New Internationalist

Fusion illusion

Issue 382

As work begins to build the world’s most ambitious fusion reactor in France, and as proponents try to sell us the promise of a new, clean, fusion age, Peter Montague wonders whether we haven’t heard it all before.

Andrew Kokotka
Andrew Kokotka

The looming calamity of global warming has begun to dawn on the men and women (really, mostly men) who fancy that they own and operate Western civilization – the petrochemical cartels and their attendant law firms and lobbyists, the insurance and banking syndicates, the big media and entertainment conglomerates, the civil and military services, the large research universities.

For two decades the response to global warming from these quarters has been mainly silence, ridicule or denial, but now accumulating facts are pressing hard upon us all. To almost everyone, it seems clear that something must be done fairly soon. But what?

In its first-ever 20-year energy plan, the US Government’s Energy Department announced in 2003 it was putting its long-term eggs in the nuclear fusion basket. To many, fusion seemed a surprising choice because some of the smartest scientists in Europe, Japan, Russia and the US have spent the last 50 years and many tens of billions of dollars trying to harness nuclear fusion to generate electricity, so far without success.

Their goal is to reproduce the same conditions that power the sun (though on a smaller scale) and confine it tightly inside an invisible magnetic container to extract the heat, to boil water, to make steam, to turn a turbine, to generate electricity. Nuclear fusion powers the sun and it also powers hydrogen bombs.

In June 2005, the EU, France, Japan, South Korea, China and the US agreed to spend $12 billion over the next 10 years to build an experimental (and peaceful) fusion machine – called ITER – in southern France. Starting in 2014, the machine will operate in research mode for 20 years, after which another experimental machine will be built and perhaps 30 years after that – if all goes well – the first commercial fusion reactor will begin selling electricity. In other words, commercial fusion lies at least 50 years in the future, even if everything goes as planned.

From fission to fusion

The science and engineering problems that must be solved are daunting. Today’s nuclear power plants employ fission – splitting atoms to release energy. A fusion reactor works by an entirely different principle. The idea of fusion is to heat up deuterium and tritium (both of which are hydrogen atoms with extra neutrons), making them so hot that their electrons are stripped away and their nuclei fuse together, forming a helium atom, releasing neutrons and energy in the process.

The heat in the middle of a fusion reaction is enormous – 100 to 300 million degrees Fahrenheit. Nothing can survive such heat intact. At those temperatures, everything turns into a gas-like state called plasma. Therefore, to fuse, the hydrogen atoms must be forced together inside an invisible ‘bottle’ created by powerful magnetic fields. Because the plasma can become contaminated and quit working, the magnetic bottle itself must be created inside a vacuum chamber.

To absorb the neutrons from the fusion reaction and breed new tritium fuel, the inner chamber of a fusion reactor needs to be surrounded by a blanket of lithium about three feet thick. Lithium burns spontaneously if it comes into contact with either air or water. Six feet from the super-hot fusion reaction, where the huge magnets sit, the neutron flux must be nearly zero and the temperature must be close to absolute zero (459 degrees below zero, Fahrenheit). Needless to say, engineering such a machine poses unprecedented challenges.

Out of the frying pan...

In 1973, 20 years into the United States’ fusion energy research programme, the American Association for the Advancement of Science (AAAS) raised a series of concerns about fusion energy – concerns that still seem valid today.1 As AAAS said in 1973, ‘Operation of a fusion reactor would present several major hazards. The hazard of an accident to the magnetic system would be considerable, because the total energy stored in the magnetic field would be… about the energy of an average lightning bolt’ (200 billion joules2, equivalent to about 47 tons of TNT). A greater hazard would be a lithium fire, which might conceivably release the energy of up to 14,000 tons of TNT (60 trillion joules). ‘But the greatest hazard of a fusion reactor… would undoubtedly be the release of tritium, the volatile and radioactive fuel, into the environment,’ the AAAS said.

Tritium is radioactive hydrogen, a tiny atom that is very difficult to contain. It can escape from some metal containers by slipping right through the metal. Furthermore, because tritium is hydrogen, it can become incorporated into water, making the water itself weakly radioactive. Since most living things, including humans, are mostly water, radioactive water poses a distinct hazard to living things. Tritium has a half-life of 12.3 years, which means it remains radioactive for about 120 years after it is created. The AAAS estimated in 1973 that each full-scale fusion reactor would release one to 60 curies3 of tritium each day of operation through routine leaks, even assuming the best containment systems. An accident, of course, could release much more because at any given moment there would be up to 100 million curies of tritium inside each full-scale machine – almost four times as much tritium as occurs naturally in Earth’s atmosphere.

into the fire

In 1983, Lawrence Lidsky, a professor of nuclear engineering at Massachusetts Institute of Technology (MIT), associate director of MIT’s Plasma Fusion Center, and editor of the journal Fusion Energy added to the world’s knowledge of potential problems with fusion energy, offering a candid critique of the technology.4

Lidsky compared the accident potential of today’s existing nuclear fission reactors to fusion reactors. Fusion reactors could not melt down the way today’s fission reactors can. And the radioactive waste from a fusion machine would be much less (perhaps 0.03 per cent as much waste as from a fission reactor, according to Lidsky).

However, he pointed out: ‘Current analyses show that the probability of a minor mishap is relatively high in both fission and fusion plants. But the probability of small accidents is expected to be higher in fusion reactors. There are two reasons for this. First, fusion reactors will be much more complex devices than fission reactors. In addition to heat-transfer and control systems, they will utilize magnetic fields, high power heating systems, complex vacuum systems, and other mechanisms that have no counterpart in fission reactors. Furthermore, they will be subject to higher stresses than fission machines because of the greater neutron damage and higher temperature gradients. Minor failures seem certain to occur more frequently,’ he warned.

Lidsky then pointed out that there would be too much radioactivity inside a fusion reactor to allow maintenance workers inside the machine. When things break, repairs will not be possible by normal procedures. This alone may make fusion plants unattractive to electric utilities, he pointed out. Lidsky said no-one was hurt at Three Mile Island, yet the accident was a financial disaster for the owner of the plant and ultimately for the nuclear power industry. An accident at a fusion plant could have similar consequences, he said.

Nuclear fusion lends itself to tight control by powerful élites, both corporate and governmental

He also noted that a fusion reactor would have to be physically much larger than a fission reactor to create an equivalent amount of electricity, perhaps 10 times as large. Such huge machines would be enormously expensive to build. From the viewpoint of generating reliable power, it would make more sense for a utility to invest in several smaller machines, rather than putting all their eggs in one large, unreliable basket. ‘All in all, the proposed fusion reactor would be a large, complex, unreliable way of turning water into steam,’ he suggests.

As a final caveat about fusion, Lidsky pointed out that: ‘One of the best ways to produce material for atomic weapons would be to put common uranium or thorium in the blanket of a D-T [deuterium-tritium fusion] reactor, where the fusion neutrons would soon transform it to weapons-grade material. And tritium, an unavoidable product of the reactor, is used in some hydrogen bombs. In the early years, research on D-T fusion was classified precisely because it would provide a ready source of material for weapons. Such a reactor would only abet the proliferation of nuclear weapons and could hardly be considered a wise power source to export to unstable governments.’ Despite these inherent problems, governments are relentlessly pursuing this expensive and unproven technology.

It is interesting to speculate why fusion might seem so attractive. For one thing its great complexity and expense mean that only wealthy countries could afford it. Each machine would create a highly centralized source of enormous power (electrical and political), controlled by a few people. The technical teams needed to develop fusion might be called upon, if needed, to lend a hand to military projects, perhaps extending to laser weapons deployed in space. In other words, unlike photovoltaic electricity and wind power that are inherently small-scale and difficult to bring under centralized control, nuclear fusion lends itself to tight control by powerful élites, both corporate and governmental. To the people who fancy that they own and operate Western civilization, such factors perhaps tip the balance in fusion’s favour.

Peter Montague is editor of Rachel’s Environment & Health News.

  1. Allen L Hammond, William D Metz, and Thomas H Maugh II, ‘Energy and the Future’ Washington DC, American Association for the Advancement of Science, 1973.
  2. A joule is a unit of energy equivalent to 1 watt per second or 0.2389 calories.
  3. A curie is a unit used to describe the intensity of radioactivity in a sample of material. 1 curie is equal to 37 billion disintegrations per second, which is approximately the same rate of decay as 1 gram of radium.
  4. Lawrence E Lidsky, ‘The Trouble With Fusion’, Technology Review Vol. 86 October, 1983. Pages 32-44.

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