Making Nuclear Fusion Real

Obtaining energy by nuclear fusion has been perpetually on the horizon for several decades. Unlike conventional nuclear fission reactors, which capture the energy released by splitting atoms, nuclear fusion devices generate energy by fusing atomic nuclei together. Compared to the scarce radioactive materials needed for fission, fusion uses as fuel light elements that are abundant in nature. It also produces much safer byproducts, not long-lived radioactive nuclear waste.

Nuclear fusion generates energy by fusing atomic nuclei together, reproducing the same process that powers the sun. If we can control it, nuclear fusion will provide ample clean and safe energy for the foreseeable future, rendering irrelevant our current energy concerns.

There two main approaches for achieving nuclear fusion. Inertial confinement, used by the National Ignition Facility (NIF) project at the Lawrence Livermore National Laboratory, uses lasers to ignite a small piece of fuel. This team made news in December 2022 by achieving “breakeven”, which means producing more energy from the fusion reaction than the energy required to power the lasers. Despite this milestone, this approach is not intended to be used by a fusion power plant and doesn’t scale to the needs of a national power grid.

The other approach is magnetic confinement, which uses strong magnetic fields to contain a torus of superheated plasma in a tokamak reactor. This method will be used by the ITER project, an international collaboration that has constructed the largest tokamak reactor in the world in the south of France. ITER is designed to generate ten times more energy from fusion than is used in its production.

The tokamak design relies on powerful superconducting magnets to create the necessary magnetic field. To work, these need to be cooled to extremely low temperatures. As an example, the niobium–tin (Nb₃Sn) or niobium–titanium (Nb–Ti) superconducting magnets used in the ITER reactor have to be cooled to 4 Kelvin (-269°C) using liquid helium.

Cooling the magnets accounts for a significant proportion of the input energy in a tokamak reactor. This energy expenditure can be entirely crossed out if the magnetic field were generated using magnets made from a room-temperature superconducting material like the ones being developed at Unearthly Materials. A change of this magnitude in the energy balance of the system would instantly make fusion energy efficacious.

The superconducting materials we have been working on at Unearthly Materials have an estimated upper critical field of 88 tesla, which is eight times higher than what is achieved by the magnets in ITER. As the square of the magnitude of the magnetic field is relative to the power output of the reactor, an eight times greater field could create 64 times more power in a reactor of the same size — a vast multiplier. But crucially, the same power could be produced by a 64 times smaller reactor. This is paramount if fusion technology is to be widely adopted around the world.

The promise of clean, cheap, and abundant energy will have an unimaginable impact on humanity. The materials developed at Unearthly Materials can bring about viable fusion energy 40 years ahead of schedule and accelerate the dissemination of its benefits to people everywhere.