Deep Fission

Deep Fission, Inc is a US-based company operating in Independent Power and Renewable Electricity Producers industry. The company is headquartered in Berkeley, California and currently employs 62 full-time employees. The company went IPO on 2026-06-18. Deep Fission, Inc. is a nuclear energy company. The company is engaged in developing small modular pressurized water reactors installed one mile underground. The company is developing a small modular reactor based on established pressurized water reactor technology, with novel emplacements in deep boreholes approximately one mile below the Earth’s surface. Its activities include test borehole construction, reactor design, safety analysis, thermal-hydraulic modeling, regulatory engagement with the Department of Energy (DOE) and the Nuclear Regulatory Commission (NRC), and supply chain development for reactor components and drilling operations. Its reactor, which it refers to as the Gravity Reactor, will leverage subsurface conditions to support key containment and operating functions, including the use of hydrostatic pressure from a water column within the borehole to support reactor operating pressure and cooling, and the surrounding geological formation to provide structural confinement and shielding.