - 49 -

1. TECHNICAL RESPONSIVENESS REVIEW ................................................................... - 49 -

2. SUBMISSIONS SPECIFICALLY NOT OF INTEREST ...................................................... - 49 -

B. REVIEW CRITERIA ........................................................................................................ - 50 -

1. CRITERIA FOR CONCEPT PAPERS ............................................................................ - 50 -

1. IMPACT OF THE PROPOSED TECHNOLOGY RELATIVE TO NOFO TARGETS (50%) .. - 50 -

2. OVERALL SCIENTIFIC AND TECHNICAL MERIT (50%) ............................................ - 50 -

2. CRITERIA FOR FULL APPLICATIONS ........................................................................ - 51 -

1. IMPACT OF THE PROPOSED TECHNOLOGY (35%).................................................... - 51 -

2. OVERALL SCIENTIFIC AND TECHNICAL MERIT (35%) ............................................ - 51 -

3. QUALIFICATIONS, EXPERIENCE, AND CAPABILITIES OF THE PROPOSED PROJECT

TEAM (10%) ................................................................................................................... - 51 -

4. SOUNDNESS OF MANAGEMENT PLAN (20%) ........................................................... - 52 -

3. CRITERIA FOR REPLIES TO REVIEWER COMMENTS ................................................ - 52 - C. PROGRAM POLICY FACTORS ........................................................................................ - 52 - D. REVIEW AND SELECTION PROCESS .............................................................................. - 53 -

1. CONCEPT PAPERS .................................................................................................... - 53 -

2. FULL APPLICATIONS ............................................................................................... - 53 -

3. REPLY TO REVIEWER COMMENTS ........................................................................... - 54 -

4. PRE-SELECTION CLARIFICATIONS AND “DOWN-SELECT” PROCESS ...................... - 54 -

5. SELECTION FOR AWARD NEGOTIATIONS ................................................................. - 54 -

E. ARPA-E REVIEWERS .................................................................................................... - 55 - F. ARPA-E SUPPORT CONTRACTORS .............................................................................. - 55 - G. RISK REVIEW ................................................................................................................. - 55 -

H. DUE DILIGENCE REVIEW FOR RESEARCH, TECHNOLOGY AND ECONOMIC SECURITY - 56

VI. AWARD NOTICES AND AWARD TYPES ................................................................ - 58 - A. AWARD NOTICES ........................................................................................................... - 58 -

1. REJECTED SUBMISSIONS ......................................................................................... - 58 -

2. CONCEPT PAPER NOTIFICATIONS ........................................................................... - 58 -

3. FULL APPLICATION NOTIFICATIONS ....................................................................... - 58 -

1. SUCCESSFUL APPLICANTS ....................................................................................... - 59 -

2. POSTPONED SELECTION DETERMINATIONS ............................................................ - 59 -

3. UNSUCCESSFUL APPLICANTS .................................................................................. - 59 -

B. PRE-AWARD COSTS ....................................................................................................... - 59 - C. RENEWAL AWARDS ....................................................................................................... - 60 - D. FUNDING AGREEMENT TYPES....................................................................................... - 60 -

1. COOPERATIVE AGREEMENTS .................................................................................. - 60 -

2. FUNDING AGREEMENTS WITH FFRDCS/DOE LABS, GOGOS, AND FEDERAL

INSTRUMENTALITIES ......................................................................................................... - 60 -

3. OTHER TRANSACTIONS AUTHORITY ........................................................................ - 61 -

VII. POST-AWARD REQUIREMENTS AND ADMINISTRATION .............................. - 62 - A. NATIONAL POLICY REQUIREMENTS ............................................................................. - 62 -

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1. NATIONAL POLICY ASSURANCES ............................................................................. - 62 -

2. ENVIRONMENTAL IMPACT QUESTIONNAIRE ........................................................... - 62 -

B. ADMINISTRATIVE REQUIREMENTS ............................................................................... - 63 -

1. COST SHARE PAYMENTS.......................................................................................... - 63 -

2. INTELLECTUAL PROPERTY AND DATA MANAGEMENT AND SHARING PLANS .......... - 63 -

3. U.S. COMPETITIVENESS .......................................................................................... - 64 -

4. NONDISCLOSURE AND CONFIDENTIALITY AGREEMENTS REPRESENTATIONS ......... - 65 -

5. INTERIM CONFLICT OF INTEREST POLICY FOR FINANCIAL ASSISTANCE ................ - 66 -

6. COMPLIANCE AUDIT REQUIREMENT ....................................................................... - 66 -

7. RESEARCH SECURITY TRAINING REQUIREMENT .................................................... - 67 -

8. FOREIGN COLLABORATION CONSIDERATIONS ........................................................ - 67 -

C. REPORTING .................................................................................................................... - 68 -

1. FRAUD, WASTE, AND ABUSE ................................................................................... - 68 -

2. COMMERCIALIZATION PLAN AND SOFTWARE REPORTING ...................................... - 68 -

VIII. OTHER INFORMATION ................................................................................ - 69 - A. TITLE TO SUBJECT INVENTIONS ................................................................................... - 69 - B. GOVERNMENT RIGHTS IN SUBJECT INVENTIONS ......................................................... - 70 -

1. GOVERNMENT USE LICENSE ................................................................................... - 70 -

2. MARCH-IN RIGHTS.................................................................................................. - 70 -

C. RIGHTS IN TECHNICAL DATA ....................................................................................... - 70 - D. PROTECTED PERSONALLY IDENTIFIABLE INFORMATION ........................................... - 71 -

IX. GLOSSARY..................................................................................................................... - 73 -

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BASIC INFORMATION

KEY DATES:

Notice of Funding Opportunity (NOFO) Issue Date: April 23, 2026 Deadline for Concept Paper Questions to ARPA-E- CO@hq.doe.gov:

5 PM ET, May 18, 2026

Submission Deadline for Concept Papers: 9:30 AM ET, May 28, 2026 Anticipated Date for Encourage/Discourage Notifications: 5 PM ET, July 13 7, 2026 Deadline for Full Application Questions to ARPA-E- CO@hq.doe.gov:

5 PM ET, TBD July 27, 2026

Submission Deadline for Full Applications: 9:30 AM ET, TBD August 6, 2026 Expected Reviewer Comment Release Date: 5 PM ET, TBD September 1, 2026 Submission Deadline for Replies to Reviewer Comments: 5 PM ET, TBD September 8, 2026 Anticipated Timeframe for Selection Notifications: September 2026 Anticipated Timeframe for Award: December 2026 Anticipated Period of Performance: December 2026 – December 2029

BASIC INFORMATION:

Total Amount to Be Awarded

Approximately $50 million, subject to the availability of appropriated funds.

Anticipated Number and Value of Awards

ARPA-E anticipates making approximately 8–10 awards. ARPA-E may issue one, multiple, or no awards under this NOFO. The Federal share of awards under this NOFO may vary between $500,000 and $7 million.

Agency Contact Information

• Questions and answers (Q&As) about ARPA-E and this specific NOFO:

http://arpa-e.energy.gov/faq.

• Send other questions about the NOFO to ARPA-E-CO@hq.doe.gov.

• Send questions about use of ARPA-E eXCHANGE to

ExchangeHelp@hq.doe.gov.

Upon the issuance of a NOFO, only the Grants Officer via ARPA-E- CO@hq.doe.gov may communicate with applicants. This “quiet period” remains in effect until ARPA-E’s selection notification letters are distributed. Emails sent to other email addresses will be disregarded.

This funding opportunity supports the development of transuranic (TRU) fuels from a largely untapped domestic fissile resource found across U.S. inventories. TRU fuels could expand the nation’s nuclear fuel supply while reducing the volume of radioactive waste.

Establishing TRU fuels as an economic source of energy will bolster American industry, energy dominance, and national security by:

• Strengthening fuel supply chains for nuclear reactors

• Reducing reliance on foreign sources

• Advancing American leadership in critical technologies

• Supporting long-term deployment of new nuclear power plants mailto:ARPA-E-CO@hq.doe.gov mailto:ARPA-E-CO@hq.doe.gov mailto:ARPA-E-CO@hq.doe.gov http://arpa-e.energy.gov/faq mailto:ARPA-E-CO@hq.doe.gov mailto:ExchangeHelp@hq.doe.gov

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High-performance Optimized Recycled Nuclear Isotopes for Gen IV reactors (HORNIG) will fund coordinated research and development efforts spanning fuel design, fabrication, testing, modeling, and qualification, along with analysis of cost, impact, and deployment pathways.

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I. FUNDING OPPORTUNITY DESCRIPTION

A. AGENCY OVERVIEW

The Advanced Research Projects Agency—Energy (ARPA-E), an organization within the Department of Energy (DOE), is chartered by Congress in the America COMPETES Act of 2007 (Public Law 110–69), as amended by the America COMPETES Reauthorization Act of 2010 (Public Law 111–358), as further amended by the Energy Act of 2020 (Public Law 116–260).

ARPA-E issues this Notice of Funding Opportunity (NOFO) under its authorizing statute codified at 42 U.S.C. § 16538.1 The NOFO and any cooperative agreements or grants made under this NOFO are subject to 2 C.F.R. Part 200 as supplemented by 2 C.F.R. Part 910.

ARPA-E funds research on, and the development of, transformative science and technology solutions to address the energy and environmental missions of the Department. The agency focuses on technologies that can be meaningfully advanced with a modest investment over a defined period of time in order to catalyze the translation from scientific discovery into early-stage technology. For the latest news and information about ARPA-E, its programs and the research projects currently supported, see: http://arpa-e.energy.gov/.

ARPA-E funds transformational research. Existing energy technologies generally progress on established “learning curves” where refinements to a technology and the economies of scale that accrue as manufacturing and distribution develop drive improvements to the cost/performance metric in a gradual fashion. This continual improvement of a technology is important to its increased commercial deployment and is appropriately the focus of the private sector or the applied technology offices within DOE. In contrast, ARPA-E supports transformative research that has the potential to create fundamentally new learning curves.

ARPA-E technology projects typically start with cost/performance estimates well above the level of an incumbent technology. Given the high risk inherent in these projects, many will fail to progress, but some may succeed in generating a new learning curve with a projected cost/performance metric that is significantly better than that of the incumbent technology.

ARPA-E will provide support at the highest funding level only for submissions with significant technology risk, aggressive timetables, and careful management of associated risk.

ARPA-E funds technology with the potential to be disruptive in the marketplace. The mere creation of a new learning curve does not ensure market penetration. Rather, the ultimate value of a technology is determined by the marketplace, and impactful technologies ultimately become disruptive—that is, they are widely adopted and displace existing technologies from the marketplace or create entirely new markets. ARPA-E understands that definitive proof of market disruption takes time, particularly for energy technologies. Therefore, ARPA-E funds the development of technologies that, if technically successful, have clear disruptive potential, e.g., by demonstrating capability for manufacturing at competitive cost and deployment at scale.

1 ARPA-E, Authorization (2026). https://arpa-e.energy.gov/about/arpa-e-at-a-glance/authorization.

http://arpa-e.energy.gov/ https://arpa-e.energy.gov/about/arpa-e-at-a-glance/authorization https://arpa-e.energy.gov/about/arpa-e-at-a-glance/authorization

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ARPA-E funds applied research and development (R&D). The Office of Management and Budget defines “applied research” as an “original investigation undertaken in order to acquire new knowledge…directed primarily toward a specific practical aim or objective” and defines “experimental development” as “creative and systematic work, drawing on knowledge gained from research and practical experience, which is directed at producing new products or processes or improving existing products or processes.”2 Applicants interested in receiving financial assistance for basic research (defined by the Office of Management and Budget as “experimental or theoretical work undertaken primarily to acquire new knowledge of the underlying foundations of phenomena and observable facts”) should contact the DOE’s Office of Science. Office of Science national scientific user facilities (http://science.energy.gov/user-facilities/) are open to all researchers, including ARPA-E applicants and awardees. These facilities provide advanced tools of modern science including accelerators, colliders, supercomputers, light sources and neutron sources, as well as facilities for studying the nanoworld, the environment, and the atmosphere. Projects focused on early-stage R&D for the improvement of technology along defined roadmaps may be more appropriate for support through the DOE applied energy offices including: the Office of Critical Minerals and Energy Innovation (CMEI), the Office of Hydrocarbon and Geothermal Energy, the Office of Nuclear Energy, and the Office of Electricity.

ARPA-E encourages submissions stemming from ideas that still require proof-of-concept R&D efforts as well as those for which some proof-of-concept demonstration already exists.

Submissions can propose a project with the end deliverable being an extremely creative, but partial solution.

2 Office of Management & Budget, OMB Circular A-11 (2025), https://www.whitehouse.gov/wp-content/uploads/2018/06/a11_web_toc.pdf.

http://science.energy.gov/ http://science.energy.gov/ http://science.energy.gov/user-facilities/ http://science.energy.gov/user-facilities/ https://www.energy.gov/cmei/about-office-energy-efficiency-and-renewable-energy https://www.energy.gov/cmei/about-office-energy-efficiency-and-renewable-energy https://www.energy.gov/hgeo/hydrocarbons-and-geothermal-energy-office http://www.energy.gov/ne/office-nuclear-energy http://www.energy.gov/ne/office-nuclear-energy https://www.energy.gov/oe/office-electricity https://www.whitehouse.gov/wp-content/uploads/2018/06/a11_web_toc.pdf

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B. PROGRAM OVERVIEW

Transuranic (TRU) elements—such as plutonium (Pu), neptunium (Np), and americium (Am)—are a significant source of fissile materials that are available across existing nuclear inventories and strategic reserves and have the potential to drive advanced reactor deployment.3,4 The technical feasibility of recycling TRU elements into new fuels has been proven at the experimental scale. 5 Advances in fabrication, safeguards, equipment design, and modeling will create the opportunity to transition from experimental success to commercial-scale deployment, enabling higher-throughput and lower-cost fuel production with real-time materials accountancy. The High-performance Optimized Recycled Nuclear Isotopes for Gen IV reactors (HORNIG) program will support research and development projects that deliver commercially deployable TRU fuel technologies, thereby strengthening U.S. energy security, reducing nuclear waste, and enabling long-term energy deployment for public benefit.

1. TECHNICAL DESCRIPTION

Nuclear fuel development in the United States follows a structured process of design, fabrication, testing, and qualification.6,7,8 The nation’s commercial fleet of light water reactors (LWR) uses uranium dioxide (UO₂) ceramic fuels enriched to approximately 5 percent U-235.

Ongoing developments in nuclear fuels span metallic alloys (e.g., U-Zr, U-Pu-Zr), ceramic fuels (e.g., nitrides, tristructural isotropic [TRISO]), and actinide-bearing molten salts for use in advanced nuclear reactors.

Fabricating these new fuels today relies on batch-scale processes with low throughput.

Most fabrication technologies have minimal online quality control or safeguards integration.

Development proceeds largely in sequence: new fuel concepts are produced at laboratory scale, tested in research reactors, and examined post-irradiation. Insights from testing inform subsequent design iterations and qualification efforts.

3 Wolf, S.F.; Bowers, D.L.; Cunnane. Analysis of high burnup spent nuclear fuel by ICP-

MS. J. Radioanal. Nucl. Chem. 2005. 263 (3), 581-586.

4 An advanced reactor in this context is any generation IV nuclear reactor.

5 Idaho National Laboratory. Review of Transmutation Fuel Studies. Carmack, J.;

Pasamehmetoglu, K.O. INL/EXT-08-13779. 20082008.

6 Crawford, D.C.; Porter, D.L.; Hayes, S.L.; Meyer, M.K.; Petti, D.A.; Pasamehmetoglu, K.O. An approach to fuel development and qualification. J. Nucl. Mater. 2007: 371 (1-3) 232-

242. https://doi.org/10.1016/j.jnucmat.2007.05.029

7 Terrani, K.A.; Capps, N.A.; Kerr, M.J.; Back, C.A.; Nelson, A.T.; Wirth, B.D.; Hayes, S.L.; Stanek, C.R. Accelerating nuclear fuel development and qualification: Modeling and simulation integrated with separate-effects testing. 2020. J. Nucl. Mater: 539.

https://doi.org/10.1016/j.jnucmat.2020.152267

8 Mika, M.; Probert, A.; Aitkaliyeva, A. Nuclear fuel qualification: History, current state, and future. Prog. Nucl. Energy. 2024: 177.

https://doi.org/10.1016/j.jnucmat.2007.05.029 https://doi.org/10.1016/j.jnucmat.2020.152267

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Although modeling and simulation tools support fuel development and qualification, current capabilities do not capture TRU-specific phenomena (including, but not limited to, plutonium redistribution, helium production, swelling from minor actinide (MA) decay, and fuel-cladding chemical interactions) with sufficient accuracy.9,10,11, 12,13

Commercial deployment of any new nuclear fuel requires demonstrating safety and performance under both normal and accident conditions. The Nuclear Regulatory Commission (NRC) regulates this qualification process with accelerated frameworks, but TRU fuels have not been qualified for commercial use.14

2. TECHNICAL NEEDS

Achieving commercial deployment of TRU fuels will require innovation in design, fabrication, testing, modeling, and qualification. Three core technical gaps must be addressed to enable scalable and economic deployment of TRU fuel:

• Fuel fabrication. Current TRU fuel fabrication methods remain predominantly small-scale and labor intensive, which limits throughput and fails to lower cost. Most technologies are not yet designed with integrated safeguards and real-time materials accountancy. Incorporating process optimization and ensuring scalability of the fabrication processes is critical to their commercial viability.

• Fuel development cycle. Fuel design, testing, and qualification are pursued sequentially or in isolation from reactor development, with limited iterations and optimization. This fragmented fuel development cycle slows progress toward deployable solutions and extends time to market. A coordinated approach across fuel and reactor development is needed to accelerate progress.

9 Idaho National Laboratory. Engineering & Microstructure Scale PIE Report on EBR-II

X441A Metallic Fuel Pins for the MORPH Experiment. Capriotti, L.; Wright, K.; Di Lemma, F.; Trowbridge, T.; Aitkaliyeva, A.; Rahn, T.T. INL/-EXT-19-55851. Jul. 2022.

10 Wright, K.E.; Lecrivain, L.; Pincock, C.; Coleman, M.; Wiscaver, P.; Barker, B.;

Albuquerque, L.G.R.; Capriotti, L.; Aitkaliyeva, A. Exploring constituent redistribution in irradiated U-19Pu-14Zr fuel via electron probe microanalysis. J. Nucl. Mater. 2025: 603.

11 Wiss, T.; Konings, R.J.M.; Staicu, D.; Benedetti, A.; Colle, J-Y.; Rondinella, V.V.;

Magueri, E.; Talip, Z.; Janssen, A.; Dieste, O.; Cognini, L.; De Bona, E.; Baldinozzi, G.;

Gueneau, C. Impact of alpha-damage and helium production on the heat capacity of actinide oxides. Front. Nucl. Eng 4. 2025: 4.

12Nguyen, B-P.; Capriotti, L.; Aitkaliyeva, A.; Wang, Y. Elucidating the effect of minor-actinide addition on fuel-cladding chemical interaction in an HT-9 clad U-Pu-Zr metallic fuel irradiated to 6.15 at.% burnup in EBR-II. J. Nucl. Mater. 2025: 616.

13 Capriotti, L.; Harp, J. Characterization of a minor actinides bearing metallic fuel pin irradiated in EBR-II. J. Nucl. Mater. 2020: 539.

14 U.S. Nuclear Regulatory Commission, “Accelerated Fuel Qualification White Paper”, October 10 2021. Agencywide Document Access and Management System (ADAMS) Accession No. ML21287A646.

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• Experimental data and modeling. Few experiments have directly assessed TRU fuel behavior under realistic conditions, so existing performance codes often rely on uranium-based data that may not capture TRU-specific phenomena and behavior. This hinders model validation, slowing the qualification process and commercial adoption. Expanded data generation and TRU-specific model development are needed to close these gaps.

C. PROGRAM OBJECTIVES

The HORNIG program seeks to overcome key technical and economic barriers that have historically prevented using TRU fuels in commercial reactors and to create a clear path to domestic nuclear fuel security by supporting the design, fabrication, and qualification of TRU fuels.15 The program will fund coordinated, multidisciplinary efforts to deliver transformative advances in fuel performance, manufacturability, cost, and regulatory readiness. Technologies developed under this program must have the potential to enable the following program metrics:

• A domestic TRU fuel supply chain

• A levelized cost of fuel (LCOF) ≤ 1¢/kWh16

• TRU fuel qualification and regulatory acceptance within seven years

By enabling production of advanced reactor fuels from domestically sourced fissile materials, the program will reduce dependence on imported uranium and enrichment services, expand U.S. fuel supply options, and support establishment of a closed fuel cycle. These objectives support ARPA-E’s statutory goals of improving energy security and resilience, improving the management of radiological waste, and maintaining U.S. technological leadership in energy technologies. If successful, HORNIG will strengthen U.S. energy security and infrastructure resilience and deliver lasting public benefit through reliable nuclear power.

D. TECHNICAL CATEGORIES OF INTEREST

This program is structured in two complementary categories. Category A focuses on the innovation and integration of TRU fuel technologies, spanning design, fabrication, testing, modeling, and qualification. Category B supports Category A with cross-cutting tools, ensuring developments made by Category A teams are viable for commercial adoption. Together, these project categories are intended to accelerate TRU fuel deployment by pairing technological advancements with economic, regulatory, and infrastructure readiness.

All advanced reactor fuels are of interest, including metallic, ceramic (e.g., nitride, TRISO), molten salt, and other breakthrough concepts. The exact fuel composition, form, and cladding configuration should be specified in the application.

15 In this NOFO, TRU fuels include, but are not limited to, fuels compositions containing

U/Pu, U/TRU, and Pu/MA elements.

16 ARPA-E has provided an optional LCOF Estimator Tool in eXCHANGE to help applicants evaluate the potential cost impact of their technologies during the application process.

During project execution, Category A teams are expected to refine their estimates based on project results, either by developing their own technoeconomic analysis or by collaborating with a Category B team.

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After reviewing the category descriptions below, refer to Section I.E., Technical Performance Targets. Although the category descriptions specify qualitative requirements and scope expectations, Section I.E. provides the quantitative performance metrics that all submissions must address.

1. CATEGORY A: FUELS

Category A applicants must use a holistic co-design approach to TRU fuel development, integrating the following five elements within a single innovation framework:

• Designing TRU fuels for optimal reactor performance

• Fabricating fuels using scalable and safeguards-compliant methods

• Generating new experimental data on fuel microstructure, properties, and performance

• Developing and validating predictive fuel performance models

• Establishing an accelerated qualification framework for the TRU fuel of interest

General requirements for Category A:

• Fuels must incorporate at least one TRU element as a primary fissile material. Fissile material must be sourced from reprocessed LWR, used nuclear fuel (UNF), and/or other strategic material reserves.

• All submissions must identify a specific advanced reactor design and the Full Application must name and include a letter of support from an engaged reactor developer that will serve as the end-user.

• Submissions must explain how fuel fabrication, performance modeling, and experimental data will be integrated to accelerate qualification and support economic viability.

• Surrogate materials may be used if TRU access is not available during early testing.

However, justification and a demonstration of transferability to TRU fuels are required.

Final validation must be performed on TRU-bearing fuels.

• Teams must be multidisciplinary, covering design, fabrication, modeling, and performance testing, with an iterative coordination plan across domains.

• Category A projects must be structured in two phases (Section I.D.4., Fuel performance modeling) with a Go/No-Go milestone between months 18–24 that aligns with their technical progress and project timeline.

Category A applicants must innovate in at least two of the co-design elements described below and should clearly identify these innovations and describe how they integrate with other project elements.

1. Fuel design

Teams should describe how they will iteratively refine fuel design through ongoing interaction with the reactor developer. This description should include how reactor requirements, performance feedback, and qualification considerations will inform design updates during the project. Teams may specify where reactor inputs are proprietary; however, they must describe how information will be exchanged, documented, and incorporated into fuel design and qualification activities while maintaining protections and enabling effective program oversight.

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Fuel design efforts must explicitly address:

• Fuel performance envelope (e.g., fuel centerline and cladding temperatures, target burnup)

• Fuel performance and failure mechanisms

• Ease of fabrication

• Domestic supply chain and recycling

• Impact on economics

2. Fuel fabrication

Fuel fabrication processes must be designed for safe, scalable, and cost-effective production of TRU fuels while meeting safeguards and materials accountancy requirements.

Teams must develop fabrication technologies that:

• Enable high-yield production of TRU fuel forms

• Operate within glovebox or hot cell environments

• Incorporate safeguards-by-design principles

• Allow meaningful process data collection to support technoeconomic analysis (TEA) and deployment planning

Teams are encouraged to:

• Integrate real-time quality control, automation, and remote handling during production

• Implement material tracking, automated recordkeeping, and inventory verification systems

• Explore other innovations that improve scalability, minimize operator exposure, and enhance cost-effectiveness

Technologies that are within scope include but are not limited to:

• Novel casting, extrusion, other approaches that offer significant improvements over legacy counter-gravity injection casting, particularly for reducing material losses, minimizing waste generation, and increasing fabrication throughput17

• Innovative fabrication methods for nitride fuels that mitigate concerns related to pyrophoricity—such as synthesis and densification routes using molten salt media, non-aqueous precursors, or chemically stable intermediates—to enable safe, scalable, and automated handling18

• TRISO fuel fabrication routes, including high-throughput kernel production, fluidized bed coating, and compact or pebble forming methods, with emphasis on enabling remote automation, in-line defect detection, and material accountability (we encourage exploring non-graphitic matrices such as magnesium oxide to improve compatibility with recycling and fuel reuse)

• Process automation, robotic handling, and nondestructive automated inspection

17 Idaho National Laboratory. Historical Review of EBR-II Metallic Fuel Fabrication.

Silva, A; Fielding, R. INL/RPT-23-74932, September 2023.

18 Status of Minor Actinide Fuel Development. IAEA Nuclear Energy Series No. NF-T-

4.6. 2010. https://www.iaea.org/publications/8224/status-of-minor-actinide-fuel-development https://www.iaea.org/publications/8224/status-of-minor-actinide-fuel-development

- 15 -methods—aided by advanced artificial intelligence and machine learning—to enable high-throughput, high-reliability operation in both shielded or hot-cell environments

• Embedded safeguard capabilities with the potential to minimize operational burden, reduce discrepancy and downtime, and enable cost-effective, proliferation-resistant fuel production at scale19

3. Testing and characterization of fuel microstructure, properties, and performance

Teams must generate new experimental data for TRU fuels that directly support model validation and qualification efforts. Data should capture as-fabricated conditions and, as appropriate, key performance-relevant properties. At a minimum, teams must:

• Characterize as-fabricated fuel microstructure (e.g., phases, key constituents) with allowed uncertainties

• Measure key thermophysical properties of fresh fuel, such as thermal conductivity, specific heat, and dimensional stability over relevant temperatures and times

• Report all data with quantitative error estimates and sufficient metadata to support reproducibility

• Document test conditions, measurement procedures, and data outputs consistently

• Produce data to support future NRC engagement for fuel qualification

Teams are encouraged to:

• Tailor characterization approaches to the proposed fuel form and its expected degradation mechanisms

• Leverage existing databases (e.g., Fuel Irradiation and Physics Database available through the Gateway for Accelerated Innovation in Nuclear (GAIN)) to reduce duplication and focus testing on unresolved performance gaps20

• Follow Nuclear Quality Assurance (NQA-1) protocols where feasible or describe equivalent data management practices that enable qualification21

Beyond fresh fuel characterization, experimental efforts that are within scope include but are not limited to:

• Integral tests (e.g., furnace transients), separate or few-effects tests, and surrogate tests (e.g., ion beam irradiations, as appropriate)

• To the extent possible, quantification of key fuel degradation mechanisms—including but not limited to creep, fission gas release, and fuel-cladding interactions—with clear descriptions of the measurement method, accuracy, and any assumptions

• Autonomous data acquisition and analysis pipelines that quantify and propagate error across multiple experiments and ensure traceability from raw measurements to reported

19 U.S. Nuclear Regulatory Commission, “Nuclear Security and Safeguards.” August 24

2020. https://www.nrc.gov/security.html 20 Access to GAIN databases can be found at https://gain.inl.gov/resources/databases/.

21 The American Society of Mechanical Engineers, NQA-1 Quality Assurance

Requirements for Nuclear Facility Applications. 2024. Information regarding NQA-1 can be found at https://www.asme.org/certification-accreditation/nuclear-quality-assurance-nqa1-certification.

https://www.nrc.gov/security.html https://gain.inl.gov/resources/databases/ https://www.asme.org/certification-accreditation/nuclear-quality-assurance-nqa1-certification https://www.asme.org/certification-accreditation/nuclear-quality-assurance-nqa1-certification

- 16 -property and microstructural data

• As feasible, neutron irradiation testing:

o Neutron irradiation may occur after teams complete the program; however, if performing neutron irradiation testing, teams must, at a minimum, identify the required test conditions and data needed to validate their performance models and support future fuel qualification.

4. Fuel performance modeling

Teams must integrate modeling and simulation to predict TRU fuel behavior under relevant operating and accident conditions. Models should actively support design iteration, experiment planning, and fuel qualification. Teams must:

• Incorporate experimentally measured microstructure and properties into models

• Show how modeling guides experimental priorities and design decisions

• Include verification, validation, and uncertainty quantification:

o Verify the methods used in the model are correctly applied o Validate predictive capability of developed models by comparing model predictions to experimental data using a quantitative metric (e.g., confidence overlap fraction) with at least 95% agreement across uncertainty bands o Quantify uncertainty and determine its impacts on model outputs

Teams are encouraged to:

• Use existing fuel performance codes or applicant-developed frameworks, provided they meet the Category A targets (Section I.E., Technical Performance Targets)

• Integrate advanced data analytics, automation, or high-performance computing where it improves predictive fidelity and decision relevance

Examples of modeling and simulation tools within scope include but not limited to:

• Multi-scale modeling approaches that couple atomistic simulations (e.g., molecular dynamics, density functional theory) with mesoscale models (e.g., phase-field) to predict microstructural evolution and are adapted to account for TRU-specific phenomena22,23

• Machine-learning models trained on experimental and simulated data to rapidly explore design spaces and guide experiment selection

• Integrated modeling-experimental workflows where simulation outputs directly inform test conditions, measurement priorities, and irradiation campaign design

5. Fuel qualification plan

22 Williamson, R.L.; Hales, J.D.; Novascone, S.R.; Pastore, G.; Gamble, K.A.; Spencer, B.W.; Jiang, W.; Pitts, S.A.; Casagranda, A.; Schwen, D.; Zabriskie, A.X.; Toptan, A.; Gardner, R.; Matthews, C.; Liu, W.; Chen, H. BISON: A flexible code for advanced simulation of the performance of multiple nuclear fuel forms. Nucl. Technol. 2021: 207.

23 Tonks, M.R.; Gaston, D.; Millett, P.C.; Andrs, D.; Talbot, P. An object-oriented finite element framework for Multiphysics phase field simulations. Comput. Mater. Sci. 2012: 51 (1).

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Applicants must propose an initial fuel qualification plan, recognizing that irradiation, post-irradiation examination, and full commercial licensing may extend beyond the program’s 36-month period of performance. The plan must clearly articulate alignment with NRC expectations based on available regulatory guidance and outline a credible path to qualification.

Applicants must:

• Develop a qualification plan with a targeted timeline of roughly seven years

• Describe how the proposed approach aligns with publicly available NRC expectations and guidance documents to support a credible qualification path within the HORNIG program timeline

• Include structured engagement with the NRC with at least one NRC interaction per year during project execution (applicants are not expected to engage with NRC before project award; engagement and feedback will occur during program execution)

• Complete as many steps in the qualification process as possible within the period of performance, including defining safety functions, mapping required data, and producing early validation data

Applicants are also encouraged to:

• Use the Accelerated Fuel Qualification (AFQ) framework or propose an alternative approach with equal or greater regulatory readiness24

• Use guidance from NUREG-2246 and NUREG/CR-7299, which outline structured methodologies for advanced reactor fuel qualification25,26

Awardees under this NOFO must provide technical data, including proprietary data, to the NRC as necessary for the licensing process.

2. CATEGORY B: CAPABILITIES

Category B teams will provide support to Category A teams by developing tools and methodologies to provide cross-cutting analysis and technical insights, ensuring consistent evaluation of emerging fuel concepts. Promising TRU fuel technologies from Category A will be assessed within a broader systems context that includes economic, infrastructure, and deployment considerations. Examples of analyses within the scope of Category B include, but are not limited to:

• TEA: Teams may develop tools to quantify the cost of TRU fuel cycles, including how different aspects of the fuel cycle affect economic viability. Tools must include protocols for handling uncertainty and conducting sensitivity analyses.

• Life-Cycle Assessment (LCA): Teams may develop tools to quantify environmental and

24 See footnote 6 (Terrani et al.).

25…