It’s an old joke that many fusion scientists have grown tired of hearing: Practical nuclear fusion power plants are just 30 years away — and always will be.
But now, finally, the joke may no longer be true: Advances in magnet technology have enabled researchers at MIT to propose a new design for a practical compact tokamak fusion reactor — and it’s one that might be realized in as little as a decade, they say. The era of practical fusion power, which could offer a nearly inexhaustible energy resource, may be coming near.
Using these new commercially available superconductors, rare-earth barium copper oxide (REBCO) superconducting tapes, to produce high-magnetic field coils “just ripples through the whole design,” says Dennis Whyte, a professor of Nuclear Science and Engineering and director of MIT’s Plasma Science and Fusion Center. “It changes the whole thing.”
The stronger magnetic field makes it possible to produce the required magnetic confinement of the superhot plasma — that is, the working material of a fusion reaction — but in a much smaller device than those previously envisioned. The reduction in size, in turn, makes the whole system less expensive and faster to build, and also allows for some ingenious new features in the power plant design. The proposed reactor, using a tokamak (donut-shaped) geometry that is widely studied, is described in a paper in the journal Fusion Engineering and Design, co-authored by Whyte, PhD candidate Brandon Sorbom, and 11 others at MIT. The paper started as a design class taught by Whyte and became a student-led project after the class ended.
Power plant prototype
The new reactor is designed for basic research on fusion and also as a potential prototype power plant that could produce significant power. The basic reactor concept and its associated elements are based on well-tested and proven principles developed over decades of research at MIT and around the world, the team says.
“The much higher magnetic field,” Sorbom says, “allows you to achieve much higher performance.”
Fusion, the nuclear reaction that powers the sun, involves fusing pairs of hydrogen atoms together to form helium, accompanied by enormous releases of energy. The hard part has been confining the superhot plasma — a form of electrically charged gas — while heating it to temperatures hotter than the cores of stars. This is where the magnetic fields are so important—they effectively trap the heat and particles in the hot center of the device.
While most characteristics of a system tend to vary in proportion to changes in dimensions, the effect of changes in the magnetic field on fusion reactions is much more extreme: The achievable fusion power increases according to the fourth power of the increase in the magnetic field. Thus, doubling the field would produce a 16-fold increase in the fusion power. “Any increase in the magnetic field gives you a huge win,” Sorbom says.
Tenfold boost in power
While the new superconductors do not produce quite a doubling of the field strength, they are strong enough to increase fusion power by about a factor of 10 compared to standard superconducting technology, Sorbom says. This dramatic improvement leads to a cascade of potential improvements in reactor design.
The world’s most powerful planned fusion reactor, a huge device called ITER that is under construction in France, is expected to cost around $40 billion. Sorbom and the MIT team estimate that the new design, about half the diameter of ITER (which was designed before the new superconductors became available), would produce about the same power at a fraction of the cost and in a shorter construction time.
But despite the difference in size and magnetic field strength, the proposed reactor, called ARC, is based on “exactly the same physics” as ITER, Whyte says. “We’re not extrapolating to some brand-new regime,” he adds.
Another key advance in the new design is a method for removing the the fusion power core from the donut-shaped reactor without having to dismantle the entire device. That makes it especially well-suited for research aimed at further improving the system by using different materials or designs to fine-tune the performance.
In addition, as with ITER, the new superconducting magnets would enable the reactor to operate in a sustained way, producing a steady power output, unlike today’s experimental reactors that can only operate for a few seconds at a time without overheating of copper coils.
Liquid protection
Another key advantage is that most of the solid blanket materials used to surround the fusion chamber in such reactors are replaced by a liquid material that can easily be circulated and replaced, eliminating the need for costly replacement procedures as the materials degrade over time.
“It’s an extremely harsh environment for [solid] materials,” Whyte says, so replacing those materials with a liquid could be a major advantage.
Right now, as designed, the reactor should be capable of producing about three times as much electricity as is needed to keep it running, but the design could probably be improved to increase that proportion to about five or six times, Sorbom says. So far, no fusion reactor has produced as much energy as it consumes, so this kind of net energy production would be a major breakthrough in fusion technology, the team says.
The design could produce a reactor that would provide electricity to about 100,000 people, they say. Devices of a similar complexity and size have been built within about five years, they say.
“Fusion energy is certain to be the most important source of electricity on earth in the 22nd century, but we need it much sooner than that to avoid catastrophic global warming,” says David Kingham, CEO of Tokamak Energy Ltd. in the UK, who was not connected with this research. “This paper shows a good way to make quicker progress,” he says.
The MIT research, Kingham says, “shows that going to higher magnetic fields, an MIT speciality, can lead to much smaller (and hence cheaper and quicker-to-build) devices.” The work is of “exceptional quality,” he says; “the next step … would be to refine the design and work out more of the engineering details, but already the work should be catching the attention of policy makers, philanthropists and private investors.”
The research was supported by the U.S. Department of Energy and the National Science Foundation.
BobInget on Fri, 14th Aug 2015 2:59 pm
http://fortune.com/2015/08/12/power-onstellation-finance-bloom-energy/
ghung on Fri, 14th Aug 2015 3:03 pm
“…a nearly inexhaustible energy resource…”
God help Planet Earth if it comes to pass. Children,, playing with fire.
Nony on Fri, 14th Aug 2015 3:13 pm
Bullshit
Lawfish1964 on Fri, 14th Aug 2015 3:19 pm
Only ten years away. Yippee! Fast-forward to 2025: only ten years away.
Personally, I think they should focus on the flux capacitor or dilithium crystals. Those are proven technologies. I’ve seen actual footage of them in action.
Plantagenet on Fri, 14th Aug 2015 4:16 pm
Some of the smartest people on the planet work at MIT. Good luck to ’em.
BC on Fri, 14th Aug 2015 4:23 pm
Will this tech allow us to travel to the Moon and then Mars where we will build colonies to prepare to join with our extraterrestrial brothers and sisters residing in the Rings of Uranus?
We have evolved collectively to have mostly vacuum between our ears at this point, so we are perfectly adapted to the cold reality of the vacuum of space.
With human apes gone to the Moon and beyond, will there be hope for gorilla . . . ???
Jimmy on Fri, 14th Aug 2015 4:24 pm
the magic porridge pot
http://www.communication4all.co.uk/Traditional%20Tales/Magic%20Porridge%20Pot%20Story%20Book.pps
Nony on Fri, 14th Aug 2015 4:30 pm
An academic reactor or reactor plant almost always has the following basic characteristics: (1) It is simple. (2) It is small. (3) It is cheap. (4) It is light. (5) It can be built very quickly. (6) It is very flexible in purpose (“omnibus reactor”). (7) Very little development is required. It will use mostly “off-the-shelf” components. (8) The reactor is in the study phase. It is not being built now.
On the other hand, a practical reactor plant can be distinguished by the following characteristics: (1) It is being built now. (2) It is behind schedule. (3) It is requiring an immense amount of development on apparently trivial items. Corrosion, in particular, is a problem. (4) It is very expensive. (5) It takes a long time to build because of the engineering development problems. (6) It is large. (7) It is heavy. (8) It is complicated.
The tools of the academic-reactor designer are a piece of paper and pencil with an eraser. If a mistake is made, it can always be erased and changed. If the practical-reactor designer errs, he wears the mistake around his neck; it cannot be erased. Everyone can see it.
The academic-reactor designer is a dilettante. He has not had to assume any real responsibility in connection with his projects. He is free to luxuriate in elegant ideas, the practical shortcomings of which can be relegated to the category of “mere technical details.” The practical-reactor designer must live with these same technical details. Although recalcitrant and awkward, they must be solved and cannot be put off until tomorrow. Their solutions require manpower, time and money.”
Bob Owens on Fri, 14th Aug 2015 5:32 pm
All MIT has to do is take this design to ITER’s people, who will see the beauty of it, and will stop all ITER work and incorporate MIT’s design using ITER’s current budget. Fusion problem solved! The World is saved. In the world of the ordinary person, however, stockpiling some food for the future would not be a bad idea.
yoananda on Fri, 14th Aug 2015 6:07 pm
the new joke will be : fusion is 10 years ahead, and always will be.
dissident on Fri, 14th Aug 2015 6:25 pm
Actually this news is significant and is the first serious innovation in tokamak fusion since the beginning. It is interesting how the new design is reducing the scale of the apparatus. This has a major impact on the plasma instability problem all by itself.
They really should cancel ITER and build this instead. But ITER is a pork barrel for contractors so it will proceed and be a $40 billion dud.
Davy on Fri, 14th Aug 2015 6:37 pm
Folks lets do some simple math. How many power plants need to be replaced? How many fusion plants need to be built? Let’s say we have 10 years starting today. Yeap, you got it, scale is waco for timing and capital expenditures. These type of plants may take around 6 years to build. The costs and liabilities are monstrous.
We know we are not in an optimum climate for massive infrastructure spending. We also want to build out AltE and other grandiose development.
Personally I think fusion is irrelevant. Even if it was ready today it could not game change our problems and predicaments. Too late, not enough money, and scale is absurd.
So why do we keep seeing these articles? I guess it is because we are fascinated by technology and feel secure with achievements. This is a typical cornucopian attitude. This thinking is a failure and the examples of these failures are multiplying.
We see all those grandiose plans for space activity, geoengineering, and energy. It is a fraud against reality yet we embrace it like we do a Hollywood blockbuster.
joe on Fri, 14th Aug 2015 7:06 pm
nuclear power promised to solve everything post ww2. its a cost/profit game. the promise of cheap energy forever if its true then lets have it now? probably its really research for a new weapon or propulsion. so the rich can flee this burnt out cinder when the time comes.
jjhman on Fri, 14th Aug 2015 7:16 pm
Note the comment about replacing solid materials with liquids. As it happens liquids aren’t very good as structural materials so there may have to be some solids in the containment vessel. I suspect that the materials that they want to replace are either to insulate the plasma from being cooled by the outside air or to shield the outside people from the 14 MeV neutrons which are not contained at all by the magnetic field. 14MeV neutrons really destroy most metals in a very short time so I’m not sure what has been done with metallurgy in the last 20 or so years but their comment about replacing them suggests that it is still a problem.
Apneaman on Fri, 14th Aug 2015 7:24 pm
Davy
Wunderwaffe
https://en.wikipedia.org/wiki/Wunderwaffe
Beery on Fri, 14th Aug 2015 8:47 pm
So now it’s ten years away, and always will be.
Makati1 on Fri, 14th Aug 2015 10:56 pm
Miniaturization BEFORE actual proven ability to generate energy at a profitable cost. LMAO!
Magnus Redin on Sat, 15th Aug 2015 2:17 am
ITER is building, finish it and get the research work done. Designs using the new magnets means that the next generation building on ITER work and data gatherd with ITER will be better. It is of course even better to work in parallell and hurry up with new designs that gather experience in parallell with ITER.
Nony on Sat, 15th Aug 2015 6:58 am
ITER is costing triple what it should because it is a big international group grope. The design is being farmed out to countries in pieces and then doesn’t go together well or they fight about how to do it.
http://www.newyorker.com/magazine/2014/03/03/a-star-in-a-bottle
dissident on Sat, 15th Aug 2015 7:19 am
People are way too dismissive of fusion research. If you are not in the field and do not do research for a living, then your understanding is superficial at best. Tokamak fusion is frustrated by fluid dynamical problems of the sort that take decades to solve if they are even solvable. They may well not be.
But one thing is promising and that is to shrink the reactors. The plasma stability problem is not scale invariant. Making the device more and more like a point would likely overcome it. But this requires more and more intense magnetic fields. Even this proposed design is still too large.
Makati1 on Sat, 15th Aug 2015 8:15 am
dissident, you must not be old enough to remember all of the promises of future power sources. Like:
“Nuclear energy will be too cheap to meter”.
And then there was that mini nuclear power plant buried in every yard to supply energy to each home for decades.
And on and on.
The fusion crowd are just over educated, over paid, tinkerers that always promise success “in another 10 years, IF you send us more billions to pay our overhead”.
“The first patent related to a fusion reactor was registered in 1946 …”WIKI
We’re still waiting … and it is only another 10 years, or so, they claim. LMAO
Beery on Sat, 15th Aug 2015 9:55 am
“People are way too dismissive of fusion research. If you are not in the field and do not do research for a living, then your understanding is superficial at best.”
It doesn’t take a fusion research scientist to know that they’ve been promising fusion reactors “in the next decade” for the last 50 years. At some point, people start thinking (and with good cause) that it’s all just talk.
Westexasfanclub on Sat, 15th Aug 2015 12:21 pm
I wonder if a stellarator like the Wendelstein 7x could also benefit from stronger magnets
http://www.ipp.mpg.de/3897638/07_15
Boat on Sat, 15th Aug 2015 12:49 pm
Maybe if Greece and the rest of the world had spent their money on fusion instead of the military and pensions for hairdressers we would have fusion.
steve on Sat, 15th Aug 2015 1:50 pm
I have to agree with dissident on this one. Too many people on here talk as if they are experts in physics and use the argument that it is always 30 years away etc…but unless you have an extensive physics background ie…PHD….Then you should not be giving your thoughts as gospel… It reminds me of the people that say peak oil has not happened therefor it will not happen…Idiots abound in all shapes and sizes…
Makati1 on Sat, 15th Aug 2015 10:48 pm
steve, as I said, over educated, over paid arrogant ‘experts’ and nothing more. You obviously worship at the alter of higher education where the promise of riches is guaranteed for every diploma. Ask those millions with the new sheepskin what they are doing today and you will find that they are mostly flipping burgers, looking for a job, and/or living in their parent’s basement.
Physics, higher math, electronics, etc., are ALL hydrocarbon energy based careers. When that excess energy supply goes away, so will they. But if they can do plumbing or wire up a small generator powered by water or wind, they may be able to earn a living, maybe. Most ‘careers’ are going to be obsolete soon. Think about what you do for your food and shelter and learn a trade if it is one of those that will disappear. Hint, economics and investment counseling will be among the first to go.