Fusion power at home, or, how small science will defeat big science


Fusion research is known for its huge projects — and its huge lack of tangible success. Big machines like the Princeton tokamak and the Livermore laser have indeed managed to fuse a few nuclei, but have required too much energy to get too little in return. A Brooklyn web developer named Mark Suppes recently created fusion in in his own home, using a much simpler device called a Farnsworth fusor. Accessing declassified experiments, and using open-source software, open-source hardware and crowdsourced funding, he has turned the traditional approach to scientific research on its head — and he makes it look easy.

In his early teenage years, Philo Farnsworth presented a concept for the all-electronic “image dissector,” and soon developed it into the first functioning television set. He successfully defended his rights to the design against larger corporations like RCA, which tried to claim it in a patent, and in the process became a legend and inspiration for private inventors and DIYers everywhere. Farnsworth’s skill at controlling electrons with electric fields later led him to develop a small nuclear fusion device. The device used inertial electrostatic confinement, as opposed to magnetic confinement which is used to fuse charged particles in the larger and more complex machines.

Suppes first heard about the Farnesworth fusor from Robert Bussard’s Google Tech Talk. With DARPA’s permission, Brussard described his work on Polywell reactors. The Polywell is a refinement of the Farnesworth fusor, but has the potential for significant net energy production. Suppes knew little of physics, but decided that with a little help from the open source community, he could make a fusor for himself. His blog
and Github repository show step-by-step exactly how he did it. In the video below, you can see a talk that Suppes gave at Wired 2012.

Can you really create fusion at home?

polywell-assembly-31

The biggest challenge to homebrew fusion is creating a spot where the conditions are just right. Typically a vacuum chamber that can tolerate some heat is needed. In university and industrial research labs a vacuum system is built using standard erector set pieces called “conflat flange” mounts. Prior to Ebay, the best way to get value out of an old vacuum system was to recycle it for the nickel and chrome in the steel. Today however, passing these systems on to someone who can use them is just a matter of a few clicks.

Another thing Suppes had going for him was the capability to design and 3D print heat resistant parts in the complex geometry needed for the Polywell device. The Polywell is basically a set of electromagnetic coils positioned in a precise geometry that enables charged particles to be confined. Ceramic is needed because other heat resistant materials, like metals, would perturb the field and let particles escape.

The most important a tool for Suppes was the willingness of skilled individuals to help him at every turn. As the 38th person to build a working fusor, there was a lot of technical know-how floating around. Suppes was able to collect that information into one place and package it in a way anyone can understand. His approach of publish first, then review, has been catching on as the new way to do science. Not every person cares about the research that their tax dollars fund, but those who do care have demanded access to it — and are getting it.

plasma

A cautionary note is perhaps in order. David Hahn, also known as the radioactive boy scout, was a child prodigy who built a subcritical fission reactor in his backyard using tiny amounts of radioactive material from many smoke detectors. He eventually became obsessed with his hobby and landed himself in the hospital for treatment of possible radiation injuries, and then in jail allegedly for larceny. The risks from radiation are not the same with fission as with fusion. High energy X-rays and neutrons are created in a fusor and need need to be respected accordingly.

The fire that Farnsworth lit years ago continues to burn bright. The untimely death of Brussard, just a year after his Google Talk and initial results with the Polywell device offered the torch, and Suppes and others have run with it. Big science concentrates all the money and knowledge on large projects that can’t fail, but it is slowly yielding to smallscience, where nimble, crowd-funded and -sourced projects can gracefully die if they don’t yield productive results. Not every scientist is compelled to fuse atoms, nor every layperson, but with enough people working on the problem and communicating their results and techniques openly, humankind will one day harness the power of the Sun (perhaps through a Sun-encompassing Dyson sphere, hm?)

FUSION REACTOR CONCEPT COULD BE CHEAPER THAN COAL


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Fusion energy almost sounds too good to be true – zero greenhouse gas emissions, no long-lived radioactive waste, a nearly unlimited fuel supply.

Perhaps the biggest roadblock to adopting fusion energy is that the economics haven’t penciled out. Fusion power designs aren’t cheap enough to outperform systems that use fossil fuels such as coal and natural gas.

University of Washington engineers hope to change that. They have designed a concept for a fusion reactor that, when scaled up to the size of a large electrical power plant, would rival costs for a new coal-fired plant with similar electrical output.

The team published its reactor design and cost-analysis findings last spring and will present results Oct. 17 at the International Atomic Energy Agency’sFusion Energy Conference in St. Petersburg, Russia.

“Right now, this design has the greatest potential of producing economical fusion power of any current concept,” said Thomas Jarboe, a UW professor of aeronautics and astronautics and an adjunct professor in physics.

The UW’s reactor, called the dynomak, started as a class project taught by Jarboe two years ago. After the class ended, Jarboe and doctoral student Derek Sutherland – who previously worked on a reactor design at the Massachusetts Institute of Technology – continued to develop and refine the concept.

The design builds on existing technology and creates a magnetic field within a closed space to hold plasma in place long enough for fusion to occur, allowing the hot plasma to react and burn. The reactor itself would be largely self-sustaining, meaning it would continuously heat the plasma to maintain thermonuclear conditions. Heat generated from the reactor would heat up a coolant that is used to spin a turbine and generate electricity, similar to how a typical power reactor works.

“This is a much more elegant solution because the medium in which you generate fusion is the medium in which you’re also driving all the current required to confine it,” Sutherland said.

There are several ways to create a magnetic field, which is crucial to keeping a fusion reactor going. The UW’s design is known as a spheromak, meaning it generates the majority of magnetic fields by driving electrical currents into the plasma itself. This reduces the amount of required materials and actually allows researchers to shrink the overall size of the reactor.

Other designs, such as the experimental fusion reactor project that’s currently being built in France – called Iter – have to be much larger than the UW’s because they rely on superconducting coils that circle around the outside of the device to provide a similar magnetic field. When compared with the fusion reactor concept in France, the UW’s is much less expensive – roughly one-tenth the cost of Iter – while producing five times the amount of energy.

The UW researchers factored the cost of building a fusion reactor power plant using their design and compared that with building a coal power plant. They used a metric called “overnight capital costs,” which includes all costs, particularly startup infrastructure fees. A fusion power plant producing 1 gigawatt (1 billion watts) of power would cost $2.7 billion, while a coal plant of the same output would cost $2.8 billion, according to their analysis.

“If we do invest in this type of fusion, we could be rewarded because the commercial reactor unit already looks economical,” Sutherland said. “It’s very exciting.”

Right now, the UW’s concept is about one-tenth the size and power output of a final product, which is still years away. The researchers have successfully tested the prototype’s ability to sustain a plasma efficiently, and as they further develop and expand the size of the device they can ramp up to higher-temperature plasma and get significant fusion power output.

The team has filed patents on the reactor concept with the UW’s Center for Commercialization and plans to continue developing and scaling up its prototypes.

Other members of the UW design team include Kyle Morgan of physics; Eric Lavine, Michal Hughes, George Marklin, Chris Hansen, Brian Victor, Michael Pfaff, and Aaron Hossack of aeronautics and astronautics; Brian Nelson of electrical engineering; and, Yu Kamikawa and Phillip Andrist formerly of the UW.

The research was funded by the U.S. Department of Energy.

What is a fusion reaction?


Prof. Dhiraj Bora, Director, Institute for Plasma Research, Gujarat, explains what a fusion reaction is, what conditions it manifests in, and what hurdles scientists face in achieving it.

Last week, the National Ignition Facility, USA, announced that it had breached the first step in triggering a fusion reaction. But what is a fusion reaction? Here are some answers from Prof. Bora – which require prior knowledge of high-school physics and chemistry. We’ll start from their basics (with my comments in square brackets).

What is meant by a nuclear reaction?

A process in which two nuclei or a nucleus and a subatomic particle collide to produce one or more different nucleii is known as a nuclear reaction. It implies an induced change in at least in one nucleus and does not apply to any radioactive decay.

What is the difference between fission and fusion reactions?

The main difference between fusion and fission reactions is that fission is the splitting of an atom into two or more smaller ones while fusion is the fusing of two or more smaller atoms into a larger one. They are two different types of energy-releasing reactions in which energy is released from powerful atomic bonds between the particles within the nucleus.

Which elements are permitted to undergo nuclear fusion?

Technically any two light nuclei below iron [in the Periodic Table] can be used for fusion, although some nuclei are better than most others when it comes to energy production. Like in fission, the energy in fusion comes from the “mass defect” (loss in mass) due to the increase in binding energy [that holds subatomic particles inside an atom together]. The greater the change in binding energy (from lower binding energy to higher binding energy), more the mass lost, results in more output energy.

What are the steps of a nuclear fusion reaction?

To create fusion energy, extremely high temperatures (100 million degrees Celsius) are required to overcome the electrostatic force of repulsion that exists between the light nuclei, popularly known as the Coulomb’s barrier [due to the protons’ positive charges]. Fusion, therefore, can occur for any two nuclei provided the temperature, density of the plasma [the superheated soup of charged particles] and confinement durations are met.

Under what conditions will a fusion chain-reaction occur?

When, say, a deuterium (D) and tritium (T) plasma is compressed to very high density, the particles resulting from nuclear reactions give their energy mostly to D and T ions, by nuclear collisions, rather than to electrons as usual. Fusion can thus proceed as a chain reaction, without the need of thermonuclear temperatures.

What are the natural forces at play during nuclear fusion?

The gravitational forces in the stars compress matter, mostly hydrogen, up to very large densities and temperatures at the star-centers, igniting the fusion reaction. The same gravitational field balances the enormous thermal expansion forces, maintaining the thermonuclear reactions in a star, like the sun, at a controlled and steady rate.

In the laboratory, the gravitational force is replaced by magnetic forces in magnetic confinement systems whereas radiation force compresses the fuel, generating even higher pressures and temperature, and resulting in a fusion reaction in the inertial confinement systems.

What approaches have human attempts to achieve nuclear fusion taken?

Two main approaches, namely magnetic containment and inertial containment, have been attempted to achieve fusion.

In the magnetic confinement scheme, various magnetic ‘cages’ have been used, the most successful being the tokamak configuration. Here, magnetic fields are generated by electric coils. Together with the current due to charged particles in the plasma, they confine the plasma into a particular shape. It is then heated to an extremely high temperature for fusion to occur.

In the inertial confinement scheme, extremely high-power lasers are concentrated on a tiny sphere consisting of the D-T mixture, creating tremendous pressure and compression. This generates even higher pressures and temperatures, creating a conducive environment for a fusion reaction to occur.

To create fusion energy in both the schemes, the reaction must be self-sustaining.

What are the hurdles that must be overcome to operate a working nuclear fusion power plant to generate electricity?

Fusion power is in the form of fast neutrons that are released, of an enegy of 14 Mev. This energy will be converted to thermal energy which then would be converted to electrical energy. Hurdles are in the form of special materials that need to be developed that are capable of withstanding extremely high heat flux in a neutron environment. Reliability of operation of fusion reactors is also a big challenge.

What kind of waste products/emissions would be produced by a fusion power plant?

All the plasma facing components are bombarded by neutrons, which will make the first layers of the metallic confinement radioactive for a short period. The confinement will be made of different materials. Efforts are being made by materials scientists to develop special-grade steel to have weaker effects struck by neutrons. All said, such irradiated components will have to be stored for at least 50 years. The extent of contamination should be reduced with the newer structural materials.

Fusion reactions are intrinsically safe as the reaction terminates itself in the event of the failure of any sub-system.

India is one of the seven countries committed to the ITER program in France. Could you tell us what its status is?

ITER project has gradually moved into construction phase. Therefore, Fusion is no more a dream but a reality. Construction at site is progressing rapidly. Various critical components are being fabricated in the seven parties through their domestic agencies.

The first plasma is expected in the end of 2020 as per the 2010 baseline. Indian industries are also involved in producing various subsystems. R&D and prototyping of many of the high tech components are progressing as per plan. India is committed to deliver its share in time.

Magnetic nanoparticles could aid heat dissipation.


Cooling systems generally rely on water pumped through pipes to remove unwanted heat. Now, researchers at MIT and in Australia have found a way of enhancing heat transfer in such systems by using magnetic fields, a method that could prevent hotspots that can lead to system failures. The system could also be applied to cooling everything from electronic devices to advanced fusion reactors, they say.

The system, which relies on a slurry of tiny particles of magnetite, a form of iron oxide, is described in the International Journal of Heat and Mass Transfer, in a paper co-authored by MIT researchers Jacopo Buongiorno and Lin-Wen Hu, and four others.

Hu, associate director of MIT’s Nuclear Reactor Laboratory, says the new results are the culmination of several years of research on nanofluids—nanoparticles dissolved in water. The new work involved experiments where the magnetite nanofluid flowed through tubes and was manipulated by magnets placed on the outside of the tubes.

The magnets, Hu says, “attract the particles closer to the heated surface” of the tube, greatly enhancing the transfer of heat from the fluid, through the walls of the tube, and into the outside air. Without the magnets in place, the fluid behaves just like water, with no change in its cooling properties. But with the magnets, the  is higher, she says—in the best case, about 300 percent better than with plain water. “We were very surprised” by the magnitude of the improvement, Hu says.

Conventional methods to increase heat transfer in  employ features such as fins and grooves on the surfaces of the pipes, increasing their surface area. That provides some improvement in heat transfer, Hu says, but not nearly as much as the particles. Also, fabrication of these features can be expensive.

The explanation for the improvement in the new system, Hu says, is that the magnetic field tends to cause the particles to clump together—possibly forming a chainlike structure on the side of the tube closest to the magnet, disrupting the flow there, and increasing the local temperature gradient.

While the idea has been suggested before, it had never been proved in action, Hu says. “This is the first work we know of that demonstrates this experimentally,” she says.

Magnetic nanoparticles could aid heat dissipation

Such a system would be impractical for application to an entire cooling system, she says, but could be useful in any system where hotspots appear on the surface of cooling pipes. One way to deal with that would be to put in a magnetic fluid, and magnets outside the pipe next to the hotspot, to enhance heat transfer at that spot.

“It’s a neat way to enhance heat transfer,” says Buongiorno, an associate professor of nuclear science and engineering at MIT. “You can imagine magnets put at strategic locations,” and if those are electromagnets that can be switched on and off, “when you want to turn the cooling up, you turn up the magnets, and get a very localized cooling there.”

While  can be enhanced in other ways, such as by simply pumping the cooling fluid through the system faster, such methods use more energy and increase the pressure drop in the system, which may not be desirable in some situations.

There could be numerous applications for such a system, Buongiorno says: “You can think of other systems that require not necessarily systemwide cooling, but localized cooling.” For example, microchips and other electronic systems may have areas that are subject to strong heating. New devices such as “lab on a chip” microsystems could also benefit from such selective cooling, he says.

Going forward, Buongiorno says, this approach might even be useful for fusion reactors, where there can be “localized hotspots where the heat flux is much higher than the average.”

But these applications remain well in the future, the researchers say. “This is a basic study at the point,” Buongiorno says. “It just shows this effect happens.”

Fusion milestone passed at US lab.


Target alignment at NIF The

Researchers at a US lab have passed a crucial milestone on the way to their ultimate goal of achieving self-sustaining nuclear fusion.

Harnessing fusion – the process that powers the Sun – could provide an unlimited and cheap source of energy.

But to be viable, fusion power plants would have to produce more energy than they consume, which has proven elusive.

Now, a breakthrough by scientists at the National Ignition Facility (NIF) could boost hopes of scaling up fusion.

NIF, based at Livermore in California, uses 192 beams from the world’s most powerful laser to heat and compress a small pellet of hydrogen fuel to the point where nuclear fusion reactions take place.

The BBC understands that during an experiment in late September, the amount of energy released through the fusion reaction exceeded the amount of energy being absorbed by the fuel – the first time this had been achieved at any fusion facility in the world.

This is a step short of the lab’s stated goal of “ignition”, where nuclear fusion generates as much energy as the lasers supply. This is because known “inefficiencies” in different parts of the system mean not all the energy supplied through the laser is delivered to the fuel.

Nuclear fusion at NIF.

Hohlraum
  • 192 laser beams are focused through holes in a target container called a hohlraum
  • Inside the hohlraum is a tiny pellet containing an extremely cold, solid mixture of hydrogen isotopes
  • Lasers strike the hohlraum’s walls, which in turn radiate X-rays
  • X-rays strip material from the outer shell of the fuel pellet, heating it up to millions of degrees
  • If the compression of the fuel is high enough and uniform enough, nuclear fusion can result

But the latest achievement has been described as the single most meaningful step for fusion in recent years, and demonstrates NIF is well on its way towards the coveted target of ignition and self-sustaining fusion.

For half a century, researchers have strived for controlled nuclear fusion and been disappointed. It was hoped that NIF would provide the breakthrough fusion research needed.

In 2009, NIF officials announced an aim to demonstrate nuclear fusion producing net energy by 30 September 2012. But unexpected technical problems ensured the deadline came and went; the fusion output was less than had originally been predicted by mathematical models.

Soon after, the $3.5bn facility shifted focus, cutting the amount of time spent on fusion versus nuclear weapons research – which was part of the lab’s original mission.

However, the latest experiments agree well with predictions of energy output, which will provide a welcome boost to ignition research at NIF, as well as encouragement to advocates of fusion energy in general.

It is markedly different from current nuclear power, which operates through splitting atoms – fission – rather than squashing them together in fusion.

NIF, based at the Lawrence Livermore National Laboratory, is one of several projects around the world aimed at harnessing fusion. They include the multi-billion-euro ITER facility, currently under construction in Cadarache, France.

However, ITER will take a different approach to the laser-driven fusion at NIF; the Cadarache facility will use magnetic fields to contain the hot fusion fuel – a concept known as magnetic confinement.