Fusion: After 50 Years, Still 30 Years Away?

March 7, 2022

Above: The Joint European Torus fusion reactor.

Nuclear Fusion, harnessing the process that powers the sun, the joke goes, has been 30 years away for the last 50 years.
Could we finally be gaining on it?

Yale Climate Connections:

In the scramble to stave off climate change, scientists are exploring every possible source of energy that does not rely on fossil fuels. Fusion is one such resource. How close are we to being able to rely on this technology?

In December 2021, the Joint European Torus (JET) reactor in Oxfordshire, UK, produced 59 megajoules of energy during a five-second period. This burst of energy – enough to boil about 60 kettles of water – was the “absolute maximum” JET could create, according to the project’s lead scientist.

One month later, China’s EAST (Experimental Advanced Superconducting Tokamak) sustained a fusion reaction at 158 million degrees Fahrenheit for more than 17 minutes – ten times longer than its prior record of 101 seconds. That earlier experiment had operated at an even higher temperature of 216 million degrees Fahrenheit.

Temperatures many times hotter than the core of the sun’s 27 million degrees Fahrenheit are needed to create fusion here on Earth given our planet’s smaller mass and lower gravity. More than 160 fusion experimental facilities have been built globally, yet none has succeeded in producing this extreme heat for more than very brief periods.

Achieving a net energy gain from nuclear fusion is another unmet challenge. The UK’s JET experiment last December consumed three times more energy than it produced. The U.S. Department of Energy’s National Ignition Facility performed slightly better in August 2021, with an energy output equaling 70 percent of energy expended, but for a period that lasted only 100 trillionths of a second. No fusion experiment to date has reached Q equals 1, the threshold at which energy output matches energy input. 

For fusion to be a practical solution to our energy woes, several multiples of Q will have to be achieved in a continuously operating plant, and at a price that can hold its own in the electric power marketplace.

In this clip from my interview with Dan Kammen of UC Berkeley – Dr Kammen runs thru the hurdles that traditional nukes have to get over, and towards the end speculates about fusion technology, but again in the 20 to 30 year away time frame.

In Massachusetts, the founders of an MIT spinoff called Commonwealth Fusion Systems (CFS) claim they are developing a fast-track platform for addressing some of these conundrums. Their proving ground will be a test facility about 40 miles west of Boston, adjacent to the Fort Devens army base. 

On a blustery morning this past December, CFS invited members of the Massachusetts environmental community, including the author of this piece,  to tour its facility, now under construction. With cranes and earthmovers rumbling in the background, Kristen Cullen, public affairs director at CFS, stressed the timeliness of her firm’s ambition: “We are in a race, a race against the clock.”

Cullen and her colleagues are driven in part by the looming specter of climate change. They look to fusion as an energy resource that can work in tandem with renewable technologies like wind and solar to meet growing global energy demand while phasing out carbon-intensive industries like coal, oil and gas. “We all know that what we’re doing is not a silver bullet,” said Cullen. “It’s not the one and only solution that’s going to save the planet, but it’s part of the mix.”

Also driving CFS is a determination to outcompete China and other nations already well-advanced in their fusion experiments. An early CFS supporter who joined that December tour stated it bluntly: “There’s a trillion-dollar export market for whoever gets there first.”  Having just landed $1.8 billion in financing from Bill Gates, Google, a major university endowment, and others, CFS is readying itself to enter this race.

Dozens of hard-hatted workers were busy assembling massive bulwarks of steel-reinforced concrete as the group approached the building that will house the CFS tokamak, which takes its name from early Soviet fusion experiments dating back to the late 1960s. Within the tokamak is a doughnut-shaped vacuum vessel specially designed to generate nuclear fusion and contain the resulting superheated plasma

To create fusion,  deuterium and tritium – two heavy isotopes of hydrogen – will be blasted by high-energy radio waves, yielding helium and also neutrons loaded with kinetic energy.  High-temperature superconducting magnets specially designed by MIT’s Plasma Science and Fusion Center will then be used to suspend the energy-rich plasma within the vacuum vessel, isolating it from direct physical contact with the vessel’s walls and other reactor machinery. The Plasma Science and Fusion Center’s director Dennis Whyte describes this arrangement as a “magnetic cage,” with MIT’s high-temperature superconducting magnets replacing the much larger and heavier magnets used in other fusion experiments. 

Tyler Ellis, a nuclear physicist and CFS advisor, explains the test facility’s initial goal: achieving an energy balance of Q greater than 1 by 2025. Once that threshold has been demonstrated, CFS will set about proving that it is possible to build a fusion-based power plant about 40 times smaller than facilities relying on low-temperature superconducting magnets, like the International Thermonuclear Experimental Reactor (ITER) in southern France. 

MIT Technology review has more.

Technology Review:

On an overcast day in early December, a yellow earth mover scooped dirt from the edge of a deep pit in Devens, Massachusetts, on the site of an old Army base some 50 miles outside of Boston. 

This is the future home of SPARC, a prototype fusion reactor that, if all goes as hoped, will achieve a goal that’s eluded physicists for nearly a century. It will produce more energy from fusing together atoms, the same phenomenon that powers the sun, than it takes to achieve and sustain those reactions.

By some point in 2025, the scientists at Commonwealth Fusion Systems expect, their machine will blow past that threshold, generating 10 times more energy than it consumes. That demonstration, they say, will enable the startup to develop full-size facilities capable of delivering as much electricity as a small coal plant by the early 2030s.

Facilities that can harness nuclear fusion should provide a cheap source of carbon-free energy from abundant fuel sources, substantially derived from water. Crucially, fusion would generate a constant, steady stream of electricity, filling in the gaps during the hours, days, or even weeks when solar and wind sources flag. In doing so, it would simplify the path to zero-emissions electricity, eliminating the need for energy storage breakthroughs, exorbitant banks of batteries, or continued reliance on coal and natural-gas plants to keep the lights on and companies humming. 

Then again, the sheer technical complexity and massive cost of achieving fusion have repeatedly dashed the hopes of scientists and hardened the stance of skeptics. The field’s best hope for a reactor that finally delivers net energy has long been ITER, an international research collaboration first conceived in the 1980s. But costs for its roughly 100-acre facility in southern France have more than tripled, rising to at least $22 billion. The project is more than a decade overdue and still years from completion. And even if ITER eventually works, its version of fusion technology could be far too costly to commercialize widely.

Commonwealth believes it can deliver a fusion machine that is the anti-ITER: small, fast to build, and far cheaper. The prototype should cost hundreds of millions of dollars, rather than tens of billions, and take years rather than decades to construct.

The key is a novel magnet the startup has developed. The field is watching the effort particularly closely because the team has already pulled off an indisputable scientific advance by using a new type of superconducting material to build the most powerful one of its kind. In a test last September, the magnet achieved a field strength of 20 tesla. It’s nearly twice as strong as ITER’s comparable magnet, which relies on earlier superconducting materials.

Magnets can be used to confine a plasma, the ultra-hot state of matter in which fusion reactions occur. The more powerful those magnets are, the more atomic collisions, reactions, and energy you can produce within a far smaller space. A fusion device built with an array of Commonwealth’s magnets should be able to produce as much energy as one relying on ITER’s at one-fortieth the size.

4 Responses to “Fusion: After 50 Years, Still 30 Years Away?”

  1. neilrieck Says:

    This is still a bit of a scam since the main actors are not correctly accounting for the total input power. This video from a real physicist explains it better than I ever could:

  2. Jim Torson Says:

    Here is a commentary on fusion by another physicist that was published by the Bulletin of the Atomic Scientists:

    ITER is a showcase… for the drawbacks fusion energy


    • rhymeswithgoalie Says:

      While the video shows the problems of achieving net grid energy production in the steady state, that article shows the serious energy hole that a reactor starts in before the first plasma is generated, among other things.

      [Compare and contrast to the overhead in energy, materials and skill-set needed to bring a solar farm, battery or even wind farm online.]

  3. neilrieck Says:

    BTW, the video from Sabine was published before the JET announcement from Britain last month. The Q of JET was 0.33 which means it did not come close to break-even. IIRC, JET was supposed to be one proof for the very much larger ITER so I do not have much hope for that one either. This is not my area of expertise but I fear that anything involving electromagnetic containment of a plasma will probably fail because fusion in the Sun employs gravitational containment so is better at keeping uncharged particles like neutrons. The Q of the NIF facility in California is better than 0.7 with old-fashioned gas lasers and I have heard speculation that an upgrade to semiconductor lasers could get them over break-even (1.0). BTW, NIF does not employ any kind of containment and works more like an internal combustion engine (drop fuel in; ignite fuel; rinse and repeat)

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