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Nuclear fusion reactor could be here as soon as 2025

A cutaway rendering of the proposed SPARC tokamak.
A cutaway rendering of the proposed SPARC tokamak.
(Image: © CFS/MIT-PSFC - CAD Rendering by T. Henderson)

A viable nuclear fusion reactor — one that spits out more energy than it consumes — could be here as soon as 2025.

That's the takeaway of seven new studies, published Sept. 29 in the Journal of Plasma Physics.

If a fusion reactor reaches that milestone, it could pave the way for massive generation of clean energy. 

During fusion, atomic nuclei are forced together to form heavier atoms. When the mass of the resulting atoms is less than the mass of the atoms that went into their creation, the excess mass is converted to energy, liberating an extraordinary amount of light and heat. Fusion powers the sun and stars, as the mighty gravity at their hearts fuse hydrogen to create helium.

Related: Science fact or fiction? The plausibility of 10 sci-fi concepts

But an enormous amount of energy is needed to force atoms to fuse together, which occurs at temperatures of at least 180 million degrees Fahrenheit (100 million degrees Celsius). However, such reactions can generate far more energy than they require. At the same time, fusion doesn't produce greenhouse gases such as carbon dioxide, which drive global warming, nor does it generate other pollutants. And the fuel for fusion — such as the element hydrogen — is plentiful enough on Earth to meet all of humanity's energy needs for millions of years.

"Virtually all of us got into this research because we're trying to solve a really serious global problem," said study author Martin Greenwald, a plasma physicist at MIT and one of the lead scientists developing  the new reactor. "We want to have an impact on society. We need a solution for global warming — otherwise, civilization is in trouble. This looks like it might help fix that."

Most experimental fusion reactors employ a donut-shaped Russian design called a tokamak. These designs use powerful magnetic fields to confine a cloud of plasma, or ionized gas, at extreme temperatures, high enough for atoms to fuse together. The new experimental device, called the SPARC (Soonest/Smallest Private-Funded Affordable Robust Compact) reactor, is being developed by scientists at MIT and a spinoff company, Commonwealth Fusion Systems.

If it succeeds, SPARC would be the first device to ever achieve a "burning plasma," in which the heat from all the fusion reactions keeps fusion going without the need to pump in extra energy. But no one has ever been able to harness the power of burning plasma in a controlled reaction here  on Earth, and more research is needed before SPARC can do so. The SPARC project, which launched in 2018, is scheduled to begin construction next June, with the reactor starting operations in 2025. This is far faster than the world's largest fusion power project, known as the International Thermonuclear Experimental Reactor (ITER), which was conceived in 1985 but not launched until 2007; and although construction began in 2013, the project is not expected to generate a fusion reaction until 2035.

One advantage that SPARC may have over ITER is that SPARC's magnets are designed to confine its plasma. SPARC will use so-called high-temperature superconducting magnets that only became commercially available in the past three to five years, long after ITER was first designed. These new magnets can produce far more powerful magnetic fields than ITER's — a maximum of 21 teslas, compared with ITER's maximum of 12 teslas. (In comparison, Earth's magnetic field ranges in strength from 30 millionths to 60 millionths of a tesla.)

These powerful magnets suggest the core of SPARC can be about three times smaller in diameter, and 60 to 70 times smaller in volume than the heart of ITER, which is slated to be 6 meters wide. "That dramatic reduction in size is accompanied by a reduction in weight and cost," Greenwald , told LiveScience. "That's really the game-changer."

In seven new studies, researchers outlined the calculations and supercomputer simulations underlying SPARC's design. SPARC is expected to generate at least twice as much as 10 times more energy as is pumped in, the studies found.

The heat from a fusion reactor would generate steam. This steam would then drive a turbine and electrical generator, the same way most electricity is produced nowadays. 

"Fusion power plants could be one-to-one replacements for fossil fuel plants, and you wouldn't have to restructure electrical grids for them," Greenwald said. In contrast, renewable energy sources such as solar and wind "are not accommodated well by the current design of electric grids."

The researchers ultimately hope SPARC-inspired fusion power plants would generate between 250 to 1,000 megawatts of electricity. "In the current power market of the United States, power plants typically generate between 100 to 500 megawatts," Greenwald said.

SPARC would only produce heat, not electricity. Once researchers have built and tested SPARC, they plan to construct the ARC (Affordable Robust Compact) reactor, which would generate electricity from that heat by 2035.

"That's very ambitious, but that's the target we're working toward," Greenwald said. "I think it's really plausible." 

Originally published on Live Science.

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  • Clark Kent
    Unlikely. Scientists have been saying that for decades. As the old trite expression goes “ Fusion is the energy source of the future and always will be”
    Reply
  • just_some_dude
    Clark Kent said:
    Unlikely. Scientists have been saying that for decades. As the old trite expression goes “ Fusion is the energy source of the future and always will be”

    That is indeed a trite expression. Do you have any specific criticms of the seven open access, peer reviewed, articles from the SPARC team that back up their assertion that a fusion reactor could be running by 2025? I personally don't have the background necessary to evalaute their merits.
    Reply
  • Robert Lucien Howe
    Not only trite but very silly. We first achieved sustained fusion in JET around 1991. Getting power over unity is only a matter of time and work now and should be achieved by ITER..
    Reply
  • Robert Lucien Howe
    Fusion for space propulsion is a quite different problem to power generation.

    On the positive.
    - A space thruster reactor only has to run for maybe 500 seconds at a time. Rockets generally only run in short pulses. If longer accelerations are needed multiple pulses can be chained together.

    On the negative.
    - Weight is an ENORMOUS problem. In the early 1970's a fission rocket reactor achieved 500 Megawatts in a 10 ton design. ITER might do about the same but would currently weight some 40,000 tons. (that figure is a few years old and not 100% reliable)
    - Fusion reactors require enormous power for a sustained time to start.
    - To maximise efficiency the reactor and thruster system ideally need to be combined as closely together as possible. Each energy conversion stage wastes energy so the system needs as few conversion stages as possible.
    - Heat dissipation is another big potential problem. In space heat is hard to get rid of without wasting reaction mass.
    Reply
  • Geomartian

    Mr. Fusion based on the fusion technology discovered in 1989.

    The Empire’s media took 40 days from the first paper to getting Nature Magazine to call “Cold Fusion” pathological science. If it wasn’t true why would the Empire care at all if people wasted their time and money researching it? This was a campaign (a war) against cold fusion coming from the very top of the American and English scientific orthodoxy.

    The Empire could not let science independently decide if “Cold Fusion” was science. I am not arguing if “Cold Fusion” was science. I am arguing that the Empire considered it a threat and revealed the extents of their power over the scientific media during this campaign.

    The Empire conspired to destroy “Cold Fusion” is a factual statement. The science behind “Cold Fusion” is irrelevant to this statement.
    Reply
  • Geomartian
    Clark Kent said:
    Unlikely. Scientists have been saying that for decades. As the old trite expression goes “ Fusion is the energy source of the future and always will be”

    The Oil Companies (seven sisters) are a key faction of the Empire. ITER and other fusion projects are just look busy projects to suck up any money related to large scale energy production not involving oil.

    If that same amount of money (spent on high temperature fusion) had been spent on green technologies, how much carbon dioxide would have never been produced?
    Reply
  • Geomartian
    When Einstein wrote his famous letter to President Roosevelt, the President’s scientific advisors had already been briefed by the Empire to expect the letter and its contents. Imperial science saw the Atom Bomb as an opportunity.

    In 1989 Pons and Fleischman discovered a new phenomenon that might be related to fusion. The Imperial executives of American Science did not view this new phenomenon as an opportunity. Instead they systematically destroyed it.

    One opportunity slaughtered Hiroshima and Nagasaki and gave the Empire a terror weapon while “Cold Fusion” was viewed as a threat to oil company profits and stamped out.

    Hot fusion was US Government financed (since the 1950’s) while all attempts to produce green or renewable energy were sabotaged (on oil company orders) or never funded. The oil companies never viewed hot fusion as a threat, and 70 years later, it is still not a threat to their profits.

    And no, criminal activities masquerading as science are not a discussion of politics.
    Reply
  • steve_foston
    Robert Lucien Howe said:
    Fusion for space propulsion is a quite different problem to power generation.

    On the positive.
    - A space thruster reactor only has to run for maybe 500 seconds at a time. Rockets generally only run in short pulses. If longer accelerations are needed multiple pulses can be chained together.

    On the negative.
    - Weight is an ENORMOUS problem. In the early 1970's a fission rocket reactor achieved 500 Megawatts in a 10 ton design. ITER might do about the same but would currently weight some 40,000 tons. (that figure is a few years old and not 100% reliable)
    - Fusion reactors require enormous power for a sustained time to start.
    - To maximise efficiency the reactor and thruster system ideally need to be combined as closely together as possible. Each energy conversion stage wastes energy so the system needs as few conversion stages as possible.
    - Heat dissipation is another big potential problem. In space heat is hard to get rid of without wasting reaction mass.

    Actually - you may be interested to see what Pulsar Fusion in the UK (https://www.pulsarfusion.com) sre doing at the moment to develop a nuclear fusion "rocket" at the moment. They reckon that they will have a viable system available by 2025.
    Reply
  • Fusion
    Pulsotron-3 fusion reactor collects 88% of the injected energy. Now Pulsotron-4 is working to improve that
    Reply
  • serhiy1635
    Robert Lucien Howe said:
    Fusion for space propulsion is a quite different problem to power generation.

    On the positive.
    - A space thruster reactor only has to run for maybe 500 seconds at a time. Rockets generally only run in short pulses. If longer accelerations are needed multiple pulses can be chained together.

    On the negative.
    - Weight is an ENORMOUS problem. In the early 1970's a fission rocket reactor achieved 500 Megawatts in a 10 ton design. ITER might do about the same but would currently weight some 40,000 tons. (that figure is a few years old and not 100% reliable)
    - Fusion reactors require enormous power for a sustained time to start.
    - To maximise efficiency the reactor and thruster system ideally need to be combined as closely together as possible. Each energy conversion stage wastes energy so the system needs as few conversion stages as possible.
    - Heat dissipation is another big potential problem. In space heat is hard to get rid of without wasting reaction mass.
    Having read all your comments guys , I have got very interested in this topic and found this information.
    If NASA begins now with a fusion propulsion program, the following questions should be asked: 1. What has already been done? 2. What missions can be accomplished with fusion? 3. What is an appropriate plan for a development program? Perhaps the most important answer to question 1 is that there was a 20 year program at NASA-Lewis on fusion energy for space power and propulsion from 1958 to 1978(Maslen 1959; Schulze 1991). Some of the fusion-related accomplishments and program areas covered included (Schulze and Roth 1991) basic research on MFE fusion confinement, the first superconducting magnet facility to be used in fusion, steady state neutron production, studies of direct conversion of plasma enthalpy to thrust for a fusion rocket, power and propulsion system studies, high-field superconducting and cryogenic magnet technology, and mission analysis and system studies of fusion propulsion systems for interplanetary missions.
    Reply