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PRI's Environmental News Magazine

The Future of Fusion

Air Date: Week of January 10, 2003

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Fusion energy research has continued in the United States, despite the damage its reputation suffered during the cold fusion debacle of the 1980s. Living On Earth’s Cynthia Graber reports on the state of fusion research and the chance that the U.S. may rejoin a worldwide effort to produce a viable fusion power plant.

Transcript

CURWOOD: When most people hear the word “fusion” they think cold fusion and the debacle from the late 1980’s. That’s when two scientists in Utah startled the world with the announcement they had accomplished the unheard of feat of producing energy from fusing hydrogen atoms together at room temperature. Their research didn’t hold up under scrutiny, and the scientific scandal gave fusion a bad name. But research has continued on efforts to imitate the way the sun fuses hydrogen to produce energy using extremely hot temperatures. And this research recently got a rather big boost.

The National Academy of Sciences has recommended the United States rejoin negotiations for an international research hydrogen fusion reactor. If commercialized, fusion could yield enormous amounts of fairly clean energy. Living on Earth’s Cynthia Graber has our story.

[ROOM SOUND]

GRABER: For decades, fusion scientists here at the Massachusetts Institute of Technology have pursued the energy of the sun. The sun and other stars are fueled by fusion, the process in which the protons in separate atoms fuse together to form a new element, releasing tremendous amounts of energy.

HUTCHINSON: Well, I think it’s awe inspiring.

GRABER: Physicist Ian Hutchinson, heads fusion research at MIT. Hutchinson says he is trying to pattern his work after the stars, which have been burning for billions of years.

HUTCHINSON: I as a human fusion reactor designer find that to be a tremendously elegant solution (laugh). I think none of our human solutions are likely to be nearly that elegant. On the other hand, if we can make it work that will be a kind of minor creation all of our own. Who knows?

GRABER: Fusion takes place when atoms are literally fused together. But our first and so far only venture into nuclear power involves splitting atoms, a process known as fission. This produces significant amounts of radioactive waste. Fusion, on the other hand, results in no radioactive waste, but does leave slightly radioactive containers. These become harmless in about a century, compared to tens of thousands of years for the wastes produced by fission.

[MACHINE SOUNDS]

HUTCHINSON: There are basically pumps, fans, electronics of one sort or another. That’s basically what you’re hearing here.

GRABER: Hutchinson is standing in a cavernous room in an old converted Nabisco Cracker factory in Cambridge, Massachusetts. He points at a huge silver cylinder in the middle of the space. This is where the fusion experiments take place. A tangle of wires, cables and ducts lead into and out of the cylinder, which is designed to hold super-heated gas called plasma.

HUTCHINSON: The plasma itself is sort of deep in there, and it’s only less than two meters across. So it’s actually quite a compact experiment. Then there are lots and lots of instruments all around us that measure different aspects of the behavior of the plasma.

GRABER: When gas is heated to a temperature of millions of degrees, it becomes plasma, a state in which atomic particles are highly energized. At that point, atoms can actually fuse together. Fusion researchers at the dozen state-of-the-art reactors around the world use two forms of hydrogen gas in the process. In the reactors known as Tokomak, these atoms fuse together and produce helium.

Scientists have managed to produce energy from this reaction. But they haven’t yet been able to make the plasma, as Hutchinson says, ignite. Hutchinson explains that it’s like trying to light a campfire.

HUTCHINSON: If you take that firelighter away, one of two things can happen. Either the fire stays lit, and it burns and keeps itself going, or when you take the firelighter away, the fire may simply go out, in which case you’re not going to get any useful heat from your work. Well, it’s the same kind of idea with a fusion fire.

GRABER: Once the plasma catches, then all scientists will need to do is guide it with small amounts of energy and feed it hydrogen as fuel, like throwing more logs on the fire. But there are a few problems in making a fusion reaction self-sustaining. For one, there’s no material on earth that can withstand fusion’s heat. So the plasma must be held together with magnetic fields.

HUTCHINSON: The plasma has lots of degrees of freedom, ways that it can try to sneak out and escape from our magnetic bottles. And so, a lot of what we do is understanding the basic physics of how a magnetic field confining a plasma really works.

GRABER: Scientists have been able to make huge advances in getting the magnets to hold the plasma together. But they can’t perform an experiment for very long at any of the fusion research centers, including MIT or Princeton.

HUTCHINSON: For example, the experiments at Princeton produce 10 megawatts of fusion power for a bit under a second.

GRABER: That’s right, a second. But that’s 100 times longer than experiments conducted decades ago. Here’s one of the problems. The magnets that hold plasma together now can’t sustain a longer reaction. In the next generation of reactor on the drawing board, super-conducting magnets will be used that can keep the experiment going for hours at a time. This will help scientists understand how best to contain the plasma and how to keep heat from escaping. Once they have these variables under control, researchers think they will be that much closer to reaching the holy grail of fusion research: the point when the reaction becomes self-sustaining. Hutchinson says scientists have already made great strides in this direction.

HUTCHINSON: And all of this gives us much greater confidence that the next step, experiment that’s been designed will actually produce the goods in terms of demonstrating a plasma that is really keeping itself hot with its own reactions.

GRABER: That next step Hutchinson refers to is called the International Thermonuclear Experimental Reactor, or ITER. It’s run by a consortium made up of Japan, the European Union, Russia, and Canada. Negotiations are underway to build a five billion dollar reactor that can do the type of experiments necessary to take fusion to the next level. The U.S. pulled out of ITER in 1998 because of the expense, and because, at the time, the science didn’t look feasible. But recent advances have lead to growing support for rejoining ITER. Dr. Rob Goldstein is head of the Department of Energy’s Fusion Lab at Princeton University.

GOLDSTEIN: Fusion is not ready for industry to get in and build systems and go compete on the market. There’s still the substantial research to be done. So there’s a tremendous advantage in banding together with other countries, both in terms of the financial and in terms of the intellectual capabilities. And so ITER gives us, through this collaboration, the ability to move the whole world forward.

(LAB SOUND]

GRABER: Fusion scientists here at MIT are excited about the possibility of rejoining ITER. If that happens, it will probably cost the U.S. about one billion dollars over 10 years. Now that the National Academy of Sciences has recommended the U.S. rejoin negotiations, it’s up to President Bush to make a decision. And according to the Department of Energy Secretary Spencer Abraham, the President is, in his words, “particularly interested in the project.” But even if the international effort goes forward, scientists say a viable economic fusion power plant is at least three decades away. If that is achieved, scientists will have succeeded in producing a form of energy that is limitless and nearly pollution-free.

For Living on Earth, I’m Cynthia Graber in Cambridge, Massachusetts.

 

 

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