Deep Fission, Inc.

Deep Fission, Inc. is an advanced nuclear energy company dedicated to revolutionizing the energy landscape by developing and deploying small modular pressurized water reactors (SMRs) designed to operate one mile underground. Founded in 2023, the company's mission is to deliver safe, reliable, and affordable low-carbon power at scale, addressing the increasing global demand for energy. Deep Fission's headquarters are located in Berkeley, California, at 2001 Addison Street, Unit 300.

The company's core product is the Gravity Nuclear Reactor™, which integrates established pressurized water reactor (PWR) technology with a novel underground emplacement strategy. This design leverages the Earth's deep subsurface as a natural containment system and utilizes hydrostatic pressure for cooling, thereby reducing the need for extensive surface infrastructure and simplifying construction. Deep Fission provides scalable reactor configurations for various applications, including onsite power for utilities, data centers, heavy industry, military, government, and large cities. The company also offers services such as licensing management and strategic development support for decarbonization goals.

Deep Fission, Inc. became a publicly traded company on NASDAQ under the ticker FISN on June 18, 2026, following a reverse merger with Surfside Acquisition Inc.. Co-founded by Elizabeth Muller (CEO) and Richard A. Muller (CTO), the company recently achieved a significant milestone on July 7, 2026, with the arrival of its prototype reactor canister at its Parsons, Kansas site, advancing its Proof-of-Concept Well program. Deep Fission is also a participant in the U.S. Department of Energy's Reactor Pilot Program and has signed non-binding Letters of Intent for up to 18.5 gigawatts of potential nuclear generation capacity with various partners.