Deep Fission, a California-based nuclear energy startup, started drilling the world’s first underground nuclear borehole March 10 in Kansas, taking a major step forward in building small modular pressurized water reactors one mile below the surface.
The test project is being funded as part of the Trump administration’s plan to breathe new life into the American nuclear sector by investing in new technology.
“It represents the shift from concept to construction and begins the process of demonstrating a fundamentally new approach to nuclear energy deployment,” Liz Muller, CEO and co-founder of Deep Fission, said.
The initial phase will include the sinking of three wells for site characterization and engineering validation.
The first well will be drilled about 6,000 feet below the ground and will be about eight inches in diameter. Workers at the site will be able to gather critical data to inform the company’s final engineering design, safety analysis, and regulatory planning.
The site’s location in the rural community of Parsons, about 130 miles east of Wichita and home to about 10,000 residents, was chosen in December for its dense and impervious shale and limestone, which provide natural containment and radiation shielding.
“By placing reactors one mile underground, the surrounding geology provides billions of tons of passive shielding and natural containment—enhancing safety and security while significantly reducing cost, surface footprint, and visual impact,” the company stated.
The company also plans to complete construction of its first reactor and achieve criticality by July 4 at the Kansas location.
Deep Fission has already signed an agreement with the Great Plains Development Authority to develop a full-scale commercial project at the same site.
The company’s design uses pressurized water reactor technology with deep-borehole drilling techniques from the oil and gas industry and geothermal heat-transfer.
Each gravity reactor is installed one mile underground, where the surrounding geology provides natural shielding and containment, while also reducing the need for above-ground megastructures, according to Deep Fission.
The company has already entered into an agreement to buy low-enriched uranium from Urenco USA for the small water reactors.
“Securing fuel is one of the most important steps for any nuclear project,” said Deep Fission’s CEO Liz Muller. “This agreement with Urenco enables us to move quickly toward commercialization and scaling our technology with high-quality fuel.”
The Department of Energy in Washington on Feb. 17, 2026. (Madalina Kilroy/The Epoch Times)
The uranium will be sourced from Urenco’s New Mexico enrichment plant and will be supplied for the demonstration and testing of the first gravity reactor, according to Deep Fission.
“Advanced reactor developers are an important part of the future energy landscape, and we are focused on ensuring a reliable domestic supply of enriched uranium to support growth in this sector,” said John Kirkpatrick, Urenco USA’s managing director.
Beyond the drilling project, the company is also working on a customer pipeline for 12.5 gigawatts of future planned power.
The company secured $80 million in cash for its operations last month.
