New underground Gravity Nuclear Reactors could revolutionise the energy industry

Deep Fission, the California-based startup aiming to revolutionize nuclear energy by burying reactors a mile underground, has signed a pivotal agreement with Urenco USA to purchase low-enriched uranium (LEU).

The fuel, sourced from Urenco’s enrichment facility in Eunice, New Mexico, will power the testing and demonstration phases of Deep Fission’s initial “Gravity” reactor.

This supply deal is a critical step toward early commercial operations and follows the company’s recent announcement of $80 million in new financing intended to scale production for AI-driven data centers and US electricity grids.

“The fuel will support testing and demonstration activities as part of the Company’s participation in the US Department of Energy’s Reactor Pilot Program as well as early commercial operations,” said the company in a press release.

Deep Fission’s “Gravity” reactor represents a radical departure from traditional nuclear plant design.

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Instead of building massive, expensive surface containment structures, the company places a 15-megawatt (MWe) small modular reactor (SMR) at the bottom of a borehole roughly one mile (1.6 km) deep.

By utilizing the Earth’s natural geology, the design achieves several engineering breakthroughs. At a depth of one mile, a column of water naturally provides the 160 atmospheres of pressure required for the reactor to function, which eliminates the need for costly surface pressure vessels.

“Each Gravity Reactor is installed one mile underground, where surrounding geology provides passive shielding and natural containment, reducing the need for above-ground megastructures,” explained the press release.

Most significantly, the company estimates this approach could slash construction costs by as much as 80 percent compared to traditional nuclear projects.

The fuel agreement with Urenco supports Deep Fission’s participation in the US Department of Energy’s Reactor Pilot Program.

The company has already broken ground on a pilot project in Parsons, Kansas, and claims a customer pipeline representing 12.5 GW of future planned power.

“Securing fuel is one of the most important steps for any nuclear project,” said Liz Muller, CEO and Co-Founder of Deep Fission.

“This agreement with Urenco enables us to move quickly toward commercialization and scaling our technology with high-quality fuel.”

The modular nature of the system allows for significant scalability. While a single borehole produces 15 MWe, the company notes that 100 reactors co-located on a single site could produce 1.5 GWe - enough to power large-scale industrial hubs or massive data center complexes - while requiring only a fraction of the land used by traditional surface plants.

By partnering with Urenco USA, a domestic fuel producer that has supplied the US market for over 15 years, Deep Fission is insulating its supply chain from geopolitical volatility.

“Advanced reactor developers are an important part of the future energy landscape,” concluded John Kirkpatrick, Managing Director of Urenco USA.

“We are focused on ensuring a reliable domestic supply of enriched uranium to support growth in this sector.”