The future of nuclear energy is going underground—literally. Deep Fission, a pioneering nuclear startup, has announced plans to use subterranean micro-reactors to power energy-hungry data centers. The company revealed a landmark agreement with data center developer Endeavour on January 7, 2025, to build 2 gigawatts of underground nuclear power capacity. This approach, which leverages depth as a protective shield, marks a departure from traditional nuclear plant designs that rely on massive amounts of concrete for safety.

Nuclear Innovation for Modern Energy Needs

Deep Fission’s underground reactors aim to address growing energy demands driven by compute-intensive workloads, particularly from artificial intelligence (AI) applications. Data centers, which require vast and reliable power supplies, are increasingly exploring nuclear energy as a sustainable solution. Major players like Google, Amazon, and Switch have already inked similar deals with nuclear startups to integrate small modular reactors into their energy mix.

The partnership with Endeavour also includes an undisclosed investment from the data center developer, boosting Deep Fission’s momentum. The startup had previously raised $4 million in August 2024, signaling strong interest in its innovative approach to nuclear energy.

The Subterranean Reactor Design

Deep Fission’s reactors are small modular pressurized-water designs, a tried-and-true technology used in nuclear submarines and large-scale power plants. What sets the company apart is its plan to deploy these reactors in boreholes—30-inch wide shafts drilled one mile deep into the earth. Once in place, the reactor would generate heat to produce steam, which would travel to the surface through pipes for electricity generation.

This innovative design eliminates the need for bulky aboveground infrastructure. The surrounding rock provides natural insulation and protection, significantly reducing construction costs compared to traditional nuclear plants. Maintenance, according to the company, is streamlined; reactors can be hauled to the surface in just one to two hours.

Deep Fission estimates its energy costs at five to seven cents per kilowatt-hour, less than half the average cost of new nuclear power in the U.S., as reported by Lazard. If successful, this cost efficiency could make underground reactors a game-changer for both energy and data center industries.

Regulatory and Industry Landscape

Deep Fission’s timeline is ambitious, with plans to activate its first reactor by 2029. However, like most nuclear startups, it faces regulatory hurdles. The company began the Nuclear Regulatory Commission (NRC) licensing process in March 2024. While past approvals could take years, recent legislation has streamlined the timeline to 18 months for small modular reactors. To date, only Kairos Power has successfully navigated the process.

This deal comes amid a broader resurgence of nuclear energy in the U.S., spurred by the need for low-carbon power solutions and technological advancements. Companies like Oklo and X-Energy are also scaling efforts to integrate small modular reactors into the energy grid. Meanwhile, Meta has adopted a unique approach, inviting nuclear developers to submit proposals for its energy needs.

A Nuclear Renaissance on the Horizon

If successful, Deep Fission’s underground reactors could redefine how nuclear energy is deployed, particularly for specialized applications like data centers. By leveraging innovative designs and targeting cost efficiency, the startup is positioning itself at the forefront of a nuclear power revival in the U.S. While challenges remain, the partnership with Endeavour represents a significant step toward making underground nuclear power a reality.