Nuclear Fusion 21 - MIT ARC Fusion Reactor Design
I have blogged about several new fusion reactor projects. The main thrust of these projects is to create a commercial fusion reactor for generating electricity. The institutions working on these designs are trying to make small, economical, safe and efficient fusion reactors that can be brought to market within the next ten years. In this blog I am going to talk about the ARC fusion reactor project at MIT.
A great deal of fusion research work has gone into what is called a "tokomak" configuration. This is a donut shaped chamber surrounded by powerful magnets that compress an ionized gas or plasma to generate extremely high temperatures. Heavy isotopes of hydrogen such as deuterium and tritium are often used for the plasma. With sufficient pressure and temperature, these can be fused to create heavier atoms such as helium while releasing more energy than is used to create and compress the plasma. There is a huge international project in France called ITER that is attempting to reach the point where it can generate more energy that it is consuming but it can only operate for a few seconds before the magnetic coils overheat.
At MIT, their new ARC reactor is based on the same tokomak design as the ITER but it is using new magnets based on superconducting materials which can generate far more powerful magnetic fields than the magnets in use at the ITER project. These new magnets can confine more plasma in a smaller space than has ever been possible in existing test tokomaks. The ARC design should provide in an increase in the power of the current tokomak reactors by a factor of 10. The new ARC reactor is about half the size of the ITER reactor be able to generate the same amount of power initially and eventually least three times as much power. This will allow the ARC design to produce much more power than it consumes. It is also surrounds by a circulating fluid that will be able to dissipate the heat better than the solid ITER design. This will permit it to operate continuously which will be necessary for a commercial power reactor. MIT says that it will be a fraction of the cost ITER.
At this point, the ARC reactor is only a conceptual design that has been tested in computer simulations. However, it operates on known principles from previous fusion research and does not require any new breakthroughs. The next step will be to refine the design and work out the technical specifications of the hardware necessary to build a prototype. MIT estimates that it can produce a prototype in about five years and that a commercial model could be available in as little as ten years. The current ARC reactor design should be able to produce power for about a hundred thousand homes.
With a half a dozen projects in various stages of development to produce economical fusion reactors within ten years, nuclear fission, fossil fuels and renewable energy sources may have a strong competitor. These reactors will be a fraction of the cost of nuclear fission reactors and may provide a steady source of competitively prices energy with zero carbon emissions.
Artist's concept of the MIT ARC fusion reactor:
