Deep Fission, a U.S.-based company, is developing a 15 MW modular nuclear reactor (SMR) designed to be located approximately 1.6 kilometers underground. The firm has signed non-binding letters of intent representing a total potential energy demand of 18 GW, which translates to plans for building 1,200 such reactors.
Unlike conventional SMR projects, Deep Fission’s reactor relies on well-established pressurized water reactor (PWR) technology and low-enriched uranium fuel (LEU, around 3-5%). The key innovation is placing the reactor deep beneath the surface, which the company claims reduces the land footprint on the surface and enhances safety by leveraging the natural shielding of the earth.
The company draws on expertise from the nuclear, oil and gas, and geothermal sectors, stating that the compact design allows multiple reactors to be installed in a single location. On June 24, 2026, Deep Fission signed letters of intent with data center operators, developers, industrial parks, and strategic partners, collectively representing an 18 GW power off-take potential.
Underground reactors to attract data centers and industry
– The growing number of projects confirms significant interest in our one-mile-deep reactor model. Data center developers and other industrial partners need a solution that can be rapidly deployed and scaled – our nuclear reactor meets these requirements perfectly – said Liz Muller, CEO and co-founder of Deep Fission.
The company is currently executing its first reactor project at the Great Plains Industrial Park in Parsons, Kansas, under the U.S. Department of Energy’s Reactor Pilot Program. Deep Fission has completed drilling the first borehole to collect data at a depth of approximately 6,000 feet (about 1,800 meters).
Commercial license application planned for 2027
The next milestones will demonstrate the ability to drill a commercial-scale borehole and to safely deploy a prototype reactor. Deep Fission emphasizes that the signed letters of intent are non-binding and do not constitute commitments to purchase electricity, finance projects, or build any specific number of reactors. Each party can terminate these agreements without penalties.
The company plans to submit a commercial license application to the U.S. Nuclear Regulatory Commission in the first half of 2027. Commercial deployment timelines, final client agreements, and future revenues will depend on successful completion of development and testing, regulatory approvals, construction, customer contracts, and other factors.
Source: WNP.PL, Photo: Deep Fission press materials
