Fusion power is one step closer to becoming a reality now that a new phase of construction has begun at the site of ITER, the world’s largest experimental fusion reactor. Twenty five years after the first talks of an international fusion energy project, the new works at the site in the south of France mark the beginning of preparations for the tokamak, the core part of the reactor. Sabina Griffith at ITER told the Euroscientist that after waiting for a year for this construction to start, it has had a great effect on the staff on site. “We can finally see ITER taking shape,” she said
Fusion happens naturally in the core of the sun, where the temperature is 15 million degrees and atoms whizz around at tremendous speeds. This means that when they collide, they have so much energy that the repulsive force between them is overcome and they fuse into one. The fused nucleus has a slightly smaller mass than the two original nuclei, and this difference is balanced by the release of huge amounts of energy.
In ITER these conditions will be created by a device called a tokamak, the name of which comes from a Russian acronym meaning a torus-shaped chamber with magnetic coils. An electrically charged gas, or plasma, travels around the torus, confined by giant magnets, exploiting the fact that charged particles in the plasma interact with the magnetic field. Material walls alone would be useless for containing the plasma, as the highly energetic particles would simply melt them. In future reactors, the heat generated by the fusion reactions in the plasma will drive turbines to generate cleaner and more efficient power than fossil and current nuclear fuels.
ITER is a truly international collaboration, with research groups all over the world contributing to it, and using results produced by more than 200 tokamaks built over the years. To give an example, during a recent visit to the ISTTOK facility at the Instituto Superior Técnico in Lisbon, researchers explained that ISTTOK, a small tokamak used for research into plasma diagnostics useful for ITER, was created from the recycled parts of TORTUR, an older tokamak from the FOM Institute for Plasma Physics at Rijnhuizen in the Netherlands. The expertise of diverse groups is needed to overcome technical challenges in building the first reactor to generate net fusion power.
There have been a few delays along the way, including a re-evaluation of costs showing that the project will far exceed the original budget of €5 billion. Combining this with the financial strain of the economic crisis on the member states, all those involved were relieved that ITER is able to continue as planned. The first plasma in ITER is scheduled for 2018, with the facility becoming fully operational around 2025. Following ten years of experiments, a ‘demo’ power plant is planned, and the first fusion power plants are expected to be operational around 2050. The future of fusion energy is bright, but tokamaks won’t be powering your light bulbs just yet.
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