Post Syndicated from Payal Dhar original https://spectrum.ieee.org/tech-talk/energy/nuclear/iter-fusion-reactor
It was a twinkle in U.S. President Ronald Reagan’s eye, an enthusiasm he shared with General Secretary Mikhail Gorbachev of the Soviet Union: boundless stores of clean energy from nuclear fusion.
That was 35 years ago.
On July 28, 2020, the product of these Cold Warriors’ mutual infatuation with fusion, the International Thermonuclear Experimental Reactor (ITER) in Saint-Paul-lès-Durance, France inaugurated the start of the machine assembly phase of this industrial-scale tokamak nuclear fusion reactor.
An experiment to demonstrate the feasibility of nuclear fusion as a virtually inexhaustible, waste-free and non-polluting source of energy, ITER has already been 30-plus years in planning, with tens of billions invested. And if there are new fusion reactors designed based on research conducted here, they won’t be powering anything until the latter half of this century.
Speaking from Elysée Palace in Paris via an internet link during last month’s launch ceremony, President Emmanuel Macron said, “[ITER] is proof that what brings together people and nations is stronger than what pulls them apart. [It is] a promise of progress, and of confidence in science.” Indeed, as the COVID-19 pandemic continues to baffle modern science around the world, ITER is a welcome beacon of hope.
ITER comprises 35 collaborating countries, including members of the European Union, China, India, Japan, Russia, South Korea and the United States, which are directly contributing to the project either in cash or in kind with components and services. The EU has contributed about 45%, while the others pitch in about 9% each. The total cost of the project could be anywhere between $22 billion to $65 billion—even though the latter figure has been disputed.
The idea for ITER was sparked back in 1985, at the Geneva Superpower Summit, where President Ronald Reagan of the United States and General Secretary Mikhail Gorbachev of the Soviet Union spoke of an international collaboration to develop fusion energy. A year later, at the US–USSR Summit in Reykjavik, an agreement was reached between the European Union’s Euratom, Japan, the Soviet Union and the United States to jointly start work on the design of a fusion reactor. At that time, controlled release of fusion power hadn’t even been demonstrated—that only happened in 1991, by the Joint European Torus (JET) in the UK.
The first big component to be installed at ITER was the 1,250-metric ton cryostat base, which was lowered into the tokamak pit in late May 2020. The cryostat is India’s contribution to the reactor, and uses specialized tools specifically procured for ITER by the Korean Domestic Agency to place components weighing hundreds of tonnes and having positioning tolerances of a few millimeters. Machine assembly is scheduled to finish by the end of 2024, and by mid-2025, we are likely to see first plasma production.
Anil Bhardwaj, group leader of the cryostat team, tells IEEE Spectrum “First plasma will only verify [various] compliances for initial preparation of the plasma. That does not mean that we are achieving fusion.”
That will come another decade or so down the line.
If everything goes to plan, the first deuterium–tritium fusion experiments will be demonstrated by 2035, and will in essence be replicating the fusion reactions that take place in the sun. ITER estimates that for 50 MW of power injected into the tokamak to heat the plasma (up to 150 million degrees Celsius), 500 MW of thermal power for 400- to 600-second periods will be output, a tenfold return (expressed as Q ≥ 10). The existing record as of now is Q = 0.67, held by the JET tokamak.
Despite recent progress, there is still a lot of uncertainty around ITER. Critics decry the hyperbole around it, especially of it being a magic-bullet solution to the world’s energy problems, in the words of Daniel Jassby, a former researcher at the Princeton Plasma Physics Lab. His 2017 article explains why “scaling down the sun” may not be the ideal fallback plan.
“In the most feasible terrestrial fusion reaction [using deuterium–tritium fuel], 80% of the fusion output is in the form of barrages of neutron bullets, whose conversion to electrical energy is a dubious endeavor,” he said in an interview. Switching to a different type of reactor based on much weaker fusion reactions might result in less neutron production, but also are unlikely to produce net energy of any type.
Delays and mismanagement have also plagued ITER, something that Jassby contends was a result of poor leadership. “There are only a few people in the world who have the technological, administrative and political expertise that allow them to make continuous progress in directing and completing a multinational project,” he said. Bernard Bigot, who took over as director-general five years ago, possesses the requisite skillset, in Jassby’s opinion. At present, ITER is running about six years behind schedule.
Critics of ITER are also concerned about diverting resources from developing existing renewable energies. “The greatest energy issue of our time is not supply, but how to choose among the plethora of existing energy sources for wide-scale deployment,” Jassby said. ITER’s value, however, he said, lies in delinking the fantasy of electricity from fusion energy, thus saving hundreds of billions of dollars in the long run.
Jassby thinks that if successful, ITER will allow physicists to study long-lived, high-temperature fusioning plasmas or the development of neutron sources. There are practical applications for fusion neutrons, he says, such as isotope production, radiography and activation analysis. He adds that ITER can have significant benefits if new technologies emerge application in other fields, such as superconducting magnets, new materials and novel fabrication techniques.
Philippa Browning, professor of astrophysics at the University of Manchester, believes that only something of the scale of ITER can test how things work in fusion reactors. “It may well be that in future alternative devices turn out to be better, but those advantages could be incorporated into the successor to ITER which will be a demonstration fusion power station… The route to fusion power is slow, [so] we can hope that it will be ready when it is really needed in the second half of this century.” Meanwhile, she added, “it is important that other approaches to fusion are explored in parallel, smaller and more agile projects.”
One of the most impressive things about ITER, Browning said, is the combination of a truly international cooperation pushing at the frontiers in many ways. “Understanding how plasmas interact with magnetic fields is a hugely challenging scientific problem… There are all sorts of scientific and technological spin-offs, as well as the direct contribution to achieving, hopefully, a fusion power station.”