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| Fig. 1: World map of countries participating in the ITER program. [9] (Source Wikimedia Commons) |
Nuclear fusion, like nuclear fission, is much more productive than other sources of energy and, in theory, is able to operate with minimal environmental harm. Fusion, the mechanism that powers stars like our Sun, is far more effective than fission. Though sustainable nuclear fusion remains elusive, recent efforts by different groups suggest that it is closer than we think. Two tokamak experiments appear to be on path to yield net energy outputs, while close links between a fusion startup and big tech giants appear promising. [1]
A private company called Commonwealth Fusion Systems has partnered with the MIT Energy Initiative to work on a compact tokamak experiment called SPARC that will produce 100 MW of energy in 10 second pulses. [2] Initial estimates indicate that this is double the required input energy - a net gain in energy. While the plant is expected to be finished in around 15 years, there is reason to be bullish about SPARC. One of the main difficulties is in creating a stable environment that is conducive to nuclear fusion. Plasma needs to be heated to temperatures in the millions of degrees for the process to be successful. Magnets must be used to keep the heated plasma from coming into contact with the rest of the plant. SPARC will benefit from the innovations in superconducting electromagnets coming out of MIT that have twice the required magnetic field strength required.
Since the early 1980s, the European Union, India, Japan, China, Russia, South Korea, and the United States (Fig 1) have supported the International Thermonuclear Experimental Reactor (ITER). The goal of the collaboration is to. Building upon decades of research, ITER has started to build a fusion power plant in the south of France also based around a tokamak design. [3] The Provence facility will be completed in 2035 and upon completion is expected to generate in excess of 500 MW during pulses of 10 min. [4] Though billions of dollars have been poured into this endeavor by a contingent of countries, the facility is far from a guaranteed success. Past fusion experiments have never been on a scale like this one. Precision in a very complex process will be necessary to prevent the high probability of plasma instability that threatens to derail the entire project. [5]
Tri Alpha Energy is an aneutronic fusion startup from the US that has attracted around 500 million dollars of funding from private and institutional investors all over the world. [6] The startup regularly publishes its various experiments in academic journals. Experiments span a wide range of configurations that have recently been optimized by a partnership with computer scientists from Google. [7] Trained on experimental plasma data, the Optometrist algorithm created by the Google Research team has been able to rapidly suggest plasma operations that have reduced systemic energy loss by 50%. [8] Stronger relationships with algorithmic powerhouses like Google will only speed up the quest for widespread nuclear fusion.
These are just a few of the promising groups leading the charge for commercial nuclear fusion. Some are experimenting with different plasma rings that allow for continuous operation. Others are playing around with the method of plasma containment. The problem is a highly complex yet a seemingly rewarding one. With so many innovators working in parallel, the chances look good for the future of fusion.
© Miguel Ayala. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. 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] F. Kadribasic, "An Overview and Basic Design Principles of Tokamak Nuclear Fusion Reactors," Physics 241, Stanford University, Winter 2013.
[2] H. Devlin, "Nuclear Fusion on Brink of Being Realised, Say MIT Scientists," The Guardian, 9 Mar 18.
[3] J. Chabolla, "International Thermonuclear Experimental Reactor (ITER)," Physics 241, Stanford University, Winter 2017.
[4] A. W. Kleyn, N. J. Lopes Cardozo, and U. Samm, "Plasma-Surface Interaction in the Context of ITER," Phys. Chem. Chem. Phys. 8, 1761 (2006).
[5] H. Fountain, "A Dream of Clean Energy at a Very High Price" , New York Times, 27 Mar 17.
[6] D. Grandoni, "Start-Ups Take On Challenge of Nuclear Fusion," New York Times, 25 Oct 15.
[7] A. Katta, "Tri Alpha Energy: Promising or Crazy Nuclear Fusion Startup? ," Physics 241, Stanford University, Winter 2016.
[8] D. Carrington, "Google Enters Race for Nuclear Fusion Fechnology," The Guardian, 25 Jul 17.
[9] "U.S. Participation in the ITER Project," U.S. Department of Energy, May 2016.
