Nuclear fusion as a power source


in Daily updates, Oxford, Science, The environment

Staircase in New College

At dinner, this evening, I was speaking with one of the Wadham College fellows about nuclear fusion. He highlighted an element that I hadn’t previously heard discussed: namely the fact that you need to build truly enormous reactors so as to have a surface area to volume ratio low enough that fusion can be sustained. He spoke of the possibility that two or three gargantuan power plants could serve areas as vast as Europe or North America, but that enormous technical hurdles remain, most of them relating to plasma control.

Remember that, once atoms form a plasma, they have been stripped of their electrons. As such, the positive charges of all protons cause them to repel one another with a force inversely proportional to the square of the distance between them. Imagine trying to push the north poles of two powerful bar magnets together, and you will begin to appreciate the kind of force dynamics at work. For fusion to be attained, that repulsion needs to be overcome. In the kind of reactors being experimentally constructed now, that is generally achieved through containment using extremely powerful electromagnets.

Under construction now, in France, is the International Experimental Thermonuclear Reactor (ITER). Construction will finish around 2016 and the device will hopefully provide the information and experience required to develop fusion reactors commercially. If they could be deployed, they would offer the benefits of existing fission plants (reliable and substantial electrical generation), with relatively few issues relating to radiactivity (though, as the fellow pointed out, the gamma rays generated in hydrogen fusion would cause the reactors themselves to become quite radioactive, over time).

The possibility of a deus ex machina stepping in to deal with energy security and climate change is certainly an alluring one. With enough power, it would be possible to produce as much hydrogen as you could desire from water. If gargantuan plants are the mechanism to make fusion feasible, energy from them could be partially distributed in that way. Even if fusion were not a panacea, it could be an important component in a response that also includes conservation, the development of renewables, and technical mechanisms to make fossil fuel use carbon neutral.

I don’t know nearly enough about nuclear physics to be able to comment on the viability of fusion as a power source. One thing you hear constantly in journalistic coverage of it is that it has been twenty years or so off for ages now. Hopefully, with the lessons learned from ITER, it will be a real twenty years this time. If that did come to pass, it would certainly not be too soon. On a political note, it is probably a good thing it is being built in France. When it (inevitably) goes way over-budget, the government is reasonably unlikely to scrap the project. By way of comparison, recall how the US government cancelled the Superconducting Super Collider in 1993, after the expected cost tripled to US$12 billion.

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{ 12 comments… read them below or add one }

Tristan Laing November 25, 2006 at 3:13 am

I think there is at least a possibility that such deus ex machina technologies will have been, on the whole, a bigger contributor to global warming than a detractor.

The basic fact is economic growth, as it is concieved of in a laisser faire economy of perverse wealth, is and never will be ‘sustainable’. The only answer is less of everything. Less people, less crash safety in autos, less trans atlantic vacations, less profits.

There can be more of some things though. More internet, more art, more community celebrations. More drinking (less working). More hiking. More writing. More reading.

Anonymous November 25, 2006 at 3:25 pm

If we do sort out viable fusion technology in the next thirty years or so, a lot of this doom-prediction about oil and climate change will seem overblown, in retrospect.

Milan November 25, 2006 at 3:32 pm


I’d say it will look more like a nasty bullet that we were able to dodge, against the odds, through a technological fix. The fact that you sidestep the charging rhino doesn’t mean that rhinos aren’t dangerous, or that you shouldn’t be glad for your good fortune.

Milan November 25, 2006 at 3:41 pm


I see three big problems with what you are saying:

1) It is extremely patronizing to just order people to want a certain kind of life (one that happens to conform to your preferences). It is theoretically fine to require people to keep their usage of common resources at such a level that equity goals can be achieved, but it seems wrong to tell them how.

2) Selling the kind of ideas above is enormously harder than selling the rather more practical efforts that would be required to deal with climate change. The biggest problem is that people have no incentive to reduce emissions. Taxes and emissions trading can change that.

3) Poverty and low environmental impact do not necessarily go hand in hand. It is only once people have reached a certain level of prosperity that they are willing to start making sacrifices for the sake of greenery. The most important examples of this today are India and China who are (quite reasonably) unwilling to give up the prospect of development because of environmental concerns.

Jessica November 26, 2006 at 4:05 am

I really like the photo on this post, very nice composition.

Milan November 26, 2006 at 5:56 pm



I also found this, on self denial.

Milan November 27, 2006 at 6:03 pm

In this week’s issue, The Economist calls ITER a white hot elephant. Elements of that may be accurate, but I definitely think there is a place for governmental subsidies directed towards blue skies research into alternative energy.

Milan December 2, 2006 at 12:09 am

Science is an edged tool, with which men play like children, and cut their own fingers.
—Arthur Eddington, 1944

Milan February 21, 2007 at 10:36 pm

Following Nicholas Stern’s talk my feelings on this are shifting slightly.

. February 12, 2014 at 1:30 pm

Scientists have made a notable advance in extracting energy from nuclear fusion, the violent process that powers the stars and that one day could offer a source of cheap and boundless power on Earth.

In the experiment, done at a U.S. Department of Energy laboratory last fall, researchers blasted the world’s most powerful laser at a target the size of a small pea. It triggered a fusion reaction that unleashed a vast amount of energy—albeit for a fraction of a second. In effect, the process created a miniature star.

“For the first time anywhere, we’ve gotten more energy out of the fuel than what was put into the fuel” when using this technique, said Omar Hurricane, physicist at the Lawrence Livermore National Laboratory and lead author of the study, published Wednesday in the journal Nature.

. August 20, 2014 at 3:38 pm

If Fusion Is the Answer, We Need To Do It Quickly

Yale’s Jason Parisi makes a compelling case for fusion power, and explains why fusion is cleaner, safer, and doesn’t provide opportunities for nuclear smuggling and proliferation. The only downside will be the transition period, when there are both fission and fusion plants available and the small amount of “booster” elements (tritium and deuterium) found in fusion power could provide would-be proliferators what they need to boost the yield of fission bombs: “The period during which both fission and fusion plants coexist could be dangerous, however. Just a few grams of deuterium and tritium are needed to increase the yield of a fission bomb, in a process known as ‘boosting.'” Details about current research into fusion power and an exploration of relative costs make fusion power seem like the answer to a civilization trying to get away from fossil fuels.


From fission to fusion: the need for a quick transition

. February 1, 2017 at 2:04 pm

Spherical tokamak ‘to put fusion power in grid’ by 2030

Experimental and theoretical research has shown ‘spherical’ tokamaks to be a “fast route to fusion” compared with more “conventional” tokamak devices such as Joint European Torus (JET), according to David Kingham, chief executive of Tokamak Energy.

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