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| Fig. 1: Illustration of the ways in which the Tokomak machine uses magnetic fields to induce plasma flow. [2] (Source: Wikimedia Commons) |
ITER, coined after the latin word for "the way", is an ambitious energy project looking to revolutionize the way humans generate and use energy. Their mission is to change the way humans think about energy by demonstrating the viability and feasibility of fusion power. To do so they are developing a Tokamak machine. The ITER Tokamak is designed to produce 500 megawatts of output power, while needing 50 megawatts of power to operate. [1] This means the machine would be producing more energy through the fusion process than the amount of energy needed to run the machine, creating a net positive amount of energy. This is something that has yet to be achieved by any reactor. This would be a groundbreaking development.
Deuterium and Tritium are examples of stable isotopes that are viable for energy creation through nuclear fusion as they require a relatively low temperature to create energy. Although, they still require temperatures that are significantly higher than the temperature of the sun in order to overcome their electrostatic repulsion that naturally prevents the process of fusion from occurring. Specifically, optimal reactions occur at temperatures exceeding 100 million degrees celsius. [1] Thus, the Tokomak machine must create an environment with these optimal conditions. In order to enable the heating of the plasma to such high temperatures, ohmic heating is utilized, which consists of running current through the plasma. These extreme temperatures create high kinetic energy, and the particles begin moving with high velocity.
In order to enable the fusion process to occur, the Tokomak machine uses magnetic fields to contain the particles in a small space. As illustrated in Fig. 1, the Tokamak machine uses toroidal field coils, which results in the circular plasma current flow through the donut shaped machine that is also depicted in Fig. 1. [2] Once the process of fusion starts, the high energy particles will no longer be confined by the magnetic fields due to their charge neutrality, and they will radiate past the magnetic fields, where they can be outputted as energy.
ITER's project is not cheap. It is estimated to have costs of around $20 billion. [3] And, after various delays and budget issues, the project is not expected to actually begins operations until 2017. This is more than 10 years later than originally planned. [3] So, while the project offers much excitement and potential for groundbreaking innovation, there are also many roadblocks that must be overcome in the next decade or two to get us there.
© Henry Hirshland. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] J. Amos, "Key Component Contract for ITER Fusion Reactor," BBC News, 14 Oct 10.
[2] J. Orwig, "ITER Organization 2015 Annual Report," ITER Organization, July 2016.
[3] W. W. Gibbs, "Triple-Threat Method Sparks Hope For Fusion," Nature 505, 9 (2014).
