Is Nuclear Fusion Actually Achievable?

By Abdul Ahad NazakatReviewed by Louis CastelNov 12 2025

How Fusion Works

Fusion happens when two light nuclei overcome their mutual electrostatic repulsion and merge. This releases energy based on Einstein's mass-energy equivalence principle. The most practical reaction for terrestrial fusion uses deuterium and tritium (D-T), two isotopes of hydrogen. To trigger fusion, these fuel atoms are heated to over 100 million degrees Celsius, forming a superhot plasma where high-energy collisions can cause the nuclei to fuse.¹

Sustained fusion requires three key conditions: extremely high temperatures, sufficient pressure, and adequate confinement time to keep the plasma stable long enough for fusion reactions to occur. Scientists measure success using the fusion gain factor, Q, which compares fusion power output to heating power input. Q = 1 represents "breakeven," where fusion energy equals input energy. For actual energy production, Q needs to be well above 1 to account for losses in heating, confinement, and converting the energy into usable forms.

Fusion research is largely focused on two main approaches: magnetic confinement and inertial confinement. Magnetic confinement relies on powerful magnetic fields to contain superheated plasma within doughnut-shaped chambers. The two leading designs in this category are tokamaks and stellarators. In contrast, inertial confinement uses intense laser pulses to rapidly compress tiny fuel pellets, triggering fusion in just a few nanoseconds. Both methods come with their own engineering hurdles, and researchers around the world are actively developing and testing each approach.²

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The Global Push for Fusion

The largest international fusion project is ITER (International Thermonuclear Experimental Reactor), a tokamak being built in France with participation from 35 nations. ITER's goal is to achieve Q of 10 or higher. It was originally expected to begin operations around 2025, but construction delays have pushed the date back.3 After ITER, the next step involves demonstration power plants. The UK's STEP program, for example, aims to have a prototype by around 2040.⁴

In December 2022, the National Ignition Facility at Lawrence Livermore National Laboratory achieved fusion ignition in a laboratory for the first time. The experiment produced about 3.15 megajoules of fusion energy, which was more than the laser energy delivered to the fuel capsule.⁵ This represented "target gain," a significant milestone for inertial fusion physics. However, the laser system itself consumed approximately 300 MJ of electrical energy to generate the laser pulse, meaning the full-system Q remained well below 1.6 Although scientifically significant, experts caution this remains far from a practical power plant, as the facility can only fire a few shots per day rather than the continuous operation required for electricity generation. In magnetic confinement, the Joint European Torus (JET) facility set a world record in February 2024, producing 69 megajoules of fusion energy over six seconds which is equivalent to burning 2 kilograms of coal. This broke JET's previous record of 59 MJ set in 2022 and demonstrated reproducible control of fusion conditions, a crucial step toward ITER's operating scenarios.⁷

Meanwhile, private companies are pursuing alternative approaches with venture capital backing exceeding $6 billion globally.⁸ Commonwealth Fusion Systems is developing SPARC, a compact high-field tokamak using advanced superconducting magnets. As Dennis Whyte, former director of MIT's Plasma Science and Fusion Center and co-founder of Commonwealth Fusion, stated: "The big change is the new superconducting magnets... They allow you to make a much smaller, lower-cost device that can get to the same performance".⁹ Helion Energy explores pulsed fusion concepts, while First Light Fusion pursues projectile-driven inertial fusion. TAE Technologies is developing an alternative magnetic configuration that aims to use hydrogen-boron fuel, avoiding radioactive tritium altogether.^{8, 10}

What's Holding Fusion Back?

Despite recent progress, obstacles remain. Materials science presents perhaps the most difficult challenge. Fusion reactors produce 14 MeV neutrons that bombard reactor walls, causing radiation damage and material degradation far beyond what current fission reactors experience. Developing materials that can withstand decades of this neutron bombardment while maintaining structural integrity remains an active research area.^{11, 12}

Tritium breeding represents another critical hurdle. Natural tritium is extremely rare, so fusion reactors must breed their own fuel by surrounding the plasma with lithium-containing blankets that capture neutrons and produce tritium. Demonstrating a self-sustaining tritium fuel cycle at reactor scale has never been accomplished.^{12, 13} Economic viability compounds these technical challenges. One recent techno-economic analysis projected costs of approximately $1,148 per MWh for a 100 MWe demonstration reactor, more than ten times current electricity prices, dropping to about $608 per MWh at 500 MWe scale.¹⁴ A separate UK government analysis of the STEP program estimated capital costs in the billions of pounds, with commercial viability heavily dependent on achieving high plant availability and long component lifetimes.

Plasma physics bottlenecks persist even after decades of research. Maintaining stable, high-performance plasma while avoiding disruptions and managing turbulent transport remains difficult. Achieving net electrical gain requires bridging the gap from experimental Q values to continuous high-efficiency operation. For inertial fusion, the challenge shifts to developing high-repetition-rate laser drivers and manufacturing millions of precision fuel targets annually.

The Current Consensus

Predictions for commercial fusion vary widely. Public programs like ITER and STEP are working toward demonstration reactors in the 2030s to 2040s, with commercial plants possibly coming in the 2040s to 2050s.⁴ Some private companies claim they can do it sooner, though independent analysts are skeptical. No credible experts predict commercial fusion within five years. Most scenarios suggest it will take several more decades.

This gap reflects an important distinction: proving fusion can work scientifically versus making it work commercially. NIF showed that fusion ignition is possible in a laboratory. ITER will likely demonstrate sustained net energy from fusion. But turning these experiments into power plants that can compete economically and that utilities will actually want to build requires solving numerous engineering, materials, and economic problems. As one commercialization review noted, technical uncertainty, capital costs, and critical material supply chains pose material constraints on both viability and timelines.¹³

What Needs to Happen Next?

The next decade will prove critical for fusion's prospects. Key breakthroughs must include: durable high-field superconducting magnets using materials like REBCO (rare-earth barium copper oxide) that can withstand the mechanical and radiation stresses of reactor operation; demonstrated tritium breeding blankets with integrated fuel processing at engineering scale; advanced plasma control systems that can prevent or mitigate disruptions in reactor-relevant conditions; and for inertial fusion, high-efficiency, high-repetition-rate drivers coupled with automated target production.^{2, 11, 12, 13, 14}

ITER's first plasma and subsequent D-T operations will provide invaluable data, even if delayed. Private demonstrators from companies like Commonwealth Fusion Systems could offer faster iteration on compact, high-field designs. Materials testing facilities will need to qualify structural components under realistic neutron fluences. Perhaps most importantly, fusion must prove it can be economically competitive with advancing renewable energy technologies and grid storage solutions.

Conclusion

Is nuclear fusion actually achievable? The scientific answer is increasingly yes, NIF proved ignition is possible, and ITER will likely demonstrate sustained net energy gain. The more pertinent question is whether fusion can become commercially viable on timescales relevant to climate change mitigation. That answer remains uncertain. Fusion is no longer "always 30 years away," but neither is it five years from powering homes. Realistic projections point to demonstration plants in the 2030s and 2040s, with commercial deployment potentially following if economic and engineering challenges can be overcome.

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References & Further Reading

1. Lux, H., Wolff, D., & Foster, J. (2022). Commercialization of fusion power plants. IEEE Transactions on Plasma Science, 50(11). https://doi.org/10.1109/TPS.2022.3194143
2. Nuttall, W. (2020). Commercialising fusion energy. IOP Publishing. https://doi.org/10.1088/978-0-7503-2719-0
3. Schirber, M. (2022). Gaining ground in nuclear fusion. Physics, 15, 195. https://doi.org/10.1103/physics.15.195
4. DIW Berlin. (2024). Power generation from nuclear fusion not expected in the foreseeable future: Applied research developing dynamically. https://www.econstor.eu/handle/10419/316364
5. Lawrence Livermore National Laboratory. (2023). Achieving fusion ignition. National Ignition Facility & Photon Science. https://lasers.llnl.gov/science/achieving-fusion-ignition
6. Abu-Shawareb, H., et al. (2022). Lawson criterion for ignition exceeded in an inertial fusion experiment. Physical Review Letters, 129, 075001. https://doi.org/10.1103/PhysRevLett.129.075001
7. EUROfusion. (2024). Breaking new ground: JET tokamak's latest fusion energy record shows mastery of fusion processes. https://euro-fusion.org/eurofusion-news/dte3record/
8. Korablev, V., Rozhansky, V., & Sarygulov, A. (2024). Physical and technical problems of fusion energy development: From fundamental research to the stage of industrial opening up. Journal of Physics and Mechanics, 17(4). https://doi.org/10.18721/jpm.17406
9. MIT Energy Initiative. (2021). The race to fusion with Dennis Whyte. https://energy.mit.edu/news/the-race-to-fusion-with-dennis-whyte/
10. Baus, C., Barron, P., D'Angio, A., et al. (2023). Kyoto Fusioneering's mission to accelerate fusion energy: Technologies, challenges and role in industrialisation. Journal of Fusion Energy, 42. https://doi.org/10.1007/s10894-023-00346-y
11. Burgess, S. M. (2023). About a fusion reactor for the replacement of fossil fuels. Research Square. https://doi.org/10.21203/rs.3.rs-2576684/v1
12. Miyazawa, J. (2023). Toward the realization of a commercial helical small-scale steady-state fusion reactor. Atomos, 65(8), 508. https://doi.org/10.3327/jaesjb.65.8_508
13. Pearson, R. J. (2020). Towards commercial fusion: Innovation, technology roadmapping for start-ups, and critical natural resource availability [Doctoral dissertation, Open University]. Open University Research Online. https://doi.org/10.21954/OU.RO.0001187B
14. Kulygin, V. M., Khvesyuk, V. I., & Chikhachev, O. S. (2022). Training and upgrading tokamak power plants with remountable superconducting magnets. arXiv. https://doi.org/10.48550/arxiv.2205.04441

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