DOE to Make Mixed Oxide Fuel at SRS to Boost HALEU Supplies

• DOE to Make Mixed Oxide Fuel at Savanah River Site to Boost HALEU Supplies
• SRNL to Recover Isotopes from Legacy Nuclear Materials
• Q&A Interview with ZetaJoule About its High Temperature Research Reactor
• ONE Nuclear Energy  IPO plans to Fund SMR Expected in 2026
• Copenhagen Atomics Secures Thorium Supply from Norway

DOE to Make MOX Fuel at SRS

• DOE’s Office of Environmental Management Restarts One-of-a-Kind Facility in South Carolina to Fuel America’s Nuclear Future

The U.S. Department of Energy’s (DOE) Office of Environmental Management (EM) announced the decision to restart HB-Line operations at the Savannah River Site (SRS) in South Carolina.

Restarting HB-Line provides the capability to power America’s nuclear future by recycling surplus plutonium and partnering with industry to produce uranium-plutonium mixed oxide (MOX) fuel for advanced nuclear reactors.

The facility is an integral part of H-Canyon, the only chemical separations facility of its kind in the United States.

New Lamps for Old – Will MOX Replace HALEU?

With the shortfall of supply of HALEU fuel for advanced reactors, DOE has decided that a faster path to uranium fuel with enrichment levels of 9-19% U235 will be to supply advanced reactors developers with MOX fuel.

GENIV design reactors are capable of burning MOX fuel. In 2025 Oklo proposed to build a $1.68 billion nuclear fuel plant at Oak Ridge, TN, that would convert plutonium into HALEU equivalent fuel to serve the fuel  needs of advanced reactors.

DOE will need new funding for this effort. Congressional appropriation of funds might not be available until FY 2027 or FY 2028.

History of Commercial Efforts to Use MOX Fuel in U.S. Advanced Reactors

The TerraPower Natrium reactor is based on the GEH PRISM reactor design that was intended to run on surplus plutonium. TerraPower runs on uranium metal fuel which can be fabricated, via reprocessing methods, from surplus plutonium.

GEH pitched the PRISM design to the UK Nuclear Decommissioning Authority (NDA) in 2012  to dispose of its huge inventory of surplus plutonium, and to make nuclear fuel from it to run the PRISM reactors, but no deal was ever signed for the project.

The PRISM design was also offered to the U.S. Department of Energy for a proposed Versatile Test Reactor (VTR) to be built at the INL. The VTR had a design configured for R&D not power generation. It would have given the INL an ‘anchor facility’ and opened up nuclear fuel and materials testing to a wider range of R&D efforts. However, Congress did not fund the program.

In 2020, GE Hitachi partnered with TerraPower to develop the Natrium reactor, which incorporates PRISM’s 840 MWt pool-type sodium-cooled architecture. This design replaces waste recycling, or geologic disposal, with a once-through HALEU metallic fuel system and adds a molten salt energy storage island. It exploits the energy potential in the surplus plutonium for peaceful purposes.

In 2022 TerraPower, which is developing the 345 MWe Natrium sodium cooled fast reactor, signed a memorandum of understanding (MOU) with the Japan Atomic Energy Agency (JAEA) and two Mitsubishi business units to collaborate on sodium fast reactor technology.  [press release].

The agreement will enable both sides to advance fast-reactor technologies for commercial use.  JAEA, Mitsubishi Heavy Industries, and Mitsubishi FBR Systems will share data and resources related to the development of advanced sodium fast reactor (SFR) technology with TerraPower.

On March, 2026, the NRC approved a constructoin permit for the first-of-a-kind Natrium reactor to be built on the windswept plains of Wyoming 150 miles northeast of Salt Lake City, UT. The reactor will burn uranium metal fuel to be produced by Framatome and fabricated into fuel assembles by GE Hitachi.

On November 5, 2025, Framatome and TerraPower achieved a key milestone in uranium metallization for advanced reactor fuel commercialization, producing successful elements of uranium metal. These metallic uranium ‘pucks’ represent a key component in the fuel supply chain for TerraPower’s Natrium reactor.

Who Will Turn DOE’s Plutonium into MOX Fuel?

DOE did not identify which private sector firms would be involved with the project either as contractors or on a shared cost basis with a firm that would operate the plant and sell the fuel to advanced reactor developers and the utilities that acquire advanced reactors.

Also, DOE did not indicate the fuel fabrication path for the MOX fuel, e.g., uranium /plutonium metal or oxide forms. It is unclear how or whether Oklo will be one of the contractors selected for the reprocessing and conversion of plutonium into HALEU fuel. DOE’s selection of one or more contractors for this work is expected to follow its standard procurement process.

Last May the agency’s Surplus Plutonium Utilization Program request for applications (RFA) contains the details of what material are being offered – oxide and metal forms, the agency’s requirements for civilian nuclear reactor developers to use it, and the outcomes the government wants from the use of the weapons grade material in civilian nuclear reactors.

Legal Mandates for Disposition of Surplus Plutonium

In late October 2025 the Department of Energy (DOE) announced a plan to dispose of about 20 tonnes of surplus plutonium by making it available to developers of advanced nuclear reactors.

DOE issued a request for applications (RFA) stating that it is establishing a program to make surplus plutonium materials available to industry for use in advanced nuclear technologies. The formal process to apply for the surplus plutonium is in DOE’s Request for Applications (RFA). Responses were required by 11/21/25.

Applicants from commercial companies were required to describe their detailed recycling and processing plans, including funding commitments and schedules to use the surplus plutonium materials for reactors that will be built and operated in the U.S. or, under export controls, operated in other countries.

The 19.7 metric tons of plutonium materials listed by DOE as surplus in the RFA reportedly include about 15.3 metric tons of plutonium in oxide form and about 4.4 metric tons in metal form. It is unclear how much work will be required to convert the materials from either form into usable fuel, e.g., HALEU levels of enrichment at less than 20% U235, for use in advanced reactors.

A key driver of DOE’s surplus plutonium program is that the National Nuclear Security Administration( NNSA) at the Savannah River Site (SRS) is under legal obligation to dispose of six tonnes of “impure” surplus plutonium which means removing it from the SRS site in South Carolina. DOE’s objective Is “to expedite the removal of plutonium from South Carolina and permanently dispose of weapons-grade plutonium declared excess to national security.”

DOE’s plan, apparently, is to hand off all the SRS material to advanced reactor firms to turn it into HALEU grade fuel. The other approximately 14 tonnes will come from other NNSA sources including the NNSA Pantex Site in Amarillo, TX, which disassembles obsolete nuclear weapons and recovers the fissile materials from them. The current announcement appears to be in line with this plan. DOE will need to arrange for securre transportation of the surplus plutonium from its current stored locations to the selected contractor’s facilities which will also need appropriate levels of physical security.

For its part the government is confident this new use of the surplus plutonium will have important benefits for developers of advanced reactors.

“Restarting HB-Line is the right decision for taxpayers, for our national security and for America’s energy future,” said EM Assistant Secretary Tim Walsh. “We are restoring a unique capability that will accelerate our mission, strengthen the domestic nuclear industrial base and deliver fuel the country needs to power advanced reactors.”

New Plans for Making MOX Fuel at SRS

At SRS the restart decision is the first step in a multi-year restart plan. Once operational, HB-Line will accelerate EM’s plutonium disposition mission by 10 to 13 years while reducing the existing cost and saving American taxpayers up to $350 million. Restarting HB-Line also creates an opportunity to recover valuable isotopes currently available in limited quantities domestically, supporting critical needs in scientific research and commercial applications.

HB-Line is a specialized processing facility within the H-Canyon complex that has supported critical national nuclear missions. Following completion of its last mission in 2018, the facility was placed in a managed layup state, preserving its one-of-a-kind capability for future use.

“Savannah River Site has been integral to America’s nuclear mission for more than 70 years, and HB-Line is one of the unique capabilities the site has to offer,” said Edwin Deshong, Savannah River Operations Office manager. “Our workforce has the expertise, experience and dedication to execute the mission safely and successfully.”

The decision directly advances White House executive orders, “Reinvigorating the Nuclear Industrial Base and Deploying Advanced Nuclear Reactor Technologies for National Security”  which call for jumpstarting America’s nuclear industrial base to ensure national and economic security.

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SRNL to Recover Isotopes from Legacy Nuclear Materials

The Department of Energy’s (DOE) National Nuclear Security Administration (NNSA), Office of Environmental Management (EM), and Office of Science collaborated to achieve a significant milestone in transforming Cold War-era legacy materials into critical national assets.

The successful transfer of the first Mark-18A target at the Savannah River Site (SRS) to the Savannah River National Laboratory (SRNL) marks the beginning of operations for a newly established radiochemical separation capability to recover valuable isotopes.  

The multi-year Mark-18A Target Recovery Program establishes a new radiochemical process at SRNL that fulfills mission needs across the DOE/NNSA complex. By combining EM’s environmental cleanup prowess with NNSA’s national security expertise, the team demonstrated how legacy materials previously destined for disposal can be recovered and transformed into valuable resources.

The Mark-18A targets contain significant quantities of heavy curium and the world’s only supply of unseparated plutonium-244. This isotope of Plutonium, which is incredibly rare, is useful in nuclear forensics. The heavy curium will later be converted into californium-252, which is a vital start-up source for nuclear reactors, among other uses.

The initiative provides hands-on opportunities for scientists, engineers, and technical personnel to address challenges presented by the nuclear industry and nonproliferation policy. This recovery process was largely designed, constructed, and programmed at SRS. It also sharpens the staff’s experience in radiochemical processing system design as well as construction and operation.

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Q&A with ZetaJoule About its High Temperature Research Reactor

Texas A&M And ZettaJoule Explore High-Temperature Research Reactor: The Texas A&M Engineering Experiment Station has signed an agreement with advanced reactor developer ZettaJoule to explore building a high-temperature gas-cooled research reactor in College Station, TX.

Under the agreement, ZettaJoule would construct its proposed ZJ0 reactor next to the TEES Nuclear Engineering & Science Center, which already operates two research reactors. The ZJ0 is a high-temperature gas-cooled reactor designed to provide process heat of up to 950°C, suitable for applications such as hydrogen production, synthetic fuels and advanced manufacturing.

Industrial Applications of High Process Heat from HTGR Reactors.
Chart: Optimum Reactor Outlet Temperatures for High Temperature Gas-Cooled Reactors Integrated with Industrial Processes, Idaho National Laboratory, INL/EXT-11-21537, April 2011

The technology is based on Japan’s High Temperature Engineering Test  Reactor.  The technology ZettaJoule has based its design for its ZJ reactor on Japan’s High
Temperature Engineering Test Reactor (HTTR) which has been in operation since 1998.

If built, the reactor would make Texas A&M the only US university with more than two nuclear research reactors on campus. The partners said the project could support expanded research collaboration with industry and federal agencies in advanced energy systems. ZettaJoule is a US- and Japan-based advanced reactor company developing high-temperature gas-cooled small modular reactor technology for industrial heat and power applications.

Prior Coverage at Neutron Bytes of Japan’s HTTR

Japans HTTR Restarts to Demonstrated Hydrogen Production

Japan Regulator Says HTTR Complies with Post Fukushima Safety Standards

Q&A with ZetaJoule

ZetaJoule Responded by email to a series of questions about the project from Neutron Bytes

1. What is the expected cost of the research reactor?

The project is estimated to cost between $500 million to $850 million over an anticipated 5–7-year development period. These figures represent very rough preliminary planning estimates, and a more accurate budget will be formally determined as the engineering design, licensing, and siting process progresses.

2. Who is paying for it?

Are there multiple research parties involved in providing funding? Are any Japanese businesses / organizations involved in the project? Given the rush of nuclear firms in the U.S. to partner with Texas universities, are any of them collaborators with ZettaJoule?

The proposed research reactor will be owned and licensed by the Texas A&M Engineering Experiment Station (TEES), which will take the lead for the fundraising with support from ZettaJoule. 

We will actively support these efforts, including facilitating discussions with potential funding entities and exploring avenues for financial participation.

3. When will the research reactor be operational?

The ZJ0 research reactor is planned for deployment in the early 2030s but the official project timeline will be determined and publicized once subsequent definitive agreements, engineering scope planning, regulatory planning, and funding milestones have been determined.

4. What are the key R&D areas for research? Will other universities and private sector firms be able to access the facility for R&D projects?

The proposed advanced small modular reactor will provide TEES and the Texas A&M University System (TAMUS), the State of Texas and national and international science and industrial communities with extensive research, applied research and educational opportunities for various scientific and engineering disciplines (nuclear, mechanical, petroleum, aerospace, chemical, biomedical, electrical, and physics).

The new facility would be unique with many external stakeholders interested in projects there. Specifics about access and operations will be addressed when definitive agreements are in final form.

5. What kinds of R&D research require extremely high outlet temperatures produced by the reactor designs?

The high temperature heat produced by the ZettaJoule reactor would be useful in a range of research areas including various scientific and engineering disciplines (nuclear, mechanical, petroleum, aerospace, chemical, biomedical, electrical, and physics). 

Another area of research would be to examine industrial heat applications for sectors such as oil refining, chemical refining, mining, steel making, and transportation. A few examples of R&D research in this area might include testing how very-high temperature process heat could replace fossil-fired heaters in petrochemical operations; how high-temperature heat can support more efficient hydrogen production for e-fuels; and how it can supply heat for energy-intensive operations in steelmaking such as hot rolling and annealing. 

6. Are there any metal alloys available in commercial quantities, e.g. INCO variants, etc., that can handle these high temperatures for a heat transfer system assuming the research reactors is a precursor to a commercial offering?

The Hastelloy family of nickel-based alloys has been successfully utilized for high-temperature service in the HTTR reference plant in Japan. We intend to recommend using this alloy for the ZJ0 and beyond.  (Note to readers: See this Wikipedia article on ‘Super Alloys” for a deep dive into these materials).

One of the major focal points for the TEES reactor will be materials research on new and existing alloys to support high-temperature environments. Combined with existing international and domestic knowledge, we expect emergent research to improve and lead to new opportunities.  

7 . Among the applications of HTGR high process heat, which industries are expected to be target markets for the ZettaJoule commercial offering.

With the promise of the ability to deliver high-temperature process heat (i.e., up to 950 degrees Celsius), supply-reliable baseload electricity, and a combination of process heat and electricity (i.e., co-generation), ZettaJoule’s reactor will have the capability to provide energy solutions across key industrial and commercial sectors – including oil refining, chemical refining, mining, trucking, aviation, shipping, steel making, data centers, and utilities. 

8. Does the firm have any MOUs or other non-binding letters of intent at this time from any of these potential customers?

Not at the moment. We are in discussions with major companies and we’re excited about exploring opportunities with additional potential customers. 

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ONE Nuclear Energy  IPO plans to Fund SMR Expected in 2026

Recently, One Energy agreed with Hennessy Capital Investment Corp. VII (NASDAQ: HVII) to become a publicly traded company on Nasdaq under the ticker (ONEN). This business agreement values ONE Nuclear at approximately $1 billion, with the possibility to raise to $210 million in gross proceeds before transaction expenses. The deal is also expected to become official in the first half of 2026. The company, filed an S-4 statement with the SEC earlier this year.  (SEC Edgar Docuemetn S-4)

Previously, in May 2024 the Findlay, OH, firm received signed commitments to purchase additional shares of One Energy Series A convertible preferred stock which, together with prior purchases and sales of OE Series A Shares represent an aggregate oversubscribed total raise of over $35 million. The Company intends to use the expected proceeds from the Additional Series A Investments to pursue the Company’s business plans and fund working capital needs.

ONE Nuclear will deploy a multi-technology approach to its energy parks by selecting the most suitable advanced nuclear technology vendor for the customer and for the site. The Company plans to use SMR nuclear technology up to 470 MW and modular technology up to 1 GW.

ONE Nuclear has identified its first two priority development sites – one in Oklahoma another in East Texas – where it plans to develop up to 2 GW of gas generation capacity by 2028 and 3 GW of advanced nuclear SMR capacity by 2034. ONE Nuclear states it has a development pipeline for gas and nuclear projects, up to an estimated 15 GW of gas and nuclear capacity by 2032.

ONE Nuclear’s business strategy is centered on a “develop-own-operate” framework, which unites technology selection, site development, financing, and operations. This might seem like a protracted process, but people will be able to witness and enjoy the benefits gradually. As of now, the corporation has identified more than 75 potential sites nationwide, with priority projects in Oklahoma and East Texas. All in, the developments intend to deliver up to 2 GW of gas generation capacity by 2028 and an extra 3 GW of advanced nuclear SMR capacity by 2034.

ONE Nuclear has agreements with Black & Veatch for engineering, procurement and construction work and with Futureworx for program management, providing proven execution capability.

Fast-Track Natural Gas Power Generators

ONE Nuclear has a strategic relationship with Rolls-Royce Solutions America, Inc. for access to natural gas power generators, to enable ONE Nuclear to build large GW-scale low-cost generation capacity at its project sites.

This approach is expected to enable ONE Nuclear to provide the earliest possible power generation demanded by customers through natural gas, while its nuclear facilities are under construction, and provides a faster path to revenue generation.

SMRs to Follow Gas Plants?

ONE Nuclear’s business model indicates it centers on developing nuclear parks that can host multiple SMR units, providing scalable clean energy solutions for industrial applications, grid power, and specialized energy-intensive operations. This approach allows for phased development and deployment while maximizing site utilization and operational efficiencies.

The firm so far while describing the benefits of building small modular reactors, has not publicly released information on which SMR design it plans to commercialize.

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Copenhagen Atomics Secures Thorium Supply from Norway

(WNN) Denmark’s Copenhagen Atomics has signed a Letter of Intent with Rare Earths Norway to secure future access to thorium – the key fertile material in its molten salt reactor technology – extracted from the Fensfeltet deposit in Norway.

Copenhagen Atomics is developing a containerized molten salt reactor. Moderated with unpressurized heavy water, the reactor consumes nuclear waste while breeding new fuel from thorium. Small enough to allow for mass manufacturing and assembly line production, the reactor has an output of 100 MWt. Copenhagen Atomics’ goal is to deliver energy at a levelised cost of $24 per MWh.

The company’s thorium reactors are expected to consume the transuranic elements in used nuclear fuel from conventional nuclear reactors, which radically reduces the amount of long-lived radioactive waste. To achieve this, Copenhagen Atomics intends to separate used nuclear fuel from light water reactors into four streams: zircaloy, uranium, fission products and transuranics. Its reactor designs can make use of plutonium (a transuranic) to ‘kickstart’ the use of thorium.

Copenhagen Atomics says its Letter of Intent (LOI) with Rare Earths Norway “represents a strategic step in establishing a long-term, European supply chain for thorium”.

The Letter of Intent outlines the intention of the parties to collaborate on the responsible utilization of thorium resources associated with Rare Earths Norway’s planned rare earth element production. Thorium occurs naturally in the Fensfeltet deposit – one of Europe’s largest known rare earth deposits – and has historically been treated as a byproduct. Through this partnership, the material may instead become a valuable energy resource.

Copenhagen Atomics expects its first nuclear test reactor to operate at the Paul Scherrer Institute in Switzerland, with commercial deployment targeted in the early 2030s.

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