Earlier this morning, the International Thermonuclear Experimental Reactor (ITER) Organization announced what has long been known: a further delay in construction of the world’s largest tokamak will extend the operation of the long-awaited nuclear fusion machine by at least a decade.
ITER is a giant doughnut-shaped magnetic fusion device called a tokamak, which uses magnetic fields to control superheated plasma and induce nuclear fusion – a reaction in which two or more light atomic nuclei come together to form a new nucleus, releasing an enormous amount of energy in the process. Nuclear fusion has been attracting attention as a viable carbon-free energy source, but there are many engineering and economic challenges that must be overcome before this can become a reality.
The project’s previous baseline – its timeframe and the benchmarks within it – was established in 2016. The global pandemic that began in 2020 disrupted many of ITER’s ongoing operations and delayed things further.
As reported by Scientific American, ITER’s costs are four times higher than originally estimated, with the latest figures putting the project at over $22 billion. At a press conference earlier today, ITER Director Pietro Barabaschi explained the causes of the delays and the latest project baseline for the experiment.
“Since October 2020, it has become clear to the public and to stakeholders that the first plasma in 2025 is no longer achievable,” Barabaschi said. “The new criteria have been redesigned to prioritize the start of research activities.”
Barabaschi said the new standards will reduce operational risks and prepare the equipment for operations using deuterium-tritium, a type of nuclear fusion reaction. Instead of generating the first plasma in 2025 as a “short, low-energy equipment test,” he said, more time will be given to ramping up the experiment and increasing external heating capabilities. Full magnetic energy operation will be delayed by three years from 2033 to 2036. Deuterium-deuterium fusion operations will continue as planned until around 2035, but the start of deuterium-tritium operations will be delayed by four years from 2035 to 2039.
ITER is being paid for by its member states: the European Union, China, India, Japan, South Korea, Russia and the U.S. ITER is more expensive than originally predicted and is progressing slowly but steadily.
Earlier this week, the ITER Organisation announced that the tokamak’s toroidal field coils – the very large magnets that help provide the conditions the machine needs to contain the plasma – have finally been shipped after 20 years. The 56-foot-tall (17-metre) coils will be cooled to minus 452.2 degrees Fahrenheit (minus 269 degrees Celsius) and wrapped around the vessel that will contain the plasma, allowing ITER scientists to control the reactions inside.
The scale of that infrastructure is as enormous as the investment: the largest cold-mass magnet in existence today is a 408-ton (370-ton) component of CERN’s ATLAS experiment, while ITER’s newly completed magnet (the total size of the toroidal field coils) has a cold mass of 6,614 tonnes (6,000 tons).
ITER’s planned goals are to demonstrate the kind of system needed to be integrated for industrial-scale fusion, and to achieve a scientific benchmark known as Q≥10 – 500 megawatts of fusion power from the device and 50 megawatts of heating power to the plasma, and Q≥5 for steady-state operation of the device. These are not easy goals to achieve, but fusion experiments in laboratory conditions, tokamaks, and lasers are helping scientists inch closer to a fusion reaction that produces more energy than is needed to power the reaction itself.
Now, as we reported on Monday, a mandatory caveat about the distinction between progress toward the scientific feasibility of nuclear fusion and fusion’s actual usefulness in addressing the world’s energy needs.
An ironic truism (one so repeated that it has become a cliché) is that a fusion energy source is always 50 years away. Fusion is beyond the limits of today’s technology, and like an ex-lover who can’t get over it, we are always told, “this time is different.” ITER aims to prove the technical feasibility of fusion power, but the key is not to prove its economic feasibility; that is another tricky problem: making fusion power not only a practical energy source, but viable for the power grid.
Barabaschi also said that ITER’s tokamak’s plasma-facing material will be made of tungsten rather than beryllium, “because tungsten is clearly more suitable for the future DEMO machine and ultimately commercial fusion devices.” Indeed, in May, the WEST tokamak used a tungsten casing to sustain a plasma more than three times hotter than the sun’s core for six minutes, and South Korea’s KSTAR tokamak has replaced its carbon divertor with a tungsten one.
As Gizmodo previously reported, nuclear fusion is a worthy area of research and development, but it shouldn’t be relied upon as a source of energy to free humanity from global-warming fossil fuels. Though the science is advancing, nuclear fusion was always meant to be an ultramarathon, not a sprint.
More: What you need to know about DOE’s big fusion announcement
