Technical Questions - Repsonse - RFI-966967 - 10-1-2026.pdf

Thank you for the detailed technical questions. It was not expected to get to this level of detail for the request for information to evaluate market interest and capabilities. We are providing details below, however, please note that technical requirements may change prior to future actions.

Round 1 Questions to RFI-966967: U-10Mo Monolithic Fuel Fabrication

October 1, 2026

No.

RFI Section (if applicable)

Question

1 2.1 What analysis equipment is required?

• Low Carbon Arc Cast molybdenum is typically provided by commercial suppliers with a material certification; no further analysis is required unless it does not meet the specification (in which case it can be rejected or accepted with further substantiation).

• HALEU is provided by the US Government with a material certification, no further analysis is required.

• U-10Mo alloy requires isotopic, transuranic, and impurity analysis as identified in SPC-70872. Qualification of the process using the analysis equipment is required and approved by the design authority. Typically, the process includes a combination of alpha spectroscopy, gamma spectroscopy, and mass spectrometry.

2 2.1 Is the required analysis equipment supplied by NNSA?

• It can be, if desired, along with fabrication equipment.

3 2.1 What crucible material is used in the VIM furnace?

• Typically, crucibles and molds are fabricated from high purity graphite. Ceramics may be acceptable for use in a VIM; they would require process verification testing.

4 2.1 Are the crucibles custom fabricated?

• The crucibles and molds are machined either in house or by a commercial supplier.

5 2.1 What surface treatment is used to prevent corrosion?

• The crucible and molds are coated to prevent corrosion and erosion. Erbium oxide is currently being used. Alternatives are available and would require process verification testing.

6 2.1 Is that process and corresponding equipment supplied by NNSA?

• If desired the equipment can be supplied by NNSA along with technical support for installation and implementation.

Alternatively, the offeror may design, select, and develop their own process using the provided process windows; process verification testing would be required.

7 2.1 What are the tolerances required for the U-10Mo ingot?

• The ingot, which is the U-10Mo ready for hot roll bonding needs to be held to normal machining tolerances (+/- 0.05 inches) for length, width, and thickness.

8 2.1 Is it possible to hit the required dimensions/tolerances without machining?

• Yes, however the surface finish from milling or cold rolling is desired as an input to the foil fabrication process.

9 2.1 In Figure 4, what constitutes "U-10Mo Returns"?

• U-10Mo Returns are portions from the blanks and billets that are not used to make ingots as well as ingots that are not expected to meet specification. These items are “returned” to the process and used as feedstock in later batches.

10 2.2 What size HIP is needed?

• A working volume of roughly 30-36 inches in diameter x 8 feet long is needed.

11 2.2.1 Are there bonding issues at the Zr/U-10Mo hot co-roll bonding step and/or the HIP step?

• The process optimization has identified/eliminated bonding issues at both steps. Parameter windows identified in the refence materials bound the operations.

• Blisters and edge cracking are known hot co-rolling issues. These issues have been addressed through process optimization.

12 2.2.1 If so, what are the known factors and their mitigations?

• Ensuring that the debond agent is evenly applied to the hot pack materials reduces sticking of the Zr to the hot pack. Annealing of the material during the homogenization step and appropriate rolling reductions, as defined in the references, reduce edge cracking.

13 2.2.1 Why are certain steps, such as flattening annealing, "as needed" if the process is mature?

• If the foil coming out of the cold rolling process does not lay flat in the cladding pocket, it is annealed to improve flatness. The tolerances on the length of the cladding pocket are tight.

14 2.2.1 What drives process variability?

• Natural variation in the feedstock (both the Uranium and the

Molybdenum) drives some impurities. Some carbon and Erbium are picked up during the casting process from the mold and crucible. Variation in ingot size drives variation in the master foil thickness. Currently, the ingots are used at the as-cast thickness.

2.2.1

Please clarify if the master foil is cold rolled or if the child foil is cold rolled. There appears to be conflicting information in Figure 8 and the preceding paragraph.

• The master foil is the Zr roll-bonded to the U-10Mo alloy through hot rolling. The cold rolling to final thickness generates the child foil. The master foil does not have cold rolling.

16 2.2.2 Is there any issue with the HIP cans being contract manufactured?

• No, HIP Cans, strongbacks, cladding, element parts are all to be commercially obtained (contract manufactured). USHPRR is setting up this supply chain, including non-reoccurring engineering costs for the HIP can tooling.

17 2.2.2 What is meant by ice formation during the HIP can evacuation step?

• Ice can form from water vapor in the atmosphere if the electron beam vacuum chamber evacuates too quickly. This is a known challenge with electron beam welders.

2.2.2

Acceptance testing and Reverse Bend Testing aren't described in the RFI. Do special test specimens need fabricated? What equipment is needed and is it provided by NNSA?

• The test is meant to evaluate whether the necessary clad-to-clad bond has formed during HIP. Reverse bend test samples can be machined from the plate ends where excess cladding is located. The test is performed by (1) clamping the cladding sample in the vise, (2) bending it 90° over a 9.53mm (3/8”) radius, (3) bending it back 180° over a 9.53mm (3/8”) radius,

(4) bending it straight up, and (5) visually checking the edge for delamination. Figure A shows the setup, Figure B shows a passed bend test and Figure C shows a failed test.

19 2.3 Have all the fuel plate geometries needed been successfully demonstrated?

• While all combinations of foil/plate thickness dimensions have been demonstrated, the largest full size plates required for ATR have not yet been demonstrated. Plate forming process optimization will occur in the next year. Initial experiments indicate that the plates will form like the current dispersion fuels.

20 2.3 Who fabricates the non-fuel portions of the aluminum fuel elements?

• Cladding and element parts are all to be commercially obtained

(contract manufactured). USHPRR is setting up this supply chain, including non-reoccurring engineering costs if needed

21 3 What portion of the facility requires the ~30 ft high bay?

• Depending on the equipment configuration, a high bay may be required for the VIM, digital x-ray, hot roll mills, and electron beam welder. As a minimum, the respondent should assume that the VIM will require a high bay.

• NOTE: the HIP may require high bay space, however typically these are installed below ground.

22 3 At what step is the acid cleaning performed? What is the acid?

• Acid cleaning is performed on the ingots prior to hot roll bonding.

Assuming there are no carbides, nitric acid is sufficient. If there are carbides, then a nitric/hydrofluoric acid combination is required.

23 3 What is the throughput of the process and equipment described in Table 1 and Figure 11?

• Table 1 and Figure 11 are for the full operating capability. As stated in the RFI, the overall market size for this fuel is about 10,000 plates and 200 elements per year and will consume 3,000 to 3,500 kg of HALEU metal a year.

24 3 What throughput has been successfully demonstrated for this manufacturing process?

• Throughput is currently at the 100s of plates per year due to the fuel’s unlicensed status. This RFI envisions an order of magnitude increase in production as the reactors are approved for unlimited use of the fuel. The equipment and process currently in use and described in the RFI is expected to support the envisioned equilibrium supply quantity.

25 3 How many workers are anticipated for the RFI concept?

• 45 FTEs is the current estimate for equilibrium supply.

26 4.1 How mature is the safety basis for this manufacturing process?

• Very mature, all manufacturing process steps are widely used commercially. The hot roll of U-10Mo is the only exception; while it is considered mature by the program, it is not a commercially available process.

27 4.1 What is the lead time for NNSA to provide major equipment?

• 12 months for standard equipment and up to36 months for specialized custom equipment.

NOTE: the lead time occurs in parallel to any U-10Mo fabrication acquisition process.

28 4.1 Is the equipment in good operating condition?

• It is anticipated that the bulk of the equipment will be new. A few items may be refurbished by the OEM to like-new condition.

29 4.1 How well defined are the overall facility needs (HVAC, Fire Protection, Life Safety, etc.)?

• This would depend on the local jurisdiction. The NRC is considering revisions to the requirements for a CAT 2 facility at this time.

30 6 Where can we find a copy of SPC-70872?

• Attached 31 N/A What slab thickness is required for the production area?

• This would depend on the local code and seismic conditions. The hot roll mill weighs ~80,000 lbs. and must have a sufficient slab.

4.1

What are the criticality safety guidelines and controls that are expected for this facility? Is a moderator exclusion/control area expected? Is water cooling (for furnaces) and water-based fire protection systems acceptable?

• Yes, it is anticipated this will be a CAT 2 facility and will require moderator exclusion in a controlled area. Water-based fire protection and equipment cooling systems may be acceptable but will rely on the respondent’s criticality and fire protection requirements, oversight, and regulatory requirements.

4.1

What is the amount of U scrap that is expected? and are there existing guidelines for scrap recovery? Is the scrap expected to be recovered or disposed of as waste?

• Overall waste scrap is anticipated to be around 30% (kg HALEU metal in/kg fuel out). Until a cost-effective source of HALEU metal is commercially available, waste scrap will be sent to recovery (in-house approved process or by others).

2.2

Are the plates HIPed in the vertical or horizontal position? Is there a requirement for one? Is there a flattening step after HIP?

• HIP is an isostatic process. Orientation isn’t specified and will depend on the HIP installation.

• If needed, a roller leveler operation can be performed following HIP. However, usually the plates just need to be polished to size.

2.2

Is there any environmental control required during hot rolling? or can it be done in air?

• Hot rolling and machining of the U-10Mo alloy can be done in air with the proper settings (i.e. the chips are burned directly to oxide during the process). However, hot rolling is often done in salt baths to control contamination.