UC Berkeley press release


New book by UC Berkeley's Ken Fowler explores long path to the "unlimited energy" of controlled fusion

by Robert Sanders

Berkeley -- One of the great unfulfilled promises of the 20th century is controlled fusion and the dream of safe, cheap, unlimited power.

Touted by environmentalists and scientists alike as the ultimate clean alternative to coal, oil and nuclear fission, controlled fusion has been difficult to achieve. Scientific problems combined with the ups and downs of federal funding made it seem at times as if we wouldn't even see practical fusion power in the 21st century.

Today though the goal is in sight, if only society has the will to push for its development, says theoretical physicist T. Kenneth Fowler, a professor in the graduate school at UC Berkeley and for 17 years director of fusion research at Lawrence Livermore National Laboratory.

"I'd have to say that fusion is now feasible," Fowler says. "That's not to say that there are no scientific issues, but the interesting science now is trying to make fusion behave, to make it more simple and a better mousetrap.

"The greatest obstacle today is perceived need, one of the most complex issues."

As evidence he notes the successes scored in Europe and the U.S. in the early 1990s that produced fusion energy -- though for a brief second, and totaling far less energy than that required to initiate the reaction.

Following on these successes, two new experimental fusion devices are being built to reach the holy grail, the point at which controlled fusion produces more energy than it consumes.

In his new book "The Fusion Quest" (Johns Hopkins University Press, 1997), Fowler details the many scientific, technical and political roadblocks that have impeded progress toward a viable fusion reactor since work began a half century ago. His insider position at LLNL put him in the center of many of the significant developments in the field, providing insight into the personalities and politics as well as the science.

He also explores the practicalities that will determine whether fusion will become a priority during the early part of the 21st century.

"The issue today is the environment, not the energy supply," he argues. "People have become complacent about energy."

During the 1970s the oil crisis served to boost funding for alternative energy sources, including fusion. Since then, however, political changes have brought oil prices under control, and funding for all alternatives has steadily dropped.

"With global warming, how we make energy may become the real problem in the future," he says. "I'm hopeful that trying fusion could maybe open the way to a more sensible look at energy."

A member of the National Academy of Sciences, Fowler has been involved with fusion research his entire career, since taking a job at Oak Ridge National Laboratory in 1957. After a stint at General Atomics he went to the Lawrence Livermore National Laboratory, where he served from 1970 until 1987 as associate director and head of magnetic fusion research. He came to UC Berkeley as a professor of nuclear engineering in 1988.

In his book he gently guides the reader through the intricacies of plasma physics, the branch of physics that deals with gases so hot that every atom is ionized. The goal of fusion research has been to confine such plasmas -- heated to temperatures of 10 to 100 million degrees, typical of that at the center of the Sun -- to allow atoms to collide and fuse, releasing enormous amounts of energy.

Since hot gases like these would quickly cool down if they contacted any metal housing, confinement within a strong magnetic field has been the most popular technique. The tokamak, a doughnut-shaped magnetic confinement reactor developed by Russian physicists, achieved practical fusion in 1991 at the Joint European Torus. They used a fuel close to what would be needed in a practical reactor, a combination of deuterium and tritium, heavier isotopes of hydrogen.

This was followed in 1993 by the definitive demonstration of controlled fusion in the Tokamak Fusion Test Reactor (TFTR) at Princeton University. This reactor -- relegated earlier this month to the scrap heap because of budget cuts, despite the fact that it was still producing exciting data -- eventually produced 10 million watts of power for a second using a half-and-half mixture of deuterium and tritium. In all about 40 million watts was needed to initiate the fusion.

Building on these successes, achieved after many ups and downs in research and federal funding, two larger devices now are on the drawing board. One of these -- the International Thermonuclear Experimental Reactor (ITER), a joint project of the United States, the European Union, Japan and Russia -- is based on the successful tokamak design and will be on the scale of a commercial power reactor.

The second, to be built at Lawrence Livermore National Laboratory, is based on a different principle, inertial confinement. Called the National Ignition Facility or NIF, it involves shooting high-powered lasers at fuel pellets to create a powerful implosion that ignites the fusion process, similar to what goes on inside a hydrogen bomb. In fact, the Department of Energy is funding NIF primarily to obtain data on thermonuclear explosions that will help assess, without testing, the reliability of the nation's aging nuclear stockpile.

Nevertheless the spin-off of both projects could be practical fusion power in the early part of the 21st century, Fowler says.

In his book he delves also into the economics and environmental aspects of fusion relative to today's fuels, and concludes that while the cost would be about the same, safety and environmental costs would be much improved. The one imponderable, he says, is the will of the public.

"What we need to make this happen is not a scientific breakthrough but a political breakthrough," he writes.

Apart from magnetic confinement in the tokamak and inertial confinement in the form of laser fusion, Fowler has his own pet idea, affectionately called the spheromak. Fusion would take place inside a sphere rather than a doughnut, which could be scaled down to a much smaller size than other types of reactors.

"The plasma creates itself without any middle, which allows the whole thing to be small with all the magnets and coils outside the machine," he says. "Industry might be able to adapt this more easily, perhaps to replace the heat source, bringing fusion power to the market on a shorter time scale."

The problem is getting the theory to work in practice, but Fowler is not deterred. With more money becoming available for alternative research in fusion, he is optimistic that development will continue on the spheromak, and that it can be engineered to work.

"At the moment the spheromak is where I've got my hopes for a better alternative," he says. "But that moment has already gone on since the mid-1980s."

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