Fusion Science and Technology ISSN: (Print) (Online) Journal homepage: www.tandfonline.com/journals/ufst20 Tritium Opportunities and Challenges for Fusion Developments Worldwide—CNL and UKAEA View Stephen Strikwerda, Paul A. Staniec, Monica Jong, Ben Wakeling, Stephen Reynolds, Ian Castillo, Sam Suppiah, Hugh Boniface, Donald Ryland, Todd Whitehorne, Kathrin Abraham, Steve Wheeler, Damian Brennan & Rachel Lawless To cite this article: Stephen Strikwerda, Paul A. Staniec, Monica Jong, Ben Wakeling, Stephen Reynolds, Ian Castillo, Sam Suppiah, Hugh Boniface, Donald Ryland, Todd Whitehorne, Kathrin Abraham, Steve Wheeler, Damian Brennan & Rachel Lawless (2024) Tritium Opportunities and Challenges for Fusion Developments Worldwide—CNL and UKAEA View, Fusion Science and Technology, 80:3-4, 607-615, DOI: 10.1080/15361055.2023.2210277 To link to this article: https://doi.org/10.1080/15361055.2023.2210277 Published online: 26 Jun 2023. Submit your article to this journal Article views: 600 View related articles View Crossmark data Citing articles: 2 View citing articles Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=ufst20 FUSION SCIENCE AND TECHNOLOGY · VOLUME 80 · 607–615 · APRIL–MAY 2024 © 2023 Canadian Nuclear Laboratories and UK Atomic Energy Authority DOI: https://doi.org/10.1080/15361055.2023.2210277 Tritium Opportunities and Challenges for Fusion Developments Worldwide—CNL and UKAEA View Stephen Strikwerda,a* Paul A. Staniec,b Monica Jong,b Ben Wakeling,b Stephen Reynolds,b Ian Castillo,a Sam Suppiah,a Hugh Boniface,a Donald Ryland,a Todd Whitehorne,a Kathrin Abraham,a Steve Wheeler,b Damian Brennan,b and Rachel Lawlessb aCanadian Nuclear Laboratories, 286 Plant Road, Chalk River, Ontario, K0J 1J0, Canada bUnited Kingdom Atomic Energy Authority, Culham Science Centre, Abingdon, OX14 3DB, United Kingdom Received November 24, 2022 Accepted for Publication April 28, 2023 Abstract — The commercial generation of electricity and high-temperature thermal energy via fusion technology remains one of the promising alternatives to help meet the challenging targets to decarbonize the global energy system. Fusion technology can play a significant role as part of the long-term switch away from carbon-based fuels for electricity and heat due to high energy output, usage of abundant fuel that can be made available without environmental degradation, and avoidance of long-lived and toxic transuranics. Many countries have their own fusion research and development programs, while large research efforts are being undertaken in multicountry collaborations, such as ITER. Recently, fairly new (semi-) commercial organizations have been successful in initiating independent development programs funded by government grants and private investments. Different fusion reactor technologies still share many challenges, with one of the major issues being the management of the deuterium-tritium (DT) fuel cycle and associated auxiliary systems. These different fusion technology developers could benefit immensely from existing and available DT expertise, allowing them to focus primarily on the physics and mechanical aspects of their reactor technologies while finding support for common tritium technological challenges through collaboration. As world-leading experts in DT technology, Canadian Nuclear Laboratories (CNL) and the United Kingdom Atomic Energy Agency(UKAEA), are well positioned to support such needs of the fusion industry. This paper broadly explores the worldwide DT challenges, identifies opportunities where tritium expertise is key to the development of fusion infrastructure, and presents a view of how CNL and UKAEA are addressing these opportunities for the various fusion developers. This paper presents a holistic view that may be informative to future tritium roadmap and decision-making exercises conducted within the community. Keywords — Tritium processing, fusion reactors, infrastructure, regulation. Note — Some figures may be in color only in the electronic version. I. INTRODUCTION are planning to use deuterium-tritium (DT) reactions to provide the most energy-favorable route to positive The delivery of fusion solutions for power generation energy production. Historically, tritium capabilities have has attracted increased attention and significant private been targeted for delivery just in time for large fusion DT investment in the last 36 months.[1] The majority of experimental milestones. This has allowed for directing fusion power plant technologies that have been proposed the initial investment toward early milestones, such as achieving confinement and first plasma. However, the *E-mail: [email protected] subsequent integration of the tritium infrastructure has 607 608 STRIKWERDA et al. · TRITIUM OPPORTUNITIES AND CHALLENGES FOR FUSION DEVELOPMENTS WORLDWIDE frequently proved more challenging than anticipated and out on short timescales compared to the residual radiolo- led to program delays. The resulting extended timeframe gical activity of the equipment. and associated additional costs have been accommodated While many currently proposed fusion reactors are of by large long-term national research projects, but could different designs, most will ultimately share common be prohibitive to private companies. high-level requirements for tritium support facilities and High-performance DT plasma is now being targeted associated auxiliary systems, and therefore, their demon- in multiple facilities on short timescales, which are more strator evolutionary stages will be similar. CNL and ambitious than those previously envisaged. This repre- UKAEA’s experience with tritium facilities will be sents a significant change in the challenge portfolio asso- a great asset when designing future facilities to ensure ciated with tritium technology and requires a substantial there is a viable, timely, and cost-effective path to appro- review of the landscape. It has increased the severity of priate upgrades as ventures progress. risks associated with tritium supply, tritium breeding, DT While the ultimate scale of the supporting tritium plant fuel processing, tritium emissions, waste, regulation will vary in line with the reactor design and approach uncertainty, and limited specialist availability. Canadian being considered, with differing tritium flow and inventory Nuclear Laboratories (CNL) and the United Kingdom requirements, the development stages of the infrastructure Atomic Energy Authority (UKAEA) plan to use their will be similar for most cases and can be divided into four knowledge and existing capabilities to support the accel- to five incremental stages. Thus, in Fig. 1, the x-axis erated delivery of tritium technologies to meet the represents the relative complexity and size of the plant expected expanding demand for tritium processing infra- for any unique demonstrator requirements, while the structure at different scales. CNL and UKAEA are both y-axis indicates the growing technology readiness level accustomed to taking leading roles working with technol- (TRL) requirements and supply chain maturity. The ogies at different maturity levels and supply chains to aid requirements are summarized in Table I and are as follows: industry and academia. A.The most basic setup is only available to experi- ments that may be demonstrated with negligible II. TRITIUM SUPPORT FACILITY DEVELOPMENTAL STAGES inventories and gas volumes. Here, tritium can be delivered directly from small, sealed vials and The European fusion program has different tritium any trace unburnt tritium vented directly to the plant requirements to support the increasingly large toka- atmosphere. This requires only minimal contain- mak devices (JET, ITER, and DEMO) for demonstrating ment and monitoring, and little infrastructure. growing magnitudes of fusion performance.[2] Similarly, B. The next stage is reached as soon as inventories it is expected that commercial ventures will follow surpass the small amount of tritium that can be a series of increasingly challenging fusion-related gates/ acceptably vented directly. Exhaust gases must be milestones and set the tritium infrastructure requirements processed to capture the unburnt tritium, which and investment at each stage accordingly. can later be reprocessed by external third parties. Historically, many national and international publicly Full containment and monitoring are required. funded programs have hosted evolving iterations of fusion The exhaust detritiation and capture represents devices at separate locations. Consequently, supporting a low energy cost. tritium plants were single-purpose constructions specific C. This stage is reached when experiments require to one iteration of a fusion reactor technology and not a tritium feed that cannot be viably (due to cost required to significantly upgrade or upscale to support or availability) continually sourced externally. The subsequent larger, higher-performance reactors. However, unburnt and captured tritium must now be recycled developing bespoke one-off tritium plants for each itera- in house and returned to the feed. Burnt tritium tion of a fusion device will be an unattractive prospect for may be replaced with occasional external top-ups. private ventures, each requiring significant financial and The addition of the reprocessing systems increases time investments in design, regulatory approval, construc- the plant’s operational energy costs. tion, and commissioning. Therefore, the first new chal- lenge is enabling the reuse and repurposing of the tritium D. Once the experiment is burning considerable facilities to scaleup and modify the plant performance to tritium, it will become less viable to replace meet the increasing and changing demands of evolving via external top-ups of tritium. At this stage, demonstration devices. These upgrades must be carried local breeding is required to offset the tritium FUSION SCIENCE AND TECHNOLOGY · VOLUME 80 · APRIL–MAY 2024 TRITIUM OPPORTUNITIES AND CHALLENGES FOR FUSION DEVELOPMENTS WORLDWIDE · STRIKWERDA et al. 609 Fig. 1. The development of a tritium plant and fuel cycle supporting a fusion demonstrator facility divided into five incremental stages. JET and TFTR are indicated as stage C. The future ITER plant could be identified as C or D, as breeder demonstrators may be incorporated, but ITER is not planned to be self-sufficient. TABLE I Requirements of a Tritium Plant and Fuel Cycle Supporting a Fusion Demonstrator Facility Divided into Five Incremental Stages Requirement A B C D E Full secondary containment and monitoring ✔ ✔ ✔ ✔ Feed: external per experiment ✔ ✔ Feed: startup + top-up ✔ Feed: startup only ✔ ✔ Exhaust processing to capture unburned tritium ✔ ✔ ✔ ✔ External processing of captured tritium ✔ Reprocessing of captured tritium (return to feed) ✔ ✔ ✔ Breeding of tritium ✔ ✔ Optimization of process ✔ Can support batch operation ✔ ✔ ✔ Can support continuous operation ✔ ✔ ✔ consumption to produce a self-sufficient fuel E. The final stage is optimization of the process cycle. The additional breeding and recovery and potentially reducing the flexibility of the systems further increase the plant’s operational infrastructure to reduce operational overheads energy costs. to increase the economic viability of the final FUSION SCIENCE AND TECHNOLOGY · VOLUME 80 · APRIL–MAY 2024 610 STRIKWERDA et al. · TRITIUM OPPORTUNITIES AND CHALLENGES FOR FUSION DEVELOPMENTS WORLDWIDE infrastructure. The optimized processes and To reduce this risk, fusion organizations should con- technological solutions lower the plant’s tact tritium suppliers far in advance to ensure an adequate operational energy costs compared to stage 4. tritium supply will be available to meet the milestones of their reactor deployment. The current upsurge in DT fusion demonstrators is a significant opportunity for III. CHALLENGES AND OPPORTUNITIES investment and development in tritium supply and the associated logistics. Increased tritium sales and expres- Work on various national fusion programs has iden- sions of interest will improve the economics of tritium tified fundamental challenges linked to power-plant-scale extraction from existing heavy water reactors and invite tritium plants, with each of the challenges having its own potential investment into additional sources, thereby complexities and interdependencies. Here, the authors potentially increasing the global tritium inventory and outline some of the key challenges and opportunities the number of tritium suppliers in the long term, such where CNL/UKAEA can support emerging demonstrator as the Cernavoda Tritium Removal Facility (TRF).[9] initiatives. UKAEA has recent experience in the import of tritium from Canada, and thus this experience from both sides of III.A. Supply and Logistics of Startup Tritium the process is available to be shared. Tritium transport logistics is also an area requiring Regardless of the tritium-breeding plans, all nuclear rapid development. Most civilian tritium is transported fusion reactors relying on tritium fuel will require a from the Darlington TRF to the CNL in the CNL’s 50-g supply of external tritium to enable an efficient startup. tritium container and then distributed via the smaller The tritium supply currently has multiple challenges: General Electric Healthcare Type B(U) 3605D, which export controls, limited supply availability (both in inven- can only contain up to ~11.2 g of tritium.[10] These tory and civilian suppliers), and restrictively small trans- logistics are insufficient to support upcoming fusion port containers. demonstrator experiments or to provide startup fuel for Regardless of the tritium-breeding plans, all nuclear future fusion power plants where the transport of kilo- fusion reactors relying on tritium fuel will require a grams of tritium from suppliers and between fusion sites supply of external tritium to enable an efficient startup. will be required. To enable seamless global tritium logis- For member countries of the Nuclear Suppliers Group, tics, leading fusion organizations and tritium suppliers the transfer of dual-use materials, such as tritium, require should collaborate on the development and licensing of legal measures to ensure the peaceful end use of tritium a large standard tritium container. CNL has the expertise and nonproliferation controls.[3] If there is no agreement to develop and license large tritium transport containers in place, nuclear fusion organizations need to engage with once a path forward is agreed on between suppliers and their governments to develop this at an early stage, as consumers. agreements can be slowed down by a multitude of poli- tical issues. III.B. Breeding and Extraction of Tritium At this time, large inventories of civilian tritium are limited to two CANDU tritium removal facilities: Full-scale DT fusion reactors will consume more Darlington, Canada, and Wolsong, Korea, and the pre- tritium than can be practically supplied externally. sently available inventory is limited to a few tens of Instead, tritium must be produced from breeder blankets kilograms. The lack of tritium inventory stock and (see Ref. [11] and references therein). However, lithium sources represents a challenge to an expanding DT fusion breeder blanket technologies and the associated tritium community, as full-scale fusion reactors such as CFETR, extraction are at a low level of development. A number of DEMO, K-DEMO, and STEP will each need a few kilo- breeder blanket technologies have been conceptually grams of tritium for an efficient startup.[4–7] Even greater identified that breed tritium in differing carrier mediums tritium inventories will be committed to supporting large- and concentrations, which necessitate different extraction scale experiments with limited breeding capabilities, such methodologies. The concept of lithium first walls and as ITER.[8] It is likely that there will be insufficient divertors may also impact this selection.[12,13] Each of tritium inventory supply to support the rapid growth of these arrangements must be reviewed, with promising fusion demonstrations. If tritium inventories start to candidates selected for experimental assessment and become depleted, national governments may begin to then incrementally scaled up from lab scale to demonstra- consider these inventories to be strategic assets. tion scale. FUSION SCIENCE AND TECHNOLOGY · VOLUME 80 · APRIL–MAY 2024 TRITIUM OPPORTUNITIES AND CHALLENGES FOR FUSION DEVELOPMENTS WORLDWIDE · STRIKWERDA et al. 611 The generation of high fluxes of neutrons for testing separation functions. For example, for isotope separation, breeder blankets is challenging and costly. Therefore, at gas chromatography can be used as a batch process, demonstration scale, the testing should ideally utilize the whereas cryogenic distillation can be used for continuous neutron flux from operational fusion demonstrators, processing.[19,20] which has the added benefit of more closely mimicking The batch mode infrastructure is well established and real conditions. CNL has conducted studies for private is still directly applicable to many upcoming early fusion firms, giving recommendations on what extraction demonstrators (A, B, and C in Fig. 1). Only once the techniques are best to pursue for the development of their demonstrator has evolved toward the latter stages (C, D, breeder blanket and for the preliminary sizing for tritium and E in Fig. 1), will operations need to switch to extraction and processing. To begin the process of lab- a continuous mode of operation. It is economically attrac- scale demonstrations, CNL has selected one initial option tive for the plant infrastructure to be designed to accom- and is currently designing test molten lead lithium eutec- modate this shift or upgrade. tic loops. The optimal configuration for a continuous fuel cycle Fuel containing a natural isotopic ratio of lithium may tritium loop is still to be decided and will likely be specific become 6Li depleted, especially if fast neutrons are to the fusion device’s requirements. A continuous tritium shielded or deenergized by material between the breeder loop was demonstrated (without breeding or coolant pro- blanket and the plasma, requiring a more rapid wholesale cessing) in the 1980s at the Tritium Systems Test replacement or 6Li top-up. Current 6Li stockpiles and Assembly (TSTA),[21] which was subsequently decommis- production are limited to military activity, with separation sioned in 2003.[22] However, this involved passing the full historically resulting in high mercury emissions.[14] The process loop through a cryogenic distillation system, available neutron flux and impact on the breeder blanket which has implications for high operational costs and fuel will need to be assessed for each demonstrator mobile tritium inventories. New architectures, including arrangement. CNL is currently planning an assessment of isotopic rebalancing with only partial streams entering the supply of lithium and a development path for new or isotopic separation, are now being considered. revised technology for civilian lithium isotope separation. While existing technologies suitable for batch operation at modest scale mostly have a high TRL, this cannot be said III.C. Processing and Recycling of DT Fuel for some of the technologies applicable to high-flow and continuous operation (e.g., inline tritium monitoring, direct A tritium processing plant is required to perform internal recycling, quick response for storage and delivery multiple functions to support a fusion reactor: capturing systems). Meanwhile, breeding, extraction, and associated and recycling unburnt DT fuel, removing any impurities, coolant technologies have very low TRLs. The complexity isotopic balancing, and storage. The topics of breeding of combining new and existing technologies into new con- and detritiation are covered in other sections. figurations for operating in continuous mode and demonstrat- To date, the only tritium plants that have fueled a DT ing tritium compatibility, while minimizing mobile tritium reactor are the Active Gas Handling System (AGHS) at inventories and operational costs, will be challenging. JET (recently reprocessing over 1 kg of tritium during These challenges are exacerbated due to the large DTE2) and the TFTR.[15–17] These operate in a batch parameter space associated with the many different fusion mode to support limited short-pulse reactions. Future approaches currently being explored. There is no clear power plants will either operate high-frequency pulses consensus on inventory and flow scales, coolant mediums or semicontinuous plasmas (depending on the reactor or breeder materials, and extraction routes. Furthermore, technology). A batch infrastructure does not practically each fusion approach also offers differing off-normal con- or economically scale up to provide sufficient throughput ditions that must also be accommodated. Last, the tritium for such operations and instead a continuous mode of inventory must be minimized for safety and regulatory plant operation is required.[18] assurances, as well as startup viability, meaning moderate In a batch mode, process subsystems take in a finite changes in operating configurations and scale can poten- quantity of gas and process it before releasing it fully, and tially have a significant impact on the infrastructure design the cycle repeats. In a continuous mode, gas is moving continuously through the subsystem or the gas levels are and technology selection. A holistic knowledge and under- otherwise regularly topped up and bled out. Predominately, standing of the different tritium technologies, and the this concerns the infrastructure relating to the exhaust potential impact of different demonstrator design choices, processing, impurity processing, and isotopic rebalancing/ is therefore essential when identifying pathways forward. FUSION SCIENCE AND TECHNOLOGY · VOLUME 80 · APRIL–MAY 2024 612 STRIKWERDA et al. · TRITIUM OPPORTUNITIES AND CHALLENGES FOR FUSION DEVELOPMENTS WORLDWIDE With a suitably broad knowledge of the technology (absorption and permeation), or both. Such radioactive landscape, CNL and UKAEA are continuing to work to waste from fusion reactors will differ from the fission identify key gaps and to advance the TRL for a selection industry, and thus established disposal routes may need to of technologies relevant to the continuous fuel cycle. be verified as appropriate for the fusion industry. New UKAEA is currently in the process of building The ITER disposal routes may be required to be developed to com- Relevant Tritium Loop (TIRTL) facility, a reduced-scale plement existing routes and ensure the continued avail- pilot plant demonstration of a continuous fuel cycle. This ability of these routes post expected lifetimes, which in operational experience will support the development of many cases have been based on forecast arising rates future tritium plants and will act as a test bed of new and based on existing fission plants without considering maturing technologies. Furthermore, UKAEA has extensive a future fusion industry. Waste classifications and dispo- experience gained from operating the AGHS for several sal route waste acceptance criteria should also be decades, while undergoing several upgrades, which can be reviewed to assess the specific hazards associated with used to support current demonstration activities. fusion radioactive waste following a risk-based approach. The tritium levels in CANDU waste make it espe- III.D. Recovering Fugitive Tritium and Reducing cially relevant for fusion, and this is currently being Emissions experienced at CNL as the old tritium facility is being dismantled. UKAEA is similarly developing a program Like hydrogen, tritium in elemental form will leak for the decommissioning of JET.[26] Separation and through small cracks and permeate through warm metals. decontamination techniques will help reduce the radio- Tritium leaks and permeation, especially into the coolant active waste liability, such as the techniques being devel- loops,[23] could result in unacceptable levels of tritium oped at UKAEA’s Material Detritiation Facility.[27] contamination and emissions. Similar issues have been It is essential to minimize the generation of radio- experienced in heavy water reactors and their TRFs,[24,25] active waste over the full lifecycle of a tritium plant (i.e., but are exacerbated in the fusion DT fuel cycle by higher operation and decommissioning) for economic and envir- temperatures and large flows of high-concentration ele- onmental reasons, and for public acceptance of fusion mental tritium. Using previous studies on tritium emis- power. UKAEA has established lifecycle expertise gained sions and abatement from CANDU reactors and TRFs through managing the full lifetime of JET. will be useful to minimize leakage throughout the fuel Reducing tritium permeation will have the greatest cycle lifetime. Tritium compatibility guidelines have been impact on both retention in materials and on fugitive developed by various groups, which have measures to emissions, which can be achieved through improved reduce tritium leakage. In order to reduce tritium permea- material selection or advanced coatings, and CNL and tion, materials, coatings, and manufacturing techniques UKAEA are already working in this area. Optimizing are being developed, and permeation through them are processes in the DT fuel cycle will further reduce the being tested with tritium at CNL and UKAEA. These tritiated waste by decreasing the exposed material or barrier materials will be especially useful for hot, thin- increasing lifetimes, such as using lessons learned from walled applications, such as heat exchangers. UKAEA’s AGHS facility and information gained at the Regardless of efforts in reducing tritium leaks and new Hydrogen-3 Advanced Technology TIRTL facility. permeation, the capture of fugitive tritium must be included in the DT fuel cycle design. This is done by III.F. Regulation Related to the DT Fuel Cycle using secondary enclosures, capturing or scrubbing tri- tium from air or gas, and treating tritiated water. Various Delayed regulatory approval could present air and water detritiation technologies are fully developed a significant risk to project deadlines, and therefore, early and commercialized for the CANDU industry and at engagement is important. However, one of the key chal- UKAEA. These will only require minor changes to fit lenges faced by the developing fusion community is the various DT fuel cycle needs, and both organizations can lack of regulatory frameworks explicitly supporting the advise in these fields. tritium fuel cycle in fusion power plants. This problem is further compounded due to the risk of a global environ- III.E. Disposal and Recycling of Tritiated Waste ment with disparate legal frameworks. Where relevant frameworks exist, they are often focused on nonprolifera- Operating a fusion facility will lead to some compo- tion aspects and the nuclear fission environment. In the nents becoming neutron activated, tritium contaminated absence of prescriptive guidance and frameworks, entities FUSION SCIENCE AND TECHNOLOGY · VOLUME 80 · APRIL–MAY 2024 TRITIUM OPPORTUNITIES AND CHALLENGES FOR FUSION DEVELOPMENTS WORLDWIDE · STRIKWERDA et al. 613 designing the first DT power plants and demonstrators The mobility of the workforce will be greatly enhanced must engage in detailed discussions with regulators. by the international cross acceptance of qualifications via Many regulatory bodies are rightly cautious and conserva- the harmonization of regulations. In particular, the wealth tive concerning the regulation of active materials, but the of operational experience gained by a small number of absence of existing nuclear fusion power plants leads to individuals must be shared to support the design of next- limited relevant examples that new safety cases can draw generation tritium plants and to build on recent lessons on. Specifically, there is an absence of operational data for learned. These individuals should be used as consultants large-scale and continuously operating tritium fuel cycles. to maximize the dissemination of their experience. This It is essential that facilities with operational experience in could also include providing an intermediary interface tritium fuel cycles (even if only limited to batch-mode with manufacturing industries to act as intelligent custo- operations or laboratory-level tritium handling) support mers for new bespoke components. engagement with global regulators and assist with generat- Given the anticipated expansion of the fusion sector ing the supporting information required to assure regula- in the coming decades, it is important to begin training tors and support safety case developments. and growing the next generation of tritium scientists and Globally, there is a need for international and govern- engineers. The community must provide tritium handling mental bodies to develop more fusion-specific regulator and DT fuel cycle training for students and apprentices frameworks and guidance, rather than amalgamate fusion and establish career development pipelines for the future power into fission frameworks. Many bodies have workforce. UKAEA and CNL are well placed to share the already started to explore their regulatory approach, considerable tritium operational experience they have including the United Kingdom,[28] Canada,[29] and the gained over recent decades. European Union,[30] where review exercises are under- way. Therefore, there is a time-limited, but very impor- IV. COLLABORATIVE RESEARCH AND DEVELOPMENT AND tant, window of opportunity for the fusion industry to THE NEED FOR A TRITIUM ROADMAP engage internationally to avoid the regulation of tritium technology becoming divergent and impeding interna- There are many common challenges facing the fusion tional collaboration and investment. community. The success of timely on-grid fusion power A separate, but related, challenge is the absence of requires that information and experience is well communi- equipment that is manufacturer certified for tritium opera- cated within the community, within the limits of commercial tion, which hinders approval processes due to the consider- sensitivity. Well-communicated research approaches and able time needed to qualify and demonstrate individual interlinked research themes on these common challenges components. This currently relies on the support of will increase the success rate on set timelines and will allow a narrow pool of experts with familiarity in tritium opera- for targeted investments in research and development. Cross- tion, and is not a long-term sustainable approach. There is cutting initiatives that prevent excessive and unnecessary therefore a need for the development of internationally duplication of efforts will therefore be hugely beneficial. accredited equipment tritium standards, which will be espe- While there have been a few recent roadmap exercises, cially valuable in supporting smaller commercial startups. these have been focused on specific device initiatives and timetables. There is, therefore, a strong need for a global III.G. Development of a Skilled Workforce roadmap to support the common challenges in the broader tritium fuel cycle community. The UKAEA is currently in With the recent upsurge in commercial fusion start- collaboration with the International Atomic Energy Agency ups and demonstrators, a shortage of a skilled and experi- and conducting a landscape survey of the tritium community. enced tritium workforce will become increasingly UKAEA and CNL are collaborating with the Fusion Fuel pronounced. Those with experience in DT fuel cycle Cycles and Blankets Workshop (2023) initiated by design and experimental work are in short supply, with Commonwealth Fusion Systems to deliver a tritium roadmap. those having experience in DT operations especially scarce. There are undoubtedly some transferable skills that are shared with those working in the fission industry, V. CONCLUSIONS but there will still be a need for some retraining. It is essential that this limited pool of experience be The rapidly increasing private investment in the fusion leveraged and disseminated effectively through training sector and the growth of different fusion demonstrator programs, collaborations, and commercial partnerships. concepts with ambitious delivery milestones can only FUSION SCIENCE AND TECHNOLOGY · VOLUME 80 · APRIL–MAY 2024 614 STRIKWERDA et al. · TRITIUM OPPORTUNITIES AND CHALLENGES FOR FUSION DEVELOPMENTS WORLDWIDE have a positive impact on the realization of fusion power 7. M. LORD, UK Atomic Energy Authority, “STEP Start-Up plants. However, this draws into focus the number of Tritium,” Personal Communications (2022). challenges involved in providing timely supporting tritium 8. “ITER Research Plan with the Staged Approach (Level III – fuel cycles and infrastructure for continuous self-sufficient Provisional Version), Appendix I: Tritium Availability,” ITER operation. 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