The Trump Administration Green-Lights SMRs, and CFS Raises Nearly $1 Billion in New Cash

One would think that with our name, The Fusion Report probably only covers fusion energy, particularly the commercialization of fusion energy. While our content tends to be “fusion-heavy” (and we are die-hard believers in the commercialization of fusion), it is by far not the only thing that we cover. The issue for all of us is that the U.S., and more generally the world, is moving more towards electricity, and it will need multiple sources of this electricity over the next 25-plus years to meet all of the expected demand. Today, one of those sources is nuclear fission. But before we get to that, a little fusion news:

CFS Raises $863 Million of New Cash in Series B2 Funding Round

Today, Commonwealth Fusion Systems (“CFS”) announced that they closed a Series B2 funding round for $863 million, increasing their total raise to nearly $3 billion in cash, the most of any fusion company. The round included international investors, companies such as Counterpoint Global and Google, hedge funds, and large individual investors, and is the biggest fund-raise in fusion energy since CFS’s $1.8 billion Series B round in 2021.

“Investors recognize that CFS is making fusion power a reality. They see that we are executing and delivering on our objectives,” said Bob Mumgaard, CEO and Co-founder. “This funding recognizes CFS’ leadership role in developing a new technology that promises to be a reliable source of clean, almost limitless energy — and will enable investors to have the opportunity to capitalize on the birth of a new global industry.”

The Background on Fission in a Paragraph (or Maybe Two…)

Depending on who you ask, fission is either a fairly new energy source (as compared to say, coal), or a fairly classical energy source (it has been a mainstream power source for decades). In reality, nuclear fission as an energy source has been around for roughly seventy (70) years, depending on which reactor you count as the first one (all are pictured in order on the right of the description sentences):

• S1W: The first U.S. Navy pressurized water reactor (it reached criticality in 1953), built by Westinghouse as the prototype reactor for the USS Nautilus submarine.
• Obninsk Nuclear Power Plant: Built near Moscow in 1954, it was the first grid-connected nuclear power plant in the world, with an electrical capacity of 5MWe.
• Shippingport Atomic Power Station: This reactor, with an output of 60MWe, went critical in late 1957, and was the first reactor dedicated to peaceful electricity generation.

Today, there are slightly over 400 commercial reactors worldwide, which produce roughly 9% of the world’s electricity. The most powerful nuclear power plant is Japan’s Kashiwazaki-Kariwa Nuclear power plant, having seven reactors with a total electrical generation capacity of 7,965 MWe. For comparison, the Three Gorges Hydroelectric power station produces 22,500 MWe of electricity, and the next seven largest power plants are also hydroelectric power plants.

Where is Nuclear Power Going Today?

One of the hot areas in nuclear fission power plants is small/medium reactors, also known as “SMRs” or “microreactors”. Earlier this month, the U.S. Department of Energy (DoE) selected ten companies to participate in a program to rapidly design, build, and commission next-generation reactors, many of which are SMRs. The companies that are part of the program are:

• Aalo Atomics (their site is the lead picture shown in the article)
• Antares Nuclear
• Atomic Alchemy
• Deep Fission   
• Last Energy
• Oklo
• Natural Resources
• Radiant Industries
• Terrestrial Energy
• Valar Atomics

The reactors that these companies are building all have less than 300 MW of electrical output (kind of the top end of an SMR reactor). Some of the reactors the companies are building are considerably smaller than that – for instance, the Antares reactor is a kilowatt-scale reactor.

What Makes These SMR Nuclear Reactors Different?

SMRs are not just small, though size is one of their clear differentiators (most individual nuclear fission reactors are in range of 500 MWe to 2 GWe). One of the biggest differences is that SMRs are designed to be pre-built in a factory, and then assembled onsite. They also typically utilize passive cooling systems, which reduce the number of systems required to safely operate the reactor (contemporary reactors typically use electrical pumps in the cooling system, the failure of which can lead to meltdowns). The passive cooling methods include natural water circulation, passive residual heat removal systems (PRHRS), and gas-cooled reactors. Besides (generally) having few or no mechanical components in the cooling system, they also have significantly reduced needs for human intervention to operate. They also tend to be more resilient in the face of natural disasters and severe weather, solving some of the issues that caused previous nuclear fission disasters.

Just to be clear, there are no SMRs in operation in the United States today – there is one in Russia and one in China, and that’s it. However, investors are feeling positive about the prospects of SMRs – Aalo just secured a $100 million Series B round of investment roughly a week ago, increasing their total capital raise to $136 million. The round was led by Valor Equity Partners and included other partners such as Fine Structure Ventures, Hitachi Ventures, NRG Energy, Vamos Ventures, Tishman Speyer, Kindred Ventures, 50Y, Harpoon Ventures, Crescent Enterprises, Crosscut, Alumni Ventures, MCJ, Gaingels, and Nucleation Capital. While it was not as big as some of the other SMR rounds (TerraPower raised an $830 million round in 2022, and X-Energy closed a $700 million round in February 2025), it was of the size that certainly lends credence to the SMR energy movement.

Where SMRs go next, and how important they become, still remains to be seen. Like fusion energy, it is a dynamic and evolving field, and the story certainly had chapters left in it. In any case, using SMRs to power data centers to keep them off of the grid does look quite attractive. Stay tuned…