Why we shouldn't give up on nuclear fusion

The old joke with fusion is that it's the energy of the future--and it always will be. But one industry executive says even if it takes another 50 years, it will still be worth the investment for clean, safe, cheap, domestically-sourced power.

Doug Witherspoon stands next to a vacuum chamber and plasma gun assembly arrayed with sensors and power sources.

The old joke with fusion is that it’s the energy of the future--and it always will be. But one technology research and development company executive says even if it takes another 50 years, it will still be worth the investment for clean, safe, cheap, domestically-sourced power.

Below, F. Douglas Witherspoon, president and chief scientist of HyperV Technologies Corp., answers some questions about fusion research: where it stands, where it’s headed and why it’s taking so long.

Nuclear fusion has been researched since the 1950s. Why is it taking so long to turn it into a viable energy source?

We're essentially trying—in the lab--to make the equivalent of a tiny star that we can control long enough to get useful energy out of it. That’s an incredibly difficult thing to do.

When research began on controlled thermonuclear fusion back in the ‘50s, the scientists had just come off successfully making the hydrogen bomb in a relatively short period of time, so it was pretty clear that it was possible. Everyone was excited that [fusion] could be accomplished in the same kind of time frame. But they did not realize the true difficulty of the task and ended up having to develop a whole new scientific discipline to learn about plasmas--the stuff stars are made of. It turns out that plasma is finicky and doesn't like to be confined for very long. As a result, scientists have spent the last five decades conducting basic research to map out the science needed to make nuclear fusion a viable source of energy.

What are the different approaches to controlled nuclear fusion?

There are really only two generic approaches right now to making a fusion reactor:

Magnetic Confinement: The mainline approach uses magnetic fields to form a non-material “bottle” to contain the plasma in a steady state. A tokamak reactor such as the ITER experiment now under construction in France is the leading example of this type of reactor.

Inertial Confinement: An imploding shell of dense plasma is used to crush and ignite a fuel target to trigger a fusion reaction. The best example is laser fusion now being tested at the National Ignition Facility in Livermore, California.

An imploding ball of plasma is created in an experiment using a ring of 64 small plasma jets to partially simulate the forces needed to ignite fuel inside a full scale PJMIF reactor.

What’s the next big goal for fusion research, and when might it be achieved?

The next really big milestone is to demonstrate what is termed “net gain,” which means getting more energy out of the reaction than what is put in. The laser fusion effort at the National Ignition Facility appears to be very close to achieving this with their big new laser that came online recently. They might actually demonstrate ignition, as they call it, within the next year. That will be exciting.

What evidence do we have that nuclear fusion might work?

Go stand outside on a sunny day and feel the heat from a nuclear fusion reactor that is about 93 million miles away. The sun is using its tremendous mass--or gravitational confinement--to drive the nuclear fusion reactions in its core. Obviously we need to accomplish the same thing but on a smaller scale. Both the Tokamak Fusion Test Reactor experiment at Princeton and the JET experiment in the U.K. demonstrated multi-megawatts of fusion power output several years ago. Some laser fusion experiments have also produced some fusion energy output. These experiments haven't achieved net gain yet, but they are getting much closer.

What are the potential benefits of nuclear fusion as a sustainable source of energy?

Nuclear fusion has a number of advantages:

  • It has zero emissions;
  • It doesn’t require importing fuel (you get it from seawater);
  • It’s safe. There’s no chance of a meltdown, and there’s no high-level radioactive waste generated;
  • It has a tremendous fuel energy density:
  • Four drums of fuel equals roughly a 21,000-boxcar train of coal;
  • Its powerplant footprint is small;
  • It enables a robust power grid--plants can be located in and around consumers;
  • Its power can be produced either on demand or 24/7;
  • It creates domestic high tech jobs;
  • Its reactor technology is suitable for export.

What type of nuclear fusion approach is HyperV researching?

HyperV is part of a larger research community developing the Plasma Jet Magneto Inertial Fusion (PJMIF) concept, which is kind of a hybrid approach between inertial confinement and magnetic confinement. Instead of using lasers to drive the implosion on a fuel target, the PJMIF approach uses high-performance plasma guns to produce a spherically imploding plasma shell that crushes a magnetized plasma fuel target at the center of the reactor. The shock waves produced by the implosion create--for a tiny fraction of a second--the pressures and temperatures required to achieve fusion ignition. The embedded magnetic field in the target plasma aids in confining the energy just long enough to keep it hot and fusing, and it substantially reduces the energy required in the plasma jets.

What’s a rough estimate as to how long it will take to develop a commercially viable fusion reactor?

If experiments over the next four or five years are successful, then we would need perhaps 15 years to develop a PJMIF-type reactor that can demonstrate net gain, and probably another five to 10 years to develop a reactor suitable for commercial power generation. This assumes steady and increasingly aggressive research and development funding.

We have wind and solar energy now. Why take so much time and money to develop fusion?

Because clean, plentiful energy for everybody is going to completely transform the world. Even if it took another 50 years, it would clearly still be worth it. Using energy more efficiently, along with the further development of wind and solar technologies are a great start. But they don't provide a complete solution and almost certainly not for baseload energy needs. You could think of today's cleantech technologies as the first wave of a multi-decade effort to provide the world with clean energy. Nuclear fusion is arguably the second wave of that effort. It has not only the potential to be clean, but also the capacity to support a thriving and sustainable human civilization pretty much indefinitely.

This post was originally published on Smartplanet.com

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