Microreactor startup Antares raises $96M for land, sea, and space-based nuclear power

Nuclear startup Antares said Tuesday it has raised $96 million in Series B funding as it pursues its small modular reactor design.

The round, which was led by Shine Capital with participation from Alt Capital, Caffeinated, FiftyThree Stations, Industrious, and others, consists of $71 million in equity and $25 million in debt.

Antares says it is targeting commercial, defense, and space-based applications with its R1 microreactor, which will produce between 100 kilowatts to 1 megawatt of electricity. The design uses TRISO fuel, which in Antares case is spheres of carbon- and ceramic-coated uranium embedded in graphite.

The startup is one of several companies that have benefitted recently from renewed interest in nuclear power over the last six months.

Last week, Amazon-backed X-energy said it had raised a $700 million Series D round, which came on the heels of an upsized $700 million Series C that closed in February. The company is also designing a reactor around TRISO fuel. Deep Fission, which had struggled to raise money as recently as April, went public in a $30 million reverse merger in September.

Aalo Atomics raised $100 million in August to build a demonstration data center powered by a microreactor, and in June, Nvidia contributed to a $650 million round for TerraPower, a small modular reactor startup also backed by Bill Gates.

Big nuclear plants have been given a second chance, too.

Earlier this month, Microsoft partner Constellation Energy received a $1 billion loan from the Department of Energy to restart a reactor at Three Mile Island by 2028. That project is expected to cost $1.6 billion to refurbished the reactor that was idled in 2019. In October, Google said it would work with NextEra Energy to reopen a nuclear power plant in Iowa that was damaged during a torrential downpour in 2020.

Earlier this summer, Amazon bought 1.92 gigawatts of generating capacity from a Talen Energy nuclear plant in Pennsylvania. Meta also said in June it would buy the clean energy attributes from a Constellation Energy nuclear power plant in Illinois.

And while big nuclear has been a major beneficiary, the Trump administration is bullish on small nuclear’s potential to revive the industry’s fortunes in the coming decade.

In August, Antares was named one of 11 participants in the Department of Energy’s reactor pilot program, which aims to have at least three of those begin operation by July 4, 2026, a timeline that’s significantly faster than the nuclear industry is accustomed to.

Antares has said it aims to demonstrate its reactor for the DOE next year, and is planning to turn on its full-power reactor sometime in 2027.