There are at least five good reasons why nuclear fusion matters. 1) It releases zero carbon emissions. Helium, a non-environment-harming gas, is the only byproduct. 2) Nuclear fusion can produce four million times oil and coal energy. 3) We can source the materials needed for internal fusion reactions (deuterium, tritium, lithium) from the earth; deuterium can be extracted from oceans and the upper atmosphere, and lithium is in the earth’s crust. 4) It takes 0.1g of deuterium and 0.3g of lithium to power the average American for a year (CFS estimate). That’s small, like the size of lint small. 5) Successful scaling of nuclear fusion can power 458M+ people in the world’s least developed countries who don’t have access to electricity.
In my nuclear fusion research, I’ve been intrigued by Commonwealth Fusion Systems because of their use of the superconductor. In this one-pager, I explain how CFS technology works and what the future of nuclear fusion looks like.
How does CFS tech work?
It needs three things: very high temperatures (this is what creates collisions between nuclei), plasma particle density (increases the likelihood that collisions occur), and confinement time (to ensure that the plasma holds for hours).
Heat generation occurs when two nuclei merge to form a heavier core. The leftover mass created by the two nuclei merging becomes energy. Nuclear fusion uses isotopes from weak elements like hydrogen because the binding energy of these isotopes creates a more significant reaction than a more vital element like uranium. In other words, as more nucleons accumulate in an element’s nucleus, the binding energy per nucleon decreases.
Because like charges tend to repel and fusion uses protons/electrons for the reaction, elements with smaller atomic numbers require less energy to break the Coulomb barrier  and have a nuclear response. The reaction that occurs in nuclear fusion is deuterium + tritium (hydrogen isotopes) converted to helium and a free neutron. The new neuron’s mass creates excess energy. The energy from the extra neutron is what makes 500M kWh of electricity through nuclear fusion. This works because Einstein equates E=mc^2.
Tokamaks, donut-shaped magnetic chambers, are giant magnets (if you were to unravel the interest, it would be 166 miles long) that control the shape of the plasma. In Sep. 2021, CFS was able to generate 20 Teslas with their high-temperature superconducting magnet. They can develop a strong magnetic field in a small space that releases more fusion power than the heat it takes in. The relationship between fusion power output and heat input is measured by Q. The goal is to maximize the output of fusion because large amounts of heat are generated to power steam which powers commercial electrical systems, without requiring large amounts of heat input. Most fusion reactors today have a Q rating of 0.7. For fusion to be a reliable form of energy, a rating between 10-25 is necessary. These powerful magnetic fields confine the plasma, too, allowing for longer times of home power.
What does the future of nuclear fusion look like?
Solving physics challenges: One of the problems with fusion is reducing the reactor's size so it can be scaled up to homes and communities without omitting critical parts of the generating infra larger reactors have.
Reinforcement Learning x Fusion: Because plasma is like jelly, confinement time remains one of the most complex problems. DeepMind uses reinforcement learning to predict how the plasma moves and shifts the magnetic field accordingly.
IoT x Fusion: I think eventually, we’ll be able to control our nuclear fusion reactor like we own our home thermostat. Because of the ability of the reactor to produce abundant energy at low cost, reactors can be deployed in neighborhoods; we can scale the form factor down so it can fit in a backyard too.