Promoting Fusion Energy Leadership with U.S. Tritium Production Capacity
As a fusion energy future becomes increasingly tangible, the United States should proactively prepare for it if/when it arrives. A single, commercial-scale fusion reactor will require more tritium fuel than is currently available from global civilian-use inventories. For fusion to be viable, greater-than-replacement tritium breeding technologies will be essential. Before the cycle of net tritium gain can begin, however, the world needs sufficient tritium to complete R&D and successfully commission first-of-a-kind (FOAK) fusion reactors. The United States has the only proven and scalable tritium production supply chain, but it is largely reserved for nuclear weapons. Excess tritium production capacity should be leveraged to ensure the success of and U.S. leadership in fusion energy.
The Trump administration should reinforce U.S. investments and leadership in commercial fusion with game changing innovation in the provision of tritium fuel. The Congressional Fusion Energy Caucus has growing support in the House with 92 members and an emerging Senate counterpart chaired by Sen. Martin Heinrich. Energy security and independence are important areas of bipartisan cooperation, but strong leadership from the White House will be needed to set a bold, America-first agenda.
Challenge and Opportunity
Fusion energy R&D currently relies on limited reserves of tritium from non-scalable production streams. These reserves reduce by ~5% each year due to radioactive decay, which makes stockpiling difficult. One recent estimate suggests that global stocks of civilian-use tritium are just 25–30kg, while commissioning and startup of a single commercial fusion reactor may require up to 10kg. The largest source of civilian-use tritium is Canada, which produces ~2kg/yr as a byproduct of heavy water reactor operation, but most of that material is intended to fuel the International Thermonuclear Experimental Reactor (ITER) in the next decade. This tritium production is directly coupled to the power generation rate of its fleet of Canadian Deuterium Uranium (CANDU) reactors; therefore, the only way to increase the tritium production rate is to build more CANDU power reactors.
The National Nuclear Security Administration (NNSA) (an Office of the U.S. Department of Energy (DOE)) – in cooperation with the Tennessee Valley Authority (TVA) – will produce up-to ~4kg of tritium over the next fuel cycles (i.e., ~18-month cycles offset by 6 months) for the two Watts Bar nuclear (WBN) reactors. This would exceed the current, combined 2.8kg production goal, which could be further outstripped if the reactors were operated at their maximum licensed limit, producing ~4.7kg of tritium. All this tritium is designated for military use. However, the NNSA and DOE could leverage production capacities in excess of defense requirements to promote the deployment of FOAK reactors and support U.S. leadership in fusion energy. The DOE could build off the success of its current Milestone-Based Fusion Program by integrating the option for additional tritium availability to meet the commissioning demands of pilot and commercial fusion reactors.
This program could be called “Gigatons-to-Gigawatts” (GtG), a name inspired by one of the most successful fissile material reduction programs in history Megatons-to-Megawatts. The increased scale signifies much higher energy densities contained in tritium vs. the uranium commonly used to fuel fission reactors. Fusion and fission reactor technologies also have very different nonproliferation implications. U.S. national security and nonproliferation goals would be furthered by a systematic transition from fission to fusion energy. Lowering reliance on dual-use nuclear fuel cycle technologies such as centrifuges for uranium enrichment would lower overall proliferation risks. Just as it did by promoting an open fuel cycle, the United States could leverage its technological leadership to promote the adoption of a more proliferation-resistant fusion infrastructure.
However, it is important to note another key difference with Megatons-to-Megawatts: because GtG leverages near-term tritium production capacities in concert with reserves rather than repurposing stockpiled weapons-useable material for civilian use such a program could affect the U.S. nuclear deterrent posture as well. The National Nuclear Security Administration (NNSA) Strategic Integrated Roadmap highlights the goal to “Demonstrate enhanced tritium production capability” for 2025 which is coded as “Nuclear Deterrent.” The anticipated excess production quantities noted above would correspond with this goal. Starting from this demonstrated capability, a GtG program would extend this production capacity into a longer-term effort directed toward a fusion energy future. Furthermore, in support of the long-term goal of nuclear disarmament, GtG would also provide a ready-made framework for repurposing valuable tritium from decommissioned warheads.
One way the United States demonstrates the credibility of its nuclear deterrent is through the Stockpile Stewardship and Management Plan (SSMP). Allies and adversaries alike must believe that the United States has sufficient tritium capability to replenish this critical and slowly decaying resource. An enhanced tritium production capability also has a supporting role to play in reassuring U.S. policymakers that key material design requirements are being sustainably met and that future nuclear weapon tests will be unnecessary. Even though GtG would be programmatically dedicated to the peaceful use of tritium, the technological mechanisms used to reach this goal would nonetheless be compatible with and/or even complementary to the existing nuclear defense posture.
Key facts highlighted in the 2024 Fusion Industry Association (FIA) global reports include: (i) tritium remains the key fuel source for most fusion technologies being developed; (ii) tritium self-sufficiency was seen as one of the major near-term challenges and by a slim margin the major challenge after 2030; and (iii) supply chain partners noted tritium was one of the top 3 constraints to scalability. The easiest reaction to achieve is deuterium–tritium (D–T) fusion. Other more technologically challenging approaches to fusion energy rely on different reactions such as deuterium–deuterium (D–D) and deuterium–Helium-3 (D–He-3) fusion. The Earth has a functionally limitless supply of deuterium; however, even though He-3 is radioactively stable, it slowly leaks from the atmosphere into space. Until humanity can mine the vast quantities of He-3 on the moon, one of the only terrestrial sources of this material is from the tritium decay process. A GtG program would directly support an increase in tritium supply and indirectly support long-term He-3 reserves since it can be stockpiled. Even if fusion with He-3 proves viable, it will be necessary to produce the tritium first.
Once commercial fusion reactors begin operation, breeding tritium to replace burned fuel is a major concern because there is no alternative supply sufficient to replace shortfalls from even modest inefficiency. Operating a 1 GW fusion reactor for a year may require more than 55kg of tritium. Tritium self-sufficiency is nonnegotiable for a functional fusion industry. If technological development falters as companies strive toward a sustainable tritium breeding cycle, they may find themselves in the awkward position of needing tritium more than additional funding.
Of the countries leading the way in private fusion ventures and public investment, the only not closely allied with the U.S. is China, which is also the country most capable of leveraging military tritium production for fusion R&D. In stark contrast with the United States, there is no public information on Chinese tritium production capacities or how much they currently possess. Since China is rapidly expanding their nuclear weapon stockpile, their material margins for repurposing tritium for peaceful-use material will be constrained. If a U.S. investment of tritium into fusion R&D accelerates the growth of domestic companies, then China may be forced to choose between advancing their nuclear weapons agenda and competing with the West for a fusion energy breakthrough.
The United States already has a significant lead in technological capabilities for future generations of fusion energy based on Inertial Confinement Fusion (ICF). The National Ignition Facility (NIF) at Lawrence Livermore National Labs (LLNL) first demonstrated fusion ignition from ICF using tritium in 2022. Largely heralded as a breakthrough for the future of nuclear energy, the facility and ICF tests also provide critical, experimental support for the SSMP. To better position the United States to capitalize on these long-term investments in science and technology, fusion energy leadership should not be ceded to other nations.
Plan of Action
Recommendation 1. Name a White House “Gigatons-to-Gigawatts” czar to coordinate a long-term tritium strategy and interagency cooperation harmonizing national security and fusion energy leadership goals.
A Senior Advisor on the National Security Team of the White House Office of Science and Technology Policy (OSTP) serving as the White House czar for GtG would (i) guide and lead efforts, (ii) coordinate interagency partners, and (iii) facilitate private/public stakeholder forums. Key interagency partners include:
- The Nuclear Weapons Council (NWC)
- DOE National Nuclear Security Administration (NNSA) Office of Tritium and Domestic Uranium Enrichment
- DOE NNSA Tritium Modernization Program (NA-19)
- DOE NNSA Office of Nuclear Material Integration (ONMI) (NA-532)
- DOE Office of Science
- The Office of Fusion Energy Sciences (FES) at DOE Office of Science
- DOE Advanced Research Projects Agency – Energy (ARPA-E)
- State Bureau of International Security and Nonproliferation (ISN)
- TVA Tritium Production Program
- Nuclear Regulatory Commission (NRC) Office of Nuclear Material Safety and Safeguards (NMSS)
- Savannah River National Lab (SRNL)
- Los Alamos National Lab (LANL)
- Pacific Northwest National Lab (PNNL)
- Idaho National Lab (INL) Safety and Tritium Applied Research (STAR)
- Environmental Protection Agency (EPA) Office of Radiation and Indoor Air (ORIA)
- Fusion Energy Sciences Advisory Committee (FESAC)
Key private partners include:
- Savannah River Nuclear Solutions (SRNS) and the Savannah River Tritium Enterprise (SRTE) program
- Westinghouse Government Services (WGS) Columbia Fuel Fabrication Facility (CFFF)
- Fusion Industry Association (FIA)
A central task of the GtG czar would be to coordinate with the NWC to review Presidential Policy Directive 9 (PPD-9) and associated/superseding planning documents related to the assessment of tritium demand requirements including (i) laboratory research, development, and surveillance and (ii) presidentially mandated tritium reserve. These two components of the tritium requirement could potentially be expanded to address GtG needs. If deemed appropriate, the President of the United States could be advised to expand the presidentially mandated reserve. Otherwise, the former requirement could be expanded based on optimal quantities to stand up a GtG program capability. A reference target would be the accumulation of ~10kg of tritium on projected timelines for commissioning full-scale FOAK fusion reactors.
The following recommendations could be coordinated by a GtG czar or done independently.
Recommendation 2. The Secretary of Energy should direct the Office of Science to evaluate the Milestone-Based Fusion Development Program for integrating GtG tritium production and supply targets with projected industry demands for commissioning fusion power plants.
The Milestone-Based Fusion Development Program has already provided awards of $46 million to 8 US companies. It is crucial to ensure that any tritium produced for a GtG program is not accumulated without a viable success path for FOAK fusion plant commissioning. Given the modest production capacities currently available at the WBN site, timelines of 5–10 years will be necessary to accumulate tritium. Each fuel cycle could allow for adjustments in production targets, but sufficient lead time will be required to anticipate and plan for necessary core changes and fuel-assembly production.
GtG tritium awards aligned with the Milestone-Based Fusion Development Program would also be more viable and attractive if costs were equitably shared between private awardees and the DOE. The U.S. Government produces tritium at WBN at a premium of ~$50,000/g whereas the market rate for tritium produced in Canada is closer to $30,000/g. A fusion company awarded tritium through the GtG program should be required to pay the prevailing market rate for tritium upon extraction at the Savannah River Site (SRS). This would allow a fusion company to benefit from increased tritium availability, while the DOE shoulders the cost differences of Tritium-Producing Burnable Absorber Rod (TPBAR) production methods. Additionally, this pay-as-you-go requirement will incentivize fusion energy companies to lay out realistic timeframes for FOAK reactor deployments.
The Director of the Office of Science should also direct the FESAC to prepare a report on tritium demand scenarios that would apply to leading fusion technology development timelines and assess the necessary tritium breeding efficiencies needed to sustain fusion power plant operations. The FESAC should give special consideration to projecting possible mitigation and recovery strategies for tritium breeding shortfalls. The committee should also provide thresholds for FOAK fusion reactors’ short-term recoverability from tritium breeding shortfalls. Tritium quantities based on this FESAC report should be considered for future tritium hedges after these fusion reactors begin power operations.
Recommendation 3. The NNSA ONMI (NA-532) should coordinate an interagency review of the tritium supply chain infrastructure.
Raising tritium production targets beyond previously projected requirements would necessitate review from TPBAR assembly at Westinghouse’s CFFF, irradiation at TVA’s Watts Bar Reactors, and then extraction and processing through the SRTE program at SRS. Because this review naturally involves civilian reactors and the transport of nuclear materials the NRC should also be consulted to ensure regulatory compliance is maintained. This review will provide realistic bounding limits to the quantities of tritium and production timelines that could be designated for a GtG program. The outcome of this review will inform industry-facing efforts to better assess how additional tritium supplies could best support fusion energy R&D and pilot plant commissioning.
As part of this process, the NA-532 office should determine which existing tritium supply chain models are best suited for assessing commercial applications, including the LANL Tritium Supply and Demand Model and those developed internally by the NNSA. If no model is determined fit for purpose, then a new model should be developed to best capture the dynamics of commercial fusion R&D. In any case, existing models should form the basis for integrating military requirements and civilian markets to ensure a GtG program adequately accounts for both.
An added-value option for this recommendation would be to prepare an unclassified and publicly accessible version of the commercial tritium supply chain model. This would reinforce the transparency and public accountability already built into the production of tritium in the commercial power reactors at Watts Bar. Furthermore, such a resource would also help explain the rationale and intent behind the use of public funds to support fusion R&D and the commissioning of FOAK fusion reactors.
Recommendation 4. The Secretary of Energy should direct a review of DOE Technical Standards for addressing tritium-related radiological risks.
While the general scientific consensus is that low-level tritium exposure poses negligible human health and ecosystem risks, there are several unknowns that should be better understood before the advent of fusion energy releases unprecedented quantities of tritium into the environment. This adequacy review should include at least [i] a comprehensive analysis of risks from Organically Bound Tritium (OBT) and [ii] more precisely quantifying and considering the potential for damaging mitochondrial DNA and fetuses. These efforts would help ensure the responsible, consent-based rollout of tritium-intensive technologies and allow for an informed public to better understand the magnitude of risks to be weighed against potential benefits.
Key DOE Technical Standards to include in this review:
- Derived Concentration Technical Standard (DOE-STD-1196-2022)
- Internal Dosimetry (DOE-STD-1121-2008 (Reaffirmed 2022))
- Nuclear Materials Control and Accountability (DOE-STD-1194-2019)
Recommendation 5. The Administrator of the Environmental Protection Agency (EPA) should direct the Office of Radiation and Indoor Air (ORIA) to assess the adequacy of radioactive dose calculations in the Federal Guidance Report on External Exposure to Radionuclides in Air, Water, and Soil (FGR 15) last issued in 2019.
This recommendation, along with recommendation 3 above, will provide sufficient lead time to address any uncertainties and unknowns regarding the radiological risks posed by tritium. As in this previous case, this adequacy review should include at least [i] a comprehensive analysis of risks from Organically Bound Tritium (OBT) and [ii] more precisely quantifying and considering the potential for damaging mitochondrial DNA and fetuses. FGR 15 currently calculates effective dose rates for “computational phantom” models of 6 different age groups, including newborns, that incorporate both male and female sex-specific tissues. However, effective dose rates and potential effects are not considered for developing fetuses. The uncertainty surrounding tritium’s radiological risks prompts an extensive precautionary approach to potential exposures for declared pregnant workers. However, the potential for higher levels of tritium exposure for pregnant members of the public should also be taken into consideration when assessing the radiological risks of fusion energy.
Conclusion
With a strategically calibrated GtG program, the United States could remain technology leaders in fusion energy and potentially reduce the rollout timeline of a multi-unit fleet by several years. In the context of state-level technological competition and a multi-polar nuclear security environment, years matter. A strategic GtG reserve will take years to plan and accumulate to ensure sufficient tritium is available at the right time.
The long-term utility of a GtG framework is not limited to the designation of new tritium production for peaceful use. Once nuclear-weapons states return to the negotiating table to reduce the number of nuclear weapons in the world, the United States would have a clear roadmap for repurposing the tritium from decommissioned weapons in support of fusion power. Previously, the United States held onto large reserves of this valuable and critical material for years while transitioning from military to civilian production. The years between 2025 and 2040 will provide more chances to put that material to productive use for fusion energy. Let us not waste this opportunity to ensure the U.S. remains at the vanguard of the fusion revolution.
This action-ready policy memo is part of Day One 2025 — our effort to bring forward bold policy ideas, grounded in science and evidence, that can tackle the country’s biggest challenges and bring us closer to the prosperous, equitable and safe future that we all hope for whoever takes office in 2025 and beyond.
A U.S. Government Accountability Office (GAO) report from 2000 provided unclassified approximations of total life-cycle cost ranged from ~$34,000 to $57,000 per gram of tritium. With several program delays and at least one major capital investment (i.e., a 500,000 gallon Tritiated Water Storage Tank (TWST) system) costing ~$20 million, the actual life-cycle costs are likely higher. The cost of tritium produced in Canada is closer to $30,000 per gram, but, as noted above, only fixed and limited amounts of tritium can be made available through this process.
This is unlikely. The SSMP projects tritium needs far enough into the future that demand changes could allow for adjustments to production levels over the span of 1–2 fuel cycles (i.e., one and a half to three years). Barring a catastrophic loss of military tritium reserves or a significant nuclear accident at Watts Bar, there is unlikely to be a tritium supply emergency requiring an immediate response.
Historical tritium production amounts and capacities at SRS remain restricted data. However, due to NRC regulatory requirements for commercial reactors, this information cannot be protected for tritium production at Watts Bar. Since tritium production transparency has been the norm since 2003, the United States may further demonstrate nuclear stockpile credibility by openly producing material in excess of current military requirements.
Unobligated fuel demand would slightly increase. Unobligated fuel requirements are largely a sunk cost. Regardless of how many TPBARs are being irradiated the entire core will be composed of unobligated fuel. However, increased tritium production (i.e., irradiating more TPBARs) would require additional fresh fuel bundles per fuel cycle. The 2024 SSMP currently projects meeting Watts Bar’s unobligated fuel needs through 2044.
This would possibly require new license amendments for each reactor, but if the amounts were below the previously analyzed conditions, then a new Environmental Impact Statement (EIS) would not be required. The current license for each reactor allows for the irradiation of up to 2,496 TPBARs per fuel cycle per reactor. The EIS analysis is bounded at a maximum of 6,000 TPBARs combined per fuel cycle. The average yield of each TPBAR is 0.95g of tritium.
Fusion industry leaders have demonstrated confidence that existing and future supplies of civilian-use tritium, while modest, are sufficient to fuel the necessary near-term R&D. In particular, the planned refurbishments to aging Canadian CANDU reactors and the additional delays at ITER have propped open the tritium window for several more years until tritium breeding blanket technologies can mature. However, tritium supply chain bottlenecks could constrain industry momentum and/or advantage states capable of backstopping any shortages.
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