Fusion power research gets a boost

Schematic of STEP, U.K's proposed fusion power plant based on a spherical tokamak design

THE British government has announced the allotment of £220 million ($248 m) over the next four years towards the design of a commercially viable fusion power station called the Spherical Tokamak for Energy Production (STEP). It will also use the tokamak technology that forms the basis of the International Thermonuclear Experimental Reactor (ITER) project coming up in Cadarache, France, as also fusion power’s predecessor plants such as the JET (Joint European Torus) in the United Kingdom.

The “spherical” tokamak technology is currently being pioneered at the Culham Centre for Fusion Energy (CCFE) of the U.K. Atomic Energy Authority (UKAEA). Involving over 300 people, the design effort, led by the CCFE, is expected to be completed by 2024. The other two tokamak machines in the U.K., JET, built in 1983, and Mega Amp Spherical Tokamak (MAST), built in 1999, are also housed at the CCFE.

JET is aimed at investigating the conditions approaching those in a fusion power plant and is the only plant that uses the same deuterium-tritium fuel mix that will be used for commercial fusion power.

With MAST, since 1999, the U.K. has experimented with the use of spherical “tokamaks”, which contain a spherical plasma, much like a cored apple instead of a doughnut- or torus-shaped plasma in a conventional tokamak design. (Actually, the use of the word tokamak would be a misnomer for such a compact spherical shape.)

The compact spherical design allows confinement of highly pressurised plasmas with a lower magnetic field than what is used in JET. This, it is believed, could lower the cost of fusion power generation. The new proposal for STEP is for research towards a conceptual design report for a fusion reactor based on the spherical tokamak design.

“This is a bold and ambitious investment in the energy technology of the future,” Andrea Leadsom, U.K. Secretary of State for Business, Energy and Industrial Strategy, has been quoted as saying in news reports. “Nuclear fusion has the potential to be an unlimited clean, safe and carbon-free energy source and we want the first commercially viable machine to be in the U.K.”

The investment is expected to come up with an integrated design that will form the basis for a plant capable of generating hundreds of megawatts of net electrical energy that would be up and running by the early 2040s.

No fusion reactor has so far been able to generate more energy than it takes to operate the device. But the race for fusion power is very much on given its potential as a clean and limitless source of energy that powers stars like the sun.