Gretchen ERTL
The idea is straightforward: Fill the donut with hydrogen gas, and then heat that gas until it turns into an electrically charged plasma. In this ionic state, the plasma will be held in place by magnets located around the tokamak. Scientists have calculated that to achieve fusion on Earth without the extreme pressure of a star’s interior would require temperatures about 10 times hotter than the center of our Sun – about 100 million degrees Celsius. So the trick would be to get the hot plasma suspended so well in the surrounding magnetic field that it cannot touch the internal surfaces of the chamber. Such contact would cool it instantly, stopping the fusion reaction.
The good thing about it was security. In the event of failure, a fusion power plant will not melt down – quite the contrary. The bad thing was that the gaseous plasma was not very cooperative – any slight irregularity in the chamber walls could cause unstable turbulence. But the concept was so attractive that by the mid-1980s, there were tokamaks in 75 universities and government institutions around the world. If one could achieve fusion – the most energy-dense reaction in the universe – the deuterium in a liter of seawater could meet one person’s electricity needs for a year. Effectively this would be an unlimited resource.
Apart from the unrest there were two other major obstacles. The magnets surrounding the plasma need to be really powerful – i.e. really big. In 1986, 35 countries representing half the world’s population – including the US, China, India, Japan, what is now the entire European Union, South Korea, and Russia – agreed to jointly build a $40 billion giant tokamak, the International Thermonuclear Experimental Reactor, in southern France. Standing 100 feet high on a 180-acre site, ITER (the acronym also coined the Latin word for “travel”) is equipped with 18 magnets weighing 360 tons each, made of the best superconductors available at the time. If it works, ITER will produce 500 megawatts of electricity – but not before 2035, if then. It is still under construction. The second hurdle is the biggest: many tokamaks have achieved fusion for short periods of time, but doing so always takes more energy than they produce.
After receiving his doctorate in 1992, White worked on ITER prototypes at the National Fusion Facility in San Diego, taught at the University of Wisconsin, and was hired by MIT in 2006. By then, he understood how big the stakes were, and how life-changing fusion energy could be on a commercial scale – if it could be sustained, and if it could be produced affordably.
MIT had been trying since 1969. The red brick buildings of its Plasma Science and Fusion Center, where White came to work, were originally the National Biscuit Company. PSFC’s sixth tokamak, Alcator C-Mod, built in 1991, was in Nabisco’s old Oreo cookie factory. The C-Mod’s magnets were coiled with copper to serve as a conductor (think of how copper wire wrapped around a nail and connected to a battery turns it into an electromagnet). Before C-Mod was finally deactivated, its magnetic field, which was 160,000 times stronger than Earth’s, set a world record for the highest plasma pressure in the tokamak.
As Ohm’s law describes, however, metals like copper have high internal resistance, so it can only last about four seconds before overheating—and igniting its fusion reactions requires more energy than it can release. Like the 160 similar tokamaks now around the world, C-Mod was an interesting science experiment but mainly reinforced the joke that fusion energy was 20 years away and would always be so.
Every year, Whyte challenged the PhD students in his fusion design classes to design something as compact as the C-Mod, at one-800th the scale of ITER, that could achieve and sustain fusion with the energy gains. But in 2013, as he approached 50, doubts grew in his mind. He had dedicated his career to the fusion dream, but unless something fundamentally changed, he feared it would not happen in his lifetime.
The US Department of Energy decided to reduce fusion. This informed MIT that funding for the Alcatar C-Mod would end in 2016. So White decided he would either leave Fusion and do something else or try something different to get there faster.
