Nuclear energy startup, Deep Fission Nuclear is reimagining nuclear energy with a bold, underground approach.
Announced on Sunday, the startup secured USD$30 million in funding to install a micro-reactor in a mile-deep borehole by July 4, 2026.
This effort is part of the US Department of Energy’s Reactor Pilot Program. Over a year ago, the company first revealed plans to place reactors in what seems an unusual location. Deep Fission intends to drill a 30-inch (76-cm) borehole into solid rock in a geologically stable area.
The plan is to lower a complete nuclear reactor on a cable to a depth of one mile. At first glance, this may appear strange. However, there is solid engineering logic behind it. Cost, safety, and security are three of the biggest concerns in nuclear power. Conventional nuclear plants, particularly in the West, have required decades of construction and tens of billions of dollars.
Additionally, catastrophic accidents and terrorist sabotage remain legitimate fears. Deep Fission addresses these issues by changing the reactor’s location. In contrast to conventional plants, most construction costs come not from the reactor itself but from extensive civil engineering needed to contain it and its systems.
By situating the reactor deep underground, the company can eliminate much of the above-ground plant and simplify design. Consequently, it estimates an 80 per cent reduction in construction costs.
The current design features a self-contained 15-MWe modular reactor fuelled with Low-Enriched Uranium (LEU). The reactor operates at 315°C and will be lowered to the bottom of the borehole, which is flooded with water. Two insulated pipelines connect the reactor to the surface. One carries water down, while the other carries live non-radioactive steam back up.
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Underground reactors enhance safety and security
This steam feeds turbines to generate electricity. Meanwhile, the surrounding water column and rock pressurize the reactor without specialized equipment. As a result, the plant footprint is only a quarter to half an acre.
Placing the reactor underground also enhances safety and security. Conventional containment structures become unnecessary, and the reactor’s depth provides natural protection.
Furthermore, by drilling deep beyond the water table in a stable area, the reactor becomes essentially self-disposing. If it suffers damage and cannot be removed, the borehole can be filled with rubble and concrete. Uranium is unlikely to leach through solid rock over millions of years, eliminating contamination risks.
Deep Fission projects rapid deployment. A pilot plant could be built in about six months. If commercialized, the technology could deliver electricity at roughly five to seven cents per kWh. Liz Muller, the co-founder and CEO of Deep Fission recognizes this as a unique moment for the nuclear industry.
“With this funding, we can begin building our pilot reactor, with the goal of completion in 2026,” said Muller. “We believe we can scale our technology rapidly and profitably to address massive energy demand from AI data centers and other customers worldwide.”
By radically shifting reactor design, Deep Fission may change nuclear energy’s future. In addition to cutting costs, it enhances safety and security. Furthermore, the underground approach could allow faster deployment and scalable electricity production. For a sector long hindered by expense and risk, Deep Fission offers a bold, innovative path forward.
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joseph@mugglehead.com
