Fusion nuclear power's unlikely ally: the semiconductor industry

When Commonwealth Fusion Systems (CFS) announced last Thursday an $85 million package from the U.S. Department of Commerce, the news at first glance seemed like just another technical energy story that would pass without much repercussion — a fusion startup gets federal funding, moves to the next milestone, we forget about it. But what actually happened was something more significant: nuclear fusion, long considered the "final frontier" of clean energy, found its most unexpected ally possible, and the answer may explain why this sector is finally moving beyond theory.

The Devens, Massachusetts-based CFS, a collaborator of MIT's Plasma Science and Fusion Center, received the funding through the CHIPS and Science Act — that bipartisan 2022 law that allocated more than $50 billion for semiconductor reindustrialization. What made less sense to many observers was how an energy startup would fit into chip legislation. The answer, as CFS co-founder and chief science officer Brandon Sorbom detailed in a technical article on the company blog, is that nuclear fusion and the semiconductor industry share much more similar problems than they appear on the surface.

The energy problem only fusion solves

A fusion power plant needs something that conventional engineering simply cannot deliver economically: extremely intense pulses of electricity to power the superconducting magnets that confine plasma inside the reactor. These pulses cannot be stored in regular batteries — the energy needed to turn the magnetic fields on and off is in the megawatt range and must happen in milliseconds. The current solution involves silicon-based power electronics, but conventional silicon has physical limits that reach an impenetrable ceiling when you need to manage voltages in the tens of kilovolts.

This is where silicon carbide (SiC) enters. This semiconductor material, already used in electric vehicles and cellular base stations, can handle much higher voltages than regular silicon, with less energy loss and greater heat resistance. For fusion, this means the converters that power the SPARC magnets — the reactor CFS plans to turn on in 2027 — can be smaller, more efficient, and cheaper. The change is not just technical; it is economic. If power components become cheaper and more reliable, the total cost of a fusion power plant drops significantly, and that is exactly what investors and regulators want to hear.

Five fronts of investment

CFS's $85 million deal covers five distinct initiatives, and each reveals a different aspect of the symbiotic relationship between fusion and semiconductors:

First, the advancement of silicon carbide power electronics. Second, the development of next-generation radio-frequency generators — devices CFS uses to heat fusion fuel inside the reactor. Third, advanced control electronics that allow faster response to reactor commands, essential for maintaining plasma stability. Fourth, radiation-hardened electronics, which extend the lifespan of electronic components inside the plant and reduce operating costs — a chronic problem in environments where neutronic radiation rapidly degrades conventional circuits. And finally, the adaptation of AI hardware, including GPUs and TPUs, to control fusion power plants in real time.

This last initiative deserves special attention. The idea of using AI processors for reactor control is not new — research already exists on neural networks to predict plasma instabilities before they occur — but what CFS's agreement proposes is taking this to the commercial production level. It is no longer about simulating a reactor on a server cluster; it is about running an entire data center in real time on fusion hardware, with AI-based controllers managing plasma stability millisecond by millisecond.

The broader context: four companies, $389 million

CFS is not alone. The Department of Commerce announced four letters of intent that same week totaling $389 million, and the context reveals a structural trend worth watching. Helion Energy, CFS's rival in the fusion space, received $175 million specifically to develop semiconductors that power and control the magnets of its fusion generators. Vertical Semiconductor, a Boston startup, received $73 million to advance vertical gallium nitride (GaN) transistors, already with application targeted at "superintelligence AI data centers" — the government language already connects power semiconductors directly to AI. Sibelco received $56 million to develop ultra-high-purity quartz purification, a critical material in the semiconductor supply chain.

What emerges from this collection is not an isolated investment in fusion. It is an explicit recognition by the U.S. government that power semiconductors — the chips that convert and distribute electricity — are the critical link between the artificial intelligence revolution and the energy revolution. AI data centers consume growing quantities of electricity, and the U.S. electrical grid is already at its limit. If fusion arrives in time, with the appropriate electronic components, it can provide the clean, consistent energy that AI needs. If it doesn't, data centers will have to compete with the rest of the country for limited electricity.

The timeline nobody says out loud

CFS has already installed SPARC's main magnet and plans to turn on the reactor at some point in 2027. This would be only the "turn on" — the first plasma. Building a commercial plant that connects energy to the electrical grid is an even bigger step. But what the $85 million agreement reveals is that CFS is no longer focused solely on the reactor. It is building the entire chain of electronic components that a commercial fusion plant needs, and doing so in partnership with the U.S. government.

It is the same reasoning that led Tesla to invest in superchargers and its own charging network: new technology doesn't scale until the support infrastructure is in place. Fusion has already passed the superchargers stage — it is now in the phase of building its own electrical grid. And in this phase, semiconductors are as important as the reactor itself.

The question that remains is not whether fusion will reach the electrical grid, but exactly when it will arrive — and whether American semiconductors will be ready to deliver the energy in time to sustain the demand that the AI revolution itself is creating.

Sources: TechCrunch, NIST / Department of Commerce, The Tokamak Times (CFS Blog)

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