Deep Fission (Nasdaq: FISN) has scheduled a business update call for Tuesday, October 20, 2026, at 11:00 AM ET. The timing is deliberate: the pilot site in Kansas is moving forward, and recent months have delivered concrete results that management is ready to share with the market.
The project centers on the Gravity Nuclear Reactor, a small pressurized water modular reactor designed to operate roughly one mile underground. The technology draws on three well-established industries: deep drilling from oil and gas, heat transfer principles from geothermal energy, and conventional PWR reactor design. Each unit generates 15 MWe using standard LEU fuel. The geometry is that of a cylinder approximately 9 meters tall — slim enough to be lowered into a borehole just under one meter in diameter. Ten reactors clustered on a single site reach 150 MWe; one hundred scale up to 1.5 GWe, while occupying a fraction of the land required by a conventional nuclear plant.
The reference site is Great Plains Industrial Park in Parsons, Kansas, where Deep Fission broke ground in December 2025. The first data acquisition well has already reached 6,000 feet — more than a mile — and a reactor canister prototype has been delivered to the site. In September 2026, the company completed a key demonstration: a 6-meter canister, a full-scale, non-nuclear replica of the vessel that will house the reactor core, was lowered to a depth of 30 meters into an 86-centimeter-diameter borehole, aligned, and retrieved. The entire operation was carried out using standard commercial equipment, with no components specifically engineered for the nuclear industry.
The advantages of deep placement go well beyond symbolism. At one mile below the surface, the overlying water column generates roughly 160 atmospheres of pressure — the same operating condition found in conventional PWR reactors — without the need for costly surface pressurization systems. The surrounding geology serves as passive containment. This cuts surface infrastructure costs and reduces construction complexity compared to a traditional plant. Deep Fission estimates a build time of approximately six months per reactor — a figure that, if confirmed, would radically change deployment timelines relative to current industry standards.
On the financial side, the company completed its Nasdaq listing in mid-2026, raising $40 million in gross proceeds through an IPO priced at $16 per share. Those funds are financing engineering, research, licensing, and construction of the pilot reactor. The U.S. Department of Energy has already approved the system’s safety design. Deep Fission is participating in the DOE’s Reactor Pilot Program, which targets first criticality through an accelerated licensing pathway. Target customers include electric utilities, heavy industry, and data centers — markets demanding reliable, low-carbon baseload power.
The October 20 call will likely serve as an opportunity to update the market on progress in large-diameter drilling and on the roadmap toward a full-scale demonstration. If the Kansas pilot program delivers the expected results, Deep Fission could become one of the few operators in the world with real-world data — not just simulations — on a nuclear reactor installed underground. That milestone would fundamentally reshape the possibilities for deploying nuclear energy in contexts that today are considered out of reach.
