The JET torus in 1996, showing a worker wearing protective clothing performing maintenance within the vessel. Photograph courtesy of EFDA-JET
It’s hard to take fusion energy seriously when its proponents employ descriptors like “power of the Sun” and “energy from a star” to explain it. This kind of hyperbole—and the fact that scientists have never created a sustained fusion reaction capable of generating more electricity than it soaks up—make fusion sound like a fantastical scheme devised by Lex Luthor. But in the wake of the current energy crisis, new money and political support may finally channel enough resources into fusion to make the elusive process a reality.
On May 24, the US, EU, Russia, China, South Korea, Japan and India signed on to help build the International Thermonuclear Experimental Reactor (ITER) in Cadarache, in the south of France. ITER is the largest fusion research project to date and one of the biggest international scientific collaborations ever. Its budget is 10 billion euros over 20 years, more than three times that of the Large Hadron Collider at CERN. The reactor is scheduled to be functional by 2016.
“[ITER] is not only a scientific and technological experiment aimed at demonstrating the scientific and technological feasibility of fusion energy, but it is also an experiment in international relations,” said Ned Sauthoff, the U.S. project manager for ITER. “Never before have the governments representing more than half the population of the world gotten together and tried to solve a global problem.”
Theoretically, fusion is an ideal energy source. It releases no carbon into the atmosphere and is fueled by hydrogen atoms, which can easily be derived from water. Traditional nuclear fission, on the other hand, requires uranium or plutonium, both limited and costly resources. While the radioactive byproducts of fission can linger for hundreds of thousands of years, the radioactive waste produced in fusion decays within 50 to 100 years. In addition, fusion eliminates the risk of a runaway reaction like the one that occurred at Chernobyl—a fusion reaction on Earth is so delicate that any error in operation would end the process rather than causing a meltdown.
In a fusion reactor, laser or charged-particle beams and radio waves heat hydrogen atoms, or the heavy hydrogen isotopes deuterium and tritium, to more than 100 million degrees Celsuis—nearly seven times the heat of the Sun—creating a free-flowing thermonuclear plasma. Atoms in the plasma collide with each other, fusing into helium atoms and release single neutrons and disproportionately large amounts of energy that can then be transformed into electricity through a steam turbine cycle.
The Sun, a fusion reactor, keeps hydrogen atoms colliding via the enormous pressure at its core. ITER will test a device, called a tokamak, meant to replicate the containing effect of the Sun’s gravity. A tokamak is a vacuum vessel that cradles the plasma within a magnetic field generated by current-carrying coils. Scientists have used tokomaks experimentally for decades, but never one as large as the device at ITER, which will be two to three times larger than the current largest tokamak, the Joint European Torus located in England, outside Oxford.
In order for fusion to become a viable energy source, scientists must overcome a number of hurdles. For one, no one has ever managed to contain the ultra-hot plasma for long enough to sustain a fusion reaction that generates more energy than is required to keep it going. Other problems include the difficulty of finding materials suitable for reactors that need to sustain temperatures as hot as the Sun, and the prohibitive upfront costs of constructing commercial fusion plants.
“You know the joke about fusion: Fusion is thirty years away, and always will be,” said John Perkins, a nuclear physicist at Lawrence Livermore National Laboratory.
Perkins was involved with ITER in its first decade, after Mikhail Gorbachev initiated the project in 1985. Then ITER was essentially a loose collective of physicists from all over the world working on the design of the large tokamak. Problems of cost and technical instability repeatedly threatened to end the endeavor entirely. In 1998, the U.S. stopped funding ITER-related projects, citing unanticipated expenses as well as papers by physicists, new at the time, that claimed the reactor would not work.
“People knew how to make a high density plasma, people knew how to make a very pure plasma, people knew how to make a long-time plasma and so forth, but nobody had done all of those things at once,” said William Dorland, now a physicist at the University of Maryland and co-author of a paper that doomed ITER in the eyes of its American backers.
However a redesign of the tokamak, and a scaling down of ITER’s goals to make the project less expensive, lured back many skeptics. The original plans for ITER included two stages of experimentation: In the first stage, researchers hoped to create a plasma that yielded more energy than it absorbed. In the second stage, researchers were to develop materials for a commercial power plant. In its new, scaled-back form, scientists at ITER will focus only on the plasma stage, while separate initiatives will tackle the materials issue. While a working reactor is a decade away, physicists predict a commercial power plant could follow any time in the following 20 to 50 years .
In creating a more convincing argument for ITER, physicists also teamed up with economists to argue the long-term economic viability of fusion as a fuel compared to coal and natural gas.
“The government borrows money to do fusion research at a certain rate, in effect, and then it gets paid back, or the world gets paid back, assuming we succeed in this R&D, at something like 80-to-1,” said Robert Goldston, director of the Princeton Plasma Physics Laboratory.
These days, few scientists debate the importance of ITER. However, some environmentally-friendly politicians in Europe, as well as Greenpeace International, have called the project a drain on much-needed resources that could be better spent on known quantities like wind and solar development. Jim Riccio, an anti-nuclear campaigner for Greenpeace USA, called fusion a “welfare program for nuclear scientists.”
But even William Dorland, who once helped damn ITER in peer-reviewed journals, has come to support the project, though he suspects that “another design is likely to be able to produce large amounts of fusion” before ITER’s tokamak is ever successful.
In January of 2003, President Bush announced the U.S. would continue its involvement in ITER’s development, and this year, the Department of Energy allocated $25 million to the project. Bush has requested another $60 million in 2007 for building components, hiring staff and financing the construction of the Cadarache facility in France. Construction will start in November of this year, once the final agreements are signed.
Speaking at the National Building Museum back in February 2003—well ahead of his controversial comments on the U.S. addiction to foreign oil—Bush presented fusion research as a necessary gamble.
“[We’re] not sure if it will be able to produce affordable energy for everyday use,” he said. “It’s worth a look because the promise is so great.”
Originally published June 21, 2006