The US Department of Energy (DOE) will provide $5.4 million for research on reusing spent nuclear fuel in thorium molten salt reactors. The Texas A&M University College of Engineering announced the grant on October 29, 2026. The plan is to carry out fuel preparation, experiments, computational modeling, and reactor design as a single integrated effort. However, the announcement concerns research funding. It does not show that nuclear waste has been reduced, nor that the approach has performed in an actual reactor.
A molten salt reactor uses salt melted at high temperature as a fuel medium and coolant. The mechanism that produces uranium-233, a nuclear fuel, from thorium differs from the mechanism that reuses heavy elements remaining in spent nuclear fuel, in both the materials handled and the processes required. If the two are simply lumped together as "technology that turns nuclear waste into fuel," it becomes hard to see what this research aims to develop and what experiments will test its performance. The grant supports research that connects fuel preparation, experimental verification, and computational prediction to reactor design. How the salt is disposed of after use as fuel is also a key issue in judging the technology's practicality.
Four Research Steps Funded by the $5.4 Million Grant
The grant recipient is the Texas A&M Engineering Experiment Station (TEES), and the research is led by Professor Lin Shao of the university's Department of Nuclear Engineering. Savannah River National Laboratory and Natura Resources are also taking part. The $5.4 million (US$5,400,000) is for research and development; it is not an estimate of reactor construction costs or power generation costs.
According to Texas A&M University's announcement, the research will cover fuel preparation and experimental testing, and will combine computational modeling with reactor design to advance these steps together. The aim is not only to produce fuel and study its properties, but also to feed those results into computational models and use them in reactor design. However, what has been made public is the research plan and the team structure. No peer-reviewed papers, specific experimental data, or computational results have been presented.
The four steps each play a different role, and success in one does not guarantee success in the others. The table below summarizes what each step needs to verify and what progress can be confirmed from this announcement.
| Research step | Main question to verify | What has been made public |
|---|---|---|
| Fuel preparation | Can the intended fuel salt composition be produced and its properties evaluated? | Research plan only. Specific salt compositions and preparation results not disclosed |
| Experimental testing | Can fuel and material behavior be verified through measurement? | Research plan only. Sample numbers, test conditions, and measured values not disclosed |
| Computational modeling | Can fuel and material behavior be predicted from experimental data? | Research plan only. Boundary conditions and comparisons with measurements not disclosed |
| Reactor design | Can knowledge about fuel and materials be reflected in the reactor configuration? | Research plan only. No results showing actual reactor performance disclosed |
Even if the intended fuel salt can be produced, it does not follow that researchers can accurately predict how its properties will change during reactor operation. Comparing experimental data with computational models and reflecting the results in reactor configuration and operating conditions requires further verification. The grant does not mean technical results have been achieved in any particular step; it is best understood as funding to carry out this series of studies.
The choice of fuel also strongly affects reactor design. In a peer-reviewed perspective article published in 2024 in Frontiers in Nuclear Engineering (DOI: 10.3389/fnuen.2024.1335980), Joanna McFarlane of Oak Ridge National Laboratory argues that the usable fuel differs depending on the molten salt reactor design. Candidates include uranium-235 as well as plutonium-239 and americium-241 found in spent nuclear fuel, and uranium-233 is involved in the thorium fuel cycle.
These, however, are fuel options considered for molten salt reactors in general, not the nuclides to be used in this US research plan. According to McFarlane, fuel choice affects not only how the salt is prepared but also the reactor's scale and configuration, as well as the safeguards for properly managing nuclear material and final waste disposal. In other words, designs must look beyond whether something can be used as fuel to the whole path from reactor use to waste disposal.
European Precedent: Four Fuel Compositions Evaluated Experimentally
In Europe, there is earlier research in which thorium-containing fuel salts were actually prepared and their quality evaluated: fuel fabrication experiments for SALIENT-03, led by the European Commission's Joint Research Centre (JRC) and NRG. A research team led by Pavel Souček published an original paper on December 19, 2024, in Materials, Volume 17, Issue 24 (article number 6215, DOI: 10.3390/ma17246215).
According to the published abstract, the study covered four fuel compositions based on lithium and thorium fluorides and containing uranium, plutonium, and other elements. "Four" here refers to the number of fuel compositions; it does not mean four samples were measured or the experiment was repeated four times. The team synthesized and purified the fuel and examined its characteristics through mass balance evaluation, X-ray diffraction, and differential scanning calorimetry. It can be described as research that actually produced fuel salts and evaluated their quality experimentally.
SALIENT-03 envisions corrosion investigations of nickel alloys using the high flux reactor in Petten, the Netherlands. However, the goals of the overall experimental program must be distinguished from the results reported in this paper. Even if fuel synthesis and purification succeed, that alone does not demonstrate post-irradiation material performance inside a reactor or long-term continuous operation in a commercial reactor. And because the specific fuel salt compositions, sample numbers, and irradiation conditions of the DOE-funded research have not been disclosed, the European experimental conditions and results cannot simply be applied to it.
Still, this earlier work offers a clue to what actually needs to be verified in the fuel preparation step. Producing a fuel salt of the intended composition and examining its properties through analysis is a distinct and important research task, separate from verifying reactor design or operating performance. SALIENT-03 is an effort independent of the current US collaboration; it is neither a follow-up of the US research plan nor evidence of the accuracy of its computational models. What the two share is the need to understand, through experiment, the composition and properties of fuel salts in order to use them safely and appropriately in a reactor.
Evaluation Must Include Disposal of Used Fuel Salt
In molten salt reactors, radioactive waste arises not only from the salt used as fuel but also from operation and maintenance. Besides volatile radionuclides, materials used to capture off-gas and components replaced during maintenance also need to be managed and disposed of. For this reason, being able to reuse some elements in spent nuclear fuel is not necessarily the same as reducing the disposal burden of radioactive waste as a whole. Evaluating the benefit of reuse requires examining not only the material that can be recovered as fuel but also the amount and nature of the waste that ultimately remains.
McFarlane's 2024 perspective article also points to the importance of considering fuel preparation and waste management in parallel with reactor design. One reason is that the chemical state of the fuel salt may continue to change even after it is removed from the reactor. Drawing on experience from the past molten salt reactor experiment MSRE, she notes that radiolysis in used salt may continue over a long period, requiring ongoing monitoring and degassing. Once use in the reactor ends, the fuel salt does not automatically become a stable state suited to final disposal.
The chemical stability of the salt is also an issue for final disposal. The paper argues that salts that dissolve easily in water need stabilization treatment to lower their water solubility. The properties required of a fuel salt prepared for use in a reactor differ from those required when converting used salt into a form that can be safely disposed of. Evaluating technology for reusing spent nuclear fuel therefore requires considering the whole process, from fuel fabrication to final disposal.
That said, this knowledge rests on a peer-reviewed perspective article published in 2024, not on measurements of the fuel salt to be used in this US research plan. The perspective article itself is also not a study that tested waste reduction rates through new experiments. Texas A&M's announcement likewise includes no results papers or replication experiments corresponding to this grant. The DOE-funded research plan, the European fuel preparation experiment, and existing research on waste disposal should each be treated as knowledge at a different stage.
When assessing the effect on nuclear waste reduction, a reduction in waste mass must also be distinguished from a decline in radioactivity. Decay heat and the amount of long-lived radionuclides are separate evaluation metrics, and this announcement alone does not allow a waste reduction rate or a shortening of management periods to be calculated. Going forward, what matters is which nuclides will be reused and under what conditions, how closely measured data on fuel and materials match computational predictions, and how used salt will be stabilized and disposed of. As this verification advances, it should become possible to assess, based on concrete measurements, how much reusing spent nuclear fuel contributes to waste management.