ITER Nuclear Fusion Facility Reaches 50% Completion Milestone

A decade into its construction, the International Thermonuclear Experimental Reactor (ITER) site, with its towering cranes and partially erected structures, has been likened to a "contemporary Stonehenge" by The New York Times in March 2017. This ambitious project, a collaboration among 35 nations including the United States, seeks to prove that nuclear fusion — the process of fusing hydrogen isotopes to create helium, akin to the energy production of stars — could serve as a sustainable power source for a world increasingly in need of energy.

Despite facing significant delays and a cost escalation to approximately 18 billion euros ($22 billion), the ITER project reached a pivotal moment in December 2017. Officials announced the completion of 50% of the construction required to achieve "First Plasma," a phase where hydrogen is transformed into a hot, charged gas, slated for 2025. However, full energy production is not expected until a decade later. A 2016 U.S. Department of Energy report highlighted the project's potential while acknowledging uncertainties about its ultimate success.

"Once we establish that fusion can serve as a practical energy source, it will ultimately replace fossil fuels, which are neither renewable nor sustainable," stated Bernard Bigot, ITER's director general, in a message on the project's official site. "Fusion will work alongside wind, solar, and other renewable energy sources. ... By proving fusion's viability as a clean, safe, and nearly inexhaustible energy source, we can leave a lasting legacy for generations to come."

In an email, Columbia University professor Gerald A. Navratil, a prominent fusion energy researcher whose contributions shaped ITER's design, called the construction milestone a "major step forward in the pursuit of practical fusion energy."

ITER will house the world's largest tokamak, a magnetic apparatus initially developed by Soviet scientists in the late 1960s. This device replicates the extreme heat and pressure found within a star's core. As detailed on the ITER website, the tokamak employs a strong electrical current to ionize hydrogen gas, stripping electrons from nuclei to create plasma — a superheated, electrically charged gas. When plasma particles collide and energize, temperatures soar to between 100 and 300 million degrees Celsius (180 million to 360 million degrees Fahrenheit). At these temperatures, hydrogen nuclei overcome their natural repulsion, fusing to form helium and releasing vast amounts of energy.

As outlined in a report by the World Nuclear Association, experimental tokamaks have produced energy for years. However, they have yet to achieve a net energy gain. ITER aims to surpass this hurdle, partly due to its unprecedented scale. A March 2017 New York Times article highlights the tokamak's dimensions: 100 feet (30.5 meters) in height and diameter, with a weight exceeding 25,000 pounds (23 metric tons) and a volume of 30,000 cubic feet (840 cubic meters). This makes it ten times larger than any previous device.

Bigger Is Definitely Better

According to the ITER website, a larger device with greater volume increases the potential for fusion reactions, boosting energy output and enhancing efficiency. When fully operational in 2035, ITER is expected to use 50 megawatts of input power to produce 500 megawatts of fusion energy as heat. Although ITER won't convert this energy into electricity, it aims to lay the groundwork for future fusion power plants that will.

"The ITER experiment's design is grounded in a cautious extrapolation of fusion performance from current devices," Navratil explains in his email. "There is strong confidence that ITER's size and magnetic field strength will enable it to achieve its goal of generating 500 megawatts of fusion power from 50 megawatts of plasma input. As ITER will be the first experiment to produce a self-heated fusion plasma, it will validate our understanding of burning plasma and may uncover new plasma physics phenomena. The data gathered from ITER will inform the design of future fusion energy systems, aiming for net electricity production and paving the way for commercial fusion energy."

Advantages Over Nuclear Power

As stated in an ITER press release, fusion power plants are expected to be cost-competitive with traditional nuclear power plants. However, unlike conventional plants, fusion facilities would not generate radioactive waste, eliminating the expensive challenge of waste disposal. Additionally, fusion energy offers a significant environmental advantage over fossil fuels by avoiding the release of large quantities of carbon dioxide and other pollutants, thereby mitigating climate change.

Navratil also highlights that fusion energy could surpass low-carbon renewable sources in certain aspects.

"If successful, fusion power plants modeled after ITER's plasma performance would deliver a continuous, carbon-free energy supply, overcoming the limitations of wind and solar systems, which only generate electricity intermittently and require energy storage or backup systems to maintain grid stability," Navratil explains. "Given the trillions invested in global energy infrastructure, the introduction of fusion power later this century will be a crucial addition to our portfolio of carbon-free energy sources."