Magnetic Plasma Confinement: Tokamaks and ITER

Tokamak fusion reactors have long been considered the most likely means of achieving practical nuclear fusion energy. Their basic design is a torus (or a donut) within which intense magnetic fields confine very hot plasma. There is a long list of tokamak reactor experiments, but the three of note are the biggest and most recent, the TFTR, JET, and ITER tokamaks. The Tokamak Fusion Test Reactor (TFTR) at Princeton University generated the highest temperature and set what was in 1994 a world record for energy generation. The Joint-European Torus (JET), pictured above, currently holds the record for the most energy generated by a controlled fusion reaction. The International Thermonuclear Experimental Reactor (ITER), still in the design phase, holds hope of being the first break-even nuclear fusion reactor in the world. (image credit: ITER)

Like any international scientific and engineering collaboration expected to cost tens of billions of dollars, ITER has been long in planning. First proposed around 1985 as an international diplomatic research effort, final agreement on a construction site was not reached until June of 2005. Construction is expected to begin in 2008 and finish in 2016. ITER is designed to generate 500 MW (about 10 times the record held by JET) and will hopefully produce more energy than is required to keep the plasma heated and confined. The success of the project is by no means guaranteed, however, and many of the criticisms surrounding it have focused on the technical challenges. Other criticisms have noted that the neutrons released in the deuterium-tritium fusion would create secondary radiation within the metallic parts of the reactor chamber. This secondary radiation would create radiological waste disposal problem, and would also shorten the life of the components in the reactor through radiative metal fatigue.

If ITER is largely successful, research done there over the years between 2015 and 2035 will show us what yet needs developing before commercial nuclear fusion is feasible. Following ITER, a hypothetical successor is project DEMO which will produce commercial nuclear fusion energy for the first time. If ITER is unsuccessful for technical reasons, the timeline for nuclear fusion will likely be driven even further back, keeping the "30 years away" projection true no matter when it is said.