ML26005A226
| ML26005A226 | |
| Person / Time | |
|---|---|
| Site: | 99902103 |
| Issue date: | 01/05/2026 |
| From: | Stephanie Devlin-Gill Office of Nuclear Reactor Regulation |
| To: | Joshua Borromeo Office of Nuclear Reactor Regulation |
| References | |
| EPID L-2023-LRM-0022 | |
| Download: ML26005A226 (0) | |
Text
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - EXPORT CONTROLLED INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - EXPORT CONTROLLED INFORMATION January 5, 2026 MEMORANDUM TO:
Josh Borromeo, Chief Advanced Reactor Licensing Branch 1 Division of Advanced Reactors and Non-power Production and Utilization Facilities Office of Nuclear Reactor Regulation FROM:
Stephanie Devlin-Gill, Senior Project Manager
/RA/
Advanced Reactor Licensing Branch 1 Division of Advanced Reactors and Non-power Production and Utilization Facilities Office of Nuclear Reactor Regulation
SUBJECT:
SUMMARY
OF THE JULY 23, 2025, CLOSED MEETING WITH ARC CLEAN TECHNOLOGY (EPID L-2023-LRM-0022)
Meeting Information:
Applicant: ARC Clean Technology (ARC)
Project No.: 99902103 Public Meeting Notice Agencywide Documents Access and Management System (ADAMS)
Accession No.: ML25169A325 Presentation Slides Accession Nos.: ML25193A008 Meeting Attendees: See Enclosure 1 for a list of meeting attendees CONTACT: Stephanie Devlin-Gill, NRR/DANU (301) 415-5301
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - EXPORT CONTROLLED INFORMATION 2
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - EXPORT CONTROLLED INFORMATION Meeting Summary:
The U.S. Nuclear Regulatory Commission (NRC) staff conducted the meeting in accordance with NRC Management Directive 3.5, Attendance at NRC Staff-Sponsored Meetings (ML21180A271). The NRC staff discussed with ARC its conceptual design for the ARC-100 sodium-cooled fast reactor.
ARC requested a meeting with NRC staff to present information related to their fuel design in support of their fuel qualification strategy. The meeting was closed to the public due to the discussion of export controlled and proprietary information specific to the ARC-100 design.
The meeting began with introductory remarks by the lead project manager, followed by participant introductions. It then proceeded directly to technical discussions. Key discussion points are summarized in Enclosure 2 of this letter.
No regulatory decisions were made as a result of this meeting.
Enclosures:
- 1. List of Attendees
- 2. Meeting overview cc: ARC Clean Technology ARC-100 via GovDelivery
Package: ML26005A220 Public: ML26005A226 Non-Public: ML26005A227 OFFICE NRR/DANU/UAL1:PM NRR/DANU/UAL1:BC NRR/DANU/UAL1:PM NAME SDevlin-Gill JBorromeo SDevlin-Gill DATE 11/17/2025 01/05/2026 01/05/2026
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - EXPORT CONTROLLED INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - EXPORT CONTROLLED INFORMATION LIST OF MEETING ATTENDEES JULY 23, 2025, PARTIALLY CLOSED MEETING WITH ARC CLEAN TECHNOLOGY (EPID L-2023-LRM-0022)
Name Organization Reed Anzalone U.S. Nuclear Regulatory Commission (NRC)
Deion Atkinson NRC Stephanie Devlin-Gill NRC Mike Orenak NRC Hakan Ozaltun NRC Alex Siwy NRC Irfan Ali ARC Clean Technology (ARC)
Raymond Burski ARC Robert Chiavaro ARC Robert Iotti ARC Pavel Medvedev Idaho National Laboratory
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - EXPORT CONTROLLED INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - EXPORT CONTROLLED INFORMATION MEETING OVERVIEW JULY 23, 2025, CLOSED MEETING WITH ARC CLEAN TECHNOLOGY (EPID L-2023-LRM-0022)
On July 23, 2025, ARC Clean Technology (ARC) presented slides entitled Additional Information of Relevant to Fuel Qualification (ML25193A008). The following bullets describe the main points of discussion during this presentation:
o The U.S. Nuclear Regulatory Commission staff (the staff) and ARC discussed how this meeting is in response to the staffs feedback (ML24219A399) provided on the White Paper on Fuel Qualification, Revision 0.0 (ML23285A290).
o On slide 1 and 2, the staff asked about how this additional information could be used to support fuel qualification activities. ARC clarified that several pins, previously not considered, specifically ((
)), were irradiated at ((
)) compared to those in the ARC-100 design. These pins experienced
((
)). ARC postulated that the results from these experiments could be considered representative and bounding for the ARC-100 fuel design.
o On slide 3, the staff asked ARC about the cladding thickness of ((
)) millimeters (mm) in X430, X430A and X430B series experiments. ARC clarified that the number was a typographical error and that the cladding thickness was actually ((
)) mm in those irradiation experiments. ARC emphasized that the cladding thickness of these experiments was the ((
)). In response, the staff noted that the ARC fuel pin is ((
)).
o On slide 4, o ARC compared the geometric and operational parameters of ARC-100 fuel with the parameters of select Experimental Breeder Reactor-II (EBR-II) experiments.
ARC postulated that the irradiation results are applicable to support fuel qualification activities, as the ((
)).
o The staff commented that quality assurance (QA) is an important aspect of fuel qualification and ensures usability of experimental data to support qualification efforts. ARC stated it used all the data possible for these preliminary results and that not all the data has gone through an NRC-approved QA program. However ARC acknowledged the need for appropriate QA of the data ultimately used for fuel qualification. ARC also reiterated that the purpose of this presentation was to provide the staff a preview of the data, analysis, and results.
o The staff also commented on the irradiation parameters provided by ARC and indicated that, in general, the performance of metallic alloy-based fuels can be
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - EXPORT CONTROLLED INFORMATION 2
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - EXPORT CONTROLLED INFORMATION quite sensitive to the fission rate. The staff then asked how fast the fuel burned (i.e. fission rate) in those previous experiments and how they compared to the ARC-100 fuel. ARC responded that slide 5 explains the use of Fission Acceleration factor.
o The staff considered the acceleration factors presented by ARC in slide 5, and asked for confirmation of the peak fission rates shown in the table that were approximately ((
)) for the X431 and X432 sets. ARC responded and confirmed that proposed fuel of ARC would burn roughly ((
)) of EBR-II.
o On slide 7, ARC presented ((
)) irradiation tests and provided a comparative evaluation. The staff inquired about the details in the graph and the meaning of the ((
)). ARC clarified that the ((
)). ARC further emphasized that, in its FEA, it used the actual geometry and irradiation history of the pin. Citing the comparative evaluation, ARC stated that the experimental and modeling results were in good agreement. In response, the staff asked for a clarification on a ((
)). ARC stated it is still trying to understand the difference and had two initial rationales: ((
)). ARC stated that there is currently reasonable agreement for these preliminary results, but the results will be refined in the future.
o On slide 8, the staff commented on the difference between the ((
)). The staff asked ((
)).
o On slide 11, o The staff commented on the differences in the strain values shown in the graph for X432 T833. ARC emphasized that the results are being verified by another code, ((
)), and asserted that when two different codes provide the same results, this should provide sufficient assurance of the code's accuracy. The staff
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - EXPORT CONTROLLED INFORMATION 3
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - EXPORT CONTROLLED INFORMATION cautioned that if both packages use incomplete behavioral models, even though both packages provide the same result, they could both be erroneous, masking large errors since they rely on the same model.
o The staff acknowledged that software-to-software benchmarks could be useful in providing confidence in the results, provided the reference code is validated against a set of experiments and approved for use by the NRC in a safety evaluation. In response, ARC referred to FRAPCON, an NRC-sponsored code for analysis of steady-state thermal-mechanical performance of oxide-based fuel rods for light water reactors. The staff commented that the NRC uses FAST for confirmatory analysis of fuel performance assessments for sodium-cooled fast reactors.
o On slide 12 and 13, ARC indicated that BISON is NQA-1 compliant, and, therefore, that results generated using BISON are reliable. The staff noted, however, that NQA-1 compliance alone does not ensure the validity of results for a given application. It is necessary to demonstrate that the selected code is applied using appropriate physics and models. It is also necessary to demonstrate that the ((
)). ARC stated its goal is to ((
)). The staff commented that while this would be a reasonable approach, it will evaluate how ARCs newly referenced set of ((
)) in its review of a future licensing submittal. ARC acknowledged the comment.
o On slide 14, o The staff asked about the gap closure. ARC indicated that the gap closure is expected at around 2.5 years. ARC stated that it is planned to remove and examine the first fuel assembly at ((
)) to verify if the cladding is in contact with the fuel.
o In response, the staff referred to ARCs white paper on fuel qualification and cited the previous estimates for removal and examination at ((
)), with the first removal being at roughly the ((
)) mark. Since the new simulations estimated a faster gap closure and ((
)), the staff questioned the accuracy of the new estimate and the sensitivity of gap closure to the new geometry. The staff asked what kind of assurance ARC has regarding the accuracy of the estimates for gap closures. ARC stated that it is re-evaluating the experimental database, with a particular focus on the new set of data from the new pins. They are also working on fine-tuning the code to more accurately capture the swelling and creep behavior.
o The staff commented on ARCs confidence in the stress magnitudes (120 megapascals) and inquired about how ARC plans to verify these magnitudes.
ARC stated ARC-100 has design limits (thermal creep strain and stress) based on those established for EBR-II and ARC intends to validate these design limits
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - EXPORT CONTROLLED INFORMATION 4
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - EXPORT CONTROLLED INFORMATION by comparing the measurements of cladding stress and strains to the predicted values.
o On slide 15, the staff asked about the ((
)) seen in the graph, which is indicative of ((
)). ARC stated that such
((
)) occur because the BISON code ((
)) to solve the thermo-mechanically coupled heat transfer equation between the cladding and coolant in the plenum region due to the small temperature difference. ARC also stated that the ((
)).
o At the end of the presentation, the staff asked ARC about o The recent announcement [ARC] Clean Technology achieves major milestone with completion of Canadian regulatory design review for ARC-100 advanced small modular reactor.1 Specifically, to enhance its understanding of the ARC-100 design, the staff asked if ARC would share the documentation from the completion of Phase 2 of the Canadian regulatory vendor design review for the ARC-100 via ARCs electronic reading room. ARC said it will place the report in ARCs electronic reading room for the staff.
o Future meetings between the ARC and the staff. ARC stated that in approximately August 2025, ARC would like to meet with the staff to discuss licensing basis events (LBEs) as defined using the draft proposed rulemaking package for Title 10 of the Code of Federal Regulations (CFR) Part 53, Risk Informed, Technology-Inclusive Regulatory Framework for Advanced Reactors.
o At the close of the meeting, the staff thanked ARC for the detailed information presented and indicated that it will continue to consider the information, as requested, to support future meetings or licensing submittals.
o The meeting on July 23, 2025, was adjourned at 11:25 AM eastern time.