Category:	Science and Technology
Domain:	Energy
Keywords:	Energy - nuclear, fusion, cold fusion
Outlook:	Fusion could be the answer to the world's energy needs. ITER, a $5bn experimental reactor will come on-line in about a decade but success is not guaranteed.
Summary Analysis:	When small atomic nuclei combine to form larger nuclei, energy is released. This ‘fusion energy’ is what powers the sun. Hydrogen bombs generate energy by fusion but more controlled fusion reactions are harder to achieve. Huge electrostatic forces between nuclei must be overcome before the nuclei can fuse. This requires the nuclei to be travelling very fast. It is relatively straight forward to induce fusion in the laboratory but it has so far proved extremely difficult to do so in a way that releases more energy than was required to induce the fusion reaction. If a self-sustaining fusion reaction could be achieved it would make a very attractive energy source. The deuterium (H2) and helium-3 (He3) fuel required is abundantly available. Although the by-product is tritium (H3) which is a radioactive gas, it decays quickly (the radioactivity is short-lived) and so poses less of a disposal problem than radioactive waste from existing (fission) nuclear reactors. Attempts to develop fusion reactors have been pursued since the 1950s. Most of these have involved containing the fuel in a magnetic field. The magnetic field can be used to heat up the fuel to temperatures of over 100 million °C (so the nuclei will be travelling fast enough when they meet) and to squeeze the fuel in what is effectively a vacuum to allow nuclei to come into contact with one another. It also prevents the hot fuel from touching the sides of the container (which it would vaporise). Usually, the magnets are formed into a torus (doughnut) shape and the fuel injected into the circular tube created by this arrangement. Alternative approaches include using super-powerful lasers directed uniformly at all sides of a pellet of fuel create the heat and density needed to initiate fusion. Two approaches to ‘cold fusion’ have also been explored. As the main engineering problem in fusion is the containment of the hot plasma, a fusion reaction that takes place at room temperatures would make the technology a lot more accessible. The reported discovery of fusion reactions in a test-tube containing water and platinum electrode have proved to be difficult to reproduce and the claim is now thoroughly discredited and receives little attention. On the other hand, after initial scepticism, reports of fusion reactions taking place in the course of experiments to explore the puzzling phenomenon of ‘sonoluminescence’ are now being taken more seriously. However, there is as yet no consensus that fusion is occurring in these experiments and no conception at the moment of what technological development of the phenomenon would involve. Conceivably though, if the results are confirmed and explained theoretically, a new avenue of fusion research may be opened. The main effort towards fusion power technology has, since the 1950s, involved toroidal ‘hot’ fusion reactors. A European project called JET (Joint European Torus) achieved controlled fusion but the energy input was greater than the output. JET has proven the process and operating parameters but is simply a physics experiment. JET has been superseded by a new international project called ITER (International Thermonuclear Experimental Reactor). ITER is an experimental reactor at realistic (but not commercial) scale which will explore the real engineering problems coupled with the in-process generation of tritium (He3) which arises from neutron bombardment of a lithium breeder blanket surrounding the plasma. There will be challenging structural materials problems due to the high radiation energy and massive thermal fluxes. France will host the $5 billion facility and construction will commence imminently and should be completed in 2016. $7 billion has been earmarked for operating costs and decommissioning after its 30-year life span. Engineers and scientists in the field are optimistic about ITER but, as a result of long experience, they remain circumspect about the prospects for success. A high possibility of technical failure remains, and commercial fusion, engineers will tell you, is at least 40 years away. The problem is, it has been 40 years away since the 1950s.

	Implications:	Potential for an ample and clean source of energy, solving most of the world’s energy problems Continuing need to rely on other energy sources due to the unlikelihood of a fusion breakthrough, especially anytime in the next few decades
	Early Indicators:	Announcement of France as the site of ITER
	What to Watch:	Progress at ITER is rapid, encouraging further funding. Scientists at ITER run up against unforeseen hurdles, increasing the cost of the research and the likelihood of it being shelved.
	Parallels/Precedents:	US research into nuclear fission in the Manhattan Project
	Enablers/drivers:	Increased funding for research into fusion technology Increasing world need for massive supplies of nonpolluting energy
	Leaders:	Regions: UK France (the home of ITER) EU, Japan, Russia, China, South Korea, USA, India (supporters of ITER) Institutions: ITER [link] European Fusion Development Authority [link] European Fusion Network [link] UKAEA Fusion Association at Culham Science Centre [link] JET [link] World Nuclear Association [link] University of California (Irvine and San Diego)
	Figures:
	Sources:	Hammond Allen L. et al "Energy and the Future" AAAS. 1973. 79-85 [link] Key M.H. "Fast track to fusion energy" Nature. 2001. 412. pp775-6 [link] "Nuclear ambitions" Economist. Jun 30 2005 [link] King, D. "Fast Forward to Fusion" New Scientist. April 10. 2004 [link] "International Energy Agency" International Energy Agency [link] Fowler, T. Kenneth. "The Fusion Quest." Baltimore: Johns Hopkins University Press, 1997. The Engineering and Physical Sciences Research Council, UK [link] Fusion and sonoluminescence: Rusi Taleyarkhan et al 2002 Science 295 1868

	At A Glance:	When:	21–50 years +
		Where:	Global
		How Fast:	Years
		Likelihood:	Medium
		Impact:	Medium-Low
		Controversy:	High

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