Why we invested in Novatron — in pursuit of commercial fusion power
Our sun is a nuclear fusion engine. Under great pressure and heat atoms fuse together, releasing enormous amounts of energy in the process. This process is distinct from nuclear fission, where atoms are split to release energy — a technology we humans commercialised back in the 1950s. At Climentum we are big fans of nuclear fission, but we would also like to see nuclear fusion mature to commercialisation for low-carbon baseload power generation.
The primary reason for this is that the fuel for fusion is deuterium, which is naturally abundant in the ocean and easily accessible as opposed to uranium, found in limited mining sites globally. There are other benefits around safety and waste, but these are minor when considering the latest generation of nuclear fission power plants and waste management solutions.
Why don’t we have nuclear fusion plants already?
If the sun is able to continually generate fusion energy, why haven’t we been able to replicate it on earth? In essence, fusion ignition requires sufficient amounts of heat, pressure, and time for plasma to form. This is called the triple product: heat (temperature) multiplied by pressure (fuel density) multiplied by time (plasma confinement time) needs to be high enough for fusion ignition.Once ignition is achieved, the subsequent challenge is to sustain stability to extract energy from the plasma over an extended duration.
To get a high enough triple product, most fusion reactor designs aim for temperatures around 100 million degrees celsius. This is a lot hotter than the sun, but that’s because we can’t mimic the pressure in the sun, driven by its enormous gravitational forces. To get the pressure piece right, most reactor designs look to magnets. Strategic arrangement of magnets and the application of electrical currents result in electromagnetic forces that can generate impressive amounts of pressure. Finally, to keep the plasma in place, scientists and engineers have worked with a few different designs — including the most famous tokamak reactor design (doughnut shaped) and the less famous magnetic mirror reactor design.
As the graph below shows, we humans have made steady progress in terms of reaching the required triple product for fusion ignition. At present there are dozens of private and public entities working to get even higher triple products, while tackling questions of maintaining fusion reactions (stability) and commercialization (cost of energy production).
Source: https://www.fusionenergybase.com/article/measuring-progress-in-fusion-energy-the-triple-products
Magnetic mirrors: a fusion reactor concept overlooked since the 80s
The above graph clearly shows that the tokamak design has been the centre of attention in recent decades. This is changing rapidly. Companies are now working with a wide range of fusion reactor designs. One of them, championed by Novatron, is the magnetic mirror.
At this point it is important to note that we do not consider fusion to be a winner-take-all space. It is entirely feasible that several designs achieve commercial success. We believe that Novatron could be one of them. Also, the various innovations Novatron has made (and is planning to make) could be modularly relevant for other reactor designs, so there is more than one path for success for the company.
Coming back to the basics: the original magnetic mirror fusion reactor designs hark back to the 1950s. The basic idea is to configure electromagnets in such a way as to create an area with an increasing density of magnetic field lines at either end of a confinement volume, causing particles approaching the ends to reverse direction and return to the confinement area. This design optimises for confinement time, but has issues with so-called “leakage”: the mirror effect will occur only for particles within a limited range of velocities and angles of approach, while those outside the limits will escape. Also, the design implies the use of convex magnetic surfaces, which are fundamentally undesirable for maximising plasma containment and stability (you want all magnetic forces pointing inward).
From the 1950s to the 1980s, there were numerous efforts with magnetic mirror designs, but the results ultimately fell behind the performance of the tokamak designs, leading public funding to focus entirely in that direction. Since the last major public project closed in the 1980s, little attention has been given to the magnetic mirror design.
Novatron’s innovative magnetic mirror reactor design
Novatron is now bringing the magnetic mirror design back to the fore. Taking a fresh look at the challenges of leakage and containment/stability, Novatron has developed a new reactor design that overcomes the old challenges and further shows the promise of lower-cost energy production.
Innovations around electromagnetic field design & control with consistently concave magnetic fields shows the promise of unprecedented plasma containment and stability. Innovations around leakage control also bring down overall leakage significantly, while enabling the conversion of the remaining leakage into direct electricity production (as opposed to conversion from thermal energy). In combination, these innovations not only hold the promise of a stable and continuous fusion process, but also a lower cost of electricity production.
With these innovations on the magnetic mirror, Novatron’s reactor design is the only known concept with increasing magnetic fields outwards everywhere in the confinement region. Like a ball inside a bowl, the plasma will be pushed back by the repelling magnetic force when trying to escape its magnetic confinement. This brilliant design simplifies the engineering required for a fully operating fusion reactor. For example, Novatron can use conventional copper electromagnets, as opposed to the ultra-expensive cryogenically cooled superconducting magnets used in more famous tokamak and stellarator reactor designs.
The fully concave external magnetic field has the added benefit of not requiring a ramping up of currents to produce stabilising magnetic fields (as with e.g. tokamaks). This design should also allow for higher temperatures than tokamaks. And thanks to the symmetry of the reactor, and the fact that it has open magnetic field lines, it will be a lot easier to add fuel and remove by-products continuously during operations.
All-in-all the Novatron reactor concept holds the promise of reaching commercially attractive fusion power as one of the first, if not the first, in the world. To follow how the commercialisation of Nuclear fusion unfolds, follow Climentum and Novatron Fusion.
