IAEA WORLD FUSION OUTLOOK 2025 3RD EDITION IAEA.ORG | OCTOBER 2025 INTERNATIONAL ATOMIC ENERGY AGENCY “The fusion energy landscape continues to develop at an extraordinary pace. What was once confined to experimental research and long term aspirations is now rapidly becoming a cornerstone of national energy strategies and industrial planning.” — Rafael Mariano Grossi, IAEA Director General Foreword: “Fusion energy represents more than just a new power source. It is a catalyst for scientific innovation, industrial transformation and international cooperation.” The fusion energy landscape continues to develop at an extraordinary pace. What was once confined to experimental research and long term aspirations is now rapidly becoming a cornerstone of national energy strategies and industrial planning. Countries are formulating dedicated fusion policies, companies are selecting sites and designing the first generation of power plants, and regulatory bodies are beginning to issue tailored guidance. End users are entering into power purchase agreements, utilities are forging strategic alliances with fusion developers, and major industries — from automotive and aerospace to digital technology and conventional energy — are incorporating fusion into their long term portfolios. This convergence of scientific progress, commercial interest and policy attention marks a decisive shift: fusion energy is entering a new phase of real world implementation. The IAEA World Fusion Outlook, launched in 2023, provides a structured, authoritative view of this dynamic and fast-evolving global landscape. The 2025 edition combines cutting edge analysis of scientific and technical developments with in-depth reporting on fusion plant siting, emerging national policies, and new patterns of international collaboration and market engagement. For the first time, it also includes global modelling of fusion energy deployment, showcasing the findings of a study undertaken by the Massachusetts Institute of Technology to explore how fusion could contribute to future electricity systems across a range of policy, cost and technological assumptions. Fusion energy is not advancing along a single, uniform trajectory. Instead, it is progressing through multiple parallel efforts, reflecting the diversity of technologies, approaches and regional contexts that are currently shaping the fusion industry. Today, nearly 40 countries operate active fusion programmes. Global private investment has surpassed US $10 billion. More than 160 fusion devices are now operational, under construction or planned, ranging from pilot plants aiming for demonstration in the near term to larger scale facilities laying the foundations for future industrial deployment. This diversity is a strength, enabling innovation and resilience as the field explores multiple paths towards commercialization. To foster coherence amid this growing diversity, the IAEA established the World Fusion Energy Group in 2024. This global initiative brings together public and private stakeholders, research institutions, academia and regulatory authorities to enhance dialogue, align efforts and share emerging best practices. As part of this initiative, the IAEA convened leading experts to define a set of Fusion Key Elements — a shared conceptual foundation to guide international efforts in research and development, safety, financing, and commercialization in the years ahead. Fusion energy represents more than just a new power source. It is a catalyst for scientific innovation, industrial transformation and international cooperation. Its promise — clean, safe, abundant energy for all — comes with the responsibility to pursue its development wisely, sustainably and with respect for intellectual property rights. The realization of this transformative technological achievement will require sustained public investment and rigorous international standards, supported by the collaborative efforts of governments, industry and civil society. The IAEA remains committed to supporting all Member States in this important endeavour. I hope that the World Fusion Outlook 2025 will continue to serve as a trusted reference and common foundation for the global fusion community as we collectively chart the course towards a fusion powered future. “It is important to deepen the collaboration between industry, universities and research institutes to ensure that fusion energy development remains innovative, coordinated and collaborative.” — Shan Zhongde, Chairman, China Atomic Energy Authority The Earth is home to all human beings, and the global quest for peace, development, cooperation and mutual benefit has never been more important. It is our common aspiration to build an open, inclusive, clean and beautiful world of lasting peace, universal security and shared prosperity. The pursuit of low carbon energy is critical to our future. China attaches great importance to this endeavour and is actively advancing the energy revolution through its consumption, supply, technological development and systems reform efforts. Nuclear energy is an important source of green energy, and it must be developed openly, safely and innovatively in order to realize its full potential. Chinese President Xi Jinping has pointed out that “the peaceful use of nuclear energy is an important way to ensure energy security and to address climate change. Like the fire that Prometheus brought to the world, nuclear energy has ignited the flame of hope and opened up a bright future for mankind.” China is modernizing on all fronts by pursuing high quality energy development. It has set two clear targets: reaching peak carbon dioxide emissions before 2030 and achieving carbon neutrality before 2060. Nuclear energy is key to achieving these targets as an important way to build a new, clean, safe, efficient, low carbon energy system. China is now one of the largest and fastest growing nuclear energy countries in the world. Fusion energy points the way to the peaceful use of nuclear energy. It offers major advantages such as higher energy density, more abundant fuel resources, less radioactive waste and greater inherent safety, making fusion energy an ideal solution for the future development of clean energy. China places a high priority on the innovative exploration and peaceful use of fusion energy. This October, the Second Ministerial Meeting of the IAEA World Fusion Energy Group and the 30th IAEA Fusion Energy Conference (FEC 2025) will be held in Sichuan, bringing the international community together to promote the safe, innovative and open development of global fusion energy. It is essential to build basic fusion energy platforms for international research and cooperation to ensure the advancement of fusion energy development through cooperative, collective and joint efforts. The Chinese Government has adopted a three step nuclear development strategy, progressing from thermal reactors to fast reactors to fusion reactors. China has been actively advancing the safe, innovative and international development of fission energy. For fusion energy, China has boosted its R&D along the pathway from experimental reactors to demonstration reactors to commercial reactors, achieving steady progress in fusion physics, materials science, engineering, construction and equipment manufacturing, and contributing Chinese solutions, expertise and resources to global innovation and international cooperation in fusion. It is important to deepen the collaboration between industry, universities and research institutes to ensure that fusion energy development remains innovative, coordinated and collaborative. The Chinese Government has pursued an innovation driven development strategy. In recent years, China has issued relevant policy documents and included fusion energy as a key source for achieving peak carbon and carbon neutrality and for developing cutting-edge green and low carbon technologies. Over 100 Chinese enterprises, universities and research institutes have set up the Fusion Innovation Consortium and the Fusion Industry Alliance to promote integration and innovation among academia, research and industry. It is vital for the international community to make concerted efforts to ensure that fusion energy development is safe, open and mutually beneficial. China is willing to participate in comprehensive, open international cooperation for energy security. The ITER project represents the human desire for the peaceful use of fusion energy and stands as one of the most important international scientific collaborations today. As a key partner in the ITER project, China has always honoured its international obligations and made concerted efforts with international counterparts to contribute Chinese expertise and resources to the smooth progress of the project. China upholds a rational, coordinated and balanced nuclear safety outlook and implements the International Science and Technology Cooperation Initiative. China is committed to working closely with other countries to foster an open, fair, equitable and non-discriminatory international environment for science and technology development. China cooperates with more than 140 fusion research institutions in over 50 countries, and the Southwestern Institute of Physics, affiliated with China National Nuclear Corporation, has been recognized as the IAEA Collaborating Centre for Research and Training in Fusion Energy. Recent scientific and technological developments and industrial transformation have accelerated the transition of fusion technology from scientific research to engineering and commercialization. However, the commercialization of fusion energy also faces scientific and engineering difficulties such as achieving self-sustaining burning plasma, developing materials resistant to high energy neutron irradiation and high heat load, advancing superconducting magnets and achieving tritium self-sufficiency, on the one hand, and challenges in establishing a sound fusion energy industry characterized by a mature supply chain, economic viability and sustained investment, and adapting a regulatory framework commensurate to its safety requirements, on the other. In the face of these opportunities and challenges, openness and cooperation are more imperative than ever. No country can overcome all these obstacles alone or benefit from the research outcomes in isolation. China is committed to pursuing the four global initiatives of Development, Security, Civilization and Governance. China embraces a development philosophy rooted in innovation, coordination, sustainability, openness and inclusive growth. China endeavours to build new platforms for international cooperation, to add new impetus to global progress, to foster global partnerships and to promote sustainable energy development while safeguarding global energy security together with all countries. China will work closely with the IAEA, the ITER Organization and other global partners to jointly support the IAEA World Fusion Energy Group mechanism in building a more just and equitable governance system for fusion R&D and a more open and orderly framework for international scientific cooperation, and in fostering a universally beneficial and inclusive environment for global fusion science and technology development. China remains committed to advancing green and low carbon development and to promoting harmony between humans and nature in order to build a clean, beautiful and sustainable world and a community with a shared future for mankind. A selection of recent advancements and breakthroughs since the IAEA World Fusion Outlook 2024, based on publicly reported developments. ITER (France): ITER delivers strongest performance to date as assembly progresses. In France, the international ITER project is progressing steadily in the tokamak assembly phase. Required repairs to major components (vacuum vessel sector field joints and thermal shield cooling piping) are largely complete. The relationship with the French Nuclear Safety and Radiation Protection Authority (ASNR) has been restored. The ITER Council has signalled its overall approval of the baseline schedule, as well as approval of the project cost profile — subject to approval from member governments — for this initial phase through the end of 2028. As of April 2025, fabrication of all major magnets is complete. The first vacuum vessel sector module was installed in mid-April, and the second in mid-June, six weeks ahead of schedule. The cryogenics plant has achieved helium liquefaction, and construction is under way on a test facility that will use the cryogenics system for additional pre-installation testing of some magnets. Gyrotron installation has begun for the electron cyclotron heating system, and divertor manufacturing is under way. ITER is also engaging with private sector fusion initiatives across multiple channels. ITER’s accumulated knowledge is being shared through technical visits, conversations with technical experts and document sharing. The first of two volumes of the ITER Design Handbook will be published by the end of 2025. The first private sector fusion company has been admitted to the committees of the International Tokamak Physics Activity collaboration. Approvals are largely complete for open sourcing ITER’s core software, and progress is being made on the compilation of a global fusion supply chain catalogue. Throughout 2024 and the first half of 2025, the project has maintained a cost performance index (CPI) of 1.0, meaning that 100% of what has been planned is being achieved. Canada: Liquid lithium liner and LM26 plans (General Fusion). Canadian company General Fusion is developing a fusion system that uses a liquid lithium liner to compress plasma. The company recently achieved plasma compression using its magnetized target fusion technology with a liquid lithium liner, as confirmed by a peer-reviewed study published in the IAEA journal Nuclear Fusion. The company’s experiments demonstrated stable, high density plasma compression, significantly increasing neutron yield (exceeding 600 million neutrons per second in one compression shot) and validating theoretical predictions for plasma heating. These results lay the foundation for General Fusion’s LM26 machine, targeting key fusion research milestones in the coming years. China: - EAST, CRAFT and BEST (Institute of Plasma Physics, Chinese Academy of Sciences): The EAST tokamak recently surpassed its previous record for sustained high-confinement mode (H-mode) operation, maintaining fusion plasma at 70 million degrees Celsius for 1066 seconds after upgrades that doubled heating power and expanded diagnostics. CRAFT, now in final stages of construction in Hefei, brings together some 20 specialized test stands. The BEST tokamak is being built adjacent to CRAFT to explore steady state control of D-T plasmas, targeting 2027 for first deuterium plasma. - HL-3 (Southwestern Institute of Physics / CNNC): Achieved major milestones sustaining plasma currents exceeding 1 MA, ion temperatures surpassing 100 million °C, H-mode operation, and a triple product on the order of 10^20 m^-3 * s * keV. HL-3 achieved 1.5 MA H-mode plasmas with record ion and electron temperatures of 120 million and 160 million °C, respectively. - Jingtian magnet (Energy Singularity): High temperature superconducting (HTS) magnet achieved peak magnetic field strength of 21.7 T. - EXL-50U and EHL-2 (ENN): EXL-50U achieved 1 million amperes of plasma current using hydrogen-boron fuel, with toroidal field coils operating stably at 150 kA producing 1.2 T. Construction of next-generation EHL-2 is expected by mid-2027. France: WEST (CEA): Achieved its longest plasma duration to date at 824 seconds with 1.93 GJ of energy injected, optimizing startup with newly installed tungsten wall tiles and boronization. Germany: W7-X (Max Planck Institute for Plasma Physics): World's largest optimized stellarator sustained high performance plasma for 43 seconds, achieving a record energy turnover of 1.8 GJ during a 360-second plasma pulse, and plasma pressure reaching 3% of magnetic pressure. Japan and European Union: JT-60SA: World's largest superconducting tokamak set a new record with a plasma volume of 160 m^3 (previous benchmark 100 m^3), designed to sustain plasma heated to 200 million °C for up to 100 seconds. Japan: GEKKO XII, LFEX and SENJU (ILE, University of Osaka): Demonstrating fast ignition laser fusion, SENJU high-repetition laser delivers 100 J pulses at 100 Hz. Upgrades aiming for completion by 2027 to achieve >100 g/cm^3 compression and >10 keV heating by 2030. Spain: SMART (University of Seville): First spherical tokamak designed to operate with negative triangularity achieved first plasma. Sweden: N1 (Novatron Fusion Group): Axisymmetric magnetic mirror machine achieved system integration and first hydrogen plasma at KTH Stockholm. United Kingdom: JET (UKAEA): Concluded operational journey on 18 December 2023 after over 100,000 pulses, delivering critical deuterium-tritium confinement and transport data for ITER and EU-DEMO. United States of America: - Boron and DIII-D (General Atomics / PPPL): Applying boron powder injection to protect tungsten walls and prevent sputtering. - NIF (LLNL): Achieved fusion ignition 8 times; in April 2025 achieved record fusion yield of 8.6 MJ from 2.08 MJ laser energy (target gain > 4). Planned upgrades target 2.6 MJ laser energy and >30 MJ yield. - WHAM (University of Wisconsin-Madison / Realta / CFS): Axisymmetric mirror machine using HTS mirror magnets produced first plasma in 2024. - SPARC and ARC (Commonwealth Fusion Systems): Installed SPARC cryostat base and tested central solenoid model coil (CSMC) at 50,000 A and 5.7 T (3.7 MJ stored energy). ARC commercial plant planned in Chesterfield County, Virginia (400 MWe, early 2030s). - Century (Zap Energy): Sheared-flow-stabilized Z-pinch test platform ran continuously for 3 hours, firing 1080 pulses (>100 kA each) inside flowing liquid metal. Dozens of fusion plant concepts are under development globally with target completion dates from the late 2020s to mid-2050s. Indicative Criteria for a Successful Fusion Plant: 1. Operational performance: 100-500 MW net fusion time-averaged thermal power; >=50 MW(e) peak electricity generation; Sustained safe operation across multiple environmental cycles. 2. Components: Design strategy, cost, and timescale for removal/replacement of degraded components. 3. Fuel cycle and materials: Boundary plasma innovations, materials science, tritium accountability. 4. Reliability and availability: Remote maintenance, modular replaceable components. 5. Environmental and safety: Mitigation of fuel cycle risks, waste minimization (< Class C waste), safe decommissioning. 6. Economics: Competitive LCOE, high plant availability, clear financing/commercialization pathways. Key Fusion Plant Concepts: - General Fusion Plant (Canada): Magnetized target fusion with liquid metal liner, ~300 MW(e) from two 150 MW units (early-to-mid 2030s). - CFEDR (China): China Fusion Engineering DEMO Reactor, 1.5-3 GW fusion power, Q = 15-30, R=7.8m, a=2.5m, Ip=15 MA, B=6.3 T, TBR > 1 (2040s). - EU-DEMO (European Union): Low aspect ratio baseline, R=8.6m, targeting 350 MW(e) net electric output with 2-hour pulse duration. - LightHouse (Focused Energy, Germany/USA): Direct-drive inertial fusion pilot plant planned at repurposed Biblis nuclear site, 150-250 MW fusion power (late 2030s). - VNS (EUROfusion): Volumetric Neutron Source compact DT tokamak (R=2.67m, a=0.62m, 38 MW fusion power) for testing breeding blankets. - Gauss GIGA (Gauss Fusion, Germany): Gigawatt-class stellarator with demountable superconducting coils and modular blankets. - Stellaris (Proxima Fusion, Germany): Quasi-isodynamic stellarator concept targeted for 2030s. - Tao Machine (nT-Tao, Israel): Compact modular pulsed magnetic confinement, 10-20 MW(e) for distributed power. - FAST (Kyoto Fusioneering, Japan): Compact HTS tokamak targeting 50-100 MW power output and DT operation up to 1000 s. - Helical stellarator (Helical Fusion, Japan): Steady state helical stellarator with HTS cables and liquid metal blanket (demo 2034, commercial 2040s). - JA DEMO (Japan): 1.5 GW fusion power, 12.3 MA plasma current, Qsci = 17.5, targeting electricity demo in 2030s. - K-DEMO (Republic of Korea): R=6.8m, a=2.1m, B=7 T, Ip > 12 MA (engineering design completion 2035). - DEMO-RF (Russian Federation): Tokamak / hybrid reactor targeting completion by 2055, and DEMO Fusion Neutron Source by 2033. - NOVATRON N4 (Novatron Fusion Group, Sweden): Full scale commercial mirror reactor prototype >1 GW(e) in 2030s. - Tokamak Energy fusion pilot plant (UK/USA): Low aspect ratio tokamak with HTS magnets. - STEP (UK Industrial Fusion Solutions): Spherical Tokamak for Energy Production at West Burton coal site, target operations 2040. - ARC (Commonwealth Fusion Systems, USA): 400 MW(e) commercial tokamak in Virginia (early 2030s). - Polaris & Orion (Helion Energy, USA): Pulsed non-ignition D-He3 direct energy conversion; Orion plant in Malaga, WA targeting >=50 MW(e) by 2028. - Longview Fusion Energy Systems (USA): 1 GW(e) laser IFE plant design with Fluor Corporation. - Da Vinci (TAE Technologies, USA): Field-reversed configuration with hydrogen-boron fuel, targeted for early 2030s. - Infinity Two (Type One Energy, USA): 350 MW(e) quasi-isodynamic stellarator with non-planar HTS magnets (mid-2030s). - Zap Energy fusion plant (USA): Modular sheared-flow-stabilized Z-pinch units (50 MW(e) per 3m module). Global pursuit of fusion energy entered an industrial phase in 2025, driven by public-private partnerships, strategic policies, and regulatory initiatives. IAEA World Fusion Energy Group (WFEG): Inaugurated in November 2024 in Rome, Italy, co-organized with the Italian Government, establishing Fusion Key Elements and coordinating global safety, regulation, supply chains, and deployment. National Strategies: - Canada: CNL expanded Clean Energy Siting Program (Chalk River / Whiteshell) and formed Fusion Fuel Cycles joint venture with Kyoto Fusioneering to build UNITY-2 tritium facility by 2026. - China: Launched China Fusion Energy state-backed enterprise ($1.6B SOE investment + $1.4B Shanghai Future Industry Fund) and unveiled Crimson Skyblade linear plasma device. - Germany: Fusion 2040 programme (€370M through 2028), DioHELIOS laser project, IFE Targetry HUB, and €20M support for Biblis laser fusion project. - Italy: Outlined goal of 400 MW fusion by 2050; approved draft law for nuclear reintroduction; unveiled first DTT superconducting magnet (16 tonnes, >6m tall) targeting 2030 first plasma. - Japan: Updated Fusion Energy Innovation Strategy (2025) aiming for power generation demonstration in 2030s; joined IFMIF-DONES (5% share); bilateral cooperation with UK. - Republic of Korea: Compact Pilot Device (CPD) trilateral agreement between KFE, General Atomics, and Daejeon City as stepping stone to K-DEMO. - Romania: Poured first concrete for Cernavodă Tritium Removal Facility (€145M EIB loan, $200M EPC contract with KHNP). - Russian Federation: Finalized design of TRT tokamak (construction by 2030). - Spain: IFMIF-DONES groundbreaking in Granada (€202M EU funding, 55% Spain share). - United Kingdom: £2.5B ($3.2B) fusion R&D funding over 5 years; £410M for STEP; £200M LIBRTI tritium fuel programme; £20M Starmaker One fund; UKAEA-Eni H3AT facility (2028). - USA: DOE secretarial order recognized fusion as a strategic technology; $107M for six FIRE collaboratives; Great Lakes Fusion Energy Alliance formed. Supply Chain & Private Investment: - Cumulative global private fusion investment exceeded US $10 billion. - Private fusion company supply chain spending reached US $434 million in 2024 (up 73% from $250M in 2023), with 25% growth projected in 2025. - Major 2024-2025 funding rounds: Commonwealth Fusion Systems (>US $2.1B raised to date, nearing $3B), Helion Energy ($425M round led by SoftBank/Lightspeed, total >$1B), Proxima Fusion (€130M Series A, Europe's largest), TAE Technologies ($150M+ round, total >$1.3B), Zap Energy (strategic investment from UAE's Plynth Energy). - Key corporate partnerships: CFS with Google (200 MW power agreement) and Dominion Energy; Helion with Microsoft (power delivery by 2028) and Nucor; Type One Energy with TVA. Evolving Regulatory Frameworks: - Canada: CNSC published 2024 position paper separating fusion from fission, and May 2025 discussion paper (DIS-25-01) proposing two facility categories based on risk. - European Union: EU Parliament hearings (2025) and EU Fusion Expert Group opinion paper outlining 5 pillars (Advancing ITER, Industrial innovation, Dedicated regulation, Global partnerships, Strengthened governance). - Germany: ReFus pilot project under Fusion 2040 exploring adaptation of radiation protection laws vs dedicated fusion framework. - Italy: National Platform recommendations proposing a tailored intermediate framework between radiation sources and fission by 2030. - Japan: Cabinet Office approved basic policy regulating fusion under radioisotope frameworks rather than reactor legislation. - United Kingdom: UK Energy Act 2023 established fusion outside nuclear site licensing (regulated by EA and HSE); 2025 national policy statement response on siting. - United States: ADVANCE Act of 2024 codified NRC regulation of fusion under byproduct material framework separate from fission reactors. Based on the MIT Energy Initiative (MITEI) and Plasma Science and Fusion Center (PSFC) study: The Role of Fusion Energy in a Decarbonized Electricity System using the EPPA model. Key Demand & Decarbonization Context: - Global electricity consumption is projected to grow by 340% between 2020 and 2100 (from ~25,000 TWh to >85,000 TWh). - In deep decarbonization scenarios (Accelerated Actions 1.5°C pathway), variable renewable energy (wind/solar) expands 20-fold but faces integration limits, land constraints, and declining marginal value at high grid shares. - Fusion provides dispatchable, firm, zero-carbon power with high power density, complementing renewables. Cost & Deployment Projections: - Base case assumes fusion commercial availability in 2035 at $11,000/kW overnight capital cost, declining endogenously to $8,000/kW by 2050 and $4,300/kW by 2100 (capacity factor rising from 40% in 2035 to 85% by 2060). - Global fusion generation in base case reaches 375 TWh in 2050 and ~25,000 TWh by 2100 (representing 15% of global electricity by 2075 and 27% by 2100). - Sensitivity analysis for 2050 capital costs: * $2.8K/kW case: Fusion generates 30% of global electricity by 2075 and 50% by 2100. * $5.6K/kW case: Fusion generates 22% by 2075 and 38% by 2100. * $8.0K/kW base case: Fusion generates 15% by 2075 and 27% by 2100. * $11.3K/kW case: Fusion generates 4% by 2075 and 10% by 2100. - Regional growth: Faster electricity growth in India (8.2-fold) and Africa (9.3-fold) relative to US/Europe/China (1.9- to 2.4-fold). Economic Value to Society: - Undiscounted cumulative global GDP benefit (2035–2100) from fusion availability is $68 trillion in the base case ($8K in 2050) and $175 trillion in the $5.6K case. - Net Present Value (discounted at 6% to 2024) is $3.6 trillion (base case) and $8.7 trillion ($5.6K case). - Cumulative global GDP is 0.4% higher (base case) and 0.9% higher ($5.6K case) compared to deep decarbonization without fusion. High-temperature superconducting (HTS) magnets have transformed magnetic confinement fusion by enabling higher magnetic fields in compact geometries (fusion power scales with B^4). HTS Applications in Projects: - SPARC (CFS): REBCO TF coils (TFMC achieved 40 kA at 20 K and 20 T); VIPER cables in CS and PF coils; >10,000 km REBCO tape procured. - WHAM (Wisconsin/Realta): Operational mirror with 17 T HTS magnets. - Design Concepts: ARC (CFS HTS TF coils), STEP (detachable TF coils), Tokamak Energy pilot plant (partially insulated TF coils), Infinity Two (Type One Energy, VIPER cables), Stellaris (Proxima Fusion modular HTS coils), Gauss GIGA (demountable modular HTS coils), Eos (Thea Energy planar HTS coils), Hammir (Realta Fusion tandem mirror). - R&D Programmes: EU-DEMO SECAS conductor (68 kA at 18 T, 4.5 K), BEST CS HFRC conductor, Helical Fusion UROCOIC conductor, Energy Singularity Jingtian coil (>21 T). Conductor Categories: a. Roebel-type conductors b. TSTC-type conductors (e.g., VIPER) c. CORC-type stranded conductors d. Bi-2212 cable stranded conductors e. Simply stacked tape conductors (e.g., STARS) f. Flexible conductors with low-melting-point metal impregnation (e.g., UROCOIC) g. Non-insulated non-twisting (NINT) embedded tape windings Technical Challenges: - Tape properties & cost: YBCO is preferred over GdBCO due to lower neutron degradation from thermal neutron capture. - Mechanical stress: High Lorentz forces require robust mechanical reinforcement against edge-wise bending and delamination. - Quench protection & detection: Slow normal zone propagation in HTS necessitates novel detection such as optical fiber sensors. - Insulation & irradiation: Tolerance up to 400 MGy for insulators; fast neutron fluence limits around 2-3 x 10^22 n/m^2 for YBCO. - Conductor joints and AC loss mitigation. Key Metrics from IAEA Fusion Device Information System (FusDIS) and 30th IAEA FEC: FEC 2025 Submissions: Total of 735 papers submitted: - China: 196 papers (27%) - United States of America: 113 papers (15%) - Japan: 88 papers (12%) - Other countries: 91 papers (12%) - Germany: 46 papers (6%) - Russian Federation: 47 papers (6%) - Republic of Korea: 36 papers (5%) - United Kingdom: 35 papers (5%) - India: 30 papers (4%) - Italy: 30 papers (4%) - France: 21 papers (3%) Global Device Statistics (2025): - Total Devices: 172 (up from 119 in 2021, 134 in 2022, 136 in 2023, 159 in 2024). - Operating status: 59% Operating (101 devices), 10% Under construction (18 devices), 31% Planned (53 devices). - Device class: 85% Experimental (145 devices), 15% Fusion plants (27 devices). - Device type: Tokamaks (46%, 79 devices), Stellarators (17%, 30 devices), Alternative concepts (28%, 49 devices), Laser/Inertial (8%, 14 devices). - Ownership/Funding: 67% Public funding, 33% Private funding (private funding doubled since 2021). - Regional distribution (Experimental / Fusion Plants): Asia & Pacific (64 / 7), Europe (31 / 8), North America (44 / 11), Latin America & Caribbean (5 / 0), Africa (2 / 0).