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

Antares, a nuclear startup developing a small modular reactor, announced Tuesday that it has raised $96 million in Series B funding.

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

Antares says its R1 microreactor is designed for commercial, defence, and space-based applications and can produce between 100 kilowatts and 1 megawatt of electricity. The reactor uses TRISO fuel — carbon- and ceramic-coated uranium particles embedded in graphite.

The company is one of several benefiting from a surge of interest in nuclear energy over the past six months.

Last week, Amazon-backed X-energy announced a $700 million Series D after closing an expanded $700 million Series C in February. X-energy is also developing a TRISO-fueled reactor. Deep Fission, which struggled to raise funds earlier this year, went public in September through a $30 million reverse merger.

In August, Aalo Atomics raised $100 million to build a demonstration data centre powered by a microreactor. In June, Nvidia participated in a $650 million round for TerraPower, a small modular reactor company backed by Bill Gates.

Larger nuclear projects are also seeing renewed momentum.

Earlier this month, Constellation Energy — a Microsoft partner — secured a $1 billion loan from the U.S. Department of Energy to restart a reactor at Three Mile Island by 2028. The refurbishment is expected to cost $1.6 billion. In October, Google announced a partnership with NextEra Energy to reopen a nuclear plant in Iowa that was damaged during severe flooding in 2020.

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

While large-scale nuclear has benefited from renewed support, the Trump administration has emphasised the potential of small nuclear reactors to revive the industry in the coming decade.

In August, Antares was selected as one of 11 participants in the Department of Energy’s reactor pilot program, which aims to have at least three reactors begin operation by July 4, 2026 — an ambitious timeline for an industry known for long development cycles.

Antares says it plans to demonstrate its reactor to the DOE next year and expects to activate its full-power reactor in 2027.