Technology

Pressurized water reactors placed one mile underground, delivering clean, secure, low-cost electricity

Traditional Reactor,
Boring Placement

Unlike other small modular reactor (SMR) designs, Deep Fission combines standard borehole drilling technology with the most common reactor type, a pressurized water reactor (PWR), to create a small modular reactor that can be placed in a 30-inch borehole, one mile underground.

Each Deep Fission reactor generates 15 MWe. With a small footprint and dense power output, ten reactors produce 150 MWe, while 100 reactors on one site can deliver 1.5 GWe, requiring a fraction of the land needed for traditional surface nuclear.

Using the traditional PWR design for its fuel assemblies and power control methods, Deep Fission reactors also operate at the same pressure (160 atmospheres) and core temperatures (about 315°C, equal to 600°F).

The heat produced is transferred to a steam generator at depth to boil water, and the non-radioactive steam rises rapidly to the surface, where a standard steam turbine converts the energy to electricity.

Cables attached to the reactor allow it to be raised to the surface, if inspection is deemed necessary.

The reactor uses standard LEU fuel, which can be sourced domestically, reducing exposure to geopolitical risk.

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Natural containment
below ground

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“Free” pressure underground
(160 atmospheres , 2250 psi)

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No cost / safety
trade-offs

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Protected from
natural disasters

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Minimal
proliferation risk

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Lower likelihood of
costly accidents

Deep Fission plans to be commercially operational in Fall 2029.

2025: First site confirmed 

2026: Licensing application submitted 

2028: Construction and operation approved