Deep Fission (NASDAQ:FISN) is targeting commercial electricity generation from its first underground nuclear reactor in Parsons, Kansas, by the end of 2027, Chief Executive Officer Liz Muller said during a company presentation.
Muller said the company has been accepted into the U.S. Department of Energy’s Reactor Pilot Program and has begun construction-related work. The company plans to deploy a pressurized-water reactor in a borehole about one mile underground, using drilling, geothermal and existing nuclear technologies to reduce the cost and complexity of conventional nuclear plant construction.
Underground Design Intended to Simplify Construction
Muller said a one-mile water column would create approximately 160 atmospheres of pressure, eliminating the need for a conventional pressurizer. She also said the underground configuration could reduce the need for above-ground safety-related construction and use geothermal-style systems to bring heat from the reactor to surface turbines.
“The best thing to manufacture is nothing,” Muller said, describing the company’s focus on removing components rather than relying solely on mass manufacturing to lower reactor costs.
The company’s reactor canister is expected to cost in the “single-digit millions” of dollars, compared with what Muller described as roughly $1 billion each for conventional reactor vessels and pressurizers. She said the canister could be manufactured by dozens of U.S. suppliers in less than six months for a first-of-a-kind unit.
Use of Existing Nuclear Technology
Deep Fission plans to use pressurized-water reactor technology, which Muller said represents the most common commercially operating nuclear technology in the United States. She cited 67 gigawatts of pressurized-water reactor capacity operating in the country, supplying about 12% of U.S. electricity.
The company intends to use low-enriched uranium in standardized fuel assemblies that have already been approved and licensed by the Nuclear Regulatory Commission, according to Muller. She said this approach allows Deep Fission to rely on established reactor physics, fuel designs and safety measures rather than developing an entirely new reactor technology.
Deep Fission is conducting commercial borehole proof-of-concept work in 2026, including drilling tests and emplacement analysis. Muller said the company is also testing the coordination of nuclear and drilling teams before beginning operations in a nuclear environment.
- First reactor deployment is planned for the first half of 2027 under the DOE Reactor Pilot Program.
- The initial unit is expected to operate at less than full power and produce 5 megawatts of electricity.
- Deep Fission is targeting grid connection and commercial generation during the second half of 2027.
Kansas Site and Licensing Plans
The first project is planned at an industrial park in Parsons, Kansas. Muller said the site has a security perimeter, roads, rail access, water resources and industrial and nuclear zoning. Deep Fission has leased 100 acres at the location and expects that footprint could support approximately 100 reactors, or about 1.5 gigawatts of generation capacity.
The company has signed letters of intent totaling 18.5 gigawatts, which Muller described as the largest pipeline among advanced reactor companies. The Kansas site alone has an LOI for 2 gigawatts, she said.
Deep Fission expects to pursue a commercial license through the Nuclear Regulatory Commission under Part 57, a proposed regulatory pathway aimed at high-volume deployment. Muller said the company plans to submit its commercial license application after the final Part 57 rule is released, which it expects by the end of the year.
The DOE has already accepted the company’s Documented Safety Analysis agreement, Muller said. The document provides a foundation for the company’s safety case and addresses elements specific to its underground reactor design.
Reactor Replacement and Spent Fuel Approach
Muller said Deep Fission expects reactors to operate for roughly 10 years before being replaced. The company’s preliminary plan is to lower used reactor units deeper into the borehole for temporary storage in water, rather than immediately bringing them to the surface for fuel handling.
After multiple operating cycles, the company would decide whether to retrieve the stored units for shipment to a disposal or reprocessing facility, or potentially seal them in the borehole. Muller said any permanent disposal approach would depend on community consent and regulatory approvals.
In response to analyst questions, Muller said the company expects to place roughly one reactor per acre. She said the Kansas location involves drilling through granite beginning at about 2,000 feet, a condition that may slow drilling but could represent a more challenging case than some other potential rock formations.
About Deep Fission (NASDAQ:FISN)
Deep Fission Inc develops and deploys small modular nuclear reactors placed deep underground to generate electricity. Deep Fission Inc is based in Berkeley, California.
