Scientists Fire Up the World Largest Fusion Reactor First Time

Scientists in Japan have achieved "first plasma" in the JT-60SA experimental reactor, a significant milestone in fusion power research. The reactor is part of a collaboration between Japan and the EU to develop fusion technology, and it will guide the development of the much larger ITER reactor being built in France. While private fusion power startups have emerged with more aggressive schedules, government-run projects still lead the way. The goal of fusion power is to generate more power than it uses, and achieving this would be a crucial milestone in the road to commercial fusion power plants.

Fusion power startups have garnered significant attention and investment in recent years. However, the recent activation of the world's largest fusion reactor in Japan highlights the continued lead of long-term, government-run projects.

Last week, scientists at the National Institutes for Quantum Science and Technology in Naka achieved a significant milestone with the JT-60SA experimental reactor. They successfully switched on the machine, marking the "first plasma" stage. While this is a noteworthy achievement, the reactor still has a long way to go before conducting meaningful tests or producing power.

Nevertheless, this accomplishment is crucial for the reactor's purpose of paving the way for the larger ITER reactor being constructed in France. The ITER reactor is expected to be the first of its kind to generate more power than it consumes. Both projects stem from a 2007 agreement between Japan and the EU to collaborate on fusion research, and the lessons learned from operating JT-60SA will inform the development of ITER.

The reactor follows a well-established design known as a tokamak, featuring a doughnut-shaped chamber surrounded by coiled superconducting magnets. These magnets generate powerful magnetic fields capable of containing an extremely hot cloud of ionized gas called plasma. In this case, the plasma consists of hydrogen and its isotope deuterium.

When the plasma reaches high temperatures, the atoms within fuse together, producing a substantial amount of energy in the form of radiation and heat. This energy is absorbed by the reactor's walls and used to convert water into steam, which can drive a turbine to generate electricity.

The JT-60SA reactor stands at 15.5 meters tall and can accommodate 135 cubic meters of plasma, making it the largest tokamak constructed to date. However, it is still far from functioning as a power plant. Like its predecessors, achieving fusion will require significantly more power than the reaction generates.

Nevertheless, the primary goal of the new reactor is not to achieve energy breakeven. Instead, its purpose is to serve as a test bed for ITER. By investigating plasma stability and its impact on power output, the JT-60SA reactor will contribute to the development of ITER. ITER will be nearly twice as tall as JT-60SA and capable of holding 830 cubic meters of plasma.

Once fully operational, ITER is projected to generate 500 megawatts of power from its plasma while only using 50 megawatts to heat it up. Although ITER is not designed to generate electricity from this power, achieving such energy gain would be a significant milestone on the path to commercial fusion power plants.

The JT-60SA reactor is expected to reach full power within the next two years, while ITER aims to achieve first plasma by 2025 and full operation by 2035. However, both projects have faced substantial delays and frequent updates to their timelines, contributing to fusion power's reputation as a technology that always seems to be 20 years away.

In the meantime, a new wave of fusion power startups has emerged with more aggressive schedules. Companies like Commonwealth Fusion Systems believe they can have a functioning fusion power plant up and running by the early 2030s. Helion Energy has even signed an energy purchase agreement with Microsoft, aiming to supply electricity as early as 2028.

These companies are betting on surpassing the slower-paced government-run initiatives that have made incremental progress over several decades. Whether these ambitious goals come to fruition remains to be seen. It is worth noting that the Lawrence Livermore National Laboratory is currently the only facility to have achieved a net energy gain in a fusion reaction.

However, the presence of both private and public investment in fusion power can only be beneficial. The more individuals and organizations working on the problem, the more likely it is to be solved expeditiously.

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